Re: [PATCH 0/4] Add support for XMM fast hypercalls

[Siddharth Chandrasekaran]

On Thu, Apr 08, 2021 at 03:38:13PM +0000, Wei Liu wrote:
> On Thu, Apr 08, 2021 at 05:30:26PM +0200, Paolo Bonzini wrote:
> > On 08/04/21 17:28, Wei Liu wrote:
> > > > Although the Hyper-v TLFS mentions that a guest cannot use this feature
> > > > unless the hypervisor advertises support for it, some hypercalls which
> > > > we plan on upstreaming in future uses them anyway.
> > >
> > > No, please don't do this. Check the feature bit(s) before you issue
> > > hypercalls which rely on the extended interface.
> >
> > Perhaps Siddharth should clarify this, but I read it as Hyper-V being buggy
> > and using XMM arguments unconditionally.
> >
> 
> There is no code in upstream Linux that uses the XMM fast hypercall
> interface at the moment.
> 
> If there is such code, it has bugs in it and should be fixed. :-)

None of the existing hypercalls are buggy. These are some hypercalls we
are working on (and planning on upstreaming in the near future). 

~ Sid.



Amazon Development Center Germany GmbH
Krausenstr. 38
10117 Berlin
Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B
Sitz: Berlin
Ust-ID: DE 289 237 879