KVM/arm64 fixes for 5.12, take #3

- Fix GICv3 MMIO compatibility probing
 - Prevent guests from using the ARMv8.4 self-hosted tracing extension
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Merge tag 'kvmarm-fixes-5.12-3' of git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 5.12, take #3

- Fix GICv3 MMIO compatibility probing
- Prevent guests from using the ARMv8.4 self-hosted tracing extension

arch/arm64/include/asm/kvm_arm.h

@@ -278,6 +278,7 @@
 #define CPTR_EL2_DEFAULT	CPTR_EL2_RES1
 
 /* Hyp Debug Configuration Register bits */
+#define MDCR_EL2_TTRF		(1 << 19)
 #define MDCR_EL2_TPMS		(1 << 14)
 #define MDCR_EL2_E2PB_MASK	(UL(0x3))
 #define MDCR_EL2_E2PB_SHIFT	(UL(12))

arch/arm64/kernel/cpufeature.c

@@ -383,7 +383,6 @@ static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = {
 	 * of support.
 	 */
 	S_ARM64_FTR_BITS(FTR_HIDDEN, FTR_NONSTRICT, FTR_EXACT, ID_AA64DFR0_PMUVER_SHIFT, 4, 0),
-	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64DFR0_TRACEVER_SHIFT, 4, 0),
 	ARM64_FTR_BITS(FTR_HIDDEN, FTR_STRICT, FTR_EXACT, ID_AA64DFR0_DEBUGVER_SHIFT, 4, 0x6),
 	ARM64_FTR_END,
 };

arch/arm64/kvm/debug.c

@@ -89,6 +89,7 @@ void kvm_arm_reset_debug_ptr(struct kvm_vcpu *vcpu)
  *  - Debug ROM Address (MDCR_EL2_TDRA)
  *  - OS related registers (MDCR_EL2_TDOSA)
  *  - Statistical profiler (MDCR_EL2_TPMS/MDCR_EL2_E2PB)
+ *  - Self-hosted Trace Filter controls (MDCR_EL2_TTRF)
  *
  * Additionally, KVM only traps guest accesses to the debug registers if
  * the guest is not actively using them (see the KVM_ARM64_DEBUG_DIRTY
@@ -112,6 +113,7 @@ void kvm_arm_setup_debug(struct kvm_vcpu *vcpu)
 	vcpu->arch.mdcr_el2 = __this_cpu_read(mdcr_el2) & MDCR_EL2_HPMN_MASK;
 	vcpu->arch.mdcr_el2 |= (MDCR_EL2_TPM |
 				MDCR_EL2_TPMS |
+				MDCR_EL2_TTRF |
 				MDCR_EL2_TPMCR |
 				MDCR_EL2_TDRA |
 				MDCR_EL2_TDOSA);

arch/arm64/kvm/hyp/vgic-v3-sr.c

@@ -429,6 +429,13 @@ u64 __vgic_v3_get_gic_config(void)
 	if (has_vhe())
 		flags = local_daif_save();
 
+	/*
+	 * Table 11-2 "Permitted ICC_SRE_ELx.SRE settings" indicates
+	 * that to be able to set ICC_SRE_EL1.SRE to 0, all the
+	 * interrupt overrides must be set. You've got to love this.
+	 */
+	sysreg_clear_set(hcr_el2, 0, HCR_AMO | HCR_FMO | HCR_IMO);
+	isb();
 	write_gicreg(0, ICC_SRE_EL1);
 	isb();
 
@@ -436,6 +443,8 @@ u64 __vgic_v3_get_gic_config(void)
 
 	write_gicreg(sre, ICC_SRE_EL1);
 	isb();
+	sysreg_clear_set(hcr_el2, HCR_AMO | HCR_FMO | HCR_IMO, 0);
+	isb();
 
 	if (has_vhe())
 		local_daif_restore(flags);