Re: [Part2 PATCH v9 00/38] x86: Secure Encrypted Virtualization (AMD)

From: Brijesh Singh
Date: Thu Dec 21 2017 - 11:10:26 EST




On 12/21/17 9:51 AM, Brijesh Singh wrote:
>
> On 12/21/17 7:06 AM, Paolo Bonzini wrote:
> ....
>
> Hi Paolo,
> Â
>
>> Hi Brijesh,
>>
>> I have a couple comments:
>>
>> 1) how is MSR_AMD64_SEV's value passed to the guest, and where is it in
>> the manual?
> It is a non interceptable read-only MSR set by the HW when SEV feature
> is enabled in VMRUN instruction.

I just checked both PPR and Family 17 manual and it seems both are still
missing this MSR definition. I will ping doc team to get it updated. thanks
>> 2) ECX should be 0 in the guest's 0x8000_001f leaf, because we don't
>> support nested SEV guests. Likewise, EAX bit 2 should be 0 since you
>> don't emulate the page flush MSR.
> IIRC, I do clear both EAX Page_Flush and nested virtualization case from
> Qemu SEV feature is enabled.
>> Both can be fixed on top (and I can do the second myself of course), so
>> there should be no need for a v10.
> Thanks
>