On 16.04.2024 11:15, Fouad Hilly wrote:
> Update microcode version check at Intel and AMD Level by:
> Preventing the low level code from sending errors if the microcode
> version provided is not a newer version.
And why is this change (a) wanted and (b) correct?
> Other errors will be sent like before.
> When the provided microcode version is the same as the current one, code
> to point to microcode provided.
I'm afraid I can't interpret this sentence.
> Microcode version check happens at higher and common level in core.c.
> Keep all the required code at low level that checks for signature and CPU
> compatibility
>
> [v2]
> Update message description to better describe the changes
This belongs ...
> Signed-off-by: Fouad Hilly <fouad.hi...@cloud.com>
> ---
... below the separator.
> --- a/xen/arch/x86/cpu/microcode/amd.c
> +++ b/xen/arch/x86/cpu/microcode/amd.c
> @@ -383,12 +383,8 @@ static struct microcode_patch *cf_check
> cpu_request_microcode(
> goto skip;
> }
>
> - /*
> - * If the new ucode covers current CPU, compare ucodes and store
> the
> - * one with higher revision.
> - */
> - if ( (microcode_fits(mc->patch) != MIS_UCODE) &&
> - (!saved || (compare_header(mc->patch, saved) == NEW_UCODE))
> )
> + /* If the provided ucode covers current CPU, then store its
> revision. */
> + if ( (microcode_fits(mc->patch) != MIS_UCODE) && !saved )
> {
> saved = mc->patch;
> saved_size = mc->len;
> --- a/xen/arch/x86/cpu/microcode/intel.c
> +++ b/xen/arch/x86/cpu/microcode/intel.c
> @@ -294,8 +294,7 @@ static int cf_check apply_microcode(const struct
> microcode_patch *patch)
>
> result = microcode_update_match(patch);
>
> - if ( result != NEW_UCODE &&
> - !(opt_ucode_allow_same && result == SAME_UCODE) )
> + if ( result != NEW_UCODE && result != SAME_UCODE )
> return -EINVAL;
Unlike the other two adjustments this one results in still permitting
only same-or-newer. How does this fit with the AMD change above and
the other Intel change ...
> @@ -354,12 +353,8 @@ static struct microcode_patch *cf_check
> cpu_request_microcode(
> if ( error )
> break;
>
> - /*
> - * If the new update covers current CPU, compare updates and store
> the
> - * one with higher revision.
> - */
> - if ( (microcode_update_match(mc) != MIS_UCODE) &&
> - (!saved || compare_revisions(saved->rev, mc->rev) == NEW_UCODE)
> )
> + /* If the provided ucode covers current CPU, then store its
> revision. */
> + if ( (microcode_update_match(mc) != MIS_UCODE) && !saved )
> saved = mc;
... here?
Jan
