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From: Richard Henderson <rth@twiddle.net>
To: "Paolo Bonzini" <pbonzini@redhat.com>,
	"Hervé Poussineau" <hpoussin@reactos.org>,
	qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH 4/7] target-i386: Dump illegal opcodes with -d unimp
Date: Thu, 3 Mar 2016 11:06:42 -0800	[thread overview]
Message-ID: <56D88B42.7060208@twiddle.net> (raw)
In-Reply-To: <56D80D2C.3060706@redhat.com>

On 03/03/2016 02:08 AM, Paolo Bonzini wrote:
>> Do you want LOG_UNIMP or LOG_GUEST_ERROR?
>
> I would actually use LOG_IN_ASM.  As you noticed, guests sometimes use
> illegal opcodes; another example is Xen's hypercall interface.
>
> On 03/03/2016 07:57, Hervé Poussineau wrote:
>> This patch is not quiet on some operating systems:
>> OS/2:
>> ILLOPC: 000172e1: 0f a6
>>
>> Windows XP:
>> ILLOPC: 00020d1a: c4 c4
>>
>> And very verbose in Windows 3.11, Windows 9x:
>> ILLOPC: 000ffb17: 63
>> ILLOPC: 000ffb17: 63
>>
>> Is it normal?
>
> Yes, it is.  As usual, Raymond Chen explains what's going on:
>
> https://blogs.msdn.microsoft.com/oldnewthing/20041215-00/?p=37003

Wow.  That's... interesting.

I think maybe I'll re-do the patch to distinguish between those opcodes that 
are completely unrecognized (which is what I was expecting to find) and those 
that raise #UD due to cpu state (e.g. this arpl in vm86 mode).


r~

  reply	other threads:[~2016-03-03 19:06 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-03  5:30 [Qemu-devel] [PATCH 0/7] target-i386 fixes Richard Henderson
2016-03-03  5:30 ` [Qemu-devel] [PATCH 1/7] target-i386: avoid repeated calls to the bnd_jmp helper Richard Henderson
2016-03-03  5:30 ` [Qemu-devel] [PATCH 2/7] target-i386: fix smsw and lmsw from/to register Richard Henderson
2016-03-03  5:30 ` [Qemu-devel] [PATCH 3/7] target-i386: Fix SMSW for 64-bit mode Richard Henderson
2016-03-03  5:30 ` [Qemu-devel] [PATCH 4/7] target-i386: Dump illegal opcodes with -d unimp Richard Henderson
2016-03-03  6:57   ` Hervé Poussineau
2016-03-03 10:08     ` Paolo Bonzini
2016-03-03 19:06       ` Richard Henderson [this message]
2016-03-04 10:41         ` Paolo Bonzini
2016-03-04 18:12           ` Richard Henderson
2016-03-04 12:15         ` Paolo Bonzini
2016-03-03  5:30 ` [Qemu-devel] [PATCH 5/7] target-i386: fix addr16 prefix Richard Henderson
2016-03-03  5:30 ` [Qemu-devel] [PATCH 6/7] target-i386: Use gen_nop_modrm for prefetch instructions Richard Henderson
2016-03-03  5:30 ` [Qemu-devel] [PATCH 7/7] target-i386: Fix inhibit irq mask handling Richard Henderson
2016-03-03  8:46   ` Paolo Bonzini
2016-03-03  6:49 ` [Qemu-devel] [PATCH 0/7] target-i386 fixes Hervé Poussineau

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