Re: [PATCH v5 00/75] x86: SEV-ES Guest Support

Mike Stunes
2020-07-30T23:23:56Z

Hi Joerg,

> On Jul 30, 2020, at 5:26 AM, Joerg Roedel <joro@8bytes.org> wrote:
>
> Hi Mike,
>
> On Thu, Jul 30, 2020 at 01:27:48AM +0000, Mike Stunes wrote:
>> Thanks for the updated patches! I applied this patch-set onto commit
>> 01634f2bd42e ("Merge branch 'x86/urgent’”) from your tree. It boots,
>> but CPU 1 (on a two-CPU VM) is offline at boot, and `chcpu -e 1` returns:
>>
>> chcpu: CPU 1 enable failed: Input/output error
>>
>> with nothing in dmesg to indicate why it failed. The first thing I thought
>> of was anything relating to the AP jump table, but I haven’t changed
>> anything there on the hypervisor side. Let me know what other data I can
>> provide for you.
>
> Hard to tell, have you enabled FSGSBASE in the guest? If yes, can you
> try to disable it?

Yes, FSGSBASE was enabled. If I disable it*, this kernel boots fine, with
both CPUs online.

*That is, by forcing guest-CPUID[7].EBX bit 0 to 0.

Thanks!
Mike