On Tue, Jan 31, 2023, Joerg Roedel wrote: > On Tue, Jan 31, 2023 at 03:53:39PM +0000, Sean Christopherson wrote: > > 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. > > Not from the hardware architecture side, but the GHCB spec does not > list NAE events for DR0-DR6 accesses, so a guest is not required to > handle them in the VC handler. > > Linux under SEV-ES will crash if the HV intercepts debug registers, > except DR7. Right, I'm just objecting to the wording of "DR0-DR6 are not intercepted". E.g. from a security perspective, the kernel shouldn't rely on DR0-DR6 to execute cleanly.
