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FROMGIT: KVM: arm64: Don't access PMSELR_EL0/PMUSERENR_EL0 when no PMU is available

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When running under a nesting hypervisor, it isn't guaranteed that
the virtual HW will include a PMU. In which case, let's not try
to access the PMU registers in the world switch, as that'd be
deadly.

Reported-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Link: https://lore.kernel.org/r/20210209114844.3278746-3-maz@kernel.org
(cherry picked from commit 913e36d3f29d776385ae6a15506522da9b161dcd
 git://git.kernel.org/pub/scm/linux/kernel/git/kvmarm/kvmarm.git fixes)
Signed-off-by: Will Deacon <willdeacon@google.com>
Bug: 178098380
Test: atest VirtualizationHostTestCases on an EL2-enabled device
Change-Id: I123f0d3fe543899723ceb909b7b0acd342ddfdcd
This commit is contained in:
Marc Zyngier 2021-02-09 11:48:44 +00:00 committed by Quentin Perret
parent 13dbdc0759
commit 41760bc380
2 changed files with 9 additions and 3 deletions
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3
arch/arm64/kernel/image-vars.h
View File

@ -101,6 +101,9 @@ KVM_NVHE_ALIAS(__stop___kvm_ex_table);
/* Array containing bases of nVHE per-CPU memory regions. */
KVM_NVHE_ALIAS(kvm_arm_hyp_percpu_base);
/* PMU available static key */
KVM_NVHE_ALIAS(kvm_arm_pmu_available);
#endif /* CONFIG_KVM */
#endif /* __ARM64_KERNEL_IMAGE_VARS_H */

9
arch/arm64/kvm/hyp/include/hyp/switch.h
View File

@ -90,15 +90,18 @@ static inline void __activate_traps_common(struct kvm_vcpu *vcpu)
* counter, which could make a PMXEVCNTR_EL0 access UNDEF at
* EL1 instead of being trapped to EL2.
*/
write_sysreg(0, pmselr_el0);
write_sysreg(ARMV8_PMU_USERENR_MASK, pmuserenr_el0);
if (kvm_arm_support_pmu_v3()) {
write_sysreg(0, pmselr_el0);
write_sysreg(ARMV8_PMU_USERENR_MASK, pmuserenr_el0);
}
write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2);
}
static inline void __deactivate_traps_common(void)
{
write_sysreg(0, hstr_el2);
write_sysreg(0, pmuserenr_el0);
if (kvm_arm_support_pmu_v3())
write_sysreg(0, pmuserenr_el0);
}
static inline void ___activate_traps(struct kvm_vcpu *vcpu)