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

[Christian Borntraeger]

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.