On Thu, Jun 04, 2020 at 05:19:53PM +0200, Borislav Petkov wrote: > On Thu, Jun 04, 2020 at 01:54:13PM +0200, Joerg Roedel wrote: > > It is not only the trace-point, this would also eliminate exception > > handling in case the MSR access triggers a #GP. The "Unhandled MSR > > read/write" messages would turn into a "General Protection Fault" > > message. > > But the early ones can trigger a #GP too. And there we can't handle > those #GPs. > > Why would the late ones need exception handling all of a sudden? And > for the GHCB MSR, of all MSRs which the SEV-ES guest has used so far to > bootstrap?! For example when there is a bug in the code which triggers an SEV-ES-only code-path at runtime on bare-metal or in a non-SEV-ES VM. When the MSR is accessed accidentially in that code-path the exception handling will be helpful. Joerg
