On 23/06/2020 13:47, Peter Zijlstra wrote: > On Tue, Jun 23, 2020 at 12:51:03PM +0100, Andrew Cooper wrote: > >> There are cases which are definitely non-recoverable. >> >> For both ES and SNP, a malicious hypervisor can mess with the guest >> physmap to make the the NMI, #VC and #DF stacks all alias. >> >> For ES, this had better result in the #DF handler deciding that crashing >> is the way out, whereas for SNP, this had better escalate to Shutdown. >> Crashing out hard if the hypervisor is misbehaving is acceptable. > Then I'm thinking the only sensible option is to crash hard for any SNP > #VC from kernel mode. > > Sadly that doesn't help with #VC needing to be IST :-( IST is such a > frigging nightmare. I presume you mean any #VC caused by RMP faults (i.e. something went wrong with the memory owner/etc metadata) ? If so, then yes. Any failure here is a bug in the kernel or hypervisor (and needs fixing) or a malicious hypervisor and the guest should terminate for its own safety. ~Andrew
