Commit bed9b8ec authored by Oliver Upton's avatar Oliver Upton
Browse files

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: default avatarJanne Grunau <j@jannau.net>
Reviewed-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250305202641.428114-11-oliver.upton@linux.dev


Signed-off-by: default avatarOliver Upton <oliver.upton@linux.dev>
parent 2c433f70

arch/arm64/kvm/pmu-emul.c

+11 −1
Original line number Diff line number Diff line
@@ -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;