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Re: [Qemu-devel] QEMU savevm RAM page offsets
From: |
Laszlo Ersek |
Subject: |
Re: [Qemu-devel] QEMU savevm RAM page offsets |
Date: |
Tue, 13 Aug 2013 18:51:43 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130621 Thunderbird/17.0.7 |
On 08/13/13 18:03, Andreas Färber wrote:
> Hi,
>
> Am 13.08.2013 15:30, schrieb Juerg Haefliger:
>> I'm writing/extending a little tool (courtesy of Andrew @pikewerks)
>> that dumps the RAM pages from a savevm file to a raw memory dump file
>> so that it can be analysed using tools that require a raw dump as
>> input.
>
> Can't you just use QEMU's guest-memory-dump API? Either directly or
> after loadvm'ing it.
That used to suffer from the exact same problem Juerg described, but I
fixed it for 1.6.
See the series at
http://thread.gmane.org/gmane.comp.emulators.qemu/226715
(See patch 4/4 for a diagram that has been called "nice" in a private
email.)
Commit hashes:
1 2cac260 dump: clamp guest-provided mapping lengths to ramblock sizes
2 5ee163e dump: introduce GuestPhysBlockList
3 c5d7f60 dump: populate guest_phys_blocks
4 56c4bfb dump: rebase from host-private RAMBlock offsets to
guest-physical addresses
(Red Hat BZ: <https://bugzilla.redhat.com/show_bug.cgi?id=981582>.)
In short, you have to use guest-physical addresses (hwaddr) instead of
qemu-internal RAMBlock offsets (ram_addr_t), because the vmcore analysis
tool ("crash" eg.) works with guest-phys addresses as well.
See also the HACKING file, section "2.1. Scalars".
So yes, use the dump-guest-memory QMP/HMP command.
Laszlo
- [Qemu-devel] QEMU savevm RAM page offsets, Juerg Haefliger, 2013/08/13
- Re: [Qemu-devel] QEMU savevm RAM page offsets, Andreas Färber, 2013/08/13
- Re: [Qemu-devel] QEMU savevm RAM page offsets,
Laszlo Ersek <=
- Re: [Qemu-devel] QEMU savevm RAM page offsets, Laszlo Ersek, 2013/08/13
- Re: [Qemu-devel] QEMU savevm RAM page offsets, Juerg Haefliger, 2013/08/13
- Re: [Qemu-devel] QEMU savevm RAM page offsets, Paolo Bonzini, 2013/08/13
- Re: [Qemu-devel] QEMU savevm RAM page offsets, Juerg Haefliger, 2013/08/13
- Re: [Qemu-devel] QEMU savevm RAM page offsets, Laszlo Ersek, 2013/08/13
- Re: [Qemu-devel] QEMU savevm RAM page offsets, Juerg Haefliger, 2013/08/16