Commit 56290316 authored by Oliver Upton's avatar Oliver Upton
Browse files

KVM: arm64: Move PMUVer filtering into KVM code 



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

Tested-by: default avatarJanne Grunau <j@jannau.net>
Reviewed-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250305202641.428114-9-oliver.upton@linux.dev


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parent 3d6d9172

arch/arm64/include/asm/cpufeature.h

+0 −23
Original line number Diff line number Diff line
@@ -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);

arch/arm64/kvm/pmu-emul.c

+9 −6
Original line number Diff line number Diff line
@@ -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);

}



/**