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Re: [Qemu-devel] [PATCH 4/7] target-i386: Dump illegal opcodes with -d u
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 4/7] target-i386: Dump illegal opcodes with -d unimp |
Date: |
Fri, 4 Mar 2016 11:41:18 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 |
On 03/03/2016 20:06, Richard Henderson wrote:
> 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).
Good idea. UD2 should not warn too, and also VEX prefixes outside
64-bit mode.
Any thoughts about patch 7?
Paolo
- [Qemu-devel] [PATCH 0/7] target-i386 fixes, Richard Henderson, 2016/03/03
- [Qemu-devel] [PATCH 1/7] target-i386: avoid repeated calls to the bnd_jmp helper, Richard Henderson, 2016/03/03
- [Qemu-devel] [PATCH 2/7] target-i386: fix smsw and lmsw from/to register, Richard Henderson, 2016/03/03
- [Qemu-devel] [PATCH 5/7] target-i386: fix addr16 prefix, Richard Henderson, 2016/03/03
- [Qemu-devel] [PATCH 6/7] target-i386: Use gen_nop_modrm for prefetch instructions, Richard Henderson, 2016/03/03
- [Qemu-devel] [PATCH 3/7] target-i386: Fix SMSW for 64-bit mode, Richard Henderson, 2016/03/03
- [Qemu-devel] [PATCH 4/7] target-i386: Dump illegal opcodes with -d unimp, Richard Henderson, 2016/03/03
[Qemu-devel] [PATCH 7/7] target-i386: Fix inhibit irq mask handling, Richard Henderson, 2016/03/03
Re: [Qemu-devel] [PATCH 0/7] target-i386 fixes, Hervé Poussineau, 2016/03/03