Re: [PATCH] i386: Add CPUID bit for CLZERO and XSAVEERPTR

[Paolo Bonzini <pbonzini@redhat.com>]

On 25/09/19 23:49, Sebastian Andrzej Siewior wrote:
> The CPUID bits CLZERO and XSAVEERPTR are availble on AMD's ZEN platform
> and could be passed to the guest.
> 
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> ---
> 
> I tweaked the kernel to expose these flags and figured out that this is
> also missing in order see those bits in the guest.
> 
>  target/i386/cpu.c | 2 +-
>  target/i386/cpu.h | 2 ++
>  2 files changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index fbed2eb804e32..e00ef3c917391 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -1113,7 +1113,7 @@ static FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
>      [FEAT_8000_0008_EBX] = {
>          .type = CPUID_FEATURE_WORD,
>          .feat_names = {
> -            NULL, NULL, NULL, NULL,
> +            "clzero", NULL, "xsaveerptr", NULL,
>              NULL, NULL, NULL, NULL,
>              NULL, "wbnoinvd", NULL, NULL,
>              "ibpb", NULL, NULL, NULL,
> diff --git a/target/i386/cpu.h b/target/i386/cpu.h
> index 0732e059ec989..cc475c703fc4d 100644
> --- a/target/i386/cpu.h
> +++ b/target/i386/cpu.h
> @@ -689,6 +689,8 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
>  #define CPUID_7_0_EDX_ARCH_CAPABILITIES (1U << 29)  /*Arch Capabilities*/
>  #define CPUID_7_0_EDX_SPEC_CTRL_SSBD  (1U << 31) /* Speculative Store Bypass Disable */
>  
> +#define CPUD_800_008_EBX_CLZERO		(1U << 0) /* CLZERO instruction */
> +#define CPUD_800_008_EBX_XSAVEERPTR	(1U << 2) /* Always save/restore FP error pointers */
>  #define CPUID_8000_0008_EBX_WBNOINVD  (1U << 9)  /* Write back and
>                                                                               do not invalidate cache */
>  #define CPUID_8000_0008_EBX_IBPB    (1U << 12) /* Indirect Branch Prediction Barrier */
> 

Yup, queued this one.

Paolo