On Thu, Apr 08, 2021 at 05:30:26PM +0200, Paolo Bonzini wrote: > CAUTION: This email originated from outside of the organization. Do not click links or open attachments unless you can confirm the sender and know the content is safe. > > > > 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. The guest is at fault here as it expects Hyper-V to consume arguments from XMM registers for certain hypercalls (that we are working) even if we didn't expose the feature via CPUID bits. ~ 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
