[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 4/7] [s390] reset avail and used index on reboot
From: |
Alexander Graf |
Subject: |
Re: [Qemu-devel] [PATCH 4/7] [s390] reset avail and used index on reboot |
Date: |
Thu, 26 Apr 2012 16:26:24 +0200 |
On 26.04.2012, at 15:56, Christian Borntraeger wrote:
>>> @@ -250,6 +251,12 @@ void s390_virtio_device_sync(VirtIOS390Device *dev)
>>> vring = s390_virtio_next_ring(bus);
>>> virtio_queue_set_addr(dev->vdev, i, vring);
>>> virtio_queue_set_vector(dev->vdev, i, i);
>>> + idx_addr = virtio_queue_get_avail_addr(dev->vdev, i) +
>>> + VIRTIO_VRING_AVAIL_IDX_OFFS;
>>> + stw_phys(idx_addr, 0);
>>> + idx_addr = virtio_queue_get_used_addr(dev->vdev, i) +
>>> + VIRTIO_VRING_USED_IDX_OFFS;
>>> + stw_phys(idx_addr, 0);
>>
>> Are you sure this is correct to do in the sync callback? The idea of "sync"
>> was to have a callback that can be called every time config information
>> changes.
>>
>> That could even be something as simple as a byte changing in the virtio
>> device specific config space. But because we don't get callbacks when the
>> guest accesses them, we need to synchronize it with real memory.
>
> Hmm, currently it is only called on init and virtio reset hypercall. Are you
> talking about
> an intended user which is not yet finished?
It's about the intended idea behind the "sync", yeah. So far, all virtio
devices are ok with a simple workflow, where they never touch the config space
again once they're initialized. But we can't guarantee that this will always be
the case.
How about resetting the queues only on reset?
Alex
- [Qemu-devel] [PATCH 0/7] Fixes for s390, Christian Borntraeger, 2012/04/23
- [Qemu-devel] [PATCH 2/7] [s390] fix error handling on kernel and initrd failures, Christian Borntraeger, 2012/04/23
- [Qemu-devel] [PATCH 5/7] [s390] support reboot for kvm on s390, Christian Borntraeger, 2012/04/23
- [Qemu-devel] [PATCH 6/7] [s390] remove default cdrom, sd-card and floppy support, Christian Borntraeger, 2012/04/23
- [Qemu-devel] [PATCH 1/7] [s390] fix kernel_commandline handling, Christian Borntraeger, 2012/04/23
- [Qemu-devel] [PATCH 3/7] [s390] reboot: reset device pages on reboot, Christian Borntraeger, 2012/04/23
- [Qemu-devel] [PATCH 7/7] [s390] dont call system_shutdown on disabled wait, Christian Borntraeger, 2012/04/23
- [Qemu-devel] [PATCH 4/7] [s390] reset avail and used index on reboot, Christian Borntraeger, 2012/04/23
- Re: [Qemu-devel] [PATCH 4/7] [s390] reset avail and used index on reboot, Jens Freimann, 2012/04/26
Re: [Qemu-devel] [PATCH 0/7] Fixes for s390, Alexander Graf, 2012/04/26