On Wed, Feb 01, 2023, Mathias Krause wrote:
> Make use of the kvm_read_cr{0,4}_bits() helper functions when we only
> want to know the state of certain bits instead of the whole register.
>
> This not only makes the intend cleaner, it also avoids a VMREAD in case
> the tested bits aren't guest owned.
>
> Signed-off-by: Mathias Krause <minipli@xxxxxxxxxxxxxx>
> ---
> arch/x86/kvm/pmu.c | 4 ++--
> arch/x86/kvm/vmx/vmx.c | 4 ++--
> 2 files changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
> index d939d3b84e6f..d9922277df67 100644
> --- a/arch/x86/kvm/pmu.c
> +++ b/arch/x86/kvm/pmu.c
> @@ -439,9 +439,9 @@ int kvm_pmu_rdpmc(struct kvm_vcpu *vcpu, unsigned idx, u64 *data)
> if (!pmc)
> return 1;
>
> - if (!(kvm_read_cr4(vcpu) & X86_CR4_PCE) &&
> + if (!(kvm_read_cr4_bits(vcpu, X86_CR4_PCE)) &&
Purely as an FYI, I proposed adding helpers to query single CR0/CR4 bits in a
separate thread[*]. No need to do anything on your end, I'll plan on applying
this patch first and will handle whatever conflicts arise.
[*] https://lore.kernel.org/all/ZAuRec2NkC3+4jvD@xxxxxxxxxx
