* kvm guest debug using gdb on x86
@ 2009-05-19 18:53 Aneesh Kumar K.V
2009-05-19 19:10 ` Aneesh Kumar K.V
0 siblings, 1 reply; 10+ messages in thread
From: Aneesh Kumar K.V @ 2009-05-19 18:53 UTC (permalink / raw)
To: kvm, jan.kiszka
Hi,
With the latest qemu-kvm and 2.6.30-rc6 kernel i am not able to get
the guest debugging with gdb. I get the following error.
$gdb ./vmlinux
GNU gdb 6.8-debian
Copyright (C) 2008 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later
<http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law. Type "show
copying"
and "show warranty" for details.
This GDB was configured as "i486-linux-gnu"...
(gdb) b do_fork
Breakpoint 1 at 0xc106cfc8: file kernel/fork.c, line 1347.
(gdb) target remote localhost:1234
Remote debugging using localhost:1234
[New Thread 1]
Remote 'g' packet reply is too long:
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
00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
(gdb)
any patches that i can try ?
-aneesh
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: kvm guest debug using gdb on x86
2009-05-19 18:53 kvm guest debug using gdb on x86 Aneesh Kumar K.V
@ 2009-05-19 19:10 ` Aneesh Kumar K.V
2009-05-20 8:10 ` Jan Kiszka
0 siblings, 1 reply; 10+ messages in thread
From: Aneesh Kumar K.V @ 2009-05-19 19:10 UTC (permalink / raw)
To: kvm, jan.kiszka
On Wed, May 20, 2009 at 12:23:12AM +0530, Aneesh Kumar K.V wrote:
> Hi,
>
> With the latest qemu-kvm and 2.6.30-rc6 kernel i am not able to get
> the guest debugging with gdb. I get the following error.
>
> $gdb ./vmlinux
> GNU gdb 6.8-debian
> Copyright (C) 2008 Free Software Foundation, Inc.
> License GPLv3+: GNU GPL version 3 or later
> <http://gnu.org/licenses/gpl.html>
> This is free software: you are free to change and redistribute it.
> There is NO WARRANTY, to the extent permitted by law. Type "show
> copying"
> and "show warranty" for details.
> This GDB was configured as "i486-linux-gnu"...
> (gdb) b do_fork
> Breakpoint 1 at 0xc106cfc8: file kernel/fork.c, line 1347.
> (gdb) target remote localhost:1234
> Remote debugging using localhost:1234
> [New Thread 1]
> Remote 'g' packet reply is too long:
> 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
0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
> (gdb)
>
> any patches that i can try ?
Works better with the four patches found at
http://git.kiszka.org/?p=kvm-userspace.git;a=shortlog;h=refs/heads/queues/gdb
But a next and continue doesn't get the prompt back on gdb. The guest
does stops the execution.
-aneesh
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: kvm guest debug using gdb on x86
2009-05-19 19:10 ` Aneesh Kumar K.V
@ 2009-05-20 8:10 ` Jan Kiszka
2009-05-20 8:40 ` Aneesh Kumar K.V
0 siblings, 1 reply; 10+ messages in thread
From: Jan Kiszka @ 2009-05-20 8:10 UTC (permalink / raw)
To: Aneesh Kumar K.V; +Cc: kvm
Aneesh Kumar K.V wrote:
> On Wed, May 20, 2009 at 12:23:12AM +0530, Aneesh Kumar K.V wrote:
>> Hi,
>>
>> With the latest qemu-kvm and 2.6.30-rc6 kernel i am not able to get
>> the guest debugging with gdb. I get the following error.
>>
>> $gdb ./vmlinux
>> GNU gdb 6.8-debian
>> Copyright (C) 2008 Free Software Foundation, Inc.
>> License GPLv3+: GNU GPL version 3 or later
>> <http://gnu.org/licenses/gpl.html>
>> This is free software: you are free to change and redistribute it.
>> There is NO WARRANTY, to the extent permitted by law. Type "show
>> copying"
>> and "show warranty" for details.
