Re: [PATCH v9 29/43] x86/boot: Add Confidential Computing type to setup_data

[Borislav Petkov]

On Fri, Jan 28, 2022 at 11:17:50AM -0600, Brijesh Singh wrote:
> +/*
> + * AMD SEV Confidential computing blob structure. The structure is
> + * defined in OVMF UEFI firmware header:
> + * https://github.com/tianocore/edk2/blob/master/OvmfPkg/Include/Guid/ConfidentialComputingSevSnpBlob.h

So looking at that typedef struct CONFIDENTIAL_COMPUTING_SNP_BLOB_LOCATION there:

typedef struct {
  UINT32    Header;
  UINT16    Version;
  UINT16    Reserved1;
  UINT64    SecretsPhysicalAddress;
  UINT32    SecretsSize;
  UINT64    CpuidPhysicalAddress;
  UINT32    CpuidLSize;
} CONFIDENTIAL_COMPUTING_SNP_BLOB_LOCATION;

> + */
> +#define CC_BLOB_SEV_HDR_MAGIC	0x45444d41
> +struct cc_blob_sev_info {
> +	u32 magic;

That's called "Header" there.

> +	u16 version;
> +	u16 reserved;
> +	u64 secrets_phys;
> +	u32 secrets_len;
> +	u32 rsvd1;

You've added that member for padding but the fw blob one doesn't have
it.

But if we get a blob from the firmware and the structure layout differs,
how is this supposed to even work?

> +	u64 cpuid_phys;
> +	u32 cpuid_len;
> +	u32 rsvd2;

That one too.

Or are you going to change the blob layout in ovmf too, to match?

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette