Re: [PATCH v2 08/14] platform/x86/intel/ifs: Add metadata support

Hans de Goede
2022-11-10T21:09:57Z

Hi,

On 11/7/22 23:53, Jithu Joseph wrote:
> From: Ashok Raj <ashok.raj@intel.com>
>
> One of the existing reserved fields in microcode header has been
> allocated to indicate the size for metadata structures.
>
> The metadata section within microcode header is as shown below:
>
> Microcode Format
> +----------------------+ Base
> |Header Version |
> +----------------------+
> |Update revision |
> +----------------------+
> |Date DDMMYYYY |
> +----------------------+
> |Sig |
> +----------------------+
> |Checksum |
> +----------------------+
> |Loader Version |
> +----------------------+
> |Processor Flags |
> +----------------------+
> |Data Size |
> +----------------------+
> |Total Size |
> +----------------------+
> |Meta Size |
> +----------------------+
> |Reserved |
> +----------------------+
> |Reserved |
> +----------------------+ Base+48
> | |
> | |
> | |
> | |
> | Microcode |
> | |
> | Data |
> | |
> | |
> +----------------------+ Base+48+data_size-
> | | meta_size
> | Meta Data |
> | structure(s) |
> | |
> +----------------------+ Base+48+data_size
> | Extended Signature |
> | Table |
> | |
> | |
> | |
> | |
> | |
> +----------------------+ Base+total_size
>
> Add an accessor function which will return a pointer to the
> start of a specific meta_type being queried.
>
> In subsequent patches, IFS test image file (which reuse microcode header
> format) will make use of metadata section.
>
> Reviewed-by: Tony Luck <tony.luck@intel.com>
> Signed-off-by: Ashok Raj <ashok.raj@intel.com>
> Signed-off-by: Jithu Joseph <jithu.joseph@intel.com>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <hdegoede@redhat.com>

Regards,

Hans

> ---
> drivers/platform/x86/intel/ifs/load.c | 32 +++++++++++++++++++++++++++
> 1 file changed, 32 insertions(+)
>
> diff --git a/drivers/platform/x86/intel/ifs/load.c b/drivers/platform/x86/intel/ifs/load.c
> index 89ce265887ea..60ba5a057f91 100644
> --- a/drivers/platform/x86/intel/ifs/load.c
> +++ b/drivers/platform/x86/intel/ifs/load.c
> @@ -44,6 +44,38 @@ static const char * const scan_authentication_status[] = {
> [2] = "Chunk authentication error. The hash of chunk did not match expected value"
> };
>
> +#define META_TYPE_END (0)
> +
> +struct metadata_header {
> + unsigned int type;
> + unsigned int blk_size;
> +};
> +
> +static struct metadata_header *ifs_find_meta_data(void *ucode, unsigned int meta_type)
> +{
> + struct metadata_header *meta_header;
> + unsigned long data_size, total_meta;
> + unsigned long meta_size = 0;
> +
> + data_size = get_datasize(ucode);
> + total_meta = ((struct microcode_intel *)ucode)->hdr.metasize;
> +
> + if (!total_meta)
> + return NULL;
> +
> + meta_header = (ucode + MC_HEADER_SIZE + data_size) - total_meta;
> +
> + while ((meta_header->type != META_TYPE_END) && meta_header->blk_size &&
> + meta_size < total_meta) {
> + meta_size += meta_header->blk_size;
> + if (meta_header->type == meta_type)
> + return meta_header;
> +
> + meta_header = (void *)meta_header + meta_header->blk_size;
> + }
> + return NULL;
> +}
> +
> /*
> * To copy scan hashes and authenticate test chunks, the initiating cpu must point
> * to the EDX:EAX to the test image in linear address.