From: Stefan Weil <sw@weilnetz.de>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Michael W. Bombardieri" <mb@ii.net>,
qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] qemu 1.6.1
Date: Sat, 26 Oct 2013 11:51:07 +0200 [thread overview]
Message-ID: <526B908B.20104@weilnetz.de> (raw)
In-Reply-To: <5269958A.50400@redhat.com>
Am 24.10.2013 23:47, schrieb Paolo Bonzini:
> Il 24/10/2013 17:37, Stefan Weil ha scritto:
>> Yes, that works, too. It also fixes the problem with the assertion
>> (tested with Wine).
>>
>> No, we cannot remove from_, because the same interface is also used
>> for Linux and other hosts which don't have a 'current' variable.
>> Or we would have to call qemu_coroutine_self() to get the current
>> coroutine.
> Yes, I was thinking of using qemu_coroutine_self().
>
> By the way, can you post the two assembly language outputs for just
>
> - CoroutineWin32 *from = DO_UPCAST(CoroutineWin32, base, from_);
> + CoroutineWin32 *from = DO_UPCAST(CoroutineWin32, base, current);
>
> which AIUI works and is enough to fix the bug?
>
> Paolo
See disassembled code below. I removed compiler option -fstack-protector-all
to simplify the assembler code and tested that the result was not affected
by this removal.
The C and assembler code from the test is also available at
http://qemu.weilnetz.de/test/coroutine-win32/.
Stefan
unpatched QEMU, crash with assertion
00448670 <_qemu_coroutine_switch>:
448670: 53 push %ebx
448671: 83 ec 18 sub $0x18,%esp
448674: c7 04 24 a8 62 6d 00 movl $0x6d62a8,(%esp)
44867b: 8b 5c 24 24 mov 0x24(%esp),%ebx
44867f: e8 ec 9e 27 00 call 6c2570
<___emutls_get_address>
448684: 89 18 mov %ebx,(%eax)
448686: 8b 44 24 28 mov 0x28(%esp),%eax
44868a: 89 43 24 mov %eax,0x24(%ebx)
44868d: 8b 43 20 mov 0x20(%ebx),%eax
448690: 89 04 24 mov %eax,(%esp)
448693: ff 15 c0 5f 83 00 call *0x835fc0
448699: 83 ec 04 sub $0x4,%esp
44869c: 8b 44 24 20 mov 0x20(%esp),%eax
4486a0: 8b 40 24 mov 0x24(%eax),%eax
4486a3: 83 c4 18 add $0x18,%esp
4486a6: 5b pop %ebx
4486a7: c3 ret
patched, works
00448620 <_qemu_coroutine_switch>:
448620: 83 ec 1c sub $0x1c,%esp
448623: c7 04 24 a8 62 6d 00 movl $0x6d62a8,(%esp)
44862a: 89 5c 24 14 mov %ebx,0x14(%esp)
44862e: 8b 5c 24 24 mov 0x24(%esp),%ebx
448632: 89 74 24 18 mov %esi,0x18(%esp)
448636: e8 25 9f 27 00 call 6c2560
<___emutls_get_address>
44863b: 8b 30 mov (%eax),%esi
44863d: 89 18 mov %ebx,(%eax)
44863f: 8b 44 24 28 mov 0x28(%esp),%eax
448643: 89 43 24 mov %eax,0x24(%ebx)
448646: 8b 43 20 mov 0x20(%ebx),%eax
448649: 89 04 24 mov %eax,(%esp)
44864c: ff 15 c0 5f 83 00 call *0x835fc0
448652: 8b 46 24 mov 0x24(%esi),%eax
448655: 83 ec 04 sub $0x4,%esp
448658: 8b 5c 24 14 mov 0x14(%esp),%ebx
44865c: 8b 74 24 18 mov 0x18(%esp),%esi
448660: 83 c4 1c add $0x1c,%esp
448663: c3 ret
next prev parent reply other threads:[~2013-10-26 9:51 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-23 7:39 [Qemu-devel] qemu 1.6.1 Michael W. Bombardieri
2013-10-23 9:00 ` Paolo Bonzini
2013-10-23 20:26 ` Stefan Weil
2013-10-24 10:38 ` Paolo Bonzini
2013-10-24 16:37 ` Stefan Weil
2013-10-24 21:47 ` Paolo Bonzini
2013-10-26 9:51 ` Stefan Weil [this message]
2013-10-27 6:54 ` Paolo Bonzini
2013-10-27 10:44 ` Stefan Weil
2013-10-27 15:38 ` Stefan Weil
2014-06-23 14:39 ` [Qemu-devel] broken win32 coroutines (was Re: qemu 1.6.1) Paolo Bonzini
2014-06-24 1:41 ` Michael W. Bombardieri
2014-06-24 5:22 ` Paolo Bonzini
2014-06-25 6:48 ` Michael W. Bombardieri
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