[Virtio-fs] [PATCH v1 5/9] hw/virtio: introduce virtio_device_should_start

[Christian Borntraeger]

Am 15.11.22 um 15:31 schrieb Alex Bennée:
> 
> "Michael S. Tsirkin" <mst at redhat.com> writes:
> 
>> On Mon, Nov 14, 2022 at 06:15:30PM +0100, Christian Borntraeger wrote:
>>>
>>>
>>> Am 14.11.22 um 18:10 schrieb Michael S. Tsirkin:
>>>> On Mon, Nov 14, 2022 at 05:55:09PM +0100, Christian Borntraeger wrote:
>>>>>
>>>>>
>>>>> Am 14.11.22 um 17:37 schrieb Michael S. Tsirkin:
>>>>>> On Mon, Nov 14, 2022 at 05:18:53PM +0100, Christian Borntraeger wrote:
>>>>>>> Am 08.11.22 um 10:23 schrieb Alex Bennée:
>>>>>>>> The previous fix to virtio_device_started revealed a problem in its
>>>>>>>> use by both the core and the device code. The core code should be able
>>>>>>>> to handle the device "starting" while the VM isn't running to handle
>>>>>>>> the restoration of migration state. To solve this dual use introduce a
>>>>>>>> new helper for use by the vhost-user backends who all use it to feed a
>>>>>>>> should_start variable.
>>>>>>>>
>>>>>>>> We can also pick up a change vhost_user_blk_set_status while we are at
>>>>>>>> it which follows the same pattern.
>>>>>>>>
>>>>>>>> Fixes: 9f6bcfd99f (hw/virtio: move vm_running check to virtio_device_started)
>>>>>>>> Fixes: 27ba7b027f (hw/virtio: add boilerplate for vhost-user-gpio device)
>>>>>>>> Signed-off-by: Alex Bennée <alex.bennee at linaro.org>
>>>>>>>> Cc: "Michael S. Tsirkin" <mst at redhat.com>
>>>>>>>
>>>>>>> Hmmm, is this
>>>>>>> commit 259d69c00b67c02a67f3bdbeeea71c2c0af76c35
>>>>>>> Author:     Alex Bennée <alex.bennee at linaro.org>
>>>>>>> AuthorDate: Mon Nov 7 12:14:07 2022 +0000
>>>>>>> Commit:     Michael S. Tsirkin <mst at redhat.com>
>>>>>>> CommitDate: Mon Nov 7 14:08:18 2022 -0500
>>>>>>>
>>>>>>>        hw/virtio: introduce virtio_device_should_start
>>>>>>>
>>>>>>> and older version?
>>>>>>
>>>>>> This is what got merged:
>>>>>> https://lore.kernel.org/r/20221107121407.1010913-1-alex.bennee%40linaro.org
>>>>>> This patch was sent after I merged the RFC.
>>>>>> I think the only difference is the commit log but I might be missing
>>>>>> something.
>>>>>>
>>>>>>> This does not seem to fix the regression that I have reported.
>>>>>>
>>>>>> This was applied on top of 9f6bcfd99f which IIUC does, right?
>>>>>>
>>>>>>
>>>>>
>>>>> QEMU master still fails for me for suspend/resume to disk:
>>>>>
>>>>> #0  0x000003ff8e3980a6 in __pthread_kill_implementation () at /lib64/libc.so.6
>>>>> #1  0x000003ff8e348580 in raise () at /lib64/libc.so.6
>>>>> #2  0x000003ff8e32b5c0 in abort () at /lib64/libc.so.6
>>>>> #3  0x000003ff8e3409da in __assert_fail_base () at /lib64/libc.so.6
>>>>> #4  0x000003ff8e340a4e in  () at /lib64/libc.so.6
>>>>> #5 0x000002aa1ffa8966 in vhost_vsock_common_pre_save
>>>>> (opaque=<optimized out>) at
>>>>> ../hw/virtio/vhost-vsock-common.c:203
>>>>> #6  0x000002aa1fe5e0ee in vmstate_save_state_v
>>>>>       (f=f at entry=0x2aa21bdc170, vmsd=0x2aa204ac5f0
>>>>> <vmstate_virtio_vhost_vsock>, opaque=0x2aa21bac9f8,
>>>>> vmdesc=vmdesc at entry=0x3fddc08eb30,
>>>>> version_id=version_id at entry=0) at ../migration/vmstate.c:329
>>>>> #7 0x000002aa1fe5ebf8 in vmstate_save_state
>>>>> (f=f at entry=0x2aa21bdc170, vmsd=<optimized out>,
>>>>> opaque=<optimized out>, vmdesc_id=vmdesc_id at entry=0x3fddc08eb30)
>>>>> at ../migration/vmstate.c:317
>>>>> #8 0x000002aa1fe75bd0 in vmstate_save (f=f at entry=0x2aa21bdc170,
>>>>> se=se at entry=0x2aa21bdbe90, vmdesc=vmdesc at entry=0x3fddc08eb30) at
>>>>> ../migration/savevm.c:908
>>>>> #9 0x000002aa1fe79584 in
>>>>> qemu_savevm_state_complete_precopy_non_iterable
>>>>> (f=f at entry=0x2aa21bdc170, in_postcopy=in_postcopy at entry=false,
>>>>> inactivate_disks=inactivate_disks at entry=true)
>>>>>       at ../migration/savevm.c:1393
>>>>> #10 0x000002aa1fe79a96 in qemu_savevm_state_complete_precopy
>>>>> (f=0x2aa21bdc170, iterable_only=iterable_only at entry=false,
>>>>> inactivate_disks=inactivate_disks at entry=true) at
>>>>> ../migration/savevm.c:1459
>>>>> #11 0x000002aa1fe6d6ee in migration_completion (s=0x2aa218ef600) at ../migration/migration.c:3314
>>>>> #12 migration_iteration_run (s=0x2aa218ef600) at ../migration/migration.c:3761
>>>>> #13 migration_thread (opaque=opaque at entry=0x2aa218ef600) at ../migration/migration.c:3989
>>>>> #14 0x000002aa201f0b8c in qemu_thread_start (args=<optimized out>) at ../util/qemu-thread-posix.c:505
>>>>> #15 0x000003ff8e396248 in start_thread () at /lib64/libc.so.6
>>>>> #16 0x000003ff8e41183e in thread_start () at /lib64/libc.so.6
>>>>>
>>>>> Michael, your previous branch did work if I recall correctly.
>>>>
>>>> That one was failing under github CI though (for reasons we didn't
>>>> really address, such as disconnect during stop causing a recursive
>>>> call to stop, but there you are).
>>> Even the double revert of everything?
>>
>> I don't remember at this point.
>>
>>> So how do we proceed now?
>>
>> I'm hopeful Alex will come up with a fix.
> 
> I need to replicate the failing test for that. Which test is failing?


Pretty much the same as before. guest with vsock, managedsave and restore.