Messages in this thread | | | From | Andy Lutomirski <> | Date | Sat, 25 Apr 2020 11:15:35 -0700 | Subject | Re: [PATCH] Allow RDTSC and RDTSCP from userspace |
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On Sat, Apr 25, 2020 at 5:49 AM Joerg Roedel <jroedel@suse.de> wrote: > > Hi Dave, > > On Fri, Apr 24, 2020 at 03:53:09PM -0700, Dave Hansen wrote: > > Ahh, so any instruction that can have an instruction intercept set > > potentially needs to be able to tolerate a #VC? Those instruction > > intercepts are under the control of the (untrusted relative to the > > guest) hypervisor, right? > > > > >From the main sev-es series: > > > > +#ifdef CONFIG_AMD_MEM_ENCRYPT > > +idtentry vmm_communication do_vmm_communication has_error_code=1 > > +#endif > > The next version of the patch-set (which I will hopefully have ready > next week) will have this changed. The #VC exception handler uses an IST > stack and is set to paranoid=1 and shift_ist. The IST stacks for the #VC > handler are only allocated when SEV-ES is active.
shift_ist is gross. What's it for? If it's not needed, I'd rather not use it, and I eventually want to get rid of it for #DB as well.
--Andy
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