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From: Paolo Bonzini <pbonzini@redhat.com>
To: Andriy Gapon <avg@FreeBSD.org>
Cc: "Andreas Färber" <afaerber@suse.de>,
	"Gleb Natapov" <gleb@redhat.com>,
	qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] in_asm substitute for accel=kvm:tcg
Date: Thu, 19 Sep 2013 19:26:09 +0200	[thread overview]
Message-ID: <523B33B1.3030100@redhat.com> (raw)
In-Reply-To: <523B31ED.9020504@FreeBSD.org>

Il 19/09/2013 19:18, Andriy Gapon ha scritto:
> on 19/09/2013 19:53 Paolo Bonzini said the following:
>> 1) Can you try loading the kvm_intel module with
>> emulate_invalid_guest_state=0?
> 
> Will do.
> 
>> 2) What are the contents of fs and gs?  Why are they not zeroed?
>> Perhaps that is causing invalid guest state emulation to run, and then
>> something is triggering a bug in emulate_invalid_guest_state itself.
> 
> I will try to find this out.
> 
>> 3) What is at 0x9315?
> 
> This I can answer immediately.  It looks like this address even gets executed
> earlier:
>  qemu-system-x86-12024 [002] 278153.809990: kvm_emulate_insn:     0:9315:ea 1a
> 93 00 00 (real)
>  qemu-system-x86-12024 [002] 278153.809991: kvm_entry:            vcpu 0
>  qemu-system-x86-12024 [002] 278153.809992: kvm_emulate_insn:     0:931a:31 c0
> (real)
> 
> I guess it's a jump to 931a.

Yes, it is.

> Puzzling that later it becomes a jump to self.

I don't think that's what happens.  It's more likely that for some
reason the emulator mis-parses the instruction.

Please confirm with "info cpus" that QEMU is looping there (just in
case), and attach the output of "info registers" (you can use "-monitor
stdio" to do this and to answer question 2 from my previous email).

Paolo

  reply	other threads:[~2013-09-19 17:26 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-09-17 11:37 [Qemu-devel] in_asm substitute for accel=kvm:tcg Andriy Gapon
2013-09-17 12:32 ` Andreas Färber
2013-09-17 14:33   ` Andriy Gapon
2013-09-17 18:49     ` Gleb Natapov
2013-09-19 14:36       ` Andriy Gapon
2013-09-19 16:53         ` Paolo Bonzini
2013-09-19 17:18           ` Andriy Gapon
2013-09-19 17:26             ` Paolo Bonzini [this message]
2013-09-19 18:05               ` Andriy Gapon
2013-09-19 17:49           ` Andriy Gapon
2013-09-22  6:31             ` Gleb Natapov
2013-09-22  8:05               ` Andriy Gapon
2013-09-22  8:17                 ` Gleb Natapov
2013-09-22  9:41                   ` Andriy Gapon

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