On 1/29/2026 7:09 AM, Zide Chen wrote:
> Populate selected PEBS feature names in FEAT_PERF_CAPABILITIES to make
> the corresponding bits user-visible CPU feature knobs, allowing them to
> be explicitly enabled or disabled via -cpu +/-<feature>.
>
> Once named, these bits become part of the guest CPU configuration
> contract.  If a VM is configured with such a feature enabled, migration
> to a destination that does not support the feature may fail, as the
> destination cannot honor the guest-visible CPU model.
>
> The PEBS_FMT bits are not exposed, as target/i386 currently does not
> support multi-bit CPU properties.
>
> Co-developed-by: Dapeng Mi <[email protected]>
> Signed-off-by: Dapeng Mi <[email protected]>
> Signed-off-by: Zide Chen <[email protected]>
> ---
> V2:
> - Add the missing comma after "pebs-arch-reg".
> - Simplify the PEBS_FMT description in the commit message.
>
>  target/i386/cpu.c | 6 +++---
>  1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/target/i386/cpu.c b/target/i386/cpu.c
> index d3e9d3c40b0a..f2c83b4f259c 100644
> --- a/target/i386/cpu.c
> +++ b/target/i386/cpu.c
> @@ -1618,10 +1618,10 @@ FeatureWordInfo feature_word_info[FEATURE_WORDS] = {
>          .type = MSR_FEATURE_WORD,
>          .feat_names = {
>              NULL, NULL, NULL, NULL,
> +            NULL, NULL, "pebs-trap", "pebs-arch-reg",
>              NULL, NULL, NULL, NULL,
> -            NULL, NULL, NULL, NULL,
> -            NULL, "full-width-write", NULL, NULL,
> -            NULL, NULL, NULL, NULL,
> +            NULL, "full-width-write", "pebs-baseline", NULL,
> +            NULL, "pebs-timing-info", NULL, NULL,
>              NULL, NULL, NULL, NULL,
>              NULL, NULL, NULL, NULL,
>              NULL, NULL, NULL, NULL,

LGTM.

Reviewed-by: Dapeng Mi <[email protected]>



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