Hi Alex,

Regarding ARMv8 VM migration , in qemu command we have tried with SMP1 and SMP 2 option , we are facing same error .

We have applied patch on kernel version 3.16 and used qemu version link shared with you in previous discussion.

I remember that in our previous discussion , you were talking about merging of timer code and that you needed some hardware for testing. We have ARMv8 hardware. Would it be possible for you to share the testcase procedure to test the timer stuff .

As mentioned and as suggested, we have gone through the following documents and related code :

1. API .txt

2. Qemu code

3. Kernel KVM related code.

Also, do you have some document related to ARM VM migration internals, or some links that we can refer for our better understanding?

Thanks,

Yash

On Mon, Nov 10, 2014 at 8:17 PM, Alex Bennée alex.bennee@linaro.org wrote:

Christoffer Dall christoffer.dall@linaro.org writes:

...

On Mon, Nov 10, 2014 at 1:37 PM, Yash Nandkeolyar yashnky7@gmail.com

wrote:

...

...

Hi,

We are trying to do VM Migration using the version of Qemu obtained

from the

...

...

following branch:

https://github.com/stsquad/qemu/tree/armv8-migration/v4

And we are also using Linux Kernel 3.16 compiled with the patches for AArch64 migration support obtained from the following link:

http://patches.linaro.org/patchwork/bundle/alex.bennee@linaro.org/armv8-migr...

...

...

We have tried both online and offline migration. However, we end up

getting

...

...

the following error at runtime during migration:

qemu-system-aarch64: Unknown combination of migration flags: 0

qemu: warning: error while loading state section id 3

qemu-system-aarch64: load of migration failed: Input/output error

Could anyone please suggest on this.

Alex, any quick suggestions?

However, since this is work-in-progress and these patches haven't actually been verified to work yet (we are working through some known issues) I'm afraid you're mostly going to have to look into the details on your own.

The patches had been smoke tested for non-SMP systems although it's likely the same breakage (lack of vgic state serialisation) could bite in the non-SMP case as well.

The generic timer patch has gone upstream. At the moment the only outstanding patch is the MP_STATE ioctl support. I've re-based that tree to the current -rc:

http://git.linaro.org/people/alex.bennee/linux.git/shortlog/refs/heads/wip/m...

...

We'll post updated and working patches on the lists as soon as we have them.

Currently the QEMU migration/v4 branch is the latest I have. It likely will need a re-base and hard think about the pstate/cspar re-factor approach.

If the remaining state is exported via the GET/SET_ONE_REG interface it's pretty transparent to QEMU which just serialises the data. Whether this makes sense for vgic state remains to be seen.

Finally I have some expect scripts which I'd been using to test migration which can be found at:

http://git.linaro.org/people/alex.bennee/test-definitions.git/blob/refs/head...

run via LAVA:

http://git.linaro.org/people/alex.bennee/test-definitions.git/blob/refs/head...

...

-Christoffer

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-- Alex Bennée