On Tue, Jan 31, 2023, Joerg Roedel wrote: > On Mon, Jan 30, 2023 at 09:30:38AM -0800, H. Peter Anvin wrote: > > It's somewhat odd to me that reading %dr7 is volatile, but %dr6 is > > not... %dr6 is the status register! > > The reason is that on SEV-ES only accesses to DR7 will cause #VC > exceptions, DR0-DR6 are not intercepted. I don't think that is technically true. A _well-behaved_ hypervisor will not intercept DR0-DR6 accesses for SEV-ES guests, but AFAICT nothing in the SEV-ES architecture enforces that behavior.
