Re: [PATCH 1/2] KVM: TDX: Handle TDG.VP.VMCALL<GetQuote>

[Binbin Wu <binbin.wu@linux.intel.com>]

On 4/3/2025 6:19 AM, Huang, Kai wrote:
> On Wed, 2025-04-02 at 08:15 +0800, Binbin Wu wrote:
>> +::
>> +
>> +		/* KVM_EXIT_TDX_GET_QUOTE */
>> +		struct tdx_get_quote {
>> +			__u64 ret;
>> +			__u64 gpa;
>> +			__u64 size;
>> +		};
>> +
> The shared buffer pointed by the @gpa also has a format defined in the GHCI
> spec.  E.g., it has a 'status code' field.  Does userspace VMM need to setup
> this 'status code' as well?

Yes.
>
> I recall that we used to set the GET_QUOTE_IN_FLIGHT flag in Qemu but not sure
> whether it is still true?
It's still true.

>
> I am thinking if Qemu needs to set it, then we need to expose the structure of
> the shared buffer to userspace too.

For the structure of the shared buffer, since KVM doesn't care about it.
IMHO, it's not necessary to define the structure in KVM and userspace can
define the structure according to GHCI directly.