Re: [PATCH Part1 RFC v3 11/22] x86/sev: Add helper for validating pages in early enc attribute changes

[Brijesh Singh]

On 6/16/2021 9:36 AM, Brijesh Singh wrote:
> 
> 
> On 6/16/2021 8:10 AM, Brijesh Singh wrote:
>>
>> On 6/16/21 8:02 AM, Borislav Petkov wrote:
>>> On Wed, Jun 16, 2021 at 07:49:25AM -0500, Brijesh Singh wrote:
>>>> If you still think ...
>>> I think you should answer my question first:
>>>
>>>> Imagine you're a guest owner and you haven't written the SNP code and
>>>> you don't know how it works.
>>>>
>>>> You start a guest in the public cloud and it fails because the
>>>> hypervisor violates the GHCB protocol and all that guest prints before
>>>> it dies is
>>>>
>>>> "general request termination"
>>>>
>>>> How are you - the guest owner - going to find out what exactly happened?
>>>>
>>>> Call support?
>>> And let me paraphrase it again: if the error condition with which the
>>> guest terminates is not uniquely identifiable but simply a "general
>>> request", how are such conditions going to be debugged?
>>> I thought I said it somewhere in our previous conversation, I would look
>> at the KVM trace log, each vmgexit entry and exit are logged. The log
>> contains full GHCB MSR value, and in it you can see both the request and
>> response code and decode the failure reason.
>>
> 
> I now realized that in this case we may not have the trace's. It's
> a production environment and my development machine :(.

I am mean to say *not* my development machine