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KVM: arm64: Advertise PMUv3 if IMPDEF traps are present

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Advertise a baseline PMUv3 implementation when running on hardware with
IMPDEF traps of the PMUv3 sysregs.

Tested-by: Janne Grunau <j@jannau.net>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250305202641.428114-11-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Oliver Upton 2025-03-05 12:26:37 -08:00
parent 2c433f70dc
commit bed9b8ec8c
1 changed files with 11 additions and 1 deletions
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12
arch/arm64/kvm/pmu-emul.c
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@ -1231,7 +1231,17 @@ u8 kvm_arm_pmu_get_pmuver_limit(void)
pmuver = SYS_FIELD_GET(ID_AA64DFR0_EL1, PMUVer,
read_sanitised_ftr_reg(SYS_ID_AA64DFR0_EL1));
/* Treat IMPLEMENTATION DEFINED functionality as unimplemented */
/*
* Spoof a barebones PMUv3 implementation if the system supports IMPDEF
* traps of the PMUv3 sysregs
*/
if (cpus_have_final_cap(ARM64_WORKAROUND_PMUV3_IMPDEF_TRAPS))
return ID_AA64DFR0_EL1_PMUVer_IMP;
/*
* Otherwise, treat IMPLEMENTATION DEFINED functionality as
* unimplemented
*/
if (pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF)
return 0;