Re: [PATCH v6 7/7] KVM: x86: Expose LAM feature to userspace VMM

[Chao Gao <chao.gao@intel.com>]

On Sun, Mar 19, 2023 at 04:49:27PM +0800, Binbin Wu wrote:
>From: Robert Hoo <robert.hu@linux.intel.com>
>
>LAM feature is enumerated by CPUID.7.1:EAX.LAM[bit 26].
>Expose the feature to guest as the final step after the following

Nit: s/guest/userspace/. Because it is QEMU that decides whther or not
to expose a feature to guests.

>supports:
>- CR4.LAM_SUP virtualization
>- CR3.LAM_U48 and CR3.LAM_U57 virtualization
>- Check and untag 64-bit linear address when LAM applies in instruction
>  emulations and vmexit handlers.
>
>Signed-off-by: Robert Hoo <robert.hu@linux.intel.com>
>Signed-off-by: Binbin Wu <binbin.wu@linux.intel.com>
>Reviewed-by: Jingqi Liu <jingqi.liu@intel.com>

Reviewed-by: Chao Gao <chao.gao@intel.com>

>---
> arch/x86/kvm/cpuid.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
>diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
>index 8f8edeaf8177..13840ef897c7 100644
>--- a/arch/x86/kvm/cpuid.c
>+++ b/arch/x86/kvm/cpuid.c
>@@ -670,7 +670,7 @@ void kvm_set_cpu_caps(void)
> 	kvm_cpu_cap_mask(CPUID_7_1_EAX,
> 		F(AVX_VNNI) | F(AVX512_BF16) | F(CMPCCXADD) |
> 		F(FZRM) | F(FSRS) | F(FSRC) |
>-		F(AMX_FP16) | F(AVX_IFMA)
>+		F(AMX_FP16) | F(AVX_IFMA) | F(LAM)
> 	);
> 
> 	kvm_cpu_cap_init_kvm_defined(CPUID_7_1_EDX,
>-- 
>2.25.1
>