Re: [PATCH 1/2] KVM: nSVM: move nested_vmcb_check_cr3_cr4 logic in nested_vmcb_valid_sregs

Maxim Levitsky
2021-08-11T20:38:08Z

On Mon, 2021-08-09 at 16:53 +0200, Emanuele Giuseppe Esposito wrote:
> nested_vmcb_check_cr3_cr4 is not called by anyone else, and removing the
> call simplifies next patch

Tiny nitpick: I would call this 'inline the nested_vmcb_check_cr3_cr4' instead of
move, but please feel free to ignore.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>

>
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
> ---
> arch/x86/kvm/svm/nested.c | 35 +++++++++++++----------------------
> 1 file changed, 13 insertions(+), 22 deletions(-)
>
> diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
> index 5e13357da21e..0ac2d14add15 100644
> --- a/arch/x86/kvm/svm/nested.c
> +++ b/arch/x86/kvm/svm/nested.c
> @@ -257,27 +257,6 @@ static bool nested_vmcb_check_controls(struct kvm_vcpu *vcpu,
> return true;
> }
>
> -static bool nested_vmcb_check_cr3_cr4(struct kvm_vcpu *vcpu,
> - struct vmcb_save_area *save)
> -{
> - /*
> - * These checks are also performed by KVM_SET_SREGS,
> - * except that EFER.LMA is not checked by SVM against
> - * CR0.PG && EFER.LME.
> - */
> - if ((save->efer & EFER_LME) && (save->cr0 & X86_CR0_PG)) {
> - if (CC(!(save->cr4 & X86_CR4_PAE)) ||
> - CC(!(save->cr0 & X86_CR0_PE)) ||
> - CC(kvm_vcpu_is_illegal_gpa(vcpu, save->cr3)))
> - return false;
> - }
> -
> - if (CC(!kvm_is_valid_cr4(vcpu, save->cr4)))
> - return false;
> -
> - return true;
> -}
> -
> /* Common checks that apply to both L1 and L2 state. */
> static bool nested_vmcb_valid_sregs(struct kvm_vcpu *vcpu,
> struct vmcb_save_area *save)
> @@ -299,7 +278,19 @@ static bool nested_vmcb_valid_sregs(struct kvm_vcpu *vcpu,
> if (CC(!kvm_dr6_valid(save->dr6)) || CC(!kvm_dr7_valid(save->dr7)))
> return false;
>
> - if (!nested_vmcb_check_cr3_cr4(vcpu, save))
> + /*
> + * These checks are also performed by KVM_SET_SREGS,
> + * except that EFER.LMA is not checked by SVM against
> + * CR0.PG && EFER.LME.
> + */
> + if ((save->efer & EFER_LME) && (save->cr0 & X86_CR0_PG)) {
> + if (CC(!(save->cr4 & X86_CR4_PAE)) ||
> + CC(!(save->cr0 & X86_CR0_PE)) ||
> + CC(kvm_vcpu_is_illegal_gpa(vcpu, save->cr3)))
> + return false;
> + }
> +
> + if (CC(!kvm_is_valid_cr4(vcpu, save->cr4)))
> return false;
>
> if (CC(!kvm_valid_efer(vcpu, save->efer)))