Re: xen/arm Problem with virtual disks

[Julien Grall <julien.grall@linaro.org>]

On 09/18/2013 03:03 PM, Andrii Anisov wrote:
> Hello,

Hello,

> I'm trying to provide my DomU with virtual disk but have faced some
> strange issue. Disk device is discovered in DomU but it is not usable.
> In DomU some trash is read from the xvd* device, and does not reflect
> what is read from the correspondent device in Dom0. Moreover trash read
> from the device differs each time (I checked that by dd)
> I have xen 4.3 release with my patches for panda5 board.

Xen 4.3 was only a tech preview and doesn't contains a couple of
important ARM fixes. If it's possible I advise you to move to xen 4.4
unstable.

> Dom0 is K3.8, DomU is K3.4.
> Dom0 environment is busybox, /etc/xen/scripts/block and related scripts
> are adjusted to be executed by busybox ash.
> 
> In my config I have following disk definition:
> 
>     disk = ["phy:/dev/mmcblk0,xvdb,w"]
> 
> 
> on verbose create, related output is:
> 
>     ibxl: debug: libxl_device.c:257:libxl__device_disk_set_backend: Disk
>     vdev=xvdb spec.backend=phy
>     libxl: debug: libxl_event.c:559:libxl__ev_xswatch_register: watch
>     w=0x379f8 wpath=/local/domain/0/backend/vbd/1/51728/state token=3/0:
>     register slotnum=3
>     libxl: debug: libxl_create.c:1241:do_domain_create: ao 0x36880:
>     inprogress: poller=0x36808, flags=i
>     libxl: debug: libxl_event.c:503:watchfd_callback: watch w=0x379f8
>     wpath=/local/domain/0/backend/vbd/1/51728/state token=3/0: event
>     epath=/local/domain/0/backend/vbd/1/51728/state
>     libxl: debug: libxl_event.c:647:devstate_watch_callback: backend
>     /local/domain/0/backend/vbd/1/51728/state wanted state 2 still
>     waiting state 1
>     libxl: debug: libxl_event.c:503:watchfd_callback: watch w=0x379f8
>     wpath=/local/domain/0/backend/vbd/1/51728/state token=3/0: event
>     epath=/local/domain/0/backend/vbd/1/51728/state
>     libxl: debug: libxl_event.c:643:devstate_watch_callback: backend
>     /local/domain/0/backend/vbd/1/51728/state wanted state 2 ok
>     libxl: debug: libxl_event.c:596:libxl__ev_xswatch_deregister: watch
>     w=0x379f8 wpath=/local/domain/0/backend/vbd/1/51728/state token=3/0:
>     deregister slotnum=3
>     libxl: debug: libxl_event.c:608:libxl__ev_xswatch_deregister: watch
>     w=0x379f8: deregister unregistered
>     libxl: debug: libxl_device.c:959:device_hotplug: calling hotplug
>     script: /etc/xen/scripts/block add
> 
> 
> When DomU discovers virtual disk, in Dom0 console I see following output:
> 
>     xen-blkback:ring-ref 8, event-channel 3, protocol 1 (arm-abi) 
> 
> Could it be a problem in contradiction of blkfront and blkback in
> different kernels?
> Could you please give me some clue to debug such an issue?
>

Few ideas:
   - list of possibly missing commits in xen 4.3:
	* d4435fe5e2f0dfadb41ef46c38f462f45d67762e: avoid the guest to update
the ACTLR himself
	* 8348707ce1c76e2fecbe9d413d5d8f2085bf57cb: correctly configure NSACR
to set ACTLR.SMP
   - http://lists.xen.org/archives/html/xen-devel/2013-06/msg01778.html.
I didn't find any conclusion/commit about this thread.

Perhaps Ian can add more input.

Cheers,


> *Sincerely,*
> *Andrii Anisov.*
> 
> 
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> 


-- 
Julien Grall