>> This GDB was configured as "i486-linux-gnu"...
>> (gdb) b do_fork
>> Breakpoint 1 at 0xc106cfc8: file kernel/fork.c, line 1347.
>> (gdb) target remote localhost:1234
>> Remote debugging using localhost:1234
>> [New Thread 1]
>> Remote 'g' packet reply is too long:
>> 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
0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000000000000000000000000000000000000000000000000000000000000000000
>> (gdb)
>>
>> any patches that i can try ?
>
> Works better with the four patches found at
>
> http://git.kiszka.org/?p=kvm-userspace.git;a=shortlog;h=refs/heads/queues/gdb
>
> But a next and continue doesn't get the prompt back on gdb. The guest
> does stops the execution.
What arch is host and guest (x86-32 or -64)? What KVM versions are you
using? Are you sure that guest and vmlinux matches?
Jan
--
Siemens AG, Corporate Technology, CT SE 2
Corporate Competence Center Embedded Linux
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: kvm guest debug using gdb on x86
2009-05-20 8:10 ` Jan Kiszka
@ 2009-05-20 8:40 ` Aneesh Kumar K.V
2009-05-20 8:57 ` Jan Kiszka
0 siblings, 1 reply; 10+ messages in thread
From: Aneesh Kumar K.V @ 2009-05-20 8:40 UTC (permalink / raw)
To: Jan Kiszka; +Cc: kvm
On Wed, May 20, 2009 at 10:10:59AM +0200, Jan Kiszka wrote:
> Aneesh Kumar K.V wrote:
> > On Wed, May 20, 2009 at 12:23:12AM +0530, Aneesh Kumar K.V wrote:
> >> Hi,
> >>
> >> With the latest qemu-kvm and 2.6.30-rc6 kernel i am not able to get
> >> the guest debugging with gdb. I get the following error.
> >>
> >> $gdb ./vmlinux
> >> GNU gdb 6.8-debian
> >> Copyright (C) 2008 Free Software Foundation, Inc.
> >> License GPLv3+: GNU GPL version 3 or later
> >> <http://gnu.org/licenses/gpl.html>
> >> This is free software: you are free to change and redistribute it.
> >> There is NO WARRANTY, to the extent permitted by law. Type "show
> >> copying"
> >> and "show warranty" for details.
> >> This GDB was configured as "i486-linux-gnu"...
> >> (gdb) b do_fork
> >> Breakpoint 1 at 0xc106cfc8: file kernel/fork.c, line 1347.
> >> (gdb) target remote localhost:1234
> >> Remote debugging using localhost:1234
> >> [New Thread 1]
> >> Remote 'g' packet reply is too long:
> >> 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
000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
> 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000
> >> (gdb)
> >>
> >> any patches that i can try ?
> >
> > Works better with the four patches found at
> >
> > http://git.kiszka.org/?p=kvm-userspace.git;a=shortlog;h=refs/heads/queues/gdb
> >
> > But a next and continue doesn't get the prompt back on gdb. The guest
> > does stops the execution.
>
> What arch is host and guest (x86-32 or -64)? What KVM versions are you
> using? Are you sure that guest and vmlinux matches?
>
Both host and guest are x86-32. For kvm user space I did a git clone
from git://git.kernel.org/pub/scm/virt/kvm/qemu-kvm.git. I tested with
commit 22d239bcee126742df46938ee8ddc7c6b9209e23. That version fails
with the "remote g packet reply is too long" error. Then i applied the
four patches from your git repo. That gets the guest to stop execution
on breakpoint, i can check the stack. but single stepping doesn't work.
