Re: [PATCH v8 2/4] x86/sev: Change snp_guest_issue_request's fw_err

[Peter Gonda]

On Fri, Nov 4, 2022 at 5:01 PM Dionna Glaze <dionnaglaze@xxxxxxxxxx> wrote:
>
> The GHCB specification declares that the firmware error value for a
> guest request will be stored in the lower 32 bits of EXIT_INFO_2.
> The upper 32 bits are for the VMM's own error code. The fw_err argument
> is thus a misnomer, and callers will need access to all 64 bits.
>
> The type of unsigned long also causes problems, since sw_exit_info2 is
> u64 (unsigned long long) vs the argument's previous unsigned long*.
> The signature change requires the follow-up change to
> drivers/virt/coco/sev-guest to use the new expected type in order to
> compile.
>
> The firmware might not even be called, so we bookend the call with the
> no firmware call error and clearing the error.
>
> Cc: Tom Lendacky <Thomas.Lendacky@xxxxxxx>
> Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> Cc: Joerg Roedel <jroedel@xxxxxxx>
> Cc: Peter Gonda <pgonda@xxxxxxxxxx>
> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: Dave Hansen <dave.hansen@xxxxxxxxxxxxxxx>
> Cc: Ingo Molnar <mingo@xxxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxxxx>
> Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
> Cc: Venu Busireddy <venu.busireddy@xxxxxxxxxx>
> Cc: Michael Roth <michael.roth@xxxxxxx>
> Cc: "Kirill A. Shutemov" <kirill@xxxxxxxxxxxxx>
> Cc: Michael Sterritt <sterritt@xxxxxxxxxx>
>
> Fixes: d5af44dde546 ("x86/sev: Provide support for SNP guest request NAEs")
> Signed-off-by: Dionna Glaze <dionnaglaze@xxxxxxxxxx>

Reviewed-by: Peter Gonda <pgonda@xxxxxxxxxx