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| author | Oliver Upton <oliver.upton@linux.dev> | 2023-10-19 21:56:17 +0300 |
|---|---|---|
| committer | Oliver Upton <oliver.upton@linux.dev> | 2023-10-24 22:26:14 +0300 |
| commit | bc512d6a9b92390760f0e8c895501c5016539929 (patch) | |
| tree | 391dfc6d58dadb5af0a773f1eef9505e81ba2ba5 /arch/arm64/kvm/sys_regs.c | |
| parent | 6465e260f48790807eef06b583b38ca9789b6072 (diff) | |
| download | linux-bc512d6a9b92390760f0e8c895501c5016539929.tar.xz | |
KVM: arm64: Make PMEVTYPER<n>_EL0.NSH RES0 if EL2 isn't advertised
The NSH bit, which filters event counting at EL2, is required by the
architecture if an implementation has EL2. Even though KVM doesn't
support nested virt yet, it makes no effort to hide the existence of EL2
from the ID registers. Userspace can, however, change the value of PFR0
to hide EL2. Align KVM's sysreg emulation with the architecture and make
NSH RES0 if EL2 isn't advertised. Keep in mind the bit is ignored when
constructing the backing perf event.
While at it, build the event type mask using explicit field definitions
instead of relying on ARMV8_PMU_EVTYPE_MASK. KVM probably should've been
doing this in the first place, as it avoids changes to the
aforementioned mask affecting sysreg emulation.
Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20231019185618.3442949-2-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Diffstat (limited to 'arch/arm64/kvm/sys_regs.c')
| -rw-r--r-- | arch/arm64/kvm/sys_regs.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index e92ec810d449..78720c373904 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -746,8 +746,12 @@ static u64 reset_pmevcntr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) static u64 reset_pmevtyper(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r) { + /* This thing will UNDEF, who cares about the reset value? */ + if (!kvm_vcpu_has_pmu(vcpu)) + return 0; + reset_unknown(vcpu, r); - __vcpu_sys_reg(vcpu, r->reg) &= ARMV8_PMU_EVTYPE_MASK; + __vcpu_sys_reg(vcpu, r->reg) &= kvm_pmu_evtyper_mask(vcpu->kvm); return __vcpu_sys_reg(vcpu, r->reg); } @@ -988,7 +992,7 @@ static bool access_pmu_evtyper(struct kvm_vcpu *vcpu, struct sys_reg_params *p, kvm_pmu_set_counter_event_type(vcpu, p->regval, idx); kvm_vcpu_pmu_restore_guest(vcpu); } else { - p->regval = __vcpu_sys_reg(vcpu, reg) & ARMV8_PMU_EVTYPE_MASK; + p->regval = __vcpu_sys_reg(vcpu, reg); } return true; |