Guest kernel I tried was linux-2.6-tip
-aneesh
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: kvm guest debug using gdb on x86
2009-05-20 8:40 ` Aneesh Kumar K.V
@ 2009-05-20 8:57 ` Jan Kiszka
2009-05-20 9:04 ` Aneesh Kumar K.V
0 siblings, 1 reply; 10+ messages in thread
From: Jan Kiszka @ 2009-05-20 8:57 UTC (permalink / raw)
To: Aneesh Kumar K.V; +Cc: kvm
Aneesh Kumar K.V wrote:
> On Wed, May 20, 2009 at 10:10:59AM +0200, Jan Kiszka wrote:
>> Aneesh Kumar K.V wrote:
>>> On Wed, May 20, 2009 at 12:23:12AM +0530, Aneesh Kumar K.V wrote:
>>>> Hi,
>>>>
>>>> With the latest qemu-kvm and 2.6.30-rc6 kernel i am not able to get
>>>> the guest debugging with gdb. I get the following error.
>>>>
>>>> $gdb ./vmlinux
>>>> GNU gdb 6.8-debian
>>>> Copyright (C) 2008 Free Software Foundation, Inc.
>>>> License GPLv3+: GNU GPL version 3 or later
>>>> <http://gnu.org/licenses/gpl.html>
>>>> This is free software: you are free to change and redistribute it.
>>>> There is NO WARRANTY, to the extent permitted by law. Type "show
>>>> copying"
>>>> and "show warranty" for details.
>>>> This GDB was configured as "i486-linux-gnu"...
>>>> (gdb) b do_fork
>>>> Breakpoint 1 at 0xc106cfc8: file kernel/fork.c, line 1347.
>>>> (gdb) target remote localhost:1234
>>>> Remote debugging using localhost:1234
>>>> [New Thread 1]
>>>> Remote 'g' packet reply is too long:
>>>> 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
0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
00
>> 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000
>>>> (gdb)
>>>>
>>>> any patches that i can try ?
>>> Works better with the four patches found at
>>>
>>> http://git.kiszka.org/?p=kvm-userspace.git;a=shortlog;h=refs/heads/queues/gdb
>>>
>>> But a next and continue doesn't get the prompt back on gdb. The guest
>>> does stops the execution.
>> What arch is host and guest (x86-32 or -64)? What KVM versions are you
>> using? Are you sure that guest and vmlinux matches?
>>
>
> Both host and guest are x86-32. For kvm user space I did a git clone
> from git://git.kernel.org/pub/scm/virt/kvm/qemu-kvm.git. I tested with
> commit 22d239bcee126742df46938ee8ddc7c6b9209e23. That version fails
> with the "remote g packet reply is too long" error. Then i applied the
> four patches from your git repo. That gets the guest to stop execution
> on breakpoint, i can check the stack. but single stepping doesn't work.
>
> Guest kernel I tried was linux-2.6-tip
Does debugging work with -no-kvm, ie. in TCG mode?
Jan
PS: For qemu-kvm.git you can now use my qemu gdb queue directly, ie. you
don't need to rebase manually.
--
Siemens AG, Corporate Technology, CT SE 2
Corporate Competence Center Embedded Linux
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: kvm guest debug using gdb on x86
2009-05-20 8:57 ` Jan Kiszka
@ 2009-05-20 9:04 ` Aneesh Kumar K.V
2009-05-20 9:41 ` Jan Kiszka
0 siblings, 1 reply; 10+ messages in thread
From: Aneesh Kumar K.V @ 2009-05-20 9:04 UTC (permalink / raw)
To: Jan Kiszka; +Cc: kvm
On Wed, May 20, 2009 at 10:57:21AM +0200, Jan Kiszka wrote:
> Aneesh Kumar K.V wrote:
> > On Wed, May 20, 2009 at 10:10:59AM +0200, Jan Kiszka wrote:
> >> Aneesh Kumar K.V wrote:
> >>> On Wed, May 20, 2009 at 12:23:12AM +0530, Aneesh Kumar K.V wrote:
> >>>> Hi,
> >>>>
> >>>> With the latest qemu-kvm and 2.6.30-rc6 kernel i am not able to get
> >>>> the guest debugging with gdb. I get the following error.
> >>>>
> >>>> $gdb ./vmlinux
> >>>> GNU gdb 6.8-debian
> >>>> Copyright (C) 2008 Free Software Foundation, Inc.
