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

I am using a custom, optimized and stripped down version, OVMF build.
Do you think it is because of the OVMF or grub?

In my case, there are 2 places where the CPUID is called: the first
one is to decide if long mode is supported, along with few other
features like SSE support and the second one is to retrieve the
encryption bit location.

-Erdem

On Wed, Jul 22, 2020 at 2:04 AM Joerg Roedel [off-list ref] wrote:

Hi Erdem,

On Tue, Jul 21, 2020 at 09:48:51AM -0700, Erdem Aktas wrote:

quoted

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