From: Oliver Upton Date: Wed, 5 Mar 2025 20:26:37 +0000 (-0800) Subject: KVM: arm64: Advertise PMUv3 if IMPDEF traps are present X-Git-Tag: v6.15-rc1~195^2~2^2~3^2~4 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=bed9b8ec8c71135c59004d12658d8affe232f27e;p=thirdparty%2Fkernel%2Flinux.git KVM: arm64: Advertise PMUv3 if IMPDEF traps are present Advertise a baseline PMUv3 implementation when running on hardware with IMPDEF traps of the PMUv3 sysregs. Tested-by: Janne Grunau Reviewed-by: Marc Zyngier Link: https://lore.kernel.org/r/20250305202641.428114-11-oliver.upton@linux.dev Signed-off-by: Oliver Upton --- diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c index 0a2023aabe184..38d9490c17fd9 100644 --- a/arch/arm64/kvm/pmu-emul.c +++ b/arch/arm64/kvm/pmu-emul.c @@ -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;