Messages in this thread | | | From | Andy Lutomirski <> | Date | Sun, 5 Jul 2020 11:22:42 -0700 | Subject | Re: [PATCH v3 2/3] Fix undefined operation fault that can hang a cpu on crash or panic |
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On Sat, Jul 4, 2020 at 1:38 PM David P. Reed <dpreed@deepplum.com> wrote: > > Fix: Mask undefined operation fault during emergency VMXOFF that must be > attempted to force cpu exit from VMX root operation. > Explanation: When a cpu may be in VMX root operation (only possible when > CR4.VMXE is set), crash or panic reboot tries to exit VMX root operation > using VMXOFF. This is necessary, because any INIT will be masked while cpu > is in VMX root operation, but that state cannot be reliably > discerned by the state of the cpu. > VMXOFF faults if the cpu is not actually in VMX root operation, signalling > undefined operation. > Discovered while debugging an out-of-tree x-visor with a race. Can happen > due to certain kinds of bugs in KVM.
Can you re-wrap lines to 68 characters? Also, the Fix: and Explanation: is probably unnecessary. You could say:
Ignore a potential #UD failut during emergency VMXOFF ...
When a cpu may be in VMX ...
> > Fixes: 208067 <https://bugzilla.kernel.org/show_bug.cgi?id=208067> > Reported-by: David P. Reed <dpreed@deepplum.com>
It's not really necessary to say that you, the author, reported the problem, but I guess it's harmless.
> Suggested-by: Thomas Gleixner <tglx@linutronix.de> > Suggested-by: Sean Christopherson <sean.j.christopherson@intel.com> > Suggested-by: Andy Lutomirski <luto@kernel.org> > Signed-off-by: David P. Reed <dpreed@deepplum.com> > --- > arch/x86/include/asm/virtext.h | 20 ++++++++++++++------ > 1 file changed, 14 insertions(+), 6 deletions(-) > > diff --git a/arch/x86/include/asm/virtext.h b/arch/x86/include/asm/virtext.h > index 0ede8d04535a..0e0900eacb9c 100644 > --- a/arch/x86/include/asm/virtext.h > +++ b/arch/x86/include/asm/virtext.h > @@ -30,11 +30,11 @@ static inline int cpu_has_vmx(void) > } > > > -/* Disable VMX on the current CPU > +/* Exit VMX root mode and isable VMX on the current CPU.
s/isable/disable/
> /* Disable VMX if it is supported and enabled on the current CPU > -- > 2.26.2 >
Other than that:
Reviewed-by: Andy Lutomirski <luto@kernel.org>
--Andy
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