From 0d0ae656b71155ccc0be9388beef77a1f7e7558e Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:47:41 +0100
Subject: [PATCH 01/21] KVM: arm64: timers: Use a per-vcpu, per-timer
 accumulator for fractional ns

Instead of accumulating the fractional ns value generated every time
we compute a ns delta in a global variable, use a per-vcpu, per-timer
variable. This keeps the fractional ns local to the timer instead of
contributing to any odd, unrelated timer.

Reviewed-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-2-maz@kernel.org
---
 arch/arm64/kvm/arch_timer.c  | 2 +-
 include/kvm/arm_arch_timer.h | 1 +
 2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index e1af4301b913..9515c645f03d 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -212,7 +212,7 @@ static u64 kvm_counter_compute_delta(struct arch_timer_context *timer_ctx,
 		ns = cyclecounter_cyc2ns(timecounter->cc,
 					 val - now,
 					 timecounter->mask,
-					 &timecounter->frac);
+					 &timer_ctx->ns_frac);
 		return ns;
 	}
 
diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index c52a6e6839da..70d47c4adc6a 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h
@@ -44,6 +44,7 @@ struct arch_timer_context {
 
 	/* Emulated Timer (may be unused) */
 	struct hrtimer			hrtimer;
+	u64				ns_frac;
 
 	/* Offset for this counter/timer */
 	struct arch_timer_offset	offset;

From eaacaa4f26ade43dfdfdd3707c95d734b5ffc530 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:47:42 +0100
Subject: [PATCH 02/21] arm64: Add CNTPOFF_EL2 register definition

Add the definition for CNTPOFF_EL2 in the description file.

Reviewed-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-3-maz@kernel.org
---
 arch/arm64/tools/sysreg | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
index dd5a9c7e310f..7063f1aacc54 100644
--- a/arch/arm64/tools/sysreg
+++ b/arch/arm64/tools/sysreg
@@ -1952,6 +1952,10 @@ Sysreg	CONTEXTIDR_EL2	3	4	13	0	1
 Fields	CONTEXTIDR_ELx
 EndSysreg
 
+Sysreg	CNTPOFF_EL2	3	4	14	0	6
+Field	63:0	PhysicalOffset
+EndSysreg
+
 Sysreg	CPACR_EL12	3	5	1	0	2
 Fields	CPACR_ELx
 EndSysreg

From 326349943ed181890b8b2af2755bd0eac93bd66d Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:47:43 +0100
Subject: [PATCH 03/21] arm64: Add HAS_ECV_CNTPOFF capability

Add the probing code for the FEAT_ECV variant that implements CNTPOFF_EL2.
Why it is optional is a mystery, but let's try and detect it.

Reviewed-by: Reiji Watanabe <reijiw@google.com>
Reviewed-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-4-maz@kernel.org
---
 arch/arm64/kernel/cpufeature.c | 11 +++++++++++
 arch/arm64/tools/cpucaps       |  1 +
 2 files changed, 12 insertions(+)

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 2e3e55139777..c331c49a7d19 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -2223,6 +2223,17 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
 		.sign = FTR_UNSIGNED,
 		.min_field_value = 1,
 	},
+	{
+		.desc = "Enhanced Counter Virtualization (CNTPOFF)",
+		.capability = ARM64_HAS_ECV_CNTPOFF,
+		.type = ARM64_CPUCAP_SYSTEM_FEATURE,
+		.matches = has_cpuid_feature,
+		.sys_reg = SYS_ID_AA64MMFR0_EL1,
+		.field_pos = ID_AA64MMFR0_EL1_ECV_SHIFT,
+		.field_width = 4,
+		.sign = FTR_UNSIGNED,
+		.min_field_value = ID_AA64MMFR0_EL1_ECV_CNTPOFF,
+	},
 #ifdef CONFIG_ARM64_PAN
 	{
 		.desc = "Privileged Access Never",
diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
index 37b1340e9646..40ba95472594 100644
--- a/arch/arm64/tools/cpucaps
+++ b/arch/arm64/tools/cpucaps
@@ -23,6 +23,7 @@ HAS_DCPOP
 HAS_DIT
 HAS_E0PD
 HAS_ECV
+HAS_ECV_CNTPOFF
 HAS_EPAN
 HAS_GENERIC_AUTH
 HAS_GENERIC_AUTH_ARCH_QARMA3

From 2b4825a8694018901e641ccc2eafd0fff58d1415 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:47:44 +0100
Subject: [PATCH 04/21] KVM: arm64: timers: Use CNTPOFF_EL2 to offset the
 physical timer

With ECV and CNTPOFF_EL2, it is very easy to offer an offset for
the physical timer. So let's do just that.

Nothing can set the offset yet, so this should have no effect
whatsoever (famous last words...).

Reviewed-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-5-maz@kernel.org
---
 arch/arm64/kvm/arch_timer.c          | 18 +++++++++++++++++-
 arch/arm64/kvm/hypercalls.c          |  2 +-
 include/clocksource/arm_arch_timer.h |  1 +
 include/kvm/arm_arch_timer.h         |  2 ++
 4 files changed, 21 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index 9515c645f03d..3118ea0a1b41 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -52,6 +52,11 @@ static u64 kvm_arm_timer_read(struct kvm_vcpu *vcpu,
 			      struct arch_timer_context *timer,
 			      enum kvm_arch_timer_regs treg);
 
+static bool has_cntpoff(void)
+{
+	return (has_vhe() && cpus_have_final_cap(ARM64_HAS_ECV_CNTPOFF));
+}
+
 u32 timer_get_ctl(struct arch_timer_context *ctxt)
 {
 	struct kvm_vcpu *vcpu = ctxt->vcpu;
@@ -84,7 +89,7 @@ u64 timer_get_cval(struct arch_timer_context *ctxt)
 
 static u64 timer_get_offset(struct arch_timer_context *ctxt)
 {
-	if (ctxt->offset.vm_offset)
+	if (ctxt && ctxt->offset.vm_offset)
 		return *ctxt->offset.vm_offset;
 
 	return 0;
@@ -432,6 +437,12 @@ static void set_cntvoff(u64 cntvoff)
 	kvm_call_hyp(__kvm_timer_set_cntvoff, cntvoff);
 }
 
+static void set_cntpoff(u64 cntpoff)
+{
+	if (has_cntpoff())
+		write_sysreg_s(cntpoff, SYS_CNTPOFF_EL2);
+}
+
 static void timer_save_state(struct arch_timer_context *ctx)
 {
 	struct arch_timer_cpu *timer = vcpu_timer(ctx->vcpu);
@@ -480,6 +491,7 @@ static void timer_save_state(struct arch_timer_context *ctx)
 		write_sysreg_el0(0, SYS_CNTP_CTL);
 		isb();
 
+		set_cntpoff(0);
 		break;
 	case NR_KVM_TIMERS:
 		BUG();
@@ -550,6 +562,7 @@ static void timer_restore_state(struct arch_timer_context *ctx)
 		write_sysreg_el0(timer_get_ctl(ctx), SYS_CNTV_CTL);
 		break;
 	case TIMER_PTIMER:
+		set_cntpoff(timer_get_offset(ctx));
 		write_sysreg_el0(timer_get_cval(ctx), SYS_CNTP_CVAL);
 		isb();
 		write_sysreg_el0(timer_get_ctl(ctx), SYS_CNTP_CTL);
@@ -767,6 +780,7 @@ void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
 	vtimer->vcpu = vcpu;
 	vtimer->offset.vm_offset = &vcpu->kvm->arch.timer_data.voffset;
 	ptimer->vcpu = vcpu;
+	ptimer->offset.vm_offset = &vcpu->kvm->arch.timer_data.poffset;
 
 	/* Synchronize cntvoff across all vtimers of a VM. */
 	timer_set_offset(vtimer, kvm_phys_timer_read());
@@ -1297,6 +1311,8 @@ void kvm_timer_init_vhe(void)
 	val = read_sysreg(cnthctl_el2);
 	val |= (CNTHCTL_EL1PCEN << cnthctl_shift);
 	val |= (CNTHCTL_EL1PCTEN << cnthctl_shift);
+	if (cpus_have_final_cap(ARM64_HAS_ECV_CNTPOFF))
+		val |= CNTHCTL_ECV;
 	write_sysreg(val, cnthctl_el2);
 }
 
diff --git a/arch/arm64/kvm/hypercalls.c b/arch/arm64/kvm/hypercalls.c
index 5da884e11337..39a4707e081d 100644
--- a/arch/arm64/kvm/hypercalls.c
+++ b/arch/arm64/kvm/hypercalls.c
@@ -47,7 +47,7 @@ static void kvm_ptp_get_time(struct kvm_vcpu *vcpu, u64 *val)
 		cycles = systime_snapshot.cycles - vcpu->kvm->arch.timer_data.voffset;
 		break;
 	case KVM_PTP_PHYS_COUNTER:
-		cycles = systime_snapshot.cycles;
+		cycles = systime_snapshot.cycles - vcpu->kvm->arch.timer_data.poffset;
 		break;
 	default:
 		return;
diff --git a/include/clocksource/arm_arch_timer.h b/include/clocksource/arm_arch_timer.h
index 057c8964aefb..cbbc9a6dc571 100644
--- a/include/clocksource/arm_arch_timer.h
+++ b/include/clocksource/arm_arch_timer.h
@@ -21,6 +21,7 @@
 #define CNTHCTL_EVNTEN			(1 << 2)
 #define CNTHCTL_EVNTDIR			(1 << 3)
 #define CNTHCTL_EVNTI			(0xF << 4)
+#define CNTHCTL_ECV			(1 << 12)
 
 enum arch_timer_reg {
 	ARCH_TIMER_REG_CTRL,
diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index 70d47c4adc6a..2dd0fd2406fb 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h
@@ -34,6 +34,8 @@ struct arch_timer_offset {
 struct arch_timer_vm_data {
 	/* Offset applied to the virtual timer/counter */
 	u64	voffset;
+	/* Offset applied to the physical timer/counter */
+	u64	poffset;
 };
 
 struct arch_timer_context {

From c605ee245097d02ed5933e63ac601a8571712457 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:47:45 +0100
Subject: [PATCH 05/21] KVM: arm64: timers: Allow physical offset without
 CNTPOFF_EL2

CNTPOFF_EL2 is awesome, but it is mostly vapourware, and no publicly
available implementation has it. So for the common mortals, let's
implement the emulated version of this thing.

It means trapping accesses to the physical counter and timer, and
emulate some of it as necessary.

As for CNTPOFF_EL2, nobody sets the offset yet.

Reviewed-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-6-maz@kernel.org
---
 arch/arm64/include/asm/sysreg.h    |  2 +
 arch/arm64/kvm/arch_timer.c        | 98 +++++++++++++++++++++++-------
 arch/arm64/kvm/hyp/nvhe/timer-sr.c | 18 ++++--
 arch/arm64/kvm/sys_regs.c          |  9 +++
 4 files changed, 98 insertions(+), 29 deletions(-)

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index 9e3ecba3c4e6..f8da9e1b0c11 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -388,6 +388,7 @@
 
 #define SYS_CNTFRQ_EL0			sys_reg(3, 3, 14, 0, 0)
 
+#define SYS_CNTPCT_EL0			sys_reg(3, 3, 14, 0, 1)
 #define SYS_CNTPCTSS_EL0		sys_reg(3, 3, 14, 0, 5)
 #define SYS_CNTVCTSS_EL0		sys_reg(3, 3, 14, 0, 6)
 
@@ -400,6 +401,7 @@
 
 #define SYS_AARCH32_CNTP_TVAL		sys_reg(0, 0, 14, 2, 0)
 #define SYS_AARCH32_CNTP_CTL		sys_reg(0, 0, 14, 2, 1)
+#define SYS_AARCH32_CNTPCT		sys_reg(0, 0, 0, 14, 0)
 #define SYS_AARCH32_CNTP_CVAL		sys_reg(0, 2, 0, 14, 0)
 
 #define __PMEV_op2(n)			((n) & 0x7)
diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index 3118ea0a1b41..bb64a71ae193 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -458,6 +458,8 @@ static void timer_save_state(struct arch_timer_context *ctx)
 		goto out;
 
 	switch (index) {
+		u64 cval;
+
 	case TIMER_VTIMER:
 		timer_set_ctl(ctx, read_sysreg_el0(SYS_CNTV_CTL));
 		timer_set_cval(ctx, read_sysreg_el0(SYS_CNTV_CVAL));
@@ -485,7 +487,12 @@ static void timer_save_state(struct arch_timer_context *ctx)
 		break;
 	case TIMER_PTIMER:
 		timer_set_ctl(ctx, read_sysreg_el0(SYS_CNTP_CTL));
-		timer_set_cval(ctx, read_sysreg_el0(SYS_CNTP_CVAL));
+		cval = read_sysreg_el0(SYS_CNTP_CVAL);
+
+		if (!has_cntpoff())
+			cval -= timer_get_offset(ctx);
+
+		timer_set_cval(ctx, cval);
 
 		/* Disable the timer */
 		write_sysreg_el0(0, SYS_CNTP_CTL);
@@ -555,6 +562,8 @@ static void timer_restore_state(struct arch_timer_context *ctx)
 		goto out;
 
 	switch (index) {
+		u64 cval, offset;
+
 	case TIMER_VTIMER:
 		set_cntvoff(timer_get_offset(ctx));
 		write_sysreg_el0(timer_get_cval(ctx), SYS_CNTV_CVAL);
@@ -562,8 +571,12 @@ static void timer_restore_state(struct arch_timer_context *ctx)
 		write_sysreg_el0(timer_get_ctl(ctx), SYS_CNTV_CTL);
 		break;
 	case TIMER_PTIMER:
-		set_cntpoff(timer_get_offset(ctx));
-		write_sysreg_el0(timer_get_cval(ctx), SYS_CNTP_CVAL);
+		cval = timer_get_cval(ctx);
+		offset = timer_get_offset(ctx);
+		set_cntpoff(offset);
+		if (!has_cntpoff())
+			cval += offset;
+		write_sysreg_el0(cval, SYS_CNTP_CVAL);
 		isb();
 		write_sysreg_el0(timer_get_ctl(ctx), SYS_CNTP_CTL);
 		break;
@@ -634,6 +647,61 @@ static void kvm_timer_vcpu_load_nogic(struct kvm_vcpu *vcpu)
 		enable_percpu_irq(host_vtimer_irq, host_vtimer_irq_flags);
 }
 