> >>>> License GPLv3+: GNU GPL version 3 or later
> >>>> <http://gnu.org/licenses/gpl.html>
> >>>> This is free software: you are free to change and redistribute it.
> >>>> There is NO WARRANTY, to the extent permitted by law. Type "show
> >>>> copying"
> >>>> and "show warranty" for details.
> >>>> This GDB was configured as "i486-linux-gnu"...
> >>>> (gdb) b do_fork
> >>>> Breakpoint 1 at 0xc106cfc8: file kernel/fork.c, line 1347.
> >>>> (gdb) target remote localhost:1234
> >>>> Remote debugging using localhost:1234
> >>>> [New Thread 1]
> >>>> Remote 'g' packet reply is too long:
> >>>> 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
000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
> 00
> >> 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000
> >>>> (gdb)
> >>>>
> >>>> any patches that i can try ?
> >>> Works better with the four patches found at
> >>>
> >>> http://git.kiszka.org/?p=kvm-userspace.git;a=shortlog;h=refs/heads/queues/gdb
> >>>
> >>> But a next and continue doesn't get the prompt back on gdb. The guest
> >>> does stops the execution.
> >> What arch is host and guest (x86-32 or -64)? What KVM versions are you
> >> using? Are you sure that guest and vmlinux matches?
> >>
> >
> > Both host and guest are x86-32. For kvm user space I did a git clone
> > from git://git.kernel.org/pub/scm/virt/kvm/qemu-kvm.git. I tested with
> > commit 22d239bcee126742df46938ee8ddc7c6b9209e23. That version fails
> > with the "remote g packet reply is too long" error. Then i applied the
> > four patches from your git repo. That gets the guest to stop execution
> > on breakpoint, i can check the stack. but single stepping doesn't work.
> >
> > Guest kernel I tried was linux-2.6-tip
>
> Does debugging work with -no-kvm, ie. in TCG mode?
Yes. debugging works with -no-kvm option. I can do single stepping.
-aneesh
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: kvm guest debug using gdb on x86
2009-05-20 9:04 ` Aneesh Kumar K.V
@ 2009-05-20 9:41 ` Jan Kiszka
2009-05-20 9:46 ` Jan Kiszka
0 siblings, 1 reply; 10+ messages in thread
From: Jan Kiszka @ 2009-05-20 9:41 UTC (permalink / raw)
To: Aneesh Kumar K.V; +Cc: kvm
Aneesh Kumar K.V wrote:
> On Wed, May 20, 2009 at 10:57:21AM +0200, Jan Kiszka wrote:
>> Aneesh Kumar K.V wrote:
>>> On Wed, May 20, 2009 at 10:10:59AM +0200, Jan Kiszka wrote:
>>>> Aneesh Kumar K.V wrote:
>>>>> On Wed, May 20, 2009 at 12:23:12AM +0530, Aneesh Kumar K.V wrote:
>>>>>> Hi,
>>>>>>
>>>>>> With the latest qemu-kvm and 2.6.30-rc6 kernel i am not able to get
>>>>>> the guest debugging with gdb. I get the following error.
>>>>>>
>>>>>> $gdb ./vmlinux
>>>>>> GNU gdb 6.8-debian
>>>>>> Copyright (C) 2008 Free Software Foundation, Inc.
>>>>>> License GPLv3+: GNU GPL version 3 or later
>>>>>> <http://gnu.org/licenses/gpl.html>
>>>>>> This is free software: you are free to change and redistribute it.
>>>>>> There is NO WARRANTY, to the extent permitted by law. Type "show
>>>>>> copying"
>>>>>> and "show warranty" for details.
>>>>>> This GDB was configured as "i486-linux-gnu"...
>>>>>> (gdb) b do_fork
>>>>>> Breakpoint 1 at 0xc106cfc8: file kernel/fork.c, line 1347.
>>>>>> (gdb) target remote localhost:1234
>>>>>> Remote debugging using localhost:1234
>>>>>> [New Thread 1]
>>>>>> Remote 'g' packet reply is too long:
>>>>>> 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
> 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
>> 00
>>>> 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000
>>>>>> (gdb)
>>>>>>
>>>>>> any patches that i can try ?
