Re: [PATCH v4 00/75] x86: SEV-ES Guest Support

[Joerg Roedel]

Hi Erdem,

On Tue, Jul 21, 2020 at 09:48:51AM -0700, Erdem Aktas wrote:
> Yes, I am using OVMF with SEV-ES (sev-es-v12 patches applied). I am
> running Ubuntu 18.04 distro. My grub target is x86_64-efi. I also
> tried installing the grub-efi-amd64 package. In all cases, the grub is
> running in 64bit but enters the startup_32 in 32 bit mode. I think
> there should be a 32bit #VC handler just something very similar in the
> OVMF patches to handle the cpuid when the CPU is still in 32bit mode.
> As it is now, it will be a huge problem to support different distro images.
> I wonder if I am the only one having this problem.

I havn't heard from anyone else that the startup_32 boot-path is being
used for SEV-ES. What OVMF binary do you use for your guest?

In general it is not that difficult to support that boot-path too, but
I'd like to keep that as a future addition, as the patch-set is already
quite large. In the startup_32 path there is already a GDT set up, so
whats needed is an IDT and a 32-bit #VC handler using the MRS-based
protocol (and hoping that there will only be CPUID intercepts until it
reaches long-mode).

Regards,

	Joerg