+/* If _pred is true, set bit in _set, otherwise set it in _clr */
+#define assign_clear_set_bit(_pred, _bit, _clr, _set)			\
+	do {								\
+		if (_pred)						\
+			(_set) |= (_bit);				\
+		else							\
+			(_clr) |= (_bit);				\
+	} while (0)
+
+static void timer_set_traps(struct kvm_vcpu *vcpu, struct timer_map *map)
+{
+	bool tpt, tpc;
+	u64 clr, set;
+
+	/*
+	 * No trapping gets configured here with nVHE. See
+	 * __timer_enable_traps(), which is where the stuff happens.
+	 */
+	if (!has_vhe())
+		return;
+
+	/*
+	 * Our default policy is not to trap anything. As we progress
+	 * within this function, reality kicks in and we start adding
+	 * traps based on emulation requirements.
+	 */
+	tpt = tpc = false;
+
+	/*
+	 * We have two possibility to deal with a physical offset:
+	 *
+	 * - Either we have CNTPOFF (yay!) or the offset is 0:
+	 *   we let the guest freely access the HW
+	 *
+	 * - or neither of these condition apply:
+	 *   we trap accesses to the HW, but still use it
+	 *   after correcting the physical offset
+	 */
+	if (!has_cntpoff() && timer_get_offset(map->direct_ptimer))
+		tpt = tpc = true;
+
+	/*
+	 * Now that we have collected our requirements, compute the
+	 * trap and enable bits.
+	 */
+	set = 0;
+	clr = 0;
+
+	assign_clear_set_bit(tpt, CNTHCTL_EL1PCEN << 10, set, clr);
+	assign_clear_set_bit(tpc, CNTHCTL_EL1PCTEN << 10, set, clr);
+
+	/* This only happens on VHE, so use the CNTKCTL_EL1 accessor */
+	sysreg_clear_set(cntkctl_el1, clr, set);
+}
+
 void kvm_timer_vcpu_load(struct kvm_vcpu *vcpu)
 {
 	struct arch_timer_cpu *timer = vcpu_timer(vcpu);
@@ -657,9 +725,10 @@ void kvm_timer_vcpu_load(struct kvm_vcpu *vcpu)
 	timer_restore_state(map.direct_vtimer);
 	if (map.direct_ptimer)
 		timer_restore_state(map.direct_ptimer);
-
 	if (map.emul_ptimer)
 		timer_emulate(map.emul_ptimer);
+
+	timer_set_traps(vcpu, &map);
 }
 
 bool kvm_timer_should_notify_user(struct kvm_vcpu *vcpu)
@@ -1292,28 +1361,11 @@ no_vgic:
 	return 0;
 }
 
-/*
- * On VHE system, we only need to configure the EL2 timer trap register once,
- * not for every world switch.
- * The host kernel runs at EL2 with HCR_EL2.TGE == 1,
- * and this makes those bits have no effect for the host kernel execution.
- */
+/* If we have CNTPOFF, permanently set ECV to enable it */
 void kvm_timer_init_vhe(void)
 {
-	/* When HCR_EL2.E2H ==1, EL1PCEN and EL1PCTEN are shifted by 10 */
-	u32 cnthctl_shift = 10;
-	u64 val;
-
-	/*
-	 * VHE systems allow the guest direct access to the EL1 physical
-	 * timer/counter.
-	 */
-	val = read_sysreg(cnthctl_el2);
-	val |= (CNTHCTL_EL1PCEN << cnthctl_shift);
-	val |= (CNTHCTL_EL1PCTEN << cnthctl_shift);
 	if (cpus_have_final_cap(ARM64_HAS_ECV_CNTPOFF))
-		val |= CNTHCTL_ECV;
-	write_sysreg(val, cnthctl_el2);
+		sysreg_clear_set(cntkctl_el1, 0, CNTHCTL_ECV);
 }
 
 static void set_timer_irqs(struct kvm *kvm, int vtimer_irq, int ptimer_irq)
diff --git a/arch/arm64/kvm/hyp/nvhe/timer-sr.c b/arch/arm64/kvm/hyp/nvhe/timer-sr.c
index 9072e71693ba..b185ac0dbd47 100644
--- a/arch/arm64/kvm/hyp/nvhe/timer-sr.c
+++ b/arch/arm64/kvm/hyp/nvhe/timer-sr.c
@@ -9,6 +9,7 @@
 #include <linux/kvm_host.h>
 
 #include <asm/kvm_hyp.h>
+#include <asm/kvm_mmu.h>
 
 void __kvm_timer_set_cntvoff(u64 cntvoff)
 {
@@ -35,14 +36,19 @@ void __timer_disable_traps(struct kvm_vcpu *vcpu)
  */
 void __timer_enable_traps(struct kvm_vcpu *vcpu)
 {
-	u64 val;
+	u64 clr = 0, set = 0;
 
 	/*
 	 * Disallow physical timer access for the guest
-	 * Physical counter access is allowed
+	 * Physical counter access is allowed if no offset is enforced
+	 * or running protected (we don't offset anything in this case).
 	 */
-	val = read_sysreg(cnthctl_el2);
-	val &= ~CNTHCTL_EL1PCEN;
-	val |= CNTHCTL_EL1PCTEN;
-	write_sysreg(val, cnthctl_el2);
+	clr = CNTHCTL_EL1PCEN;
+	if (is_protected_kvm_enabled() ||
+	    !kern_hyp_va(vcpu->kvm)->arch.timer_data.poffset)
+		set |= CNTHCTL_EL1PCTEN;
+	else
+		clr |= CNTHCTL_EL1PCTEN;
+
+	sysreg_clear_set(cnthctl_el2, clr, set);
 }
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 53749d3a0996..be7c2598e563 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1139,6 +1139,12 @@ static bool access_arch_timer(struct kvm_vcpu *vcpu,
 		tmr = TIMER_PTIMER;
 		treg = TIMER_REG_CVAL;
 		break;
+	case SYS_CNTPCT_EL0:
+	case SYS_CNTPCTSS_EL0:
+	case SYS_AARCH32_CNTPCT:
+		tmr = TIMER_PTIMER;
+		treg = TIMER_REG_CNT;
+		break;
 	default:
 		print_sys_reg_msg(p, "%s", "Unhandled trapped timer register");
 		kvm_inject_undefined(vcpu);
@@ -2075,6 +2081,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	AMU_AMEVTYPER1_EL0(14),
 	AMU_AMEVTYPER1_EL0(15),
 
+	{ SYS_DESC(SYS_CNTPCT_EL0), access_arch_timer },
+	{ SYS_DESC(SYS_CNTPCTSS_EL0), access_arch_timer },
 	{ SYS_DESC(SYS_CNTP_TVAL_EL0), access_arch_timer },
 	{ SYS_DESC(SYS_CNTP_CTL_EL0), access_arch_timer },
 	{ SYS_DESC(SYS_CNTP_CVAL_EL0), access_arch_timer },
@@ -2525,6 +2533,7 @@ static const struct sys_reg_desc cp15_64_regs[] = {
 	{ Op1( 0), CRn( 0), CRm( 2), Op2( 0), access_vm_reg, NULL, TTBR0_EL1 },
 	{ CP15_PMU_SYS_REG(DIRECT, 0, 0, 9, 0), .access = access_pmu_evcntr },
 	{ Op1( 0), CRn( 0), CRm(12), Op2( 0), access_gic_sgi }, /* ICC_SGI1R */
+	{ SYS_DESC(SYS_AARCH32_CNTPCT),	      access_arch_timer },
 	{ Op1( 1), CRn( 0), CRm( 2), Op2( 0), access_vm_reg, NULL, TTBR1_EL1 },
 	{ Op1( 1), CRn( 0), CRm(12), Op2( 0), access_gic_sgi }, /* ICC_ASGI1R */
 	{ Op1( 2), CRn( 0), CRm(12), Op2( 0), access_gic_sgi }, /* ICC_SGI0R */

From 96906a9150a86a86b0464939625279b8e19f6e88 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:47:46 +0100
Subject: [PATCH 06/21] KVM: arm64: Expose {un,}lock_all_vcpus() to the rest of
 KVM

Being able to lock/unlock all vcpus in one go is a feature that
only the vgic has enjoyed so far. Let's be brave and expose it
to the world.

Reviewed-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-7-maz@kernel.org
---
 arch/arm64/include/asm/kvm_host.h     |  3 ++
 arch/arm64/kvm/arm.c                  | 43 +++++++++++++++++++++++++++
 arch/arm64/kvm/vgic/vgic-kvm-device.c | 38 -----------------------
 arch/arm64/kvm/vgic/vgic.h            |  3 --
 4 files changed, 46 insertions(+), 41 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index bcd774d74f34..002a10cbade2 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -922,6 +922,9 @@ void kvm_reset_sys_regs(struct kvm_vcpu *vcpu);
 
 int __init kvm_sys_reg_table_init(void);
 
+bool lock_all_vcpus(struct kvm *kvm);
+void unlock_all_vcpus(struct kvm *kvm);
+
 /* MMIO helpers */
 void kvm_mmio_write_buf(void *buf, unsigned int len, unsigned long data);
 unsigned long kvm_mmio_read_buf(const void *buf, unsigned int len);
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 3bd732eaf087..ae5110cc3bad 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1484,6 +1484,49 @@ long kvm_arch_vm_ioctl(struct file *filp,
 	}
 }
 
+/* unlocks vcpus from @vcpu_lock_idx and smaller */
+static void unlock_vcpus(struct kvm *kvm, int vcpu_lock_idx)
+{
+	struct kvm_vcpu *tmp_vcpu;
+
+	for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
+		tmp_vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);
+		mutex_unlock(&tmp_vcpu->mutex);
+	}
+}
+
+void unlock_all_vcpus(struct kvm *kvm)
+{
+	lockdep_assert_held(&kvm->lock);
+
+	unlock_vcpus(kvm, atomic_read(&kvm->online_vcpus) - 1);
+}
+
+/* Returns true if all vcpus were locked, false otherwise */
+bool lock_all_vcpus(struct kvm *kvm)
+{
+	struct kvm_vcpu *tmp_vcpu;
+	unsigned long c;
+
+	lockdep_assert_held(&kvm->lock);
+
+	/*
+	 * Any time a vcpu is in an ioctl (including running), the
+	 * core KVM code tries to grab the vcpu->mutex.
+	 *
+	 * By grabbing the vcpu->mutex of all VCPUs we ensure that no
+	 * other VCPUs can fiddle with the state while we access it.
+	 */
+	kvm_for_each_vcpu(c, tmp_vcpu, kvm) {
+		if (!mutex_trylock(&tmp_vcpu->mutex)) {
+			unlock_vcpus(kvm, c - 1);
+			return false;
+		}
+	}
+
+	return true;
+}
+
 static unsigned long nvhe_percpu_size(void)
 {
 	return (unsigned long)CHOOSE_NVHE_SYM(__per_cpu_end) -
diff --git a/arch/arm64/kvm/vgic/vgic-kvm-device.c b/arch/arm64/kvm/vgic/vgic-kvm-device.c
index edeac2380591..04dd68835b3f 100644
--- a/arch/arm64/kvm/vgic/vgic-kvm-device.c
+++ b/arch/arm64/kvm/vgic/vgic-kvm-device.c
@@ -342,44 +342,6 @@ int vgic_v2_parse_attr(struct kvm_device *dev, struct kvm_device_attr *attr,
 	return 0;
 }
 
-/* unlocks vcpus from @vcpu_lock_idx and smaller */
-static void unlock_vcpus(struct kvm *kvm, int vcpu_lock_idx)
-{
-	struct kvm_vcpu *tmp_vcpu;
-
-	for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
-		tmp_vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);
-		mutex_unlock(&tmp_vcpu->mutex);
-	}
-}
-
-void unlock_all_vcpus(struct kvm *kvm)
-{
-	unlock_vcpus(kvm, atomic_read(&kvm->online_vcpus) - 1);
-}
-
-/* Returns true if all vcpus were locked, false otherwise */
-bool lock_all_vcpus(struct kvm *kvm)
-{
-	struct kvm_vcpu *tmp_vcpu;
-	unsigned long c;
-
-	/*
-	 * Any time a vcpu is run, vcpu_load is called which tries to grab the
-	 * vcpu->mutex.  By grabbing the vcpu->mutex of all VCPUs we ensure
-	 * that no other VCPUs are run and fiddle with the vgic state while we
-	 * access it.
-	 */
-	kvm_for_each_vcpu(c, tmp_vcpu, kvm) {
-		if (!mutex_trylock(&tmp_vcpu->mutex)) {
-			unlock_vcpus(kvm, c - 1);
-			return false;
-		}
-	}
-
-	return true;
-}
-
 /**
  * vgic_v2_attr_regs_access - allows user space to access VGIC v2 state
  *
diff --git a/arch/arm64/kvm/vgic/vgic.h b/arch/arm64/kvm/vgic/vgic.h
index 7f7f3c5ed85a..f9923beedd27 100644
--- a/arch/arm64/kvm/vgic/vgic.h
+++ b/arch/arm64/kvm/vgic/vgic.h
@@ -273,9 +273,6 @@ int vgic_init(struct kvm *kvm);
 void vgic_debug_init(struct kvm *kvm);
 void vgic_debug_destroy(struct kvm *kvm);
 
-bool lock_all_vcpus(struct kvm *kvm);
-void unlock_all_vcpus(struct kvm *kvm);
-
 static inline int vgic_v3_max_apr_idx(struct kvm_vcpu *vcpu)
 {
 	struct vgic_cpu *cpu_if = &vcpu->arch.vgic_cpu;

From 30ec7997d175cd689fc61bfc4059f4d35b11858c Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:47:47 +0100
Subject: [PATCH 07/21] KVM: arm64: timers: Allow userspace to set the global
 counter offset

And this is the moment you have all been waiting for: setting the
counter offset from userspace.

We expose a brand new capability that reports the ability to set
the offset for both the virtual and physical sides.

In keeping with the architecture, the offset is expressed as
a delta that is substracted from the physical counter value.

Once this new API is used, there is no going back, and the counters
cannot be written to to set the offsets implicitly (the writes
are instead ignored).

