On Thu, Apr 08, 2021 at 04:30:18PM +0000, Wei Liu wrote: > On Thu, Apr 08, 2021 at 05:54:43PM +0200, Siddharth Chandrasekaran wrote: > > On Thu, Apr 08, 2021 at 05:48:19PM +0200, Paolo Bonzini wrote: > > > On 08/04/21 17:40, Siddharth Chandrasekaran 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. > > > > > > What guest is that? > > > > It is a Windows Server 2016. > > Can you be more specific? Are you implementing some hypercalls from > TLFS? If so, which ones? Yes all of them are from TLFS. We are implementing VSM and there are a bunch of hypercalls that we have implemented to manage VTL switches, memory protection and virtual interrupts. The following 3 hypercalls that use the XMM fast hypercalls are relevant to this patch set: HvCallModifyVtlProtectionMask HvGetVpRegisters HvSetVpRegisters ~ 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
