[0/2] KVM: arm64: Prevent spurious PMU accesses when no

Message

Marc Zyngier Jan. 26, 2021, 3:15 p.m. UTC

Yet another PMU bug that is only likely to hit under Nested Virt: we
unconditionally access PMU registers without checking whether it
actually is present.

Given that we already have a predicate for this, promote it to a
static key, and use that in the world switch.

Thanks to Andre for the heads up!

Marc Zyngier (2):
  KVM: arm64: Turn kvm_arm_support_pmu_v3() into a static key
  KVM: arm64: Don't access PMSELR_EL0/PMUSERENR_EL0 when no PMU is
    available

 arch/arm64/kernel/image-vars.h          |  3 +++
 arch/arm64/kvm/hyp/include/hyp/switch.h |  9 ++++++---
 arch/arm64/kvm/perf.c                   | 10 ++++++++++
 arch/arm64/kvm/pmu-emul.c               | 10 ----------
 include/kvm/arm_pmu.h                   |  9 +++++++--
 5 files changed, 26 insertions(+), 15 deletions(-)