Reviewed-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-8-maz@kernel.org
---
 arch/arm64/include/asm/kvm_host.h |  4 +++
 arch/arm64/include/uapi/asm/kvm.h |  9 ++++++
 arch/arm64/kvm/arch_timer.c       | 54 ++++++++++++++++++++++++++++---
 arch/arm64/kvm/arm.c              |  8 +++++
 include/uapi/linux/kvm.h          |  3 ++
 5 files changed, 73 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 002a10cbade2..116233a390e9 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -221,6 +221,8 @@ struct kvm_arch {
 #define KVM_ARCH_FLAG_EL1_32BIT				4
 	/* PSCI SYSTEM_SUSPEND enabled for the guest */
 #define KVM_ARCH_FLAG_SYSTEM_SUSPEND_ENABLED		5
+	/* VM counter offset */
+#define KVM_ARCH_FLAG_VM_COUNTER_OFFSET			6
 
 	unsigned long flags;
 
@@ -1010,6 +1012,8 @@ int kvm_arm_vcpu_arch_has_attr(struct kvm_vcpu *vcpu,
 
 long kvm_vm_ioctl_mte_copy_tags(struct kvm *kvm,
 				struct kvm_arm_copy_mte_tags *copy_tags);
+int kvm_vm_ioctl_set_counter_offset(struct kvm *kvm,
+				    struct kvm_arm_counter_offset *offset);
 
 /* Guest/host FPSIMD coordination helpers */
 int kvm_arch_vcpu_run_map_fp(struct kvm_vcpu *vcpu);
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index f8129c624b07..12fb0d8a760a 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -198,6 +198,15 @@ struct kvm_arm_copy_mte_tags {
 	__u64 reserved[2];
 };
 
+/*
+ * Counter/Timer offset structure. Describe the virtual/physical offset.
+ * To be used with KVM_ARM_SET_COUNTER_OFFSET.
+ */
+struct kvm_arm_counter_offset {
+	__u64 counter_offset;
+	__u64 reserved;
+};
+
 #define KVM_ARM_TAGS_TO_GUEST		0
 #define KVM_ARM_TAGS_FROM_GUEST		1
 
diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index bb64a71ae193..771504c79711 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -851,9 +851,11 @@ void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
 	ptimer->vcpu = vcpu;
 	ptimer->offset.vm_offset = &vcpu->kvm->arch.timer_data.poffset;
 
-	/* Synchronize cntvoff across all vtimers of a VM. */
-	timer_set_offset(vtimer, kvm_phys_timer_read());
-	timer_set_offset(ptimer, 0);
+	/* Synchronize offsets across timers of a VM if not already provided */
+	if (!test_bit(KVM_ARCH_FLAG_VM_COUNTER_OFFSET, &vcpu->kvm->arch.flags)) {
+		timer_set_offset(vtimer, kvm_phys_timer_read());
+		timer_set_offset(ptimer, 0);
+	}
 
 	hrtimer_init(&timer->bg_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
 	timer->bg_timer.function = kvm_bg_timer_expire;
@@ -897,8 +899,11 @@ int kvm_arm_timer_set_reg(struct kvm_vcpu *vcpu, u64 regid, u64 value)
 		kvm_arm_timer_write(vcpu, timer, TIMER_REG_CTL, value);
 		break;
 	case KVM_REG_ARM_TIMER_CNT:
-		timer = vcpu_vtimer(vcpu);
-		timer_set_offset(timer, kvm_phys_timer_read() - value);
+		if (!test_bit(KVM_ARCH_FLAG_VM_COUNTER_OFFSET,
+			      &vcpu->kvm->arch.flags)) {
+			timer = vcpu_vtimer(vcpu);
+			timer_set_offset(timer, kvm_phys_timer_read() - value);
+		}
 		break;
 	case KVM_REG_ARM_TIMER_CVAL:
 		timer = vcpu_vtimer(vcpu);
@@ -908,6 +913,13 @@ int kvm_arm_timer_set_reg(struct kvm_vcpu *vcpu, u64 regid, u64 value)
 		timer = vcpu_ptimer(vcpu);
 		kvm_arm_timer_write(vcpu, timer, TIMER_REG_CTL, value);
 		break;
+	case KVM_REG_ARM_PTIMER_CNT:
+		if (!test_bit(KVM_ARCH_FLAG_VM_COUNTER_OFFSET,
+			      &vcpu->kvm->arch.flags)) {
+			timer = vcpu_ptimer(vcpu);
+			timer_set_offset(timer, kvm_phys_timer_read() - value);
+		}
+		break;
 	case KVM_REG_ARM_PTIMER_CVAL:
 		timer = vcpu_ptimer(vcpu);
 		kvm_arm_timer_write(vcpu, timer, TIMER_REG_CVAL, value);
@@ -1443,3 +1455,35 @@ int kvm_arm_timer_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
 
 	return -ENXIO;
 }
+
+int kvm_vm_ioctl_set_counter_offset(struct kvm *kvm,
+				    struct kvm_arm_counter_offset *offset)
+{
+	int ret = 0;
+
+	if (offset->reserved)
+		return -EINVAL;
+
+	mutex_lock(&kvm->lock);
+
+	if (lock_all_vcpus(kvm)) {
+		set_bit(KVM_ARCH_FLAG_VM_COUNTER_OFFSET, &kvm->arch.flags);
+
+		/*
+		 * If userspace decides to set the offset using this
+		 * API rather than merely restoring the counter
+		 * values, the offset applies to both the virtual and
+		 * physical views.
+		 */
+		kvm->arch.timer_data.voffset = offset->counter_offset;
+		kvm->arch.timer_data.poffset = offset->counter_offset;
+
+		unlock_all_vcpus(kvm);
+	} else {
+		ret = -EBUSY;
+	}
+
+	mutex_unlock(&kvm->lock);
+
+	return ret;
+}
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index ae5110cc3bad..1c8a4bbae684 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -220,6 +220,7 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
 	case KVM_CAP_VCPU_ATTRIBUTES:
 	case KVM_CAP_PTP_KVM:
 	case KVM_CAP_ARM_SYSTEM_SUSPEND:
+	case KVM_CAP_COUNTER_OFFSET:
 		r = 1;
 		break;
 	case KVM_CAP_SET_GUEST_DEBUG2:
@@ -1479,6 +1480,13 @@ long kvm_arch_vm_ioctl(struct file *filp,
 			return -EFAULT;
 		return kvm_vm_ioctl_mte_copy_tags(kvm, &copy_tags);
 	}
+	case KVM_ARM_SET_COUNTER_OFFSET: {
+		struct kvm_arm_counter_offset offset;
+
+		if (copy_from_user(&offset, argp, sizeof(offset)))
+			return -EFAULT;
+		return kvm_vm_ioctl_set_counter_offset(kvm, &offset);
+	}
 	default:
 		return -EINVAL;
 	}
diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index d77aef872a0a..6a7e1a0ecf04 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -1184,6 +1184,7 @@ struct kvm_ppc_resize_hpt {
 #define KVM_CAP_S390_PROTECTED_ASYNC_DISABLE 224
 #define KVM_CAP_DIRTY_LOG_RING_WITH_BITMAP 225
 #define KVM_CAP_PMU_EVENT_MASKED_EVENTS 226
+#define KVM_CAP_COUNTER_OFFSET 227
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -1543,6 +1544,8 @@ struct kvm_s390_ucas_mapping {
 #define KVM_SET_PMU_EVENT_FILTER  _IOW(KVMIO,  0xb2, struct kvm_pmu_event_filter)
 #define KVM_PPC_SVM_OFF		  _IO(KVMIO,  0xb3)
 #define KVM_ARM_MTE_COPY_TAGS	  _IOR(KVMIO,  0xb4, struct kvm_arm_copy_mte_tags)
+/* Available with KVM_CAP_COUNTER_OFFSET */
+#define KVM_ARM_SET_COUNTER_OFFSET _IOW(KVMIO,  0xb5, struct kvm_arm_counter_offset)
 
 /* ioctl for vm fd */
 #define KVM_CREATE_DEVICE	  _IOWR(KVMIO,  0xe0, struct kvm_create_device)

From 680232a94c1289aad25ffae02f2785823763b456 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:47:48 +0100
Subject: [PATCH 08/21] KVM: arm64: timers: Allow save/restoring of the
 physical timer

Nothing like being 10 year late to a party!

Now that userspace can set counter offsets, we can save/restore
the physical timer as well!

Nobody really cared so far, but you're welcome anyway.

Reviewed-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-9-maz@kernel.org
---
 arch/arm64/kvm/guest.c | 29 +++++++++++++++++------------
 1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/kvm/guest.c b/arch/arm64/kvm/guest.c
index 07444fa22888..46e910819de6 100644
--- a/arch/arm64/kvm/guest.c
+++ b/arch/arm64/kvm/guest.c
@@ -590,11 +590,16 @@ static unsigned long num_core_regs(const struct kvm_vcpu *vcpu)
 	return copy_core_reg_indices(vcpu, NULL);
 }
 
-/**
- * ARM64 versions of the TIMER registers, always available on arm64
- */
+static const u64 timer_reg_list[] = {
+	KVM_REG_ARM_TIMER_CTL,
+	KVM_REG_ARM_TIMER_CNT,
+	KVM_REG_ARM_TIMER_CVAL,
+	KVM_REG_ARM_PTIMER_CTL,
+	KVM_REG_ARM_PTIMER_CNT,
+	KVM_REG_ARM_PTIMER_CVAL,
+};
 
-#define NUM_TIMER_REGS 3
+#define NUM_TIMER_REGS ARRAY_SIZE(timer_reg_list)
 
 static bool is_timer_reg(u64 index)
 {
@@ -602,6 +607,9 @@ static bool is_timer_reg(u64 index)
 	case KVM_REG_ARM_TIMER_CTL:
 	case KVM_REG_ARM_TIMER_CNT:
 	case KVM_REG_ARM_TIMER_CVAL:
+	case KVM_REG_ARM_PTIMER_CTL:
+	case KVM_REG_ARM_PTIMER_CNT:
+	case KVM_REG_ARM_PTIMER_CVAL:
 		return true;
 	}
 	return false;
@@ -609,14 +617,11 @@ static bool is_timer_reg(u64 index)
 
 static int copy_timer_indices(struct kvm_vcpu *vcpu, u64 __user *uindices)
 {
-	if (put_user(KVM_REG_ARM_TIMER_CTL, uindices))
-		return -EFAULT;
-	uindices++;
-	if (put_user(KVM_REG_ARM_TIMER_CNT, uindices))
-		return -EFAULT;
-	uindices++;
-	if (put_user(KVM_REG_ARM_TIMER_CVAL, uindices))
-		return -EFAULT;
+	for (int i = 0; i < NUM_TIMER_REGS; i++) {
+		if (put_user(timer_reg_list[i], uindices))
+			return -EFAULT;
+		uindices++;
+	}
 
 	return 0;
 }

From 5591805d2c21b70838b723b71b8ff613de51cfff Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:47:49 +0100
Subject: [PATCH 09/21] KVM: arm64: timers: Rationalise per-vcpu timer init

The way we initialise our timer contexts may be satisfactory
for two timers, but will be getting pretty annoying with four.

Cleanup the whole thing by removing the code duplication and
getting rid of unused IRQ configuration elements.

Reviewed-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-10-maz@kernel.org
---
 arch/arm64/kvm/arch_timer.c  | 73 +++++++++++++++++++-----------------
 include/kvm/arm_arch_timer.h |  1 -
 2 files changed, 39 insertions(+), 35 deletions(-)

diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index 771504c79711..e46f04ed8f86 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -30,14 +30,9 @@ static u32 host_ptimer_irq_flags;
 
 static DEFINE_STATIC_KEY_FALSE(has_gic_active_state);
 
-static const struct kvm_irq_level default_ptimer_irq = {
-	.irq	= 30,
-	.level	= 1,
-};
-
-static const struct kvm_irq_level default_vtimer_irq = {
-	.irq	= 27,
-	.level	= 1,
+static const u8 default_ppi[] = {
+	[TIMER_PTIMER]  = 30,
+	[TIMER_VTIMER]  = 27,
 };
 
 static bool kvm_timer_irq_can_fire(struct arch_timer_context *timer_ctx);
@@ -820,12 +815,14 @@ int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu)
 	 * resets the timer to be disabled and unmasked and is compliant with
 	 * the ARMv7 architecture.
 	 */
-	timer_set_ctl(vcpu_vtimer(vcpu), 0);
-	timer_set_ctl(vcpu_ptimer(vcpu), 0);
+	for (int i = 0; i < NR_KVM_TIMERS; i++)
+		timer_set_ctl(vcpu_get_timer(vcpu, i), 0);
+
 
 	if (timer->enabled) {
-		kvm_timer_update_irq(vcpu, false, vcpu_vtimer(vcpu));
-		kvm_timer_update_irq(vcpu, false, vcpu_ptimer(vcpu));
+		for (int i = 0; i < NR_KVM_TIMERS; i++)
+			kvm_timer_update_irq(vcpu, false,
+					     vcpu_get_timer(vcpu, i));
 
 		if (irqchip_in_kernel(vcpu->kvm)) {
 			kvm_vgic_reset_mapped_irq(vcpu, map.direct_vtimer->irq.irq);
@@ -840,39 +837,47 @@ int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu)
 	return 0;
 }
 
+static void timer_context_init(struct kvm_vcpu *vcpu, int timerid)
+{
+	struct arch_timer_context *ctxt = vcpu_get_timer(vcpu, timerid);
+	struct kvm *kvm = vcpu->kvm;
+
+	ctxt->vcpu = vcpu;
+
+	if (timerid == TIMER_VTIMER)
+		ctxt->offset.vm_offset = &kvm->arch.timer_data.voffset;
+	else
+		ctxt->offset.vm_offset = &kvm->arch.timer_data.poffset;
+
+	hrtimer_init(&ctxt->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
+	ctxt->hrtimer.function = kvm_hrtimer_expire;
+	ctxt->irq.irq = default_ppi[timerid];
+
+	switch (timerid) {
+	case TIMER_PTIMER:
+		ctxt->host_timer_irq = host_ptimer_irq;
+		break;
+	case TIMER_VTIMER:
+		ctxt->host_timer_irq = host_vtimer_irq;
+		break;
+	}
+}
+
 void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
 {
 	struct arch_timer_cpu *timer = vcpu_timer(vcpu);
-	struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);
-	struct arch_timer_context *ptimer = vcpu_ptimer(vcpu);
 
-	vtimer->vcpu = vcpu;
-	vtimer->offset.vm_offset = &vcpu->kvm->arch.timer_data.voffset;
-	ptimer->vcpu = vcpu;
-	ptimer->offset.vm_offset = &vcpu->kvm->arch.timer_data.poffset;
+	for (int i = 0; i < NR_KVM_TIMERS; i++)
+		timer_context_init(vcpu, i);
 
 	/* Synchronize offsets across timers of a VM if not already provided */
 	if (!test_bit(KVM_ARCH_FLAG_VM_COUNTER_OFFSET, &vcpu->kvm->arch.flags)) {
-		timer_set_offset(vtimer, kvm_phys_timer_read());
-		timer_set_offset(ptimer, 0);
+		timer_set_offset(vcpu_vtimer(vcpu), kvm_phys_timer_read());
+		timer_set_offset(vcpu_ptimer(vcpu), 0);
 	}
 
 	hrtimer_init(&timer->bg_timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
 	timer->bg_timer.function = kvm_bg_timer_expire;
-
-	hrtimer_init(&vtimer->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
-	hrtimer_init(&ptimer->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
-	vtimer->hrtimer.function = kvm_hrtimer_expire;
-	ptimer->hrtimer.function = kvm_hrtimer_expire;
-
-	vtimer->irq.irq = default_vtimer_irq.irq;
-	ptimer->irq.irq = default_ptimer_irq.irq;
-
-	vtimer->host_timer_irq = host_vtimer_irq;
-	ptimer->host_timer_irq = host_ptimer_irq;
-
-	vtimer->host_timer_irq_flags = host_vtimer_irq_flags;
-	ptimer->host_timer_irq_flags = host_ptimer_irq_flags;
 }
 
 void kvm_timer_cpu_up(void)
diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index 2dd0fd2406fb..c746ef64220b 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h
@@ -59,7 +59,6 @@ struct arch_timer_context {
 
 	/* Duplicated state from arch_timer.c for convenience */
 	u32				host_timer_irq;
-	u32				host_timer_irq_flags;
 };
 
 struct timer_map {

From 33c549460ef9119eb115484e81f54521122341db Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:47:50 +0100
Subject: [PATCH 10/21] KVM: arm64: timers: Abstract per-timer IRQ access

As we are about to move the location of the per-timer IRQ into
the VM structure, abstract the location of the IRQ behind an
accessor. This will make the repainting sligntly less painful.

