From 4715c14bc136687bb79d12e24aafdc0f38786eb7 Mon Sep 17 00:00:00 2001 From: James Morse Date: Mon, 15 Jan 2018 19:39:01 +0000 Subject: [PATCH] KVM: arm64: Set an impdef ESR for Virtual-SError using VSESR_EL2. Prior to v8.2's RAS Extensions, the HCR_EL2.VSE 'virtual SError' feature generated an SError with an implementation defined ESR_EL1.ISS, because we had no mechanism to specify the ESR value. On Juno this generates an all-zero ESR, the most significant bit 'ISV' is clear indicating the remainder of the ISS field is invalid. With the RAS Extensions we have a mechanism to specify this value, and the most significant bit has a new meaning: 'IDS - Implementation Defined Syndrome'. An all-zero SError ESR now means: 'RAS error: Uncategorized' instead of 'no valid ISS'. Add KVM support for the VSESR_EL2 register to specify an ESR value when HCR_EL2.VSE generates a virtual SError. Change kvm_inject_vabt() to specify an implementation-defined value. We only need to restore the VSESR_EL2 value when HCR_EL2.VSE is set, KVM save/restores this bit during __{,de}activate_traps() and hardware clears the bit once the guest has consumed the virtual-SError. Future patches may add an API (or KVM CAP) to pend a virtual SError with a specified ESR. Cc: Dongjiu Geng Reviewed-by: Marc Zyngier Signed-off-by: James Morse Reviewed-by: Christoffer Dall Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/kvm_emulate.h | 5 +++++ arch/arm64/include/asm/kvm_host.h | 3 +++ arch/arm64/include/asm/sysreg.h | 1 + arch/arm64/kvm/hyp/switch.c | 3 +++ arch/arm64/kvm/inject_fault.c | 13 ++++++++++++- 5 files changed, 24 insertions(+), 1 deletion(-) diff --git a/arch/arm64/include/asm/kvm_emulate.h b/arch/arm64/include/asm/kvm_emulate.h index 5f28dfa14cee..6d3614795197 100644 --- a/arch/arm64/include/asm/kvm_emulate.h +++ b/arch/arm64/include/asm/kvm_emulate.h @@ -64,6 +64,11 @@ static inline void vcpu_set_hcr(struct kvm_vcpu *vcpu, unsigned long hcr) vcpu->arch.hcr_el2 = hcr; } +static inline void vcpu_set_vsesr(struct kvm_vcpu *vcpu, u64 vsesr) +{ + vcpu->arch.vsesr_el2 = vsesr; +} + static inline unsigned long *vcpu_pc(const struct kvm_vcpu *vcpu) { return (unsigned long *)&vcpu_gp_regs(vcpu)->regs.pc; diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h index dcdd08edf5a5..3014b39b8fe2 100644 --- a/arch/arm64/include/asm/kvm_host.h +++ b/arch/arm64/include/asm/kvm_host.h @@ -280,6 +280,9 @@ struct kvm_vcpu_arch { /* Detect first run of a vcpu */ bool has_run_once; + + /* Virtual SError ESR to restore when HCR_EL2.VSE is set */ + u64 vsesr_el2; }; #define vcpu_gp_regs(v) (&(v)->arch.ctxt.gp_regs) diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h index b5d543fc677d..52cfdc216bcf 100644 --- a/arch/arm64/include/asm/sysreg.h +++ b/arch/arm64/include/asm/sysreg.h @@ -355,6 +355,7 @@ #define SYS_DACR32_EL2 sys_reg(3, 4, 3, 0, 0) #define SYS_IFSR32_EL2 sys_reg(3, 4, 5, 0, 1) +#define SYS_VSESR_EL2 sys_reg(3, 4, 5, 2, 3) #define SYS_FPEXC32_EL2 sys_reg(3, 4, 5, 3, 0) #define __SYS__AP0Rx_EL2(x) sys_reg(3, 4, 12, 8, x) diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c index 324f4202cdd5..b425b8aab45b 100644 --- a/arch/arm64/kvm/hyp/switch.c +++ b/arch/arm64/kvm/hyp/switch.c @@ -94,6 +94,9 @@ static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu) write_sysreg(val, hcr_el2); + if (cpus_have_const_cap(ARM64_HAS_RAS_EXTN) && (val & HCR_VSE)) + write_sysreg_s(vcpu->arch.vsesr_el2, SYS_VSESR_EL2); + /* Trap on AArch32 cp15 c15 accesses (EL1 or EL0) */ write_sysreg(1 << 15, hstr_el2); /* diff --git a/arch/arm64/kvm/inject_fault.c b/arch/arm64/kvm/inject_fault.c index 8ecbcb40e317..60666a056944 100644 --- a/arch/arm64/kvm/inject_fault.c +++ b/arch/arm64/kvm/inject_fault.c @@ -164,14 +164,25 @@ void kvm_inject_undefined(struct kvm_vcpu *vcpu) inject_undef64(vcpu); } +static void pend_guest_serror(struct kvm_vcpu *vcpu, u64 esr) +{ + vcpu_set_vsesr(vcpu, esr); + vcpu_set_hcr(vcpu, vcpu_get_hcr(vcpu) | HCR_VSE); +} + /** * kvm_inject_vabt - inject an async abort / SError into the guest * @vcpu: The VCPU to receive the exception * * It is assumed that this code is called from the VCPU thread and that the * VCPU therefore is not currently executing guest code. + * + * Systems with the RAS Extensions specify an imp-def ESR (ISV/IDS = 1) with + * the remaining ISS all-zeros so that this error is not interpreted as an + * uncategorized RAS error. Without the RAS Extensions we can't specify an ESR + * value, so the CPU generates an imp-def value. */ void kvm_inject_vabt(struct kvm_vcpu *vcpu) { - vcpu_set_hcr(vcpu, vcpu_get_hcr(vcpu) | HCR_VSE); + pend_guest_serror(vcpu, ESR_ELx_ISV); }