On 28/10/2016 11:46, He Chen wrote:
> On Fri, Oct 28, 2016 at 11:31:05AM +0200, Paolo Bonzini wrote:
>>
>>
>> On 28/10/2016 11:12, He Chen wrote:
>>> The spec can be found in Intel Software Developer Manual or in
>>> Instruction Set Extensions Programming Reference.
>>>
>>> Signed-off-by: Luwei Kang <luwei.k...@intel.com>
>>> Signed-off-by: He Chen <he.c...@linux.intel.com>
>>> ---
>>> arch/x86/kvm/cpuid.c | 7 ++++++-
>>> 1 file changed, 6 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
>>> index afa7bbb..328b169 100644
>>> --- a/arch/x86/kvm/cpuid.c
>>> +++ b/arch/x86/kvm/cpuid.c
>>> @@ -376,6 +376,10 @@ static inline int __do_cpuid_ent(struct
>>> kvm_cpuid_entry2 *entry, u32 function,
>>> /* cpuid 7.0.ecx*/
>>> const u32 kvm_cpuid_7_0_ecx_x86_features = F(PKU) | 0 /*OSPKE*/;
>>>
>>> + /* cpuid 7.0.edx*/
>>> + const u32 kvm_cpuid_7_0_edx_x86_features =
>>> + 0x4 /* AVX512-4VNNIW */ | 0x8 /* AVX512-4FMAPS */;
>>
>> Please define the new features in cpufeature.h first.
>>
> These 2 new features defined as scattered features in kernel.
> In cpufeature.h, there are:
> #define X86_FEATURE_AVX512_4VNNIW (7*32+16)
> #define X86_FEATURE_AVX512_4FMAPS (7*32+17)
>
> Please see disscusion here:
> https://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1250183.html
Uff, that sucks. :( I'd agree with hpa's position in that thread.
Please do something like
/* These are scattered features in cpufeature.h. */
#define KVM_CPUID_BIT_AVX512_4VNNIW 2
#define KVM_CPUID_BIT_AVX512_4FMAPS 3
#define KF(x) bit(KVM_CPUID_BIT_##x)
and then
const u32 kvm_cpuid_7_0_edx_x86_features =
KF(AVX512_4VNNIW) | KF(AVX512_4FMAPS)
I'll think of a trick to avoid using F for scattered features...
Thanks,
Paolo