Reviewed-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-11-maz@kernel.org
---
 arch/arm64/kvm/arch_timer.c  | 38 ++++++++++++++++++------------------
 include/kvm/arm_arch_timer.h |  2 ++
 2 files changed, 21 insertions(+), 19 deletions(-)

diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index e46f04ed8f86..d08d8c2fc30d 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -392,12 +392,12 @@ static void kvm_timer_update_irq(struct kvm_vcpu *vcpu, bool new_level,
 	int ret;
 
 	timer_ctx->irq.level = new_level;
-	trace_kvm_timer_update_irq(vcpu->vcpu_id, timer_ctx->irq.irq,
+	trace_kvm_timer_update_irq(vcpu->vcpu_id, timer_irq(timer_ctx),
 				   timer_ctx->irq.level);
 
 	if (!userspace_irqchip(vcpu->kvm)) {
 		ret = kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
-					  timer_ctx->irq.irq,
+					  timer_irq(timer_ctx),
 					  timer_ctx->irq.level,
 					  timer_ctx);
 		WARN_ON(ret);
@@ -607,7 +607,7 @@ static void kvm_timer_vcpu_load_gic(struct arch_timer_context *ctx)
 	kvm_timer_update_irq(ctx->vcpu, kvm_timer_should_fire(ctx), ctx);
 
 	if (irqchip_in_kernel(vcpu->kvm))
-		phys_active = kvm_vgic_map_is_active(vcpu, ctx->irq.irq);
+		phys_active = kvm_vgic_map_is_active(vcpu, timer_irq(ctx));
 
 	phys_active |= ctx->irq.level;
 
@@ -825,9 +825,9 @@ int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu)
 					     vcpu_get_timer(vcpu, i));
 
 		if (irqchip_in_kernel(vcpu->kvm)) {
-			kvm_vgic_reset_mapped_irq(vcpu, map.direct_vtimer->irq.irq);
+			kvm_vgic_reset_mapped_irq(vcpu, timer_irq(map.direct_vtimer));
 			if (map.direct_ptimer)
-				kvm_vgic_reset_mapped_irq(vcpu, map.direct_ptimer->irq.irq);
+				kvm_vgic_reset_mapped_irq(vcpu, timer_irq(map.direct_ptimer));
 		}
 	}
 
@@ -851,7 +851,7 @@ static void timer_context_init(struct kvm_vcpu *vcpu, int timerid)
 
 	hrtimer_init(&ctxt->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
 	ctxt->hrtimer.function = kvm_hrtimer_expire;
-	ctxt->irq.irq = default_ppi[timerid];
+	timer_irq(ctxt) = default_ppi[timerid];
 
 	switch (timerid) {
 	case TIMER_PTIMER:
@@ -1295,19 +1295,19 @@ static bool timer_irqs_are_valid(struct kvm_vcpu *vcpu)
 	int vtimer_irq, ptimer_irq, ret;
 	unsigned long i;
 
-	vtimer_irq = vcpu_vtimer(vcpu)->irq.irq;
+	vtimer_irq = timer_irq(vcpu_vtimer(vcpu));
 	ret = kvm_vgic_set_owner(vcpu, vtimer_irq, vcpu_vtimer(vcpu));
 	if (ret)
 		return false;
 
-	ptimer_irq = vcpu_ptimer(vcpu)->irq.irq;
+	ptimer_irq = timer_irq(vcpu_ptimer(vcpu));
 	ret = kvm_vgic_set_owner(vcpu, ptimer_irq, vcpu_ptimer(vcpu));
 	if (ret)
 		return false;
 
 	kvm_for_each_vcpu(i, vcpu, vcpu->kvm) {
-		if (vcpu_vtimer(vcpu)->irq.irq != vtimer_irq ||
-		    vcpu_ptimer(vcpu)->irq.irq != ptimer_irq)
+		if (timer_irq(vcpu_vtimer(vcpu)) != vtimer_irq ||
+		    timer_irq(vcpu_ptimer(vcpu)) != ptimer_irq)
 			return false;
 	}
 
@@ -1322,9 +1322,9 @@ bool kvm_arch_timer_get_input_level(int vintid)
 	if (WARN(!vcpu, "No vcpu context!\n"))
 		return false;
 
-	if (vintid == vcpu_vtimer(vcpu)->irq.irq)
+	if (vintid == timer_irq(vcpu_vtimer(vcpu)))
 		timer = vcpu_vtimer(vcpu);
-	else if (vintid == vcpu_ptimer(vcpu)->irq.irq)
+	else if (vintid == timer_irq(vcpu_ptimer(vcpu)))
 		timer = vcpu_ptimer(vcpu);
 	else
 		BUG();
@@ -1358,7 +1358,7 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu)
 
 	ret = kvm_vgic_map_phys_irq(vcpu,
 				    map.direct_vtimer->host_timer_irq,
-				    map.direct_vtimer->irq.irq,
+				    timer_irq(map.direct_vtimer),
 				    &arch_timer_irq_ops);
 	if (ret)
 		return ret;
@@ -1366,7 +1366,7 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu)
 	if (map.direct_ptimer) {
 		ret = kvm_vgic_map_phys_irq(vcpu,
 					    map.direct_ptimer->host_timer_irq,
-					    map.direct_ptimer->irq.irq,
+					    timer_irq(map.direct_ptimer),
 					    &arch_timer_irq_ops);
 	}
 
@@ -1391,8 +1391,8 @@ static void set_timer_irqs(struct kvm *kvm, int vtimer_irq, int ptimer_irq)
 	unsigned long i;
 
 	kvm_for_each_vcpu(i, vcpu, kvm) {
-		vcpu_vtimer(vcpu)->irq.irq = vtimer_irq;
-		vcpu_ptimer(vcpu)->irq.irq = ptimer_irq;
+		timer_irq(vcpu_vtimer(vcpu)) = vtimer_irq;
+		timer_irq(vcpu_ptimer(vcpu)) = ptimer_irq;
 	}
 }
 
@@ -1417,10 +1417,10 @@ int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
 
 	switch (attr->attr) {
 	case KVM_ARM_VCPU_TIMER_IRQ_VTIMER:
-		set_timer_irqs(vcpu->kvm, irq, ptimer->irq.irq);
+		set_timer_irqs(vcpu->kvm, irq, timer_irq(ptimer));
 		break;
 	case KVM_ARM_VCPU_TIMER_IRQ_PTIMER:
-		set_timer_irqs(vcpu->kvm, vtimer->irq.irq, irq);
+		set_timer_irqs(vcpu->kvm, timer_irq(vtimer), irq);
 		break;
 	default:
 		return -ENXIO;
@@ -1446,7 +1446,7 @@ int kvm_arm_timer_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
 		return -ENXIO;
 	}
 
-	irq = timer->irq.irq;
+	irq = timer_irq(timer);
 	return put_user(irq, uaddr);
 }
 
diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index c746ef64220b..27cada09f588 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h
@@ -109,6 +109,8 @@ bool kvm_arch_timer_get_input_level(int vintid);
 
 #define arch_timer_ctx_index(ctx)	((ctx) - vcpu_timer((ctx)->vcpu)->timers)
 
+#define timer_irq(ctx)			((ctx)->irq.irq)
+
 u64 kvm_arm_timer_read_sysreg(struct kvm_vcpu *vcpu,
 			      enum kvm_arch_timers tmr,
 			      enum kvm_arch_timer_regs treg);

From 8a5eb2d210807e7dbe9ece7075533014cf4b9c27 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:47:51 +0100
Subject: [PATCH 11/21] KVM: arm64: timers: Move the timer IRQs into
 arch_timer_vm_data

Having the timer IRQs duplicated into each vcpu isn't great, and
becomes absolutely awful with NV. So let's move these into
the per-VM arch_timer_vm_data structure.

This simplifies a lot of code, but requires us to introduce a
mutex so that we can reason about userspace trying to change
an interrupt number while another vcpu is running, something
that wasn't really well handled so far.

Reviewed-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-12-maz@kernel.org
---
 arch/arm64/include/asm/kvm_host.h |   2 +
 arch/arm64/kvm/arch_timer.c       | 108 ++++++++++++++++++------------
 arch/arm64/kvm/arm.c              |   2 +
 include/kvm/arm_arch_timer.h      |  18 +++--
 4 files changed, 82 insertions(+), 48 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 116233a390e9..1280154c9ef3 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -223,6 +223,8 @@ struct kvm_arch {
 #define KVM_ARCH_FLAG_SYSTEM_SUSPEND_ENABLED		5
 	/* VM counter offset */
 #define KVM_ARCH_FLAG_VM_COUNTER_OFFSET			6
+	/* Timer PPIs made immutable */
+#define KVM_ARCH_FLAG_TIMER_PPIS_IMMUTABLE		7
 
 	unsigned long flags;
 
diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index d08d8c2fc30d..1d811735e05f 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -851,7 +851,6 @@ static void timer_context_init(struct kvm_vcpu *vcpu, int timerid)
 
 	hrtimer_init(&ctxt->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_HARD);
 	ctxt->hrtimer.function = kvm_hrtimer_expire;
-	timer_irq(ctxt) = default_ppi[timerid];
 
 	switch (timerid) {
 	case TIMER_PTIMER:
@@ -880,6 +879,13 @@ void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
 	timer->bg_timer.function = kvm_bg_timer_expire;
 }
 
+void kvm_timer_init_vm(struct kvm *kvm)
+{
+	mutex_init(&kvm->arch.timer_data.lock);
+	for (int i = 0; i < NR_KVM_TIMERS; i++)
+		kvm->arch.timer_data.ppi[i] = default_ppi[i];
+}
+
 void kvm_timer_cpu_up(void)
 {
 	enable_percpu_irq(host_vtimer_irq, host_vtimer_irq_flags);
@@ -1292,44 +1298,56 @@ void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu)
 
 static bool timer_irqs_are_valid(struct kvm_vcpu *vcpu)
 {
-	int vtimer_irq, ptimer_irq, ret;
-	unsigned long i;
+	u32 ppis = 0;
+	bool valid;
 
-	vtimer_irq = timer_irq(vcpu_vtimer(vcpu));
-	ret = kvm_vgic_set_owner(vcpu, vtimer_irq, vcpu_vtimer(vcpu));
-	if (ret)
-		return false;
+	mutex_lock(&vcpu->kvm->arch.timer_data.lock);
 
-	ptimer_irq = timer_irq(vcpu_ptimer(vcpu));
-	ret = kvm_vgic_set_owner(vcpu, ptimer_irq, vcpu_ptimer(vcpu));
-	if (ret)
-		return false;
+	for (int i = 0; i < NR_KVM_TIMERS; i++) {
+		struct arch_timer_context *ctx;
+		int irq;
 
-	kvm_for_each_vcpu(i, vcpu, vcpu->kvm) {
-		if (timer_irq(vcpu_vtimer(vcpu)) != vtimer_irq ||
-		    timer_irq(vcpu_ptimer(vcpu)) != ptimer_irq)
-			return false;
+		ctx = vcpu_get_timer(vcpu, i);
+		irq = timer_irq(ctx);
+		if (kvm_vgic_set_owner(vcpu, irq, ctx))
+			break;
+
+		/*
+		 * We know by construction that we only have PPIs, so
+		 * all values are less than 32.
+		 */
+		ppis |= BIT(irq);
 	}
 
-	return true;
+	valid = hweight32(ppis) == NR_KVM_TIMERS;
+
+	if (valid)
+		set_bit(KVM_ARCH_FLAG_TIMER_PPIS_IMMUTABLE, &vcpu->kvm->arch.flags);
+
+	mutex_unlock(&vcpu->kvm->arch.timer_data.lock);
+
+	return valid;
 }
 
 bool kvm_arch_timer_get_input_level(int vintid)
 {
 	struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
-	struct arch_timer_context *timer;
 
 	if (WARN(!vcpu, "No vcpu context!\n"))
 		return false;
 
-	if (vintid == timer_irq(vcpu_vtimer(vcpu)))
-		timer = vcpu_vtimer(vcpu);
-	else if (vintid == timer_irq(vcpu_ptimer(vcpu)))
-		timer = vcpu_ptimer(vcpu);
-	else
-		BUG();
+	for (int i = 0; i < NR_KVM_TIMERS; i++) {
+		struct arch_timer_context *ctx;
 
-	return kvm_timer_should_fire(timer);
+		ctx = vcpu_get_timer(vcpu, i);
+		if (timer_irq(ctx) == vintid)
+			return kvm_timer_should_fire(ctx);
+	}
+
+	/* A timer IRQ has fired, but no matching timer was found? */
+	WARN_RATELIMIT(1, "timer INTID%d unknown\n", vintid);
+
+	return false;
 }
 
 int kvm_timer_enable(struct kvm_vcpu *vcpu)
@@ -1385,23 +1403,10 @@ void kvm_timer_init_vhe(void)
 		sysreg_clear_set(cntkctl_el1, 0, CNTHCTL_ECV);
 }
 
