Hi Marc,
On 9/8/20 9:58 AM, Marc Zyngier wrote:
> As we can now hide events from the guest, let's also adjust its view of
> PCMEID{0,1}_EL1 so that it can figure out why some common events are not
> counting as they should.
Referring to my previous comment should we filter the cycle counter out?
>
> The astute user can still look into the TRM for their CPU and find out
> they've been cheated, though. Nobody's perfect.
>
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> ---
> arch/arm64/kvm/pmu-emul.c | 29 +++++++++++++++++++++++++++++
> arch/arm64/kvm/sys_regs.c | 5 +----
> include/kvm/arm_pmu.h | 5 +++++
> 3 files changed, 35 insertions(+), 4 deletions(-)
>
> diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
> index 67a731bafbc9..0458860bade2 100644
> --- a/arch/arm64/kvm/pmu-emul.c
> +++ b/arch/arm64/kvm/pmu-emul.c
> @@ -765,6 +765,35 @@ static int kvm_pmu_probe_pmuver(void)
> return pmuver;
> }
>
> +u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1)
> +{
> + unsigned long *bmap = vcpu->kvm->arch.pmu_filter;
> + u64 val, mask = 0;
> + int base, i;
> +
> + if (!pmceid1) {
> + val = read_sysreg(pmceid0_el0);
> + base = 0;
> + } else {
> + val = read_sysreg(pmceid1_el0);
> + base = 32;
> + }
> +
> + if (!bmap)
> + return val;
> +
> + for (i = 0; i < 32; i += 8) {
s/32/4?
Thanks
Eric
> + u64 byte;
> +
> + byte = bitmap_get_value8(bmap, base + i);
> + mask |= byte << i;
> + byte = bitmap_get_value8(bmap, 0x4000 + base + i);
> + mask |= byte << (32 + i);
> + }
> +
> + return val & mask;
> +}
> +
> bool kvm_arm_support_pmu_v3(void)
> {
> /*
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index 077293b5115f..20ab2a7d37ca 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -769,10 +769,7 @@ static bool access_pmceid(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> if (pmu_access_el0_disabled(vcpu))
> return false;
>
> - if (!(p->Op2 & 1))
> - pmceid = read_sysreg(pmceid0_el0);
> - else
> - pmceid = read_sysreg(pmceid1_el0);
> + pmceid = kvm_pmu_get_pmceid(vcpu, (p->Op2 & 1));
>
> p->regval = pmceid;
>
> diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
> index 6db030439e29..98cbfe885a53 100644
> --- a/include/kvm/arm_pmu.h
> +++ b/include/kvm/arm_pmu.h
> @@ -34,6 +34,7 @@ struct kvm_pmu {
> u64 kvm_pmu_get_counter_value(struct kvm_vcpu *vcpu, u64 select_idx);
> void kvm_pmu_set_counter_value(struct kvm_vcpu *vcpu, u64 select_idx, u64 val);
> u64 kvm_pmu_valid_counter_mask(struct kvm_vcpu *vcpu);
> +u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1);
> void kvm_pmu_vcpu_init(struct kvm_vcpu *vcpu);
> void kvm_pmu_vcpu_reset(struct kvm_vcpu *vcpu);
> void kvm_pmu_vcpu_destroy(struct kvm_vcpu *vcpu);
> @@ -108,6 +109,10 @@ static inline int kvm_arm_pmu_v3_enable(struct kvm_vcpu *vcpu)
> {
> return 0;
> }
> +static inline u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1)
> +{
> + return 0;
> +}
> #endif
>
> #endif
>
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