Re: [PATCH v2 06/14] x86/microcode/intel: Expose microcode_sanity_check()

Borislav Petkov
2022-11-11T14:34:08Z

On Mon, Nov 07, 2022 at 02:53:15PM -0800, Jithu Joseph wrote:
> IFS test image carries the same microcode header as regular Intel
> microcode blobs. Microcode blobs use header version of 1,
> whereas IFS test images will use header version of 2.
>
> microcode_sanity_check() can be used by IFS driver to perform
> sanity check of the IFS test images too.
>
> Refactor header version as a parameter, move it to cpu/intel.c
> and expose this function. Qualify the function name with intel.

Same comments as before.

> Reviewed-by: Tony Luck <tony.luck@intel.com>
> Reviewed-by: Ashok Raj <ashok.raj@intel.com>
> Signed-off-by: Jithu Joseph <jithu.joseph@intel.com>
> ---
> arch/x86/include/asm/cpu.h | 1 +
> arch/x86/include/asm/microcode_intel.h | 1 +
> arch/x86/kernel/cpu/intel.c | 100 ++++++++++++++++++++++++
> arch/x86/kernel/cpu/microcode/intel.c | 102 +------------------------
> 4 files changed, 104 insertions(+), 100 deletions(-)
>
> diff --git a/arch/x86/include/asm/cpu.h b/arch/x86/include/asm/cpu.h
> index e853440b5c65..4aff5f263973 100644
> --- a/arch/x86/include/asm/cpu.h
> +++ b/arch/x86/include/asm/cpu.h
> @@ -96,5 +96,6 @@ static inline bool intel_cpu_signatures_match(unsigned int s1, unsigned int p1,
>
> extern u64 x86_read_arch_cap_msr(void);
> int intel_find_matching_signature(void *mc, unsigned int csig, int cpf);
> +int intel_microcode_sanity_check(void *mc, bool print_err, int hdr_ver);
>
> #endif /* _ASM_X86_CPU_H */
> diff --git a/arch/x86/include/asm/microcode_intel.h b/arch/x86/include/asm/microcode_intel.h
> index 4c92cea7e4b5..6626744c577b 100644
> --- a/arch/x86/include/asm/microcode_intel.h
> +++ b/arch/x86/include/asm/microcode_intel.h
> @@ -41,6 +41,7 @@ struct extended_sigtable {
> #define DEFAULT_UCODE_TOTALSIZE (DEFAULT_UCODE_DATASIZE + MC_HEADER_SIZE)
> #define EXT_HEADER_SIZE (sizeof(struct extended_sigtable))
> #define EXT_SIGNATURE_SIZE (sizeof(struct extended_signature))
> +#define MICROCODE_HEADER_VER_UCODE 1

"MICROCODE" ... "UCODE" - too much.

And "header version" sounds wrong when all you wanna say is, this header
is of this or that *type*. So you simply do:

#define MC_HEADER_TYPE_MICROCODE 1
#define MC_HEADER_TYPE_IFS 2

and that's it.

> #define get_totalsize(mc) \
> (((struct microcode_intel *)mc)->hdr.datasize ? \
> diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c
> index b6f9210fb31a..f8a5a25ab502 100644
> --- a/arch/x86/kernel/cpu/intel.c
> +++ b/arch/x86/kernel/cpu/intel.c
> @@ -245,6 +245,106 @@ int intel_find_matching_signature(void *mc, unsigned int csig, int cpf)
> }
> EXPORT_SYMBOL_GPL(intel_find_matching_signature);
>
> +int intel_microcode_sanity_check(void *mc, bool print_err, int hdr_ver)

This is not how this is done:

1st patch: *only* mechanical code move, no semantic or functional changes
whatsoever.

2nd patch: Add semantical/functional changes.

Also, in the second patch, pls put a kernel-doc comment over the
function to explain what hdr_type - not hdr_ver - means here.

Thx.

--
Regards/Gruss,
Boris.