-static void set_timer_irqs(struct kvm *kvm, int vtimer_irq, int ptimer_irq)
-{
-	struct kvm_vcpu *vcpu;
-	unsigned long i;
-
-	kvm_for_each_vcpu(i, vcpu, kvm) {
-		timer_irq(vcpu_vtimer(vcpu)) = vtimer_irq;
-		timer_irq(vcpu_ptimer(vcpu)) = ptimer_irq;
-	}
-}
-
 int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
 {
 	int __user *uaddr = (int __user *)(long)attr->addr;
-	struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);
-	struct arch_timer_context *ptimer = vcpu_ptimer(vcpu);
-	int irq;
+	int irq, idx, ret = 0;
 
 	if (!irqchip_in_kernel(vcpu->kvm))
 		return -EINVAL;
@@ -1412,21 +1417,36 @@ int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
 	if (!(irq_is_ppi(irq)))
 		return -EINVAL;
 
-	if (vcpu->arch.timer_cpu.enabled)
-		return -EBUSY;
+	mutex_lock(&vcpu->kvm->arch.timer_data.lock);
+
+	if (test_bit(KVM_ARCH_FLAG_TIMER_PPIS_IMMUTABLE,
+		     &vcpu->kvm->arch.flags)) {
+		ret = -EBUSY;
+		goto out;
+	}
 
 	switch (attr->attr) {
 	case KVM_ARM_VCPU_TIMER_IRQ_VTIMER:
-		set_timer_irqs(vcpu->kvm, irq, timer_irq(ptimer));
+		idx = TIMER_VTIMER;
 		break;
 	case KVM_ARM_VCPU_TIMER_IRQ_PTIMER:
-		set_timer_irqs(vcpu->kvm, timer_irq(vtimer), irq);
+		idx = TIMER_PTIMER;
 		break;
 	default:
-		return -ENXIO;
+		ret = -ENXIO;
+		goto out;
 	}
 
-	return 0;
+	/*
+	 * We cannot validate the IRQ unicity before we run, so take it at
+	 * face value. The verdict will be given on first vcpu run, for each
+	 * vcpu. Yes this is late. Blame it on the stupid API.
+	 */
+	vcpu->kvm->arch.timer_data.ppi[idx] = irq;
+
+out:
+	mutex_unlock(&vcpu->kvm->arch.timer_data.lock);
+	return ret;
 }
 
 int kvm_arm_timer_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 1c8a4bbae684..4c5e9dfbf83a 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -148,6 +148,8 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
 
 	kvm_vgic_early_init(kvm);
 
+	kvm_timer_init_vm(kvm);
+
 	/* The maximum number of VCPUs is limited by the host's GIC model */
 	kvm->max_vcpus = kvm_arm_default_max_vcpus();
 
diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index 27cada09f588..f093ea9f540d 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h
@@ -36,14 +36,16 @@ struct arch_timer_vm_data {
 	u64	voffset;
 	/* Offset applied to the physical timer/counter */
 	u64	poffset;
+
+	struct mutex	lock;
+
+	/* The PPI for each timer, global to the VM */
+	u8	ppi[NR_KVM_TIMERS];
 };
 
 struct arch_timer_context {
 	struct kvm_vcpu			*vcpu;
 
-	/* Timer IRQ */
-	struct kvm_irq_level		irq;
-
 	/* Emulated Timer (may be unused) */
 	struct hrtimer			hrtimer;
 	u64				ns_frac;
@@ -57,6 +59,11 @@ struct arch_timer_context {
 	 */
 	bool				loaded;
 
+	/* Output level of the timer IRQ */
+	struct {
+		bool			level;
+	} irq;
+
 	/* Duplicated state from arch_timer.c for convenience */
 	u32				host_timer_irq;
 };
@@ -86,6 +93,8 @@ bool kvm_timer_should_notify_user(struct kvm_vcpu *vcpu);
 void kvm_timer_update_run(struct kvm_vcpu *vcpu);
 void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu);
 
+void kvm_timer_init_vm(struct kvm *kvm);
+
 u64 kvm_arm_timer_get_reg(struct kvm_vcpu *, u64 regid);
 int kvm_arm_timer_set_reg(struct kvm_vcpu *, u64 regid, u64 value);
 
@@ -109,7 +118,8 @@ bool kvm_arch_timer_get_input_level(int vintid);
 
 #define arch_timer_ctx_index(ctx)	((ctx) - vcpu_timer((ctx)->vcpu)->timers)
 
-#define timer_irq(ctx)			((ctx)->irq.irq)
+#define timer_vm_data(ctx)		(&(ctx)->vcpu->kvm->arch.timer_data)
+#define timer_irq(ctx)			(timer_vm_data(ctx)->ppi[arch_timer_ctx_index(ctx)])
 
 u64 kvm_arm_timer_read_sysreg(struct kvm_vcpu *vcpu,
 			      enum kvm_arch_timers tmr,

From 1a6511eb8430533920559c5f01f487f4901081cd Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:47:52 +0100
Subject: [PATCH 12/21] KVM: arm64: Elide kern_hyp_va() in VHE-specific parts
 of the hypervisor

For VHE-specific hypervisor code, kern_hyp_va() is a NOP.

Actually, it is a whole range of NOPs. It'd be much better if
this code simply didn't exist. Let's just do that.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-13-maz@kernel.org
---
 arch/arm64/include/asm/kvm_mmu.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 083cc47dca08..27e63c111f78 100644
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -63,6 +63,7 @@
  * specific registers encoded in the instructions).
  */
 .macro kern_hyp_va	reg
+#ifndef __KVM_VHE_HYPERVISOR__
 alternative_cb ARM64_ALWAYS_SYSTEM, kvm_update_va_mask
 	and     \reg, \reg, #1		/* mask with va_mask */
 	ror	\reg, \reg, #1		/* rotate to the first tag bit */
@@ -70,6 +71,7 @@ alternative_cb ARM64_ALWAYS_SYSTEM, kvm_update_va_mask
 	add	\reg, \reg, #0, lsl 12	/* insert the top 12 bits of the tag */
 	ror	\reg, \reg, #63		/* rotate back */
 alternative_cb_end
+#endif
 .endm
 
 /*
@@ -127,6 +129,7 @@ void kvm_apply_hyp_relocations(void);
 
 static __always_inline unsigned long __kern_hyp_va(unsigned long v)
 {
+#ifndef __KVM_VHE_HYPERVISOR__
 	asm volatile(ALTERNATIVE_CB("and %0, %0, #1\n"
 				    "ror %0, %0, #1\n"
 				    "add %0, %0, #0\n"
@@ -135,6 +138,7 @@ static __always_inline unsigned long __kern_hyp_va(unsigned long v)
 				    ARM64_ALWAYS_SYSTEM,
 				    kvm_update_va_mask)
 		     : "+r" (v));
+#endif
 	return v;
 }
 

From e9adde432bf7371f1c83f67d9f8d75b95810f124 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:47:53 +0100
Subject: [PATCH 13/21] KVM: arm64: timers: Fast-track CNTPCT_EL0 trap handling

Now that it is likely that CNTPCT_EL0 accesses will trap,
fast-track the emulation of the counter read which doesn't
need more that a simple offsetting.

One day, we'll have CNTPOFF everywhere. One day.

Suggested-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-14-maz@kernel.org
---
 arch/arm64/kvm/hyp/include/hyp/switch.h | 36 +++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index 07d37ff88a3f..9954368f639d 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -26,6 +26,7 @@
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_hyp.h>
 #include <asm/kvm_mmu.h>
+#include <asm/kvm_nested.h>
 #include <asm/fpsimd.h>
 #include <asm/debug-monitors.h>
 #include <asm/processor.h>
@@ -326,6 +327,38 @@ static bool kvm_hyp_handle_ptrauth(struct kvm_vcpu *vcpu, u64 *exit_code)
 	return true;
 }
 
+static bool kvm_hyp_handle_cntpct(struct kvm_vcpu *vcpu)
+{
+	struct arch_timer_context *ctxt;
+	u32 sysreg;
+	u64 val;
+
+	/*
+	 * We only get here for 64bit guests, 32bit guests will hit
+	 * the long and winding road all the way to the standard
+	 * handling. Yes, it sucks to be irrelevant.
+	 */
+	sysreg = esr_sys64_to_sysreg(kvm_vcpu_get_esr(vcpu));
+
+	switch (sysreg) {
+	case SYS_CNTPCT_EL0:
+	case SYS_CNTPCTSS_EL0:
+		ctxt = vcpu_ptimer(vcpu);
+		break;
+	default:
+		return false;
+	}
+
+	val = arch_timer_read_cntpct_el0();
+
+	if (ctxt->offset.vm_offset)
+		val -= *kern_hyp_va(ctxt->offset.vm_offset);
+
+	vcpu_set_reg(vcpu, kvm_vcpu_sys_get_rt(vcpu), val);
+	__kvm_skip_instr(vcpu);
+	return true;
+}
+
 static bool kvm_hyp_handle_sysreg(struct kvm_vcpu *vcpu, u64 *exit_code)
 {
 	if (cpus_have_final_cap(ARM64_WORKAROUND_CAVIUM_TX2_219_TVM) &&
@@ -339,6 +372,9 @@ static bool kvm_hyp_handle_sysreg(struct kvm_vcpu *vcpu, u64 *exit_code)
 	if (esr_is_ptrauth_trap(kvm_vcpu_get_esr(vcpu)))
 		return kvm_hyp_handle_ptrauth(vcpu, exit_code);
 
+	if (kvm_hyp_handle_cntpct(vcpu))
+		return true;
+
 	return false;
 }
 

From 476fcd4b7bb54ac959b683f30d0cf305c3e11f3c Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:47:54 +0100
Subject: [PATCH 14/21] KVM: arm64: timers: Abstract the number of valid timers
 per vcpu

We so far have a pretty fixed number of timers to take care of.
This is about to change as NV brings another two into the
picture, and we must be careful not to try and emulate non-valid
timers in a given VM.

For this, abstract the number of timers for a given vcpu behind
an accessor, which helpfully returns a constant for now.

Reviewed-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-15-maz@kernel.org
---
 arch/arm64/kvm/arch_timer.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index 1d811735e05f..d3a7902269c1 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -52,6 +52,11 @@ static bool has_cntpoff(void)
 	return (has_vhe() && cpus_have_final_cap(ARM64_HAS_ECV_CNTPOFF));
 }
 
+static int nr_timers(struct kvm_vcpu *vcpu)
+{
+	return NR_KVM_TIMERS;
+}
+
 u32 timer_get_ctl(struct arch_timer_context *ctxt)
 {
 	struct kvm_vcpu *vcpu = ctxt->vcpu;
@@ -255,7 +260,7 @@ static u64 kvm_timer_earliest_exp(struct kvm_vcpu *vcpu)
 	u64 min_delta = ULLONG_MAX;
 	int i;
 
-	for (i = 0; i < NR_KVM_TIMERS; i++) {
+	for (i = 0; i < nr_timers(vcpu); i++) {
 		struct arch_timer_context *ctx = &vcpu->arch.timer_cpu.timers[i];
 
 		WARN(ctx->loaded, "timer %d loaded\n", i);
@@ -815,12 +820,12 @@ int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu)
 	 * resets the timer to be disabled and unmasked and is compliant with
 	 * the ARMv7 architecture.
 	 */
-	for (int i = 0; i < NR_KVM_TIMERS; i++)
+	for (int i = 0; i < nr_timers(vcpu); i++)
 		timer_set_ctl(vcpu_get_timer(vcpu, i), 0);
 
 
 	if (timer->enabled) {
-		for (int i = 0; i < NR_KVM_TIMERS; i++)
+		for (int i = 0; i < nr_timers(vcpu); i++)
 			kvm_timer_update_irq(vcpu, false,
 					     vcpu_get_timer(vcpu, i));
 
@@ -1303,7 +1308,7 @@ static bool timer_irqs_are_valid(struct kvm_vcpu *vcpu)
 
 	mutex_lock(&vcpu->kvm->arch.timer_data.lock);
 
-	for (int i = 0; i < NR_KVM_TIMERS; i++) {
+	for (int i = 0; i < nr_timers(vcpu); i++) {
 		struct arch_timer_context *ctx;
 		int irq;
 
@@ -1319,7 +1324,7 @@ static bool timer_irqs_are_valid(struct kvm_vcpu *vcpu)
 		ppis |= BIT(irq);
 	}
 
-	valid = hweight32(ppis) == NR_KVM_TIMERS;
+	valid = hweight32(ppis) == nr_timers(vcpu);
 
 	if (valid)
 		set_bit(KVM_ARCH_FLAG_TIMER_PPIS_IMMUTABLE, &vcpu->kvm->arch.flags);
@@ -1336,7 +1341,7 @@ bool kvm_arch_timer_get_input_level(int vintid)
 	if (WARN(!vcpu, "No vcpu context!\n"))
 		return false;
 
-	for (int i = 0; i < NR_KVM_TIMERS; i++) {
+	for (int i = 0; i < nr_timers(vcpu); i++) {
 		struct arch_timer_context *ctx;
 
 		ctx = vcpu_get_timer(vcpu, i);

From 1935d34afaebe01ddb75bfaa62fb7fe957ddc210 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:47:55 +0100
Subject: [PATCH 15/21] KVM: arm64: Document KVM_ARM_SET_CNT_OFFSETS and co

Add some basic documentation on the effects of KVM_ARM_SET_CNT_OFFSETS.

Reviewed-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-16-maz@kernel.org
---
 Documentation/virt/kvm/api.rst | 38 ++++++++++++++++++++++++++++++++++
 1 file changed, 38 insertions(+)

diff --git a/Documentation/virt/kvm/api.rst b/Documentation/virt/kvm/api.rst
index 62de0768d6aa..192adcb61add 100644
--- a/Documentation/virt/kvm/api.rst
+++ b/Documentation/virt/kvm/api.rst
@@ -6029,6 +6029,44 @@ delivery must be provided via the "reg_aen" struct.
 The "pad" and "reserved" fields may be used for future extensions and should be
 set to 0s by userspace.
 
+4.138 KVM_ARM_SET_COUNTER_OFFSET
+--------------------------------
+
+:Capability: KVM_CAP_COUNTER_OFFSET
+:Architectures: arm64
+:Type: vm ioctl
+:Parameters: struct kvm_arm_counter_offset (in)
+:Returns: 0 on success, < 0 on error
+
+This capability indicates that userspace is able to apply a single VM-wide
+offset to both the virtual and physical counters as viewed by the guest
+using the KVM_ARM_SET_CNT_OFFSET ioctl and the following data structure:
+
+::
+
+	struct kvm_arm_counter_offset {
+		__u64 counter_offset;
+		__u64 reserved;
+	};
+
+The offset describes a number of counter cycles that are subtracted from
+both virtual and physical counter views (similar to the effects of the
+CNTVOFF_EL2 and CNTPOFF_EL2 system registers, but only global). The offset
+always applies to all vcpus (already created or created after this ioctl)
+for this VM.
+
+It is userspace's responsibility to compute the offset based, for example,
+on previous values of the guest counters.
+
+Any value other than 0 for the "reserved" field may result in an error
+(-EINVAL) being returned. This ioctl can also return -EBUSY if any vcpu
+ioctl is issued concurrently.
+
+Note that using this ioctl results in KVM ignoring subsequent userspace
+writes to the CNTVCT_EL0 and CNTPCT_EL0 registers using the SET_ONE_REG
+interface. No error will be returned, but the resulting offset will not be
+applied.
+
 5. The kvm_run structure
 ========================
 

From 1e0eec09d43a55125ff80e40b2d6e2f369a338b9 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:47:56 +0100
Subject: [PATCH 16/21] KVM: arm64: nv: timers: Add a per-timer, per-vcpu
 offset

Being able to set a global offset isn't enough.

