Re: [PATCH 3/3] i386/tdx: handle TDG.VP.VMCALL<GetQuote>

[Daniel P . Berrangé]

On Fri, Jun 20, 2025 at 02:47:46PM +0800, Xiaoyao Li wrote:
> On 6/20/2025 4:33 AM, Paolo Bonzini wrote:

> > +static gboolean tdx_get_quote_read(QIOChannel *ioc, GIOCondition condition,
> > +                                   gpointer opaque)
> > +{
> ...> +    if (task->receive_buf_received >= (sizeof(qgs_msg_header_t) +
> HEADER_SIZE)) {
> > +        qgs_msg_header_t *hdr = (qgs_msg_header_t *)(task->receive_buf + 
> > HEADER_SIZE);
> > +        if (hdr->major_version != QGS_MSG_LIB_MAJOR_VER ||
> > +            hdr->minor_version != QGS_MSG_LIB_MINOR_VER) {
> 
> This check makes it fail with old QGS, which defines
> 
> QGS_MSG_LIB_MINOR_VER as 0,
> 
> so what QEMU gets is 1.0 instead of 1.1.
> 
> It is really a QGS bug that when it changes QGS_MSG_LIB_MINOR_VER from 0 to
> 1, it didn't consider the compatible issue.
> 
> However, the old QGS is there. Should we relax the check here for it? or
> just let it fail with old QGS?

AFAICT, MINOR_VER==1 was introduced in DCAP 1.21 from Apr 2024

Given that this is new functionality in QEMU, I don't think we
have to worry about versions of DCAP so far behind the latest
version.


With regards,
Daniel
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