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Bug 1540836 - -device vmcoreinfo: 'vmcoreinfo' is not a valid device model name on Power platform
Summary: -device vmcoreinfo: 'vmcoreinfo' is not a valid device model name on Power pl...
Keywords:
Status: CLOSED UPSTREAM
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: qemu-kvm-rhev
Version: 7.5
Hardware: ppc64le
OS: Linux
high
high
Target Milestone: rc
: ---
Assignee: Marc-Andre Lureau
QA Contact: yilzhang
URL:
Whiteboard:
Depends On:
Blocks: 1398633
TreeView+ depends on / blocked
 
Reported: 2018-02-01 06:03 UTC by yilzhang
Modified: 2018-02-01 11:18 UTC (History)
10 users (show)

Fixed In Version:
Doc Type: If docs needed, set a value
Doc Text:
Clone Of:
Environment:
Last Closed: 2018-02-01 11:00:42 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)

Description yilzhang 2018-02-01 06:03:58 UTC 
Description of problem:
On Power platform(P8 and P9), qemu-kvm doesn't support vmcoreinfo device.
When starting qemu process with "vmcoreinfo" device, it will fail with errors.


Version-Release number of selected component (if applicable):
Host kernel: 3.10.0-837.el7.ppc64le  (Power8 Host)
qemu-kvm:    qemu-kvm-rhev-2.10.0-18.el7


How reproducible: 100%

Steps to Reproduce:
1. Start qemu with "vmcoreinfo" device


Actual results:
Starting qemu fails:
QEMU 2.10.0 monitor - type 'help' for more information
(qemu) qemu-kvm: -device vmcoreinfo: 'vmcoreinfo' is not a valid device model name


Expected results: Qemu should start successfully


Additional info:
When verifying the bug 1398633 on Power platform, if not adding "vmcoreinfo" device, gdb cannot use dump-guest-memory.py.

And the error is like:
# gdb core.44472 
... ...
(gdb) source /usr/share/qemu-kvm/dump-guest-memory.py
(gdb) set height 0
(gdb) dump-guest-memory /tmp/vmcore  ppc64-le
guest RAM blocks:
target_start     target_end       host_addr        message count
---------------- ---------------- ---------------- ------- -----
0000000000000000 0000000200000000 00003ffd86980000 added       1
0000200080000000 0000200080800000 00003ffd86170000 added       2
Python Exception <class 'gdb.error'> No symbol "vmcoreinfo_realize" in current context.: 
Error occurred in Python command: No symbol "vmcoreinfo_realize" in current context.
(gdb)
Comment 2 Marc-Andre Lureau 2018-02-01 11:00:42 UTC 
(In reply to yilzhang from comment #0)
> Description of problem:
> On Power platform(P8 and P9), qemu-kvm doesn't support vmcoreinfo device.
> When starting qemu process with "vmcoreinfo" device, it will fail with
> errors.
> 
> 
> Version-Release number of selected component (if applicable):
> Host kernel: 3.10.0-837.el7.ppc64le  (Power8 Host)
> qemu-kvm:    qemu-kvm-rhev-2.10.0-18.el7
> 
> 
> How reproducible: 100%
> 
> Steps to Reproduce:
> 1. Start qemu with "vmcoreinfo" device
> 
> 
> Actual results:
> Starting qemu fails:
> QEMU 2.10.0 monitor - type 'help' for more information
> (qemu) qemu-kvm: -device vmcoreinfo: 'vmcoreinfo' is not a valid device
> model name
> 
> 
> Expected results: Qemu should start successfully

vmcoreinfo requires fw-cfg DMA support, which isn't supported on Power. I don't know if there should be a different design for Power, and what it should be.

But since KASLR is not available on Power, we dont't have to solve this yet.

> 
> Additional info:
> When verifying the bug 1398633 on Power platform, if not adding "vmcoreinfo"
> device, gdb cannot use dump-guest-memory.py.
> 
> And the error is like:
> # gdb core.44472 
> ... ...
> (gdb) source /usr/share/qemu-kvm/dump-guest-memory.py
> (gdb) set height 0
> (gdb) dump-guest-memory /tmp/vmcore  ppc64-le
> guest RAM blocks:
> target_start     target_end       host_addr        message count
> ---------------- ---------------- ---------------- ------- -----
> 0000000000000000 0000000200000000 00003ffd86980000 added       1
> 0000200080000000 0000200080800000 00003ffd86170000 added       2
> Python Exception <class 'gdb.error'> No symbol "vmcoreinfo_realize" in
> current context.: 
> Error occurred in Python command: No symbol "vmcoreinfo_realize" in current
> context.
> (gdb)

This is a separate problem, we are treating the regression in the original bug.

Closing as upstream.
Comment 3 Marc-Andre Lureau 2018-02-01 11:18:13 UTC 
(using original bug title for clarity)
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