With NV, we also need to a per-vcpu, per-timer offset (for example,
CNTVCT_EL0 being offset by CNTVOFF_EL2).

Use a similar method as the VM-wide offset to have a timer point
to the shadow register that contains the offset value.

Reviewed-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-17-maz@kernel.org
---
 arch/arm64/kvm/arch_timer.c             | 13 ++++++++++---
 arch/arm64/kvm/hyp/include/hyp/switch.h |  2 ++
 include/kvm/arm_arch_timer.h            |  5 +++++
 3 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index d3a7902269c1..b87bf182af33 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -89,10 +89,17 @@ u64 timer_get_cval(struct arch_timer_context *ctxt)
 
 static u64 timer_get_offset(struct arch_timer_context *ctxt)
 {
-	if (ctxt && ctxt->offset.vm_offset)
-		return *ctxt->offset.vm_offset;
+	u64 offset = 0;
 
-	return 0;
+	if (!ctxt)
+		return 0;
+
+	if (ctxt->offset.vm_offset)
+		offset += *ctxt->offset.vm_offset;
+	if (ctxt->offset.vcpu_offset)
+		offset += *ctxt->offset.vcpu_offset;
+
+	return offset;
 }
 
 static void timer_set_ctl(struct arch_timer_context *ctxt, u32 ctl)
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index 9954368f639d..d07cbc313889 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -353,6 +353,8 @@ static bool kvm_hyp_handle_cntpct(struct kvm_vcpu *vcpu)
 
 	if (ctxt->offset.vm_offset)
 		val -= *kern_hyp_va(ctxt->offset.vm_offset);
+	if (ctxt->offset.vcpu_offset)
+		val -= *kern_hyp_va(ctxt->offset.vcpu_offset);
 
 	vcpu_set_reg(vcpu, kvm_vcpu_sys_get_rt(vcpu), val);
 	__kvm_skip_instr(vcpu);
diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index f093ea9f540d..209da0c2ac9f 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h
@@ -29,6 +29,11 @@ struct arch_timer_offset {
 	 * structure. If NULL, assume a zero offset.
 	 */
 	u64	*vm_offset;
+	/*
+	 * If set, pointer to one of the offsets in the vcpu's sysreg
+	 * array. If NULL, assume a zero offset.
+	 */
+	u64	*vcpu_offset;
 };
 
 struct arch_timer_vm_data {

From 81dc9504a7006b484cfcf074796094ee526b0c45 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:47:57 +0100
Subject: [PATCH 17/21] KVM: arm64: nv: timers: Support hyp timer emulation

Emulating EL2 also means emulating the EL2 timers. To do so, we expand
our timer framework to deal with at most 4 timers. At any given time,
two timers are using the HW timers, and the two others are purely
emulated.

The role of deciding which is which at any given time is left to a
mapping function which is called every time we need to make such a
decision.

Reviewed-by: Colton Lewis <coltonlewis@google.com>
Co-developed-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-18-maz@kernel.org
---
 arch/arm64/include/asm/kvm_host.h       |   4 +
 arch/arm64/include/uapi/asm/kvm.h       |   2 +
 arch/arm64/kvm/arch_timer.c             | 180 ++++++++++++++++++++++--
 arch/arm64/kvm/hyp/include/hyp/switch.h |  15 ++
 arch/arm64/kvm/trace_arm.h              |   6 +-
 arch/arm64/kvm/vgic/vgic.c              |  15 ++
 include/kvm/arm_arch_timer.h            |   9 +-
 include/kvm/arm_vgic.h                  |   1 +
 8 files changed, 220 insertions(+), 12 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
index 1280154c9ef3..633a7c0750bb 100644
--- a/arch/arm64/include/asm/kvm_host.h
+++ b/arch/arm64/include/asm/kvm_host.h
@@ -369,6 +369,10 @@ enum vcpu_sysreg {
 	TPIDR_EL2,	/* EL2 Software Thread ID Register */
 	CNTHCTL_EL2,	/* Counter-timer Hypervisor Control register */
 	SP_EL2,		/* EL2 Stack Pointer */
+	CNTHP_CTL_EL2,
+	CNTHP_CVAL_EL2,
+	CNTHV_CTL_EL2,
+	CNTHV_CVAL_EL2,
 
 	NR_SYS_REGS	/* Nothing after this line! */
 };
diff --git a/arch/arm64/include/uapi/asm/kvm.h b/arch/arm64/include/uapi/asm/kvm.h
index 12fb0d8a760a..0921f366c49f 100644
--- a/arch/arm64/include/uapi/asm/kvm.h
+++ b/arch/arm64/include/uapi/asm/kvm.h
@@ -420,6 +420,8 @@ enum {
 #define KVM_ARM_VCPU_TIMER_CTRL		1
 #define   KVM_ARM_VCPU_TIMER_IRQ_VTIMER		0
 #define   KVM_ARM_VCPU_TIMER_IRQ_PTIMER		1
+#define   KVM_ARM_VCPU_TIMER_IRQ_HVTIMER	2
+#define   KVM_ARM_VCPU_TIMER_IRQ_HPTIMER	3
 #define KVM_ARM_VCPU_PVTIME_CTRL	2
 #define   KVM_ARM_VCPU_PVTIME_IPA	0
 
diff --git a/arch/arm64/kvm/arch_timer.c b/arch/arm64/kvm/arch_timer.c
index b87bf182af33..c5c8cc3c25ae 100644
--- a/arch/arm64/kvm/arch_timer.c
+++ b/arch/arm64/kvm/arch_timer.c
@@ -16,6 +16,7 @@
 #include <asm/arch_timer.h>
 #include <asm/kvm_emulate.h>
 #include <asm/kvm_hyp.h>
+#include <asm/kvm_nested.h>
 
 #include <kvm/arm_vgic.h>
 #include <kvm/arm_arch_timer.h>
@@ -33,6 +34,8 @@ static DEFINE_STATIC_KEY_FALSE(has_gic_active_state);
 static const u8 default_ppi[] = {
 	[TIMER_PTIMER]  = 30,
 	[TIMER_VTIMER]  = 27,
+	[TIMER_HPTIMER] = 26,
+	[TIMER_HVTIMER] = 28,
 };
 
 static bool kvm_timer_irq_can_fire(struct arch_timer_context *timer_ctx);
@@ -46,6 +49,11 @@ static void kvm_arm_timer_write(struct kvm_vcpu *vcpu,
 static u64 kvm_arm_timer_read(struct kvm_vcpu *vcpu,
 			      struct arch_timer_context *timer,
 			      enum kvm_arch_timer_regs treg);
+static bool kvm_arch_timer_get_input_level(int vintid);
+
+static struct irq_ops arch_timer_irq_ops = {
+	.get_input_level = kvm_arch_timer_get_input_level,
+};
 
 static bool has_cntpoff(void)
 {
@@ -54,6 +62,9 @@ static bool has_cntpoff(void)
 
 static int nr_timers(struct kvm_vcpu *vcpu)
 {
+	if (!vcpu_has_nv(vcpu))
+		return NR_KVM_EL0_TIMERS;
+
 	return NR_KVM_TIMERS;
 }
 
@@ -66,6 +77,10 @@ u32 timer_get_ctl(struct arch_timer_context *ctxt)
 		return __vcpu_sys_reg(vcpu, CNTV_CTL_EL0);
 	case TIMER_PTIMER:
 		return __vcpu_sys_reg(vcpu, CNTP_CTL_EL0);
+	case TIMER_HVTIMER:
+		return __vcpu_sys_reg(vcpu, CNTHV_CTL_EL2);
+	case TIMER_HPTIMER:
+		return __vcpu_sys_reg(vcpu, CNTHP_CTL_EL2);
 	default:
 		WARN_ON(1);
 		return 0;
@@ -81,6 +96,10 @@ u64 timer_get_cval(struct arch_timer_context *ctxt)
 		return __vcpu_sys_reg(vcpu, CNTV_CVAL_EL0);
 	case TIMER_PTIMER:
 		return __vcpu_sys_reg(vcpu, CNTP_CVAL_EL0);
+	case TIMER_HVTIMER:
+		return __vcpu_sys_reg(vcpu, CNTHV_CVAL_EL2);
+	case TIMER_HPTIMER:
+		return __vcpu_sys_reg(vcpu, CNTHP_CVAL_EL2);
 	default:
 		WARN_ON(1);
 		return 0;
@@ -113,6 +132,12 @@ static void timer_set_ctl(struct arch_timer_context *ctxt, u32 ctl)
 	case TIMER_PTIMER:
 		__vcpu_sys_reg(vcpu, CNTP_CTL_EL0) = ctl;
 		break;
+	case TIMER_HVTIMER:
+		__vcpu_sys_reg(vcpu, CNTHV_CTL_EL2) = ctl;
+		break;
+	case TIMER_HPTIMER:
+		__vcpu_sys_reg(vcpu, CNTHP_CTL_EL2) = ctl;
+		break;
 	default:
 		WARN_ON(1);
 	}
@@ -129,6 +154,12 @@ static void timer_set_cval(struct arch_timer_context *ctxt, u64 cval)
 	case TIMER_PTIMER:
 		__vcpu_sys_reg(vcpu, CNTP_CVAL_EL0) = cval;
 		break;
+	case TIMER_HVTIMER:
+		__vcpu_sys_reg(vcpu, CNTHV_CVAL_EL2) = cval;
+		break;
+	case TIMER_HPTIMER:
+		__vcpu_sys_reg(vcpu, CNTHP_CVAL_EL2) = cval;
+		break;
 	default:
 		WARN_ON(1);
 	}
@@ -151,13 +182,27 @@ u64 kvm_phys_timer_read(void)
 
 static void get_timer_map(struct kvm_vcpu *vcpu, struct timer_map *map)
 {
-	if (has_vhe()) {
+	if (vcpu_has_nv(vcpu)) {
+		if (is_hyp_ctxt(vcpu)) {
+			map->direct_vtimer = vcpu_hvtimer(vcpu);
+			map->direct_ptimer = vcpu_hptimer(vcpu);
+			map->emul_vtimer = vcpu_vtimer(vcpu);
+			map->emul_ptimer = vcpu_ptimer(vcpu);
+		} else {
+			map->direct_vtimer = vcpu_vtimer(vcpu);
+			map->direct_ptimer = vcpu_ptimer(vcpu);
+			map->emul_vtimer = vcpu_hvtimer(vcpu);
+			map->emul_ptimer = vcpu_hptimer(vcpu);
+		}
+	} else if (has_vhe()) {
 		map->direct_vtimer = vcpu_vtimer(vcpu);
 		map->direct_ptimer = vcpu_ptimer(vcpu);
+		map->emul_vtimer = NULL;
 		map->emul_ptimer = NULL;
 	} else {
 		map->direct_vtimer = vcpu_vtimer(vcpu);
 		map->direct_ptimer = NULL;
+		map->emul_vtimer = NULL;
 		map->emul_ptimer = vcpu_ptimer(vcpu);
 	}
 
@@ -252,8 +297,11 @@ static bool vcpu_has_wfit_active(struct kvm_vcpu *vcpu)
 
 static u64 wfit_delay_ns(struct kvm_vcpu *vcpu)
 {
-	struct arch_timer_context *ctx = vcpu_vtimer(vcpu);
 	u64 val = vcpu_get_reg(vcpu, kvm_vcpu_sys_get_rt(vcpu));
+	struct arch_timer_context *ctx;
+
+	ctx = (vcpu_has_nv(vcpu) && is_hyp_ctxt(vcpu)) ? vcpu_hvtimer(vcpu)
+						       : vcpu_vtimer(vcpu);
 
 	return kvm_counter_compute_delta(ctx, val);
 }
@@ -350,9 +398,11 @@ static bool kvm_timer_should_fire(struct arch_timer_context *timer_ctx)
 
 		switch (index) {
 		case TIMER_VTIMER:
+		case TIMER_HVTIMER:
 			cnt_ctl = read_sysreg_el0(SYS_CNTV_CTL);
 			break;
 		case TIMER_PTIMER:
+		case TIMER_HPTIMER:
 			cnt_ctl = read_sysreg_el0(SYS_CNTP_CTL);
 			break;
 		case NR_KVM_TIMERS:
@@ -468,6 +518,7 @@ static void timer_save_state(struct arch_timer_context *ctx)
 		u64 cval;
 
 	case TIMER_VTIMER:
+	case TIMER_HVTIMER:
 		timer_set_ctl(ctx, read_sysreg_el0(SYS_CNTV_CTL));
 		timer_set_cval(ctx, read_sysreg_el0(SYS_CNTV_CVAL));
 
@@ -493,6 +544,7 @@ static void timer_save_state(struct arch_timer_context *ctx)
 		set_cntvoff(0);
 		break;
 	case TIMER_PTIMER:
+	case TIMER_HPTIMER:
 		timer_set_ctl(ctx, read_sysreg_el0(SYS_CNTP_CTL));
 		cval = read_sysreg_el0(SYS_CNTP_CVAL);
 
@@ -536,6 +588,7 @@ static void kvm_timer_blocking(struct kvm_vcpu *vcpu)
 	 */
 	if (!kvm_timer_irq_can_fire(map.direct_vtimer) &&
 	    !kvm_timer_irq_can_fire(map.direct_ptimer) &&
+	    !kvm_timer_irq_can_fire(map.emul_vtimer) &&
 	    !kvm_timer_irq_can_fire(map.emul_ptimer) &&
 	    !vcpu_has_wfit_active(vcpu))
 		return;
@@ -572,12 +625,14 @@ static void timer_restore_state(struct arch_timer_context *ctx)
 		u64 cval, offset;
 
 	case TIMER_VTIMER:
+	case TIMER_HVTIMER:
 		set_cntvoff(timer_get_offset(ctx));
 		write_sysreg_el0(timer_get_cval(ctx), SYS_CNTV_CVAL);
 		isb();
 		write_sysreg_el0(timer_get_ctl(ctx), SYS_CNTV_CTL);
 		break;
 	case TIMER_PTIMER:
+	case TIMER_HPTIMER:
 		cval = timer_get_cval(ctx);
 		offset = timer_get_offset(ctx);
 		set_cntpoff(offset);
@@ -663,6 +718,57 @@ static void kvm_timer_vcpu_load_nogic(struct kvm_vcpu *vcpu)
 			(_clr) |= (_bit);				\
 	} while (0)
 
