Re: [PATCH 1/5] x86/cpu-policy: Infrastructure for the AMD SVM and SEV leaves

[Jan Beulich <jbeulich@xxxxxxxx>]

On 29.04.2024 17:16, Andrew Cooper wrote:
> Allocate two new feature leaves, and extend cpu_policy with the non-feature
> fields too.
> 
> The CPUID dependency between the SVM bit on the whole SVM leaf is
> intentionally deferred, to avoid transiently breaking nested virt.

In reply to this I meant to ask that you at least add those dependencies in
commented-out form, such that from looking at gen-cpuid.py it becomes clear
they're intentionally omitted. But you don't add feature identifiers either,
making dependencies impossible to express. Maybe this sentence was really
meant for another of the patches? (Then my request would actually apply
there.)

> @@ -296,7 +298,16 @@ struct cpu_policy
>              uint32_t /* d */:32;
>  
>              uint64_t :64, :64; /* Leaf 0x80000009. */
> -            uint64_t :64, :64; /* Leaf 0x8000000a - SVM rev and features. */
> +
> +            /* Leaf 0x8000000a - SVM rev and features. */
> +            uint8_t svm_rev, :8, :8, :8;
> +            uint32_t /* b */ :32;
> +            uint32_t nr_asids;

According to the doc I'm looking at it is %ebx which holds the number of
ASIDs and %ecx is reserved. With that adjusted
Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>

Jan