Commit ec3eb9ed authored by Reiji Watanabe's avatar Reiji Watanabe Committed by Marc Zyngier
Browse files

KVM: arm64: PMU: Disallow vPMU on non-uniform PMUVer 



Disallow userspace from configuring vPMU for guests on systems
where the PMUVer is not uniform across all PEs.
KVM has not been advertising PMUv3 to the guests with vPMU on
such systems anyway, and such systems would be extremely
uncommon and unlikely to even use KVM.

Signed-off-by: default avatarReiji Watanabe <reijiw@google.com>
Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230819043947.4100985-2-reijiw@google.com
parent 6eaae198

arch/arm64/kvm/pmu-emul.c

+6 −2
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
#include <asm/kvm_emulate.h>

#include <kvm/arm_pmu.h>

#include <kvm/arm_vgic.h>

#include <asm/arm_pmuv3.h>



#define PERF_ATTR_CFG1_COUNTER_64BIT	BIT(0)
@@ -672,8 +673,11 @@ void kvm_host_pmu_init(struct arm_pmu *pmu) 
{

	struct arm_pmu_entry *entry;



	if (pmu->pmuver == ID_AA64DFR0_EL1_PMUVer_NI ||

	    pmu->pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF)

	/*

	 * Check the sanitised PMU version for the system, as KVM does not

	 * support implementations where PMUv3 exists on a subset of CPUs.

	 */

	if (!pmuv3_implemented(kvm_arm_pmu_get_pmuver_limit()))

		return;



	mutex_lock(&arm_pmus_lock);