diff mbox series

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

Message ID 20230319084927.29607-8-binbin.wu@linux.intel.com (mailing list archive)
State New, archived
Headers show
Series Linear Address Masking (LAM) KVM Enabling | expand

Commit Message

Binbin Wu March 19, 2023, 8:49 a.m. UTC 
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
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>
---
 arch/x86/kvm/cpuid.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Chao Gao March 20, 2023, 8:57 a.m. UTC | #1 
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
>
Binbin Wu March 20, 2023, noon UTC | #2 
On 3/20/2023 4:57 PM, Chao Gao wrote:
> 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.


OK. Will update it and thanks for review-by

>
>> 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
>>
diff mbox series

Patch

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,