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    SubjectRe: [PATCH v6 14/42] x86/sev: Register GHCB memory when SEV-SNP is active
    On Fri, Oct 08, 2021 at 01:04:25PM -0500, Brijesh Singh wrote:
    > + /* SEV-SNP guest requires that GHCB must be registered. */
    > + if (cc_platform_has(CC_ATTR_SEV_SNP))
    > + snp_register_ghcb(data, __pa(ghcb));

    This looks like more of that "let's register a GHCB at the time the
    first #VC fires".

    And there already is setup_ghcb() which is called in the #VC handler.
    And that thing registers a GHCB GPA.

    But then you have to do it here again.

    I think this should be changed together with the CPUID page detection
    stuff we talked about earlier, where, after you've established that this
    is an SNP guest, you call setup_ghcb() *once* and after that you have
    everything set up, including the GHCB GPA. And then the #VC exceptions
    can come.

    Right?

    Or is there a chicken-and-an-egg issue here which I'm not thinking
    about?

    --
    Regards/Gruss,
    Boris.

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

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