Re: [PATCH v2 2/2] x86/sev-es: Invalidate the GHCB after completing VMGEXIT

On Mon, May 17, 2021 at 12:42:33PM -0500, Tom Lendacky wrote:

Since the VMGEXIT instruction can be issued from userspace, invalidate the GHCB after performing VMGEXIT processing in the kernel.

Invalidation is only required after userspace is available, so call vc_ghcb_invalidate() from sev_es_put_ghcb(). Update vc_ghcb_invalidate() to additionally clear the GHCB exit code, so that a value of 0 is always present outside VMGEXIT processing in the kernel.

Fixes: 0786138c78e79 ("x86/sev-es: Add a Runtime #VC Exception Handler") Cc: stable@vger.kernel.org Signed-off-by: Tom Lendacky thomas.lendacky@amd.com

Reviewed-by: Joerg Roedel jroedel@suse.de