Re: [PATCH v3 13/18] x86/virt: KVM: Open code cpu_has_svm() into kvm_is_svm_supported()

Huang, Kai
2023-05-23T00:41:47Z

On Fri, 2023-05-12 at 16:50 -0700, Sean Christopherson wrote:
> Fold the guts of cpu_has_svm() into kvm_is_svm_supported(), its sole
> remaining user.
>
> No functional change intended.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>

The same to the reply to VMX patch:

Reviewed-by: Kai Huang <kai.huang@intel.com>

> ---
> arch/x86/include/asm/virtext.h | 28 ----------------------------
> arch/x86/kvm/svm/svm.c | 11 ++++++++---
> 2 files changed, 8 insertions(+), 31 deletions(-)
>
> diff --git a/arch/x86/include/asm/virtext.h b/arch/x86/include/asm/virtext.h
> index be50c414efe4..632575e257d8 100644
> --- a/arch/x86/include/asm/virtext.h
> +++ b/arch/x86/include/asm/virtext.h
> @@ -22,35 +22,7 @@
> /*
> * SVM functions:
> */
> -
> -/** Check if the CPU has SVM support
> - *
> - * You can use the 'msg' arg to get a message describing the problem,
> - * if the function returns zero. Simply pass NULL if you are not interested
> - * on the messages; gcc should take care of not generating code for
> - * the messages on this case.
> - */
> -static inline int cpu_has_svm(const char **msg)
> -{
> - if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
> - boot_cpu_data.x86_vendor != X86_VENDOR_HYGON) {
> - if (msg)
> - *msg = "not amd or hygon";
> - return 0;
> - }
> -
> - if (!boot_cpu_has(X86_FEATURE_SVM)) {
> - if (msg)
> - *msg = "svm not available";
> - return 0;
> - }
> - return 1;
> -}
> -
> -
> /** Disable SVM on the current CPU
> - *
> - * You should call this only if cpu_has_svm() returned true.
> */

Nit: "double **" can be removed in the comment.

> static inline void cpu_svm_disable(void)
> {
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index 0f0d04900bf2..b347173b4e29 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -526,11 +526,16 @@ static void svm_init_osvw(struct kvm_vcpu *vcpu)
> static bool kvm_is_svm_supported(void)
> {
> int cpu = raw_smp_processor_id();
> - const char *msg;
> u64 vm_cr;
>
> - if (!cpu_has_svm(&msg)) {
> - pr_err("SVM not supported by CPU %d, %s\n", cpu, msg);
> + if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
> + boot_cpu_data.x86_vendor != X86_VENDOR_HYGON) {
> + pr_err("CPU %d isn't AMD or Hygon\n", cpu);
> + return false;
> + }
> +
> + if (!boot_cpu_has(X86_FEATURE_SVM)) {
> + pr_err("SVM not supported by CPU %d\n", cpu);
> return false;
> }
>
> --
> 2.40.1.606.ga4b1b128d6-goog
>