Re: [PATCH v2] x86/kexec: Add EFI config table identity mapping for kexec kernel

Borislav Petkov
2023-07-07T08:57:39Z

On Fri, Jul 07, 2023 at 10:22:56AM +0200, Joerg Roedel wrote:
> On Fri, Jul 07, 2023 at 12:23:59PM +0800, Baoquan He wrote:
> > I am wondering why we don't detect the cpu type and return early inside
> > sev_enable() if it's Intel cpu.
> >
> > We can't rely on CONFIG_AMD_MEM_ENCRYPT to decide if the code need be
> > executed or not because we usually enable them all in distros.
>
> Looking at the code in head_64.S, by the time sev_enable() runs the SEV
> bit should already be set in sev_status. Maybe use that to detect
> whether SEV is enabled and bail out early?

There was something about getting the CPUID page on SNP *before*
actually calling CPUID but this is not the first time we had trouble in
this area. This needs to be done differently.

Michael?

--
Regards/Gruss,
Boris.