Re: [PATCH] kvm/sev: make SEV/SEV-ES asids configurable

Peter Gonda
2023-10-10T16:49:53Z

On Tue, Oct 10, 2023 at 5:22 AM José Pekkarinen
<jose.pekkarinen@foxhound.fi> wrote:
>
> There are bioses that doesn't allow to configure the
> number of asids allocated for SEV/SEV-ES, for those
> cases, the default behaviour allocates all the asids
> for SEV, leaving no room for SEV-ES to have some fun.
> If the user request SEV-ES to be enabled, it will
> find the kernel just run out of resources and ignored
> user request. This following patch will address this
> issue by making the number of asids for SEV/SEV-ES
> configurable over kernel module parameters.
>

All this patch does is introduce an error case right? Because if the
BIOS hasn't actually configured those SEV-ES asids and KVM tries to
use an SEV as an SEV-ES asid commands to the ASP will fail, right?

What happens when you try to create an SEV-ES VM with this patch, when
the BIOS hasn't allocated any SEV-ES asids?