[kvm-unit-tests PATCH 05/16] x86: Implement get_supported_xcr0() using X86_PROPERTY_SUPPORTED_XCR0_{LO,HI}

[Mi, Dapeng]

On 5/30/2025 6:19 AM, Sean Christopherson wrote:
> Use X86_PROPERTY_SUPPORTED_XCR0_{LO,HI} to implement get_supported_xcr0().
>
> Opportunistically rename the helper and move it to processor.h.
>
> Signed-off-by: Sean Christopherson <seanjc at google.com>
> ---
>  lib/x86/processor.h |  9 +++++++++
>  x86/xsave.c         | 11 +----------
>  2 files changed, 10 insertions(+), 10 deletions(-)
>
> diff --git a/lib/x86/processor.h b/lib/x86/processor.h
> index 8c6f28a3..cbfd2ee1 100644
> --- a/lib/x86/processor.h
> +++ b/lib/x86/processor.h
> @@ -442,6 +442,15 @@ static inline u8 cpuid_maxphyaddr(void)
>  	return this_cpu_property(X86_PROPERTY_MAX_PHY_ADDR);
>  }
>  
> +static inline u64 this_cpu_supported_xcr0(void)
> +{
> +	if (!this_cpu_has_p(X86_PROPERTY_SUPPORTED_XCR0_LO))
> +		return 0;
> +
> +	return (u64)this_cpu_property(X86_PROPERTY_SUPPORTED_XCR0_LO) |
> +	       ((u64)this_cpu_property(X86_PROPERTY_SUPPORTED_XCR0_HI) << 32);
> +}
> +
>  struct far_pointer32 {
>  	u32 offset;
>  	u16 selector;
> diff --git a/x86/xsave.c b/x86/xsave.c
> index 5d80f245..cc8e3a0a 100644
> --- a/x86/xsave.c
> +++ b/x86/xsave.c
> @@ -8,15 +8,6 @@
>  #define uint64_t unsigned long long
>  #endif
>  
> -static uint64_t get_supported_xcr0(void)
> -{
> -    struct cpuid r;
> -    r = cpuid_indexed(0xd, 0);
> -    printf("eax %x, ebx %x, ecx %x, edx %x\n",
> -            r.a, r.b, r.c, r.d);
> -    return r.a + ((u64)r.d << 32);
> -}
> -
>  #define XCR_XFEATURE_ENABLED_MASK       0x00000000
>  #define XCR_XFEATURE_ILLEGAL_MASK       0x00000010
>  
> @@ -33,7 +24,7 @@ static void test_xsave(void)
>  
>      printf("Legal instruction testing:\n");
>  
> -    supported_xcr0 = get_supported_xcr0();
> +    supported_xcr0 = this_cpu_supported_xcr0();
>      printf("Supported XCR0 bits: %#lx\n", supported_xcr0);
>  
>      test_bits = XSTATE_FP | XSTATE_SSE;

Reviewed-by: Dapeng Mi <dapeng1.mi at linux.intel.com>