Messages in this thread | | | Date | Tue, 23 Jun 2020 14:47:12 +0200 | From | Peter Zijlstra <> | Subject | Re: Should SEV-ES #VC use IST? (Re: [PATCH] Allow RDTSC and RDTSCP from userspace) |
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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.
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