| From | Andy Lutomirski <> | Date | Thu, 19 Mar 2020 08:44:03 -0700 | Subject | Re: [PATCH 41/70] x86/sev-es: Add Runtime #VC Exception Handler |
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On Thu, Mar 19, 2020 at 2:14 AM Joerg Roedel <joro@8bytes.org> wrote: > > From: Tom Lendacky <thomas.lendacky@amd.com> > > Add the handler for #VC exceptions invoked at runtime.
If I read this correctly, this does not use IST. If that's true, I don't see how this can possibly work. There at least two nasty cases that come to mind:
1. SYSCALL followed by NMI. The NMI IRET hack gets to #VC and we explode. This is fixable by getting rid of the NMI EFLAGS.TF hack.
2. tools/testing/selftests/x86/mov_ss_trap_64. User code does MOV (addr), SS; SYSCALL, where addr has a data breakpoint. We get #DB promoted to #VC with no stack.
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