+static void kvm_timer_vcpu_load_nested_switch(struct kvm_vcpu *vcpu,
+					      struct timer_map *map)
+{
+	int hw, ret;
+
+	if (!irqchip_in_kernel(vcpu->kvm))
+		return;
+
+	/*
+	 * We only ever unmap the vtimer irq on a VHE system that runs nested
+	 * virtualization, in which case we have both a valid emul_vtimer,
+	 * emul_ptimer, direct_vtimer, and direct_ptimer.
+	 *
+	 * Since this is called from kvm_timer_vcpu_load(), a change between
+	 * vEL2 and vEL1/0 will have just happened, and the timer_map will
+	 * represent this, and therefore we switch the emul/direct mappings
+	 * below.
+	 */
+	hw = kvm_vgic_get_map(vcpu, timer_irq(map->direct_vtimer));
+	if (hw < 0) {
+		kvm_vgic_unmap_phys_irq(vcpu, timer_irq(map->emul_vtimer));
+		kvm_vgic_unmap_phys_irq(vcpu, timer_irq(map->emul_ptimer));
+
+		ret = kvm_vgic_map_phys_irq(vcpu,
+					    map->direct_vtimer->host_timer_irq,
+					    timer_irq(map->direct_vtimer),
+					    &arch_timer_irq_ops);
+		WARN_ON_ONCE(ret);
+		ret = kvm_vgic_map_phys_irq(vcpu,
+					    map->direct_ptimer->host_timer_irq,
+					    timer_irq(map->direct_ptimer),
+					    &arch_timer_irq_ops);
+		WARN_ON_ONCE(ret);
+
+		/*
+		 * The virtual offset behaviour is "interresting", as it
+		 * always applies when HCR_EL2.E2H==0, but only when
+		 * accessed from EL1 when HCR_EL2.E2H==1. So make sure we
+		 * track E2H when putting the HV timer in "direct" mode.
+		 */
+		if (map->direct_vtimer == vcpu_hvtimer(vcpu)) {
+			struct arch_timer_offset *offs = &map->direct_vtimer->offset;
+
+			if (vcpu_el2_e2h_is_set(vcpu))
+				offs->vcpu_offset = NULL;
+			else
+				offs->vcpu_offset = &__vcpu_sys_reg(vcpu, CNTVOFF_EL2);
+		}
+	}
+}
+
 static void timer_set_traps(struct kvm_vcpu *vcpu, struct timer_map *map)
 {
 	bool tpt, tpc;
@@ -695,6 +801,22 @@ static void timer_set_traps(struct kvm_vcpu *vcpu, struct timer_map *map)
 	if (!has_cntpoff() && timer_get_offset(map->direct_ptimer))
 		tpt = tpc = true;
 
+	/*
+	 * Apply the enable bits that the guest hypervisor has requested for
+	 * its own guest. We can only add traps that wouldn't have been set
+	 * above.
+	 */
+	if (vcpu_has_nv(vcpu) && !is_hyp_ctxt(vcpu)) {
+		u64 val = __vcpu_sys_reg(vcpu, CNTHCTL_EL2);
+
+		/* Use the VHE format for mental sanity */
+		if (!vcpu_el2_e2h_is_set(vcpu))
+			val = (val & (CNTHCTL_EL1PCEN | CNTHCTL_EL1PCTEN)) << 10;
+
+		tpt |= !(val & (CNTHCTL_EL1PCEN << 10));
+		tpc |= !(val & (CNTHCTL_EL1PCTEN << 10));
+	}
+
 	/*
 	 * Now that we have collected our requirements, compute the
 	 * trap and enable bits.
@@ -720,6 +842,9 @@ void kvm_timer_vcpu_load(struct kvm_vcpu *vcpu)
 	get_timer_map(vcpu, &map);
 
 	if (static_branch_likely(&has_gic_active_state)) {
+		if (vcpu_has_nv(vcpu))
+			kvm_timer_vcpu_load_nested_switch(vcpu, &map);
+
 		kvm_timer_vcpu_load_gic(map.direct_vtimer);
 		if (map.direct_ptimer)
 			kvm_timer_vcpu_load_gic(map.direct_ptimer);
@@ -732,6 +857,8 @@ void kvm_timer_vcpu_load(struct kvm_vcpu *vcpu)
 	timer_restore_state(map.direct_vtimer);
 	if (map.direct_ptimer)
 		timer_restore_state(map.direct_ptimer);
+	if (map.emul_vtimer)
+		timer_emulate(map.emul_vtimer);
 	if (map.emul_ptimer)
 		timer_emulate(map.emul_ptimer);
 
@@ -778,6 +905,8 @@ void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu)
 	 * In any case, we re-schedule the hrtimer for the physical timer when
 	 * coming back to the VCPU thread in kvm_timer_vcpu_load().
 	 */
+	if (map.emul_vtimer)
+		soft_timer_cancel(&map.emul_vtimer->hrtimer);
 	if (map.emul_ptimer)
 		soft_timer_cancel(&map.emul_ptimer->hrtimer);
 
@@ -830,6 +959,17 @@ int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu)
 	for (int i = 0; i < nr_timers(vcpu); i++)
 		timer_set_ctl(vcpu_get_timer(vcpu, i), 0);
 
+	/*
+	 * A vcpu running at EL2 is in charge of the offset applied to
+	 * the virtual timer, so use the physical VM offset, and point
+	 * the vcpu offset to CNTVOFF_EL2.
+	 */
+	if (vcpu_has_nv(vcpu)) {
+		struct arch_timer_offset *offs = &vcpu_vtimer(vcpu)->offset;
+
+		offs->vcpu_offset = &__vcpu_sys_reg(vcpu, CNTVOFF_EL2);
+		offs->vm_offset = &vcpu->kvm->arch.timer_data.poffset;
+	}
 
 	if (timer->enabled) {
 		for (int i = 0; i < nr_timers(vcpu); i++)
@@ -843,6 +983,8 @@ int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu)
 		}
 	}
 
+	if (map.emul_vtimer)
+		soft_timer_cancel(&map.emul_vtimer->hrtimer);
 	if (map.emul_ptimer)
 		soft_timer_cancel(&map.emul_ptimer->hrtimer);
 
@@ -866,9 +1008,11 @@ static void timer_context_init(struct kvm_vcpu *vcpu, int timerid)
 
 	switch (timerid) {
 	case TIMER_PTIMER:
+	case TIMER_HPTIMER:
 		ctxt->host_timer_irq = host_ptimer_irq;
 		break;
 	case TIMER_VTIMER:
+	case TIMER_HVTIMER:
 		ctxt->host_timer_irq = host_vtimer_irq;
 		break;
 	}
@@ -1020,6 +1164,10 @@ static u64 kvm_arm_timer_read(struct kvm_vcpu *vcpu,
 		val = kvm_phys_timer_read() - timer_get_offset(timer);
 		break;
 
+	case TIMER_REG_VOFF:
+		val = *timer->offset.vcpu_offset;
+		break;
+
 	default:
 		BUG();
 	}
@@ -1038,7 +1186,7 @@ u64 kvm_arm_timer_read_sysreg(struct kvm_vcpu *vcpu,
 	get_timer_map(vcpu, &map);
 	timer = vcpu_get_timer(vcpu, tmr);
 
-	if (timer == map.emul_ptimer)
+	if (timer == map.emul_vtimer || timer == map.emul_ptimer)
 		return kvm_arm_timer_read(vcpu, timer, treg);
 
 	preempt_disable();
@@ -1070,6 +1218,10 @@ static void kvm_arm_timer_write(struct kvm_vcpu *vcpu,
 		timer_set_cval(timer, val);
 		break;
 
+	case TIMER_REG_VOFF:
+		*timer->offset.vcpu_offset = val;
+		break;
+
 	default:
 		BUG();
 	}
@@ -1085,7 +1237,7 @@ void kvm_arm_timer_write_sysreg(struct kvm_vcpu *vcpu,
 
 	get_timer_map(vcpu, &map);
 	timer = vcpu_get_timer(vcpu, tmr);
-	if (timer == map.emul_ptimer) {
+	if (timer == map.emul_vtimer || timer == map.emul_ptimer) {
 		soft_timer_cancel(&timer->hrtimer);
 		kvm_arm_timer_write(vcpu, timer, treg, val);
 		timer_emulate(timer);
@@ -1165,10 +1317,6 @@ static const struct irq_domain_ops timer_domain_ops = {
 	.free	= timer_irq_domain_free,
 };
 
-static struct irq_ops arch_timer_irq_ops = {
-	.get_input_level = kvm_arch_timer_get_input_level,
-};
-
 static void kvm_irq_fixup_flags(unsigned int virq, u32 *flags)
 {
 	*flags = irq_get_trigger_type(virq);
@@ -1341,7 +1489,7 @@ static bool timer_irqs_are_valid(struct kvm_vcpu *vcpu)
 	return valid;
 }
 
-bool kvm_arch_timer_get_input_level(int vintid)
+static bool kvm_arch_timer_get_input_level(int vintid)
 {
 	struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
 
@@ -1444,6 +1592,12 @@ int kvm_arm_timer_set_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
 	case KVM_ARM_VCPU_TIMER_IRQ_PTIMER:
 		idx = TIMER_PTIMER;
 		break;
+	case KVM_ARM_VCPU_TIMER_IRQ_HVTIMER:
+		idx = TIMER_HVTIMER;
+		break;
+	case KVM_ARM_VCPU_TIMER_IRQ_HPTIMER:
+		idx = TIMER_HPTIMER;
+		break;
 	default:
 		ret = -ENXIO;
 		goto out;
@@ -1474,6 +1628,12 @@ int kvm_arm_timer_get_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
 	case KVM_ARM_VCPU_TIMER_IRQ_PTIMER:
 		timer = vcpu_ptimer(vcpu);
 		break;
+	case KVM_ARM_VCPU_TIMER_IRQ_HVTIMER:
+		timer = vcpu_hvtimer(vcpu);
+		break;
+	case KVM_ARM_VCPU_TIMER_IRQ_HPTIMER:
+		timer = vcpu_hptimer(vcpu);
+		break;
 	default:
 		return -ENXIO;
 	}
@@ -1487,6 +1647,8 @@ int kvm_arm_timer_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
 	switch (attr->attr) {
 	case KVM_ARM_VCPU_TIMER_IRQ_VTIMER:
 	case KVM_ARM_VCPU_TIMER_IRQ_PTIMER:
+	case KVM_ARM_VCPU_TIMER_IRQ_HVTIMER:
+	case KVM_ARM_VCPU_TIMER_IRQ_HPTIMER:
 		return 0;
 	}
 
diff --git a/arch/arm64/kvm/hyp/include/hyp/switch.h b/arch/arm64/kvm/hyp/include/hyp/switch.h
index d07cbc313889..c41166f1a1dd 100644
--- a/arch/arm64/kvm/hyp/include/hyp/switch.h
+++ b/arch/arm64/kvm/hyp/include/hyp/switch.h
@@ -343,6 +343,21 @@ static bool kvm_hyp_handle_cntpct(struct kvm_vcpu *vcpu)
 	switch (sysreg) {
 	case SYS_CNTPCT_EL0:
 	case SYS_CNTPCTSS_EL0:
+		if (vcpu_has_nv(vcpu)) {
+			if (is_hyp_ctxt(vcpu)) {
+				ctxt = vcpu_hptimer(vcpu);
+				break;
+			}
+
+			/* Check for guest hypervisor trapping */
+			val = __vcpu_sys_reg(vcpu, CNTHCTL_EL2);
+			if (!vcpu_el2_e2h_is_set(vcpu))
+				val = (val & CNTHCTL_EL1PCTEN) << 10;
+
+			if (!(val & (CNTHCTL_EL1PCTEN << 10)))
+				return false;
+		}
+
 		ctxt = vcpu_ptimer(vcpu);
 		break;
 	default:
diff --git a/arch/arm64/kvm/trace_arm.h b/arch/arm64/kvm/trace_arm.h
index f3e46a976125..6ce5c025218d 100644
--- a/arch/arm64/kvm/trace_arm.h
+++ b/arch/arm64/kvm/trace_arm.h
@@ -206,6 +206,7 @@ TRACE_EVENT(kvm_get_timer_map,
 		__field(	unsigned long,		vcpu_id	)
 		__field(	int,			direct_vtimer	)
 		__field(	int,			direct_ptimer	)
+		__field(	int,			emul_vtimer	)
 		__field(	int,			emul_ptimer	)
 	),
 
@@ -214,14 +215,17 @@ TRACE_EVENT(kvm_get_timer_map,
 		__entry->direct_vtimer		= arch_timer_ctx_index(map->direct_vtimer);
 		__entry->direct_ptimer =
 			(map->direct_ptimer) ? arch_timer_ctx_index(map->direct_ptimer) : -1;
+		__entry->emul_vtimer =
+			(map->emul_vtimer) ? arch_timer_ctx_index(map->emul_vtimer) : -1;
 		__entry->emul_ptimer =
 			(map->emul_ptimer) ? arch_timer_ctx_index(map->emul_ptimer) : -1;
 	),
 
-	TP_printk("VCPU: %ld, dv: %d, dp: %d, ep: %d",
+	TP_printk("VCPU: %ld, dv: %d, dp: %d, ev: %d, ep: %d",
 		  __entry->vcpu_id,
 		  __entry->direct_vtimer,
 		  __entry->direct_ptimer,
+		  __entry->emul_vtimer,
 		  __entry->emul_ptimer)
 );
 
diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c
index d97e6080b421..ae491ef97188 100644
--- a/arch/arm64/kvm/vgic/vgic.c
+++ b/arch/arm64/kvm/vgic/vgic.c
@@ -573,6 +573,21 @@ int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid)
 	return 0;
 }
 
+int kvm_vgic_get_map(struct kvm_vcpu *vcpu, unsigned int vintid)
+{
+	struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
+	unsigned long flags;
+	int ret = -1;
+
+	raw_spin_lock_irqsave(&irq->irq_lock, flags);
+	if (irq->hw)
+		ret = irq->hwintid;
+	raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
+
+	vgic_put_irq(vcpu->kvm, irq);
+	return ret;
+}
+
 /**
  * kvm_vgic_set_owner - Set the owner of an interrupt for a VM
  *
diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index 209da0c2ac9f..52008f5cff06 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h
@@ -13,6 +13,9 @@
 enum kvm_arch_timers {
 	TIMER_PTIMER,
 	TIMER_VTIMER,
+	NR_KVM_EL0_TIMERS,
+	TIMER_HVTIMER = NR_KVM_EL0_TIMERS,
+	TIMER_HPTIMER,
 	NR_KVM_TIMERS
 };
 
