On Thu, 2023-12-21 at 09:02 -0500, Yang Weijiang wrote:
> From: Sean Christopherson <seanjc@xxxxxxxxxx>
>
> Rework and rename cpuid_get_supported_xcr0() to explicitly operate on
> vCPU state, i.e. on a vCPU's CPUID state, now that the only usage of
> the helper is to retrieve a vCPU's already-set CPUID.
>
> Prior to commit 275a87244ec8 ("KVM: x86: Don't adjust guest's CPUID.0x12.1
> (allowed SGX enclave XFRM)"), KVM incorrectly fudged guest CPUID at runtime,
> which in turn necessitated massaging the incoming CPUID state for
> KVM_SET_CPUID{2} so as not to run afoul of kvm_cpuid_check_equal().
> I.e. KVM also invoked cpuid_get_supported_xcr0() with the incoming CPUID
> state, and thus without an explicit vCPU object.
>
> Opportunistically move the helper below kvm_update_cpuid_runtime() to make
> it harder to repeat the mistake of querying supported XCR0 for runtime
> updates.
>
> No functional change intended.
>
> Signed-off-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> Signed-off-by: Yang Weijiang <weijiang.yang@xxxxxxxxx>
> ---
> arch/x86/kvm/cpuid.c | 33 ++++++++++++++++-----------------
> 1 file changed, 16 insertions(+), 17 deletions(-)
>
> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
> index 294e5bd5f8a0..624954203b40 100644
> --- a/arch/x86/kvm/cpuid.c
> +++ b/arch/x86/kvm/cpuid.c
> @@ -247,21 +247,6 @@ void kvm_update_pv_runtime(struct kvm_vcpu *vcpu)
> vcpu->arch.pv_cpuid.features = best->eax;
> }
>
> -/*
> - * Calculate guest's supported XCR0 taking into account guest CPUID data and
> - * KVM's supported XCR0 (comprised of host's XCR0 and KVM_SUPPORTED_XCR0).
> - */
> -static u64 cpuid_get_supported_xcr0(struct kvm_cpuid_entry2 *entries, int nent)
> -{
> - struct kvm_cpuid_entry2 *best;
> -
> - best = cpuid_entry2_find(entries, nent, 0xd, 0);
> - if (!best)
> - return 0;
> -
> - return (best->eax | ((u64)best->edx << 32)) & kvm_caps.supported_xcr0;
> -}
> -
> static void __kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu, struct kvm_cpuid_entry2 *entries,
> int nent)
> {
> @@ -312,6 +297,21 @@ void kvm_update_cpuid_runtime(struct kvm_vcpu *vcpu)
> }
> EXPORT_SYMBOL_GPL(kvm_update_cpuid_runtime);
>
> +/*
> + * Calculate guest's supported XCR0 taking into account guest CPUID data and
> + * KVM's supported XCR0 (comprised of host's XCR0 and KVM_SUPPORTED_XCR0).
> + */
> +static u64 vcpu_get_supported_xcr0(struct kvm_vcpu *vcpu)
> +{
> + struct kvm_cpuid_entry2 *best;
> +
> + best = kvm_find_cpuid_entry_index(vcpu, 0xd, 0);
> + if (!best)
> + return 0;
> +
> + return (best->eax | ((u64)best->edx << 32)) & kvm_caps.supported_xcr0;
> +}
> +
> static bool kvm_cpuid_has_hyperv(struct kvm_cpuid_entry2 *entries, int nent)
> {
> #ifdef CONFIG_KVM_HYPERV
> @@ -361,8 +361,7 @@ static void kvm_vcpu_after_set_cpuid(struct kvm_vcpu *vcpu)
> kvm_apic_set_version(vcpu);
> }
>
> - vcpu->arch.guest_supported_xcr0 =
> - cpuid_get_supported_xcr0(vcpu->arch.cpuid_entries, vcpu->arch.cpuid_nent);
> + vcpu->arch.guest_supported_xcr0 = vcpu_get_supported_xcr0(vcpu);
>
> kvm_update_pv_runtime(vcpu);
>
Looks like I forgot to add my reviewed-by:
Reviewed-by: Maxim Levitsky <mlevitsk@xxxxxxxxxx>
Best regards,
Maxim Levitsky
