KVM: arm64: Upgrade PMU support to ARMv8.4

Upgrading the PMU code from ARMv8.1 to ARMv8.4 turns out to be
pretty easy. All that is required is support for PMMIR_EL1, which
is read-only, and for which returning 0 is a valid option as long
as we don't advertise STALL_SLOT as an implemented event.

Let's just do that and adjust what we return to the guest.
Signed-off-by: Marc Zyngier <maz@kernel.org>

arch/arm64/include/asm/sysreg.h

@@ -846,7 +846,10 @@
 
 #define ID_DFR0_PERFMON_SHIFT		24
 
+#define ID_DFR0_PERFMON_8_0		0x3
 #define ID_DFR0_PERFMON_8_1		0x4
+#define ID_DFR0_PERFMON_8_4		0x5
+#define ID_DFR0_PERFMON_8_5		0x6
 
 #define ID_ISAR4_SWP_FRAC_SHIFT		28
 #define ID_ISAR4_PSR_M_SHIFT		24

arch/arm64/kvm/pmu-emul.c

@@ -795,6 +795,12 @@ u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1)
 		base = 0;
 	} else {
 		val = read_sysreg(pmceid1_el0);
+		/*
+		 * Don't advertise STALL_SLOT, as PMMIR_EL0 is handled
+		 * as RAZ
+		 */
+		if (vcpu->kvm->arch.pmuver >= ID_AA64DFR0_PMUVER_8_4)
+			val &= ~BIT_ULL(ARMV8_PMUV3_PERFCTR_STALL_SLOT - 32);
 		base = 32;
 	}
 

arch/arm64/kvm/sys_regs.c

@@ -1051,16 +1051,16 @@ static u64 read_id_reg(const struct kvm_vcpu *vcpu,
 		/* Limit debug to ARMv8.0 */
 		val &= ~FEATURE(ID_AA64DFR0_DEBUGVER);
 		val |= FIELD_PREP(FEATURE(ID_AA64DFR0_DEBUGVER), 6);
-		/* Limit guests to PMUv3 for ARMv8.1 */
+		/* Limit guests to PMUv3 for ARMv8.4 */
 		val = cpuid_feature_cap_perfmon_field(val,
 						      ID_AA64DFR0_PMUVER_SHIFT,
-						      kvm_vcpu_has_pmu(vcpu) ? ID_AA64DFR0_PMUVER_8_1 : 0);
+						      kvm_vcpu_has_pmu(vcpu) ? ID_AA64DFR0_PMUVER_8_4 : 0);
 		break;
 	case SYS_ID_DFR0_EL1:
-		/* Limit guests to PMUv3 for ARMv8.1 */
+		/* Limit guests to PMUv3 for ARMv8.4 */
 		val = cpuid_feature_cap_perfmon_field(val,
 						      ID_DFR0_PERFMON_SHIFT,
-						      kvm_vcpu_has_pmu(vcpu) ? ID_DFR0_PERFMON_8_1 : 0);
+						      kvm_vcpu_has_pmu(vcpu) ? ID_DFR0_PERFMON_8_4 : 0);
 		break;
 	}
 
@@ -1496,6 +1496,7 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 
 	{ SYS_DESC(SYS_PMINTENSET_EL1), access_pminten, reset_unknown, PMINTENSET_EL1 },
 	{ SYS_DESC(SYS_PMINTENCLR_EL1), access_pminten, reset_unknown, PMINTENSET_EL1 },
+	{ SYS_DESC(SYS_PMMIR_EL1), trap_raz_wi },
 
 	{ SYS_DESC(SYS_MAIR_EL1), access_vm_reg, reset_unknown, MAIR_EL1 },
 	{ SYS_DESC(SYS_AMAIR_EL1), access_vm_reg, reset_amair_el1, AMAIR_EL1 },
@@ -1918,6 +1919,8 @@ static const struct sys_reg_desc cp15_regs[] = {
 	{ Op1( 0), CRn( 9), CRm(14), Op2( 3), access_pmovs },
 	{ AA32(HI), Op1( 0), CRn( 9), CRm(14), Op2( 4), access_pmceid },
 	{ AA32(HI), Op1( 0), CRn( 9), CRm(14), Op2( 5), access_pmceid },
+	/* PMMIR */
+	{ Op1( 0), CRn( 9), CRm(14), Op2( 6), trap_raz_wi },
 
 	/* PRRR/MAIR0 */
 	{ AA32(LO), Op1( 0), CRn(10), CRm( 2), Op2( 0), access_vm_reg, NULL, MAIR_EL1 },