@@ -21,6 +24,7 @@ enum kvm_arch_timer_regs {
 	TIMER_REG_CVAL,
 	TIMER_REG_TVAL,
 	TIMER_REG_CTL,
+	TIMER_REG_VOFF,
 };
 
 struct arch_timer_offset {
@@ -76,6 +80,7 @@ struct arch_timer_context {
 struct timer_map {
 	struct arch_timer_context *direct_vtimer;
 	struct arch_timer_context *direct_ptimer;
+	struct arch_timer_context *emul_vtimer;
 	struct arch_timer_context *emul_ptimer;
 };
 
@@ -114,12 +119,12 @@ void kvm_timer_vcpu_put(struct kvm_vcpu *vcpu);
 
 void kvm_timer_init_vhe(void);
 
-bool kvm_arch_timer_get_input_level(int vintid);
-
 #define vcpu_timer(v)	(&(v)->arch.timer_cpu)
 #define vcpu_get_timer(v,t)	(&vcpu_timer(v)->timers[(t)])
 #define vcpu_vtimer(v)	(&(v)->arch.timer_cpu.timers[TIMER_VTIMER])
 #define vcpu_ptimer(v)	(&(v)->arch.timer_cpu.timers[TIMER_PTIMER])
+#define vcpu_hvtimer(v)	(&(v)->arch.timer_cpu.timers[TIMER_HVTIMER])
+#define vcpu_hptimer(v)	(&(v)->arch.timer_cpu.timers[TIMER_HPTIMER])
 
 #define arch_timer_ctx_index(ctx)	((ctx) - vcpu_timer((ctx)->vcpu)->timers)
 
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index d3ad51fde9db..402b545959af 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -380,6 +380,7 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
 int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq,
 			  u32 vintid, struct irq_ops *ops);
 int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid);
+int kvm_vgic_get_map(struct kvm_vcpu *vcpu, unsigned int vintid);
 bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int vintid);
 
 int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu);

From 0630fb8e0a4873e436f0c1c1b27fa60a37eb960c Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:47:58 +0100
Subject: [PATCH 18/21] KVM: arm64: selftests: Add physical timer registers to
 the sysreg list

Now that KVM exposes CNTPCT_EL0, CNTP_CTL_EL0 and CNT_CVAL_EL0 to
userspace, add them to the get-reg-list selftest.

Reviewed-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-19-maz@kernel.org
---
 tools/testing/selftests/kvm/aarch64/get-reg-list.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/aarch64/get-reg-list.c b/tools/testing/selftests/kvm/aarch64/get-reg-list.c
index d287dd2cac0a..1b976b333d2c 100644
--- a/tools/testing/selftests/kvm/aarch64/get-reg-list.c
+++ b/tools/testing/selftests/kvm/aarch64/get-reg-list.c
@@ -651,7 +651,7 @@ int main(int ac, char **av)
  * The current blessed list was primed with the output of kernel version
  * v4.15 with --core-reg-fixup and then later updated with new registers.
  *
- * The blessed list is up to date with kernel version v5.13-rc3
+ * The blessed list is up to date with kernel version v6.4 (or so we hope)
  */
 static __u64 base_regs[] = {
 	KVM_REG_ARM64 | KVM_REG_SIZE_U64 | KVM_REG_ARM_CORE | KVM_REG_ARM_CORE_REG(regs.regs[0]),
@@ -858,6 +858,9 @@ static __u64 base_regs[] = {
 	ARM64_SYS_REG(3, 2, 0, 0, 0),	/* CSSELR_EL1 */
 	ARM64_SYS_REG(3, 3, 13, 0, 2),	/* TPIDR_EL0 */
 	ARM64_SYS_REG(3, 3, 13, 0, 3),	/* TPIDRRO_EL0 */
+	ARM64_SYS_REG(3, 3, 14, 0, 1),	/* CNTPCT_EL0 */
+	ARM64_SYS_REG(3, 3, 14, 2, 1),	/* CNTP_CTL_EL0 */
+	ARM64_SYS_REG(3, 3, 14, 2, 2),	/* CNTP_CVAL_EL0 */
 	ARM64_SYS_REG(3, 4, 3, 0, 0),	/* DACR32_EL2 */
 	ARM64_SYS_REG(3, 4, 5, 0, 1),	/* IFSR32_EL2 */
 	ARM64_SYS_REG(3, 4, 5, 3, 0),	/* FPEXC32_EL2 */

From 056c15669a01677ba3e44456580bf4a351f71ff7 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:47:59 +0100
Subject: [PATCH 19/21] KVM: arm64: selftests: Deal with spurious timer
 interrupts

Make sure the timer test can properly handle a spurious timer
interrupt, something that is far from being unlikely.

This involves checking for the GIC IAR return value (don't bother
handling the interrupt if it was spurious) as well as the timer
control register (don't do anything if the interrupt is masked
or the timer disabled). Take this opportunity to rewrite the
timer handler in a more readable way.

This solves a bunch of failures that creep up on systems that
are slow to retire the interrupt, something that the GIC architecture
makes no guarantee about.

Reviewed-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-20-maz@kernel.org
---
 .../selftests/kvm/aarch64/arch_timer.c        | 40 ++++++++++++-------
 1 file changed, 25 insertions(+), 15 deletions(-)

diff --git a/tools/testing/selftests/kvm/aarch64/arch_timer.c b/tools/testing/selftests/kvm/aarch64/arch_timer.c
index 26556a266021..176ab41dd01b 100644
--- a/tools/testing/selftests/kvm/aarch64/arch_timer.c
+++ b/tools/testing/selftests/kvm/aarch64/arch_timer.c
@@ -121,25 +121,35 @@ static void guest_validate_irq(unsigned int intid,
 	uint64_t xcnt = 0, xcnt_diff_us, cval = 0;
 	unsigned long xctl = 0;
 	unsigned int timer_irq = 0;
+	unsigned int accessor;
 
-	if (stage == GUEST_STAGE_VTIMER_CVAL ||
-		stage == GUEST_STAGE_VTIMER_TVAL) {
-		xctl = timer_get_ctl(VIRTUAL);
-		timer_set_ctl(VIRTUAL, CTL_IMASK);
-		xcnt = timer_get_cntct(VIRTUAL);
-		cval = timer_get_cval(VIRTUAL);
+	if (intid == IAR_SPURIOUS)
+		return;
+
+	switch (stage) {
+	case GUEST_STAGE_VTIMER_CVAL:
+	case GUEST_STAGE_VTIMER_TVAL:
+		accessor = VIRTUAL;
 		timer_irq = vtimer_irq;
-	} else if (stage == GUEST_STAGE_PTIMER_CVAL ||
-		stage == GUEST_STAGE_PTIMER_TVAL) {
-		xctl = timer_get_ctl(PHYSICAL);
-		timer_set_ctl(PHYSICAL, CTL_IMASK);
-		xcnt = timer_get_cntct(PHYSICAL);
-		cval = timer_get_cval(PHYSICAL);
+		break;
+	case GUEST_STAGE_PTIMER_CVAL:
+	case GUEST_STAGE_PTIMER_TVAL:
+		accessor = PHYSICAL;
 		timer_irq = ptimer_irq;
-	} else {
+		break;
+	default:
 		GUEST_ASSERT(0);
+		return;
 	}
 
+	xctl = timer_get_ctl(accessor);
+	if ((xctl & CTL_IMASK) || !(xctl & CTL_ENABLE))
+		return;
+
+	timer_set_ctl(accessor, CTL_IMASK);
+	xcnt = timer_get_cntct(accessor);
+	cval = timer_get_cval(accessor);
+
 	xcnt_diff_us = cycles_to_usec(xcnt - shared_data->xcnt);
 
 	/* Make sure we are dealing with the correct timer IRQ */
@@ -148,6 +158,8 @@ static void guest_validate_irq(unsigned int intid,
 	/* Basic 'timer condition met' check */
 	GUEST_ASSERT_3(xcnt >= cval, xcnt, cval, xcnt_diff_us);
 	GUEST_ASSERT_1(xctl & CTL_ISTATUS, xctl);
+
+	WRITE_ONCE(shared_data->nr_iter, shared_data->nr_iter + 1);
 }
 
 static void guest_irq_handler(struct ex_regs *regs)
@@ -158,8 +170,6 @@ static void guest_irq_handler(struct ex_regs *regs)
 
 	guest_validate_irq(intid, shared_data);
 
-	WRITE_ONCE(shared_data->nr_iter, shared_data->nr_iter + 1);
-
 	gic_set_eoi(intid);
 }
 

From 2fe9e0fc21602339b82cdba58ef81a5a97d90ca2 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 30 Mar 2023 18:48:00 +0100
Subject: [PATCH 20/21] KVM: arm64: selftests: Augment existing timer test to
 handle variable offset

Allow a user to specify the global offset on the command-line.

Reviewed-by: Colton Lewis <coltonlewis@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230330174800.2677007-21-maz@kernel.org
---
 tools/testing/selftests/kvm/aarch64/arch_timer.c | 16 +++++++++++++++-
 1 file changed, 15 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/kvm/aarch64/arch_timer.c b/tools/testing/selftests/kvm/aarch64/arch_timer.c
index 176ab41dd01b..8ef370924a02 100644
--- a/tools/testing/selftests/kvm/aarch64/arch_timer.c
+++ b/tools/testing/selftests/kvm/aarch64/arch_timer.c
@@ -47,6 +47,7 @@ struct test_args {
 	int nr_iter;
 	int timer_period_ms;
 	int migration_freq_ms;
+	struct kvm_arm_counter_offset offset;
 };
 
 static struct test_args test_args = {
@@ -54,6 +55,7 @@ static struct test_args test_args = {
 	.nr_iter = NR_TEST_ITERS_DEF,
 	.timer_period_ms = TIMER_TEST_PERIOD_MS_DEF,
 	.migration_freq_ms = TIMER_TEST_MIGRATION_FREQ_MS,
+	.offset = { .reserved = 1 },
 };
 
 #define msecs_to_usecs(msec)		((msec) * 1000LL)
@@ -382,6 +384,13 @@ static struct kvm_vm *test_vm_create(void)
 	vm_init_descriptor_tables(vm);
 	vm_install_exception_handler(vm, VECTOR_IRQ_CURRENT, guest_irq_handler);
 
+	if (!test_args.offset.reserved) {
+		if (kvm_has_cap(KVM_CAP_COUNTER_OFFSET))
+			vm_ioctl(vm, KVM_ARM_SET_COUNTER_OFFSET, &test_args.offset);
+		else
+			TEST_FAIL("no support for global offset\n");
+	}
+
 	for (i = 0; i < nr_vcpus; i++)
 		vcpu_init_descriptor_tables(vcpus[i]);
 
@@ -413,6 +422,7 @@ static void test_print_help(char *name)
 		TIMER_TEST_PERIOD_MS_DEF);
 	pr_info("\t-m: Frequency (in ms) of vCPUs to migrate to different pCPU. 0 to turn off (default: %u)\n",
 		TIMER_TEST_MIGRATION_FREQ_MS);
+	pr_info("\t-o: Counter offset (in counter cycles, default: 0)\n");
 	pr_info("\t-h: print this help screen\n");
 }
 
@@ -420,7 +430,7 @@ static bool parse_args(int argc, char *argv[])
 {
 	int opt;
 
-	while ((opt = getopt(argc, argv, "hn:i:p:m:")) != -1) {
+	while ((opt = getopt(argc, argv, "hn:i:p:m:o:")) != -1) {
 		switch (opt) {
 		case 'n':
 			test_args.nr_vcpus = atoi_positive("Number of vCPUs", optarg);
@@ -439,6 +449,10 @@ static bool parse_args(int argc, char *argv[])
 		case 'm':
 			test_args.migration_freq_ms = atoi_non_negative("Frequency", optarg);
 			break;
+		case 'o':
+			test_args.offset.counter_offset = strtol(optarg, NULL, 0);
+			test_args.offset.reserved = 0;
+			break;
 		case 'h':
 		default:
 			goto err;

From a6610435ac17de1ac727c90ad62c723d86c7ea36 Mon Sep 17 00:00:00 2001
From: Marc Zyngier <maz@kernel.org>
Date: Thu, 13 Apr 2023 14:23:42 +0100
Subject: [PATCH 21/21] KVM: arm64: Handle 32bit CNTPCTSS traps

When CNTPOFF isn't implemented and that we have a non-zero counter
offset, CNTPCT and CNTPCTSS are trapped. We properly handle the
former, but not the latter, as it is not present in the sysreg
table (despite being actually handled in the code). Bummer.

Just populate the cp15_64 table with the missing register.

Reported-by: Reiji Watanabe <reijiw@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/include/asm/sysreg.h | 1 +
 arch/arm64/kvm/sys_regs.c       | 1 +
 2 files changed, 2 insertions(+)

diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
index f8da9e1b0c11..a43f21559c3e 100644
--- a/arch/arm64/include/asm/sysreg.h
+++ b/arch/arm64/include/asm/sysreg.h
@@ -403,6 +403,7 @@
 #define SYS_AARCH32_CNTP_CTL		sys_reg(0, 0, 14, 2, 1)
 #define SYS_AARCH32_CNTPCT		sys_reg(0, 0, 0, 14, 0)
 #define SYS_AARCH32_CNTP_CVAL		sys_reg(0, 2, 0, 14, 0)
+#define SYS_AARCH32_CNTPCTSS		sys_reg(0, 8, 0, 14, 0)
 
 #define __PMEV_op2(n)			((n) & 0x7)
 #define __CNTR_CRm(n)			(0x8 | (((n) >> 3) & 0x3))
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index be7c2598e563..feca77083a5c 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -2538,6 +2538,7 @@ static const struct sys_reg_desc cp15_64_regs[] = {
 	{ Op1( 1), CRn( 0), CRm(12), Op2( 0), access_gic_sgi }, /* ICC_ASGI1R */
 	{ Op1( 2), CRn( 0), CRm(12), Op2( 0), access_gic_sgi }, /* ICC_SGI0R */
 	{ SYS_DESC(SYS_AARCH32_CNTP_CVAL),    access_arch_timer },
+	{ SYS_DESC(SYS_AARCH32_CNTPCTSS),     access_arch_timer },
 };
 
 static bool check_sysreg_table(const struct sys_reg_desc *table, unsigned int n,