>>>>> Works better with the four patches found at
>>>>>
>>>>> http://git.kiszka.org/?p=kvm-userspace.git;a=shortlog;h=refs/heads/queues/gdb
>>>>>
>>>>> But a next and continue doesn't get the prompt back on gdb. The guest
>>>>> does stops the execution.
>>>> What arch is host and guest (x86-32 or -64)? What KVM versions are you
>>>> using? Are you sure that guest and vmlinux matches?
>>>>
>>> Both host and guest are x86-32. For kvm user space I did a git clone
>>> from git://git.kernel.org/pub/scm/virt/kvm/qemu-kvm.git. I tested with
>>> commit 22d239bcee126742df46938ee8ddc7c6b9209e23. That version fails
>>> with the "remote g packet reply is too long" error. Then i applied the
>>> four patches from your git repo. That gets the guest to stop execution
>>> on breakpoint, i can check the stack. but single stepping doesn't work.
>>>
>>> Guest kernel I tried was linux-2.6-tip
>> Does debugging work with -no-kvm, ie. in TCG mode?
>
>
> Yes. debugging works with -no-kvm option. I can do single stepping.
>
Sigh, confirmed, there is a regression in qemu-kvm. Will dig into this.
Older kvm-userspace should be fine (e.g. the last version you can pull
from my tree).
Jan
--
Siemens AG, Corporate Technology, CT SE 2
Corporate Competence Center Embedded Linux
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: kvm guest debug using gdb on x86
2009-05-20 9:41 ` Jan Kiszka
@ 2009-05-20 9:46 ` Jan Kiszka
2009-05-20 10:49 ` Avi Kivity
0 siblings, 1 reply; 10+ messages in thread
From: Jan Kiszka @ 2009-05-20 9:46 UTC (permalink / raw)
To: Aneesh Kumar K.V; +Cc: kvm
Jan Kiszka wrote:
> Aneesh Kumar K.V wrote:
>> On Wed, May 20, 2009 at 10:57:21AM +0200, Jan Kiszka wrote:
>>> Aneesh Kumar K.V wrote:
>>>> On Wed, May 20, 2009 at 10:10:59AM +0200, Jan Kiszka wrote:
>>>>> Aneesh Kumar K.V wrote:
>>>>>> On Wed, May 20, 2009 at 12:23:12AM +0530, Aneesh Kumar K.V wrote:
>>>>>>> Hi,
>>>>>>>
>>>>>>> With the latest qemu-kvm and 2.6.30-rc6 kernel i am not able to get
>>>>>>> the guest debugging with gdb. I get the following error.
>>>>>>>
>>>>>>> $gdb ./vmlinux
>>>>>>> GNU gdb 6.8-debian
>>>>>>> Copyright (C) 2008 Free Software Foundation, Inc.
>>>>>>> License GPLv3+: GNU GPL version 3 or later
>>>>>>> <http://gnu.org/licenses/gpl.html>
>>>>>>> This is free software: you are free to change and redistribute it.
>>>>>>> There is NO WARRANTY, to the extent permitted by law. Type "show
>>>>>>> copying"
>>>>>>> and "show warranty" for details.
>>>>>>> This GDB was configured as "i486-linux-gnu"...
>>>>>>> (gdb) b do_fork
>>>>>>> Breakpoint 1 at 0xc106cfc8: file kernel/fork.c, line 1347.
>>>>>>> (gdb) target remote localhost:1234
>>>>>>> Remote debugging using localhost:1234
>>>>>>> [New Thread 1]
>>>>>>> Remote 'g' packet reply is too long:
>>>>>>> 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
0
>> 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
>>> 00
>>>>> 0000000000000000000000000000000000000000000000000000000000000000000000000000000000000
>>>>>>> (gdb)
>>>>>>>
>>>>>>> any patches that i can try ?
