On Thu, Nov 25, 2021, Thomas Gleixner wrote: > On Wed, Nov 24 2021 at 16:20, isaku yamahata wrote: > > From: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> > > > > Define the TDCALL exit reason, which is carved out from the VMX exit > > reason namespace as the TDCALL exit from TDX guest to TDX-SEAM is really > > just a VM-Exit. > > How is this carved out? What's the value of this word salad? > > It's simply a new exit reason. Not more, not less. So what? The changelog is alluding to the fact that KVM should never directly see a TDCALL VM-Exit. For TDX, KVM deals only with "returns" from the TDX-Module. The "carved out" bit is calling out that the transition from SEAM Non-Root (the TDX guest) to SEAM Root (the TDX Module) is actually a VT-x/VMX VM-Exit, e.g. if TDX were somehow implemented without relying on VT-x/VMX, then the TDCALL exit reason wouldn't exist. > > Co-developed-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx> > > Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx> > > Signed-off-by: Sean Christopherson <sean.j.christopherson@xxxxxxxxx> > > I'm pretty sure that it does not take two engineers to add a new exit > reason define, but it takes at least two engineers to come up with a > convoluted explanation for it. Nah, just one ;-)
