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KVM: arm64: Move PMUVer filtering into KVM code

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The supported guest PMU version on a particular platform is ultimately a
KVM decision. Move PMUVer filtering into KVM code.

Tested-by: Janne Grunau <j@jannau.net>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250305202641.428114-9-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Oliver Upton 2025-03-05 12:26:35 -08:00
parent 3d6d917212
commit 56290316a4
2 changed files with 9 additions and 29 deletions
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23
arch/arm64/include/asm/cpufeature.h
View File

@ -525,29 +525,6 @@ cpuid_feature_extract_unsigned_field(u64 features, int field)
return cpuid_feature_extract_unsigned_field_width(features, field, 4);
}
/*
* Fields that identify the version of the Performance Monitors Extension do
* not follow the standard ID scheme. See ARM DDI 0487E.a page D13-2825,
* "Alternative ID scheme used for the Performance Monitors Extension version".
*/
static inline u64 __attribute_const__
cpuid_feature_cap_perfmon_field(u64 features, int field, u64 cap)
{
u64 val = cpuid_feature_extract_unsigned_field(features, field);
u64 mask = GENMASK_ULL(field + 3, field);
/* Treat IMPLEMENTATION DEFINED functionality as unimplemented */
if (val == ID_AA64DFR0_EL1_PMUVer_IMP_DEF)
val = 0;
if (val > cap) {
features &= ~mask;
features |= (cap << field) & mask;
}
return features;
}
static inline u64 arm64_ftr_mask(const struct arm64_ftr_bits *ftrp)
{
return (u64)GENMASK(ftrp->shift + ftrp->width - 1, ftrp->shift);

15
arch/arm64/kvm/pmu-emul.c
View File

@ -1226,13 +1226,16 @@ int kvm_arm_pmu_v3_has_attr(struct kvm_vcpu *vcpu, struct kvm_device_attr *attr)
u8 kvm_arm_pmu_get_pmuver_limit(void)
{
u64 tmp;
unsigned int pmuver;
tmp = read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1);
tmp = cpuid_feature_cap_perfmon_field(tmp,
ID_AA64DFR0_EL1_PMUVer_SHIFT,
ID_AA64DFR0_EL1_PMUVer_V3P5);
return FIELD_GET(ARM64_FEATURE_MASK(ID_AA64DFR0_EL1_PMUVer), tmp);
pmuver = SYS_FIELD_GET(ID_AA64DFR0_EL1, PMUVer,
read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1));
/* Treat IMPLEMENTATION DEFINED functionality as unimplemented */
if (pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF)
return 0;
return min(pmuver, ID_AA64DFR0_EL1_PMUVer_V3P5);
}
/**