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[Qemu-discuss] QEMU Snapshots on Sabrelite IMX.6 do not work
From: |
alsn |
Subject: |
[Qemu-discuss] QEMU Snapshots on Sabrelite IMX.6 do not work |
Date: |
Fri, 09 Aug 2019 08:49:50 +0200 |
User-agent: |
GWP-Draft |
Hello, I'm
trying to take and
restore a
snapshot with
the whole system state of the Sabrelite
IMX.6 board running on QEMU with commands savevm/loadvm . It seem s that
I am able to take a snapshot but loading the snapshot fails. For
comparison I checked out snapshots on 32bit ARM Virt with Debian as
well as on the Versatilepb board with a bare metal application and it
works fine. The problem occurs only with that one particular
board. At
the moment I ran out of ideas what's the reason of the problem. My
environment is: Ubuntu
18.04 QEMU
3.0.1 ( I
see the same
issue in
QEMU 4.0.0 as well) The
kernel and device tree used for the board was 5.1.14 version from
kernel.org The
file system was build from imx_v6_v7_defconfig config in
buildroot as and sd card image. Problem: Loading
snapshot stops the whole
machine and it's impossible to resume it. Steps
to reproduce problem: 1.
I converted the sdcard.img built from the buildroot to qcow2 using
command qemu-img convert -f raw -O qcow2 sdcard.img
sdcard.qcow2, sinc the raw doesn't support snapshots. 2.
I start QEMU with a command ./arm-softmmu/qemu-system-arm -m
512 -M sabrelite -kernel zImage -append "rootfstype=ext4
root=/dev/mmc rw rootwait" -rtc base=localtime,clock=vm
-dtb imx6dl-sabresd.dtb -drive
file=sdcard.qcow2,index -device
sd-card,drive=mycard -nographic -net nic -net user 3.
I run a simple program which print characters to the console in the
background and add some files in user directory, to differ from
original image. 4.
I switch to QEMU monitor, and type “savevm <name>”. When
I type “info snapshots”, the snapshot is listed. So I
assume it was saved correctly. 5.
Then I switch back to Linux console from monitor, remove the added
files and stop the background printing process. 6.
I switch back to monitor and I'm trying now to load the snapshot by
“loadvm <name>” command. That’s
where the problem occurs. QEMU stops and I can't switch back from
monitor to Linux. Typing “cont” doesn’t help. It
seems like the simulation has freezed. CPU usage on my Laptop machine
equals 100% until I exit QEMU. What’s
interesting when I exit the QEMU and then start it again the Linux
boots and after it reaches the command prompt I can see the files
which were removed after saving the snapshot. It
looks like loading the snapshots works for restoring disk space but
it fails for restoring the running processes. I
thought that this may be a problem with not enough space on the sd
card to store the snapshot but after resizing from 63M to 500MB (in
buildroot) the problem remains the same. I
will appreciate any comments or hints. Regards, …
- [Qemu-discuss] QEMU Snapshots on Sabrelite IMX.6 do not work,
alsn <=