Re: [PATCH v8 36/40] x86/sev: Provide support for SNP guest request NAEs

Borislav Petkov
2022-01-29T10:27:28Z

On Thu, Jan 27, 2022 at 11:02:13AM -0600, Brijesh Singh wrote:
> I am okay with using SZ_4G but per the spec they don't spell that its 4G
> size. It says bit 32 will should be set on error.

What does the speck call it exactly? Is it "length"? Because that's what
confused me: SNP_GUEST_REQ_INVALID_LEN - that's a length and length you
don't usually specify with a bit position...

> Typically the sev_es_ghcb_hv_handler() is called from #VC handler, which
> provides the context structure. But in this and PSC case, the caller is not
> a #VC handler, so we don't have a context structure. But as you pointed, we
> could allocate context structure on the stack and pass it down so that
> verify_exception_info() does not cause a panic with NULL deference (when HV
> violates the spec and inject exception while handling this NAE).

Yap, exactly.

--
Regards/Gruss,
Boris.