>>>>>> Works better with the four patches found at
>>>>>>
>>>>>> http://git.kiszka.org/?p=kvm-userspace.git;a=shortlog;h=refs/heads/queues/gdb
>>>>>>
>>>>>> But a next and continue doesn't get the prompt back on gdb. The guest
>>>>>> does stops the execution.
>>>>> What arch is host and guest (x86-32 or -64)? What KVM versions are you
>>>>> using? Are you sure that guest and vmlinux matches?
>>>>>
>>>> Both host and guest are x86-32. For kvm user space I did a git clone
>>>> from git://git.kernel.org/pub/scm/virt/kvm/qemu-kvm.git. I tested with
>>>> commit 22d239bcee126742df46938ee8ddc7c6b9209e23. That version fails
>>>> with the "remote g packet reply is too long" error. Then i applied the
>>>> four patches from your git repo. That gets the guest to stop execution
>>>> on breakpoint, i can check the stack. but single stepping doesn't work.
>>>>
>>>> Guest kernel I tried was linux-2.6-tip
>>> Does debugging work with -no-kvm, ie. in TCG mode?
>>
>> Yes. debugging works with -no-kvm option. I can do single stepping.
>>
>
> Sigh, confirmed, there is a regression in qemu-kvm. Will dig into this.
Hmpf, the regression is also present in qemu upstream in kvm mode.
Jan
--
Siemens AG, Corporate Technology, CT SE 2
Corporate Competence Center Embedded Linux
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: kvm guest debug using gdb on x86
2009-05-20 9:46 ` Jan Kiszka
@ 2009-05-20 10:49 ` Avi Kivity
2009-05-21 7:54 ` Jan Kiszka
0 siblings, 1 reply; 10+ messages in thread
From: Avi Kivity @ 2009-05-20 10:49 UTC (permalink / raw)
To: Jan Kiszka; +Cc: Aneesh Kumar K.V, kvm
Jan Kiszka wrote:
>> Sigh, confirmed, there is a regression in qemu-kvm. Will dig into this.
>>
>
> Hmpf, the regression is also present in qemu upstream in kvm mode.
>
We need gdb tests in kvm-autotest.
--
error compiling committee.c: too many arguments to function
^ permalink raw reply [flat|nested] 10+ messages in thread
* Re: kvm guest debug using gdb on x86
2009-05-20 10:49 ` Avi Kivity
@ 2009-05-21 7:54 ` Jan Kiszka
0 siblings, 0 replies; 10+ messages in thread
From: Jan Kiszka @ 2009-05-21 7:54 UTC (permalink / raw)
To: Avi Kivity; +Cc: Aneesh Kumar K.V, kvm
[-- Attachment #1: Type: text/plain, Size: 410 bytes --]
Avi Kivity wrote:
> Jan Kiszka wrote:
>>> Sigh, confirmed, there is a regression in qemu-kvm. Will dig into this.
>>>
>>
>> Hmpf, the regression is also present in qemu upstream in kvm mode.
That was only local confusion, the regression turned out to be
qemu-kvm-only.
>
> We need gdb tests in kvm-autotest.
>
Yes, I know. It just takes a bit free resources to set this up...
Jan
[-- Attachment #2: OpenPGP digital signature --]
[-- Type: application/pgp-signature, Size: 257 bytes --]
^ permalink raw reply [flat|nested] 10+ messages in thread
end of thread, other threads:[~2009-05-21 7:54 UTC | newest]
Thread overview: 10+ messages (download: mbox.gz follow: Atom feed
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2009-05-19 18:53 kvm guest debug using gdb on x86 Aneesh Kumar K.V
2009-05-19 19:10 ` Aneesh Kumar K.V
2009-05-20 8:10 ` Jan Kiszka
2009-05-20 8:40 ` Aneesh Kumar K.V
2009-05-20 8:57 ` Jan Kiszka
2009-05-20 9:04 ` Aneesh Kumar K.V
2009-05-20 9:41 ` Jan Kiszka
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2009-05-21 7:54 ` Jan Kiszka
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