Re: [PATCH] x86/coco, x86/sev: Use cpu_feature_enabled() to detect SEV guest flavor

[Kirill A. Shutemov]

On Tue, Dec 05, 2023 at 03:46:19PM +0100, Borislav Petkov wrote:
> On Tue, Dec 05, 2023 at 05:37:38PM +0300, Kirill A. Shutemov wrote:
> > The SEV code uses cc_platform_has() checks to detect the SEV flavor.
> > However, these checks can sometimes produce false positives depending on
> > the context.
> > 
> > For example, sev_map_percpu_data() uses CC_ATTR_GUEST_MEM_ENCRYPT to
> > detect SEV guest, but this check will also pass for TDX guests.
> 
> Well, a function prefixed with "sev_" should check cc_vendor first...

I don't think cc_platform_has() is the right check. On TDX side we use
X86_FEATURE_TDX_GUEST for this and it works better than stretching
CC_ATTRs beyond their meaning.

-- 
  Kiryl Shutsemau / Kirill A. Shutemov