Re: [PATCH 40/70] x86/sev-es: Setup per-cpu GHCBs for the runtime handler

[Tom Lendacky]

On 4/14/20 3:16 PM, Tom Lendacky wrote:
> On 4/14/20 3:12 PM, Dave Hansen wrote:
> > On 4/14/20 1:04 PM, Tom Lendacky wrote:
> > > > set_memory_decrypted needs to check the return value. I see it
> > > > consistently return ENOMEM. I've traced that back to split_large_page
> > > > in arch/x86/mm/pat/set_memory.c.
> > >
> > > At that point the guest won't be able to communicate with the
> > > hypervisor, too. Maybe we should BUG() here to terminate further
> > > processing?
> >
> > Escalating an -ENOMEM into a crashed kernel seems a bit extreme.
> > Granted, the guest may be in an unrecoverable state, but the host
> > doesn't need to be too.
>
> The host wouldn't be. This only happens in a guest, so it would be just 
> causing the guest kernel to panic early in the boot.

And I should add that it would only impact an SEV-ES guest.

Thanks,
Tom

> Thanks,
> Tom