Re: [Crash-utility] [PATCH 0/2] qemu: Parse necessary sections in crash added in qemu
BTW, this footerSecId variable should be declared as ATTRIBUTE_UNUSED:
$ make warn
... [ cut ] ...
cc -c -g -DX86_64 -DLZO -DSNAPPY -DGDB_7_6 qemu-load.c -Wall -O2 -Wstrict-prototypes
-Wmissing-prototypes -fstack-protector -Wformat-security
qemu-load.c: In function 'qemu_load':
qemu-load.c:976:13: warning: unused variable 'footerSecId' [-Wunused-variable]
uint32_t footerSecId = get_be32 (fp);
...
Dave
----- Original Message -----
----- Original Message -----
> Qemu migration code added new sections to add features
> for live migration of VM. For loading vmcore file captured
> with 'virsh dump' we need to parse these sections in crash.
>
> This series contains two patches, which parse these sections:
>
> patch1: parse 'vm_configuration' section
> patch2: parse 'vm_footer' section
>
> qemu-load.c | 20 ++++++++++++++++++++
> qemu-load.h | 4 +++-
> 2 files changed, 23 insertions(+), 1 deletion(-)
>
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>
Hi Pankaj,
I suppose I can take the patch. But, given the advent of "virsh dump
--memory-only"
back in 2012, and more recently, Oleg's added support for QEMU ramdumps by
specifying
a memory-backend-file object to the qemu-kvm command:
commit 89ed9d0a7f7da4578294a492c1ad857244ce7352
Author: Dave Anderson <anderson(a)redhat.com>
Date: Wed May 4 11:50:19 2016 -0400
Introduction of support for "live" ramdump files, such as those that
are specified by the QEMU mem-path argument of a memory-backend-file
object. This allows the running of a live crash session against a
QEMU guest from the host machine. In this example, the /tmp/MEM file
on a QEMU host represents the guest's physical memory:
$ qemu-kvm ...other-options... \
-object memory-backend-file,id=MEM,size=128m,mem-path=/tmp/MEM,share=on
\
-numa node,memdev=MEM -m 128
and a live session run can be run against the guest kernel like so:
$ crash <path-to-guest-vmlinux> live:/tmp/MEM@0
By prepending the ramdump image name with "live:", the crash session will
act as if it were running a normal live session.
(oleg(a)redhat.com)
And if the guest above crashed, the leftover file can be used as a regular
ramdump dumpfile:
commit 67a815b8749fbd5c99c29d24b4e699b1d618ddbf
Author: Dave Anderson <anderson(a)redhat.com>
Date: Wed May 4 14:34:53 2016 -0400
Added support for x86_64 ramdump files. Without the patch, the crash
session fails immediately with the message "ramdump: unsupported
machine type: X86_64".
(anderson(a)redhat.com)
So I don't know why anybody would ever want to use the old "kvmdump"
format?
It's for all practical purposes deprecated, not to mention that it's really
an unsuitable excuse for a crash dumpfile.
Dave
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