Re: [PATCH 0/6] Enable SMM page level protection.

[Laszlo Ersek <lersek@redhat.com>]

On 11/04/16 16:29, Paolo Bonzini wrote:
> 
> 
> On 04/11/2016 16:22, Laszlo Ersek wrote:
>>>> What does this *KVM internal error. Suberror: 1* mean?
>> The key message is "emulation failure" -- it means that the processor
>> exits to the hypervisor (KVM) because it finds some code that it cannot
>> execute in guest mode natively, so the hypervisor needs to emulate it.
>> And, this emulation fails. The reasons can be:
>> - the code is valid, but KVM lacks the emulation code for it,
>> - the code is actually garbage (not code) -- there was some corruption
>> in the guest (the location used to contain code but it was corrupted, or
>> the guest jumped to non-code data).
>>
>> Usually the register dump contains a short hexadecimal snippet from the
>> instruction stream (near Code=...), pinpointing the byte that caused the
>> problem. However, in this case, all we have is question marks, and this
>> is the very first time I see those. That's why I CC'd Paolo and Radim :)
> 
> The question marks usually mean that the page tables do not map a page
> at that address, but I don't know offhand why KVM would fail emulation
> instead of triple-faulting.
> 
> Try "info tlb" to dump the page tables (huge output of course, you may
> want to use the GTK+ backend which has scrollable consoles).

Thanks, I'll try "info tlb" later. (I generally use virsh
qemu-monitor-command --hmp, whose output is easy to redirect to a file.)

Thanks
Laszlo