From mboxrd@z Thu Jan  1 00:00:00 1970
From: Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: Is a "KVM internal error" a bug?
Date: Sat, 13 Dec 2014 10:08:09 +0100
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Cc: Borislav Petkov <bp@alien8.de>
To: Andy Lutomirski <luto@amacapital.net>,
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On 12/12/2014 22:39, Andy Lutomirski wrote:
> KVM internal error. Suberror: 3
> extra data[0]: 80000202
> extra data[1]: 31
> EAX=8be4df61 EBX=8be4df61 ECX=3ff6002c EDX=11d293ca
> ESI=3f08e408 EDI=3e82df7c EBP=3e82deb8 ESP=3e82de7c
> EIP=3ff51206 EFL=00000002 [-------] CPL=0 II=0 A20=1 SMM=0 HLT=0
> ES =0018 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
> CS =0010 00000000 ffffffff 00c09b00 DPL=0 CS32 [-RA]
> SS =0018 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
> DS =0018 00000000 ffffffff 00c09300 DPL=0 DS   [-WA]
> FS =0000 92c2c700 ffffffff 00c00000
> GS =0000 3ec00000 ffffffff 00c00000
> LDT=0000 00000000 ffffffff 00c00000
> TR =0040 3ec11440 00002087 00008b00 DPL=0 TSS32-busy
> GDT=     04c43171 00000020
> IDT=     ff57a000 00000fff
> CR0=00050033 CR2=022e5000 CR3=0009c000 CR4=000407f0
> DR0=0000000000000000 DR1=0000000000000000 DR2=0000000000000000
> DR3=0000000000000000
> DR6=00000000ffff0ff0 DR7=0000000000000400
> EFER=0000000000000801
> Code=0f be 11 29 d0 5b 5d c3 55 89 e5 8b 45 08 5d 8b 50 04 8b 00 <c3>
> 55 89 e5 8b 45 0c 8b 55 10 8b 4d 08 89 01 89 51 04 5d c3 55 31 c0 89
> e5 5d c3 55 89 e5
> 
> I deliberately triggered a guest bug, but I didn't expect this
> failure.  I think that the issue is that an NMI was delivered using a
> bogus IDT, but I think it should have been cleanly promoted to a
> double fault and then a triple fault.   Is this a KVM bug?

Yeah, it should have triggered a triple fault.  This looks like a failed
vmentry, due to invalid state in the VMCS.  It would be great to have a
reproducer using kvm-unit-tests, or failing that a reproducer kernel
module for the guest.

Paolo

Paolo