Re: [PATCH v3 8/8] nSVM: remove unnecessary parameter in nested_vmcb_check_controls

Maxim Levitsky
2021-10-22T14:51:53Z

On Mon, 2021-10-11 at 10:37 -0400, Emanuele Giuseppe Esposito wrote:
> Just as in nested_vmcb_valid_sregs, we only need the vcpu param
> to perform the checks on vmcb nested state, since we always
> look at the cached fields.
>
> Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
> ---
> arch/x86/kvm/svm/nested.c | 10 ++++++----
> 1 file changed, 6 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/kvm/svm/nested.c b/arch/x86/kvm/svm/nested.c
> index 13be1002ad1c..19bce3819cce 100644
> --- a/arch/x86/kvm/svm/nested.c
> +++ b/arch/x86/kvm/svm/nested.c
> @@ -209,9 +209,11 @@ static bool nested_svm_check_bitmap_pa(struct kvm_vcpu *vcpu, u64 pa, u32 size)
> kvm_vcpu_is_legal_gpa(vcpu, addr + size - 1);
> }
>
> -static bool nested_vmcb_check_controls(struct kvm_vcpu *vcpu,
> - struct vmcb_ctrl_area_cached *control)
> +static bool nested_vmcb_check_controls(struct kvm_vcpu *vcpu)
> {
> + struct vcpu_svm *svm = to_svm(vcpu);
> + struct vmcb_ctrl_area_cached *control = &svm->nested.ctl;
> +
> if (CC(!vmcb12_is_intercept(control, INTERCEPT_VMRUN)))
> return false;
>
> @@ -651,7 +653,7 @@ int nested_svm_vmrun(struct kvm_vcpu *vcpu)
> nested_copy_vmcb_save_to_cache(svm, &vmcb12->save);
>
> if (!nested_vmcb_valid_sregs(vcpu) ||
> - !nested_vmcb_check_controls(vcpu, &svm->nested.ctl)) {
> + !nested_vmcb_check_controls(vcpu)) {
> vmcb12->control.exit_code = SVM_EXIT_ERR;
> vmcb12->control.exit_code_hi = 0;
> vmcb12->control.exit_info_1 = 0;
> @@ -1367,7 +1369,7 @@ static int svm_set_nested_state(struct kvm_vcpu *vcpu,
>
> ret = -EINVAL;
> nested_copy_vmcb_control_to_cache(svm, ctl);
> - if (!nested_vmcb_check_controls(vcpu, &svm->nested.ctl))
> + if (!nested_vmcb_check_controls(vcpu))
> goto out_free_ctl;
>
> /*

Because of the issue I pointed out in patch 7, you probably want:

static bool __nested_vmcb_check_controls(struct kvm_vcpu *vcpu,
struct vmcb_ctrl_area_cached *control)
{
....
}

static bool nested_vmcb_check_controls(struct kvm_vcpu *vcpu)
{
return __nested_vmcb_check_controls(vcpu, &svm->nested.ctl);
}

Same for nested_vmcb_valid_sregs
(maybe you even want to rename it to nested_vmcb_check_save while at it?):

static bool __nested_vmcb_check_save(struct kvm_vcpu *vcpu, struct vmcb_save_area_cached *save)
{
...
}

static bool nested_vmcb_check_save(struct kvm_vcpu *vcpu)
{
return __nested_vmcb_check_save(vcpu, &svm->nested.save);

}

Best regards,
Maxim Levitsky