Re: [PATCH] x86: Begin to introduce support for MSR_ARCH_CAPS

[Jan Beulich <jbeulich@xxxxxxxx>]

On 24.08.2020 18:58, Andrew Cooper wrote:
> ... including serialisation/deserialisation logic and unit tests.
> 
> There is no current way to configure this MSR correctly for guests.
> The toolstack side this logic needs building, which is far easier to
> do with it in place.
> 
> Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
with perhaps one correction:

> @@ -23,6 +23,28 @@ struct msr_policy
>              bool cpuid_faulting:1;
>          };
>      } platform_info;
> +
> +    /*
> +     * 0x0000010a - MSR_ARCH_CAPABILITIES
> +     *
> +     * This is an Intel-only MSR, which provides miscellaneous enumeration,
> +     * including those which indicate that microarchitectrual sidechannels 
> are
> +     * fixed in hardware.
> +     */
> +    union {
> +        uint32_t raw;
> +        struct {
> +            bool rdcl_no:1;
> +            bool ibrs_all:1;
> +            bool rsba:1;
> +            bool skip_l1dfl:1;
> +            bool ssb_no:1;
> +            bool mdd_no:1;

mds_no?

> +            bool if_pschange_mc_no:1;
> +            bool tsx_ctrl:1;
> +            bool taa_no:1;
> +        };
> +    } arch_caps;

I guess eventually we will want to eliminate the duplication between
this and the ARCH_CAPS_* #define-s we have in msr-index.h?

Jan