On 25/03/19 20:10, Liran Alon wrote:
> Before this change, reading a VMware pseduo PMC will succeed even when
> PMU is not supported by guest. This can easily be seen by running
> kvm-unit-test vmware_backdoors with "-cpu host,-pmu" option.
>
> Reviewed-by: Mihai Carabas <mihai.carabas@xxxxxxxxxx>
> Signed-off-by: Liran Alon <liran.alon@xxxxxxxxxx>
> ---
> arch/x86/kvm/pmu.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
> index 58ead7db71a3..e39741997893 100644
> --- a/arch/x86/kvm/pmu.c
> +++ b/arch/x86/kvm/pmu.c
> @@ -281,9 +281,13 @@ static int kvm_pmu_rdpmc_vmware(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
> int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
> {
> bool fast_mode = idx & (1u << 31);
> + struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
> struct kvm_pmc *pmc;
> u64 ctr_val;
>
> + if (!pmu->version)
> + return 1;
> +
> if (is_vmware_backdoor_pmc(idx))
> return kvm_pmu_rdpmc_vmware(vcpu, idx, data);
>
>
Queued, thanks. I wonder if we should expose the state of
vmware_backdoors as a capability. It would surely help writing a unit
test for this stuff.
Paolo
