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    Subject[Patch v6.1] x86/kvm: Add AVX512_4VNNIW and AVX512_4FMAPS support
    From 2daa60b3c6ab5aa6414ebb33119a34403dad2048 Mon Sep 17 00:00:00 2001
    From: Luwei Kang <luwei.kang@intel.com>
    Date: Mon, 7 Nov 2016 14:03:20 +0800
    Subject: [Patch v6.1] x86/kvm: Add AVX512_4VNNIW and AVX512_4FMAPS support

    Add two new AVX512 subfeatures support for KVM guest.

    AVX512_4VNNIW:
    Vector instructions for deep learning enhanced word variable precision.

    AVX512_4FMAPS:
    Vector instructions for deep learning floating-point single precision.

    Reviewed-by: Borislav Petkov <bp@suse.de>
    Signed-off-by: He Chen <he.chen@linux.intel.com>
    Signed-off-by: Luwei Kang <luwei.kang@intel.com>
    ---
    arch/x86/kvm/cpuid.c | 14 +++++++++++++-
    1 file changed, 13 insertions(+), 1 deletion(-)

    diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
    index afa7bbb..ddcdf7c 100644
    --- a/arch/x86/kvm/cpuid.c
    +++ b/arch/x86/kvm/cpuid.c
    @@ -16,6 +16,7 @@
    #include <linux/export.h>
    #include <linux/vmalloc.h>
    #include <linux/uaccess.h>
    +#include <asm/processor.h>
    #include <asm/fpu/internal.h> /* For use_eager_fpu. Ugh! */
    #include <asm/user.h>
    #include <asm/fpu/xstate.h>
    @@ -65,6 +66,11 @@ u64 kvm_supported_xcr0(void)

    #define F(x) bit(X86_FEATURE_##x)

    +/* These are scattered features in cpufeatures.h. */
    +#define KVM_CPUID_BIT_AVX512_4VNNIW 2
    +#define KVM_CPUID_BIT_AVX512_4FMAPS 3
    +#define KF(x) bit(KVM_CPUID_BIT_##x)
    +
    int kvm_update_cpuid(struct kvm_vcpu *vcpu)
    {
    struct kvm_cpuid_entry2 *best;
    @@ -376,6 +382,10 @@ 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 =
    + KF(AVX512_4VNNIW) | KF(AVX512_4FMAPS);
    +
    /* all calls to cpuid_count() should be made on the same cpu */
    get_cpu();

    @@ -458,12 +468,14 @@ static inline int __do_cpuid_ent(struct kvm_cpuid_entry2 *entry, u32 function,
    /* PKU is not yet implemented for shadow paging. */
    if (!tdp_enabled)
    entry->ecx &= ~F(PKU);
    + entry->edx &= kvm_cpuid_7_0_edx_x86_features;
    + entry->edx &= get_scattered_cpuid_leaf(7, 0, CPUID_EDX);
    } else {
    entry->ebx = 0;
    entry->ecx = 0;
    + entry->edx = 0;
    }
    entry->eax = 0;
    - entry->edx = 0;
    break;
    }
    case 9:
    --
    2.7.4
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