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Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop |
Date: |
Wed, 16 Mar 2016 12:48:22 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.6.0 |
On 16/03/2016 12:32, Cornelia Huck wrote:
> On Wed, 16 Mar 2016 12:09:02 +0100
> Paolo Bonzini <address@hidden> wrote:
>
>> On 16/03/2016 11:49, Christian Borntraeger wrote:
>
>>> #3 0x00000000800b713e in virtio_blk_data_plane_start (s=0xba232d80) at
>>> /home/cborntra/REPOS/qemu/hw/block/dataplane/virtio-blk.c:224
>>> #4 0x00000000800b4ea0 in virtio_blk_handle_output (vdev=0xb9eee7e8,
>>> vq=0xba305270) at /home/cborntra/REPOS/qemu/hw/block/virtio-blk.c:590
>>> #5 0x00000000800ef3dc in virtio_queue_notify_vq (vq=0xba305270) at
>>> /home/cborntra/REPOS/qemu/hw/virtio/virtio.c:1095
>>> #6 0x00000000800f1c9c in virtio_queue_host_notifier_read (n=0xba3052c8) at
>>> /home/cborntra/REPOS/qemu/hw/virtio/virtio.c:1785
>>> #7 0x00000000800f1e14 in virtio_queue_set_host_notifier_fd_handler
>>> (vq=0xba305270, assign=false, set_handler=false) at
>>> /home/cborntra/REPOS/qemu/hw/virtio/virtio.c:1817
>>> #8 0x0000000080109c50 in virtio_ccw_set_guest2host_notifier
>>> (dev=0xb9eed6a0, n=0, assign=false, set_handler=false) at
>>> /home/cborntra/REPOS/qemu/hw/s390x/virtio-ccw.c:97
>>> #9 0x0000000080109ef2 in virtio_ccw_stop_ioeventfd (dev=0xb9eed6a0) at
>>> /home/cborntra/REPOS/qemu/hw/s390x/virtio-ccw.c:154
>>
>> One bug is here: virtio_ccw_stop_ioeventfd, in this case, should pass
>> assign=true to virtio_ccw_set_guest2host_notifier. (Assuming my
>> understanding of assign=true is correct; I think it means "I'm going to
>> set up another host notifier handler").
>
> Hm... I copied these semantics from virtio-pci, and they still seem to
> be the same. I wonder why we never saw this on virtio-pci?
Just because we never ran the right tests, probably. The bug is indeed
in virtio-pci as well (I didn't check mmio).
>> In dataplane, instead, all calls to
>> virtio_queue_set_host_notifier_fd_handler and
>> virtio_queue_aio_set_host_notifier_handler should have assign=true. The
>> ioeventfd is just being moved from one aiocontext to another.
>
> How can a transport know where they are called from?
That's a bug in dataplane. The calls should be changed in
hw/block/dataplane/virtio-blk.c
Paolo
- [Qemu-devel] [PATCH 3/4] virtio-blk: Use blk_drained_begin/end around dataplane stop, (continued)
- [Qemu-devel] [PATCH 3/4] virtio-blk: Use blk_drained_begin/end around dataplane stop, Fam Zheng, 2016/03/16
- [Qemu-devel] [PATCH 4/4] virtio-blk: Clean up start/stop with mutex and BH, Fam Zheng, 2016/03/16
- Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop, Paolo Bonzini, 2016/03/16
- Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop, Christian Borntraeger, 2016/03/16
- Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop, Paolo Bonzini, 2016/03/16
- Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop, Christian Borntraeger, 2016/03/16
- Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop, Paolo Bonzini, 2016/03/16
- Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop, Christian Borntraeger, 2016/03/16
- Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop, Paolo Bonzini, 2016/03/16
- Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop, Cornelia Huck, 2016/03/16
- Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop,
Paolo Bonzini <=
- Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop, Cornelia Huck, 2016/03/16
- Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop, Paolo Bonzini, 2016/03/16
- Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop, Cornelia Huck, 2016/03/16
- Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop, Paolo Bonzini, 2016/03/16
- Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop, Cornelia Huck, 2016/03/16
- Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop, Paolo Bonzini, 2016/03/16
- Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop, Cornelia Huck, 2016/03/16
- Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop, Paolo Bonzini, 2016/03/16
- Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop, Cornelia Huck, 2016/03/16
- Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop, Paolo Bonzini, 2016/03/16