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    SubjectRe: [PATCH v8 27/40] x86/boot: Add Confidential Computing type to setup_data
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    On 12/10/21 1:12 PM, Dave Hansen wrote:
    > On 12/10/21 7:43 AM, Brijesh Singh wrote:
    >> +/* AMD SEV Confidential computing blob structure */
    >> +#define CC_BLOB_SEV_HDR_MAGIC 0x45444d41
    >> +struct cc_blob_sev_info {
    >> + u32 magic;
    >> + u16 version;
    >> + u16 reserved;
    >> + u64 secrets_phys;
    >> + u32 secrets_len;
    >> + u64 cpuid_phys;
    >> + u32 cpuid_len;
    >> +};
    > This is an ABI structure rather than some purely kernel construct, right?


    This is ABI between the guest BIOS and Guest OS. It is defined in the OVMF.

    https://github.com/tianocore/edk2/blob/master/OvmfPkg/Include/Guid/ConfidentialComputingSevSnpBlob.h

    SEV-SNP FW spec does not have it documented; it's up to the guest BIOS
    on how it wants to communicate the Secrets and CPUID page location to
    guest OS.


    > I searched through all of the specs to which you linked in the cover
    > letter. I looked for "blob", "guid", the magic and part of the GUID
    > itself trying to find where this is defined to see if the struct is correct.
    >
    > I couldn't find anything.
    >
    > Where is the spec for this blob? How large is it? Did you mean to
    > leave a 4-byte hole after secrets_len and before cpuid_phys?

    Yes, the length is never going to be > 4GB.


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