[PATCH v11 25/40] virtio: allow to unbreak/break virtqueue individually

[Jason Wang]

在 2022/7/1 14:31, Michael S. Tsirkin 写道:
> On Wed, Jun 29, 2022 at 02:56:41PM +0800, Xuan Zhuo wrote:
>> This patch allows the new introduced
>> __virtqueue_break()/__virtqueue_unbreak() to break/unbreak the
>> virtqueue.
>>
>> Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
> I wonder how this interacts with the hardening patches.
> Jason?


Consider we've marked it as broken, I think we don't need to care about 
the hardening in this series. Just make it work without hardening.

And I will handle vq reset when rework the IRQ hardening.

Thanks


>
>> ---
>>   drivers/virtio/virtio_ring.c | 24 ++++++++++++++++++++++++
>>   include/linux/virtio.h       |  3 +++
>>   2 files changed, 27 insertions(+)
>>
>> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
>> index 5ec43607cc15..7b02be7fce67 100644
>> --- a/drivers/virtio/virtio_ring.c
>> +++ b/drivers/virtio/virtio_ring.c
>> @@ -2744,6 +2744,30 @@ unsigned int virtqueue_get_vring_size(struct virtqueue *_vq)
>>   }
>>   EXPORT_SYMBOL_GPL(virtqueue_get_vring_size);
>>   
>> +/*
>> + * This function should only be called by the core, not directly by the driver.
>> + */
>> +void __virtqueue_break(struct virtqueue *_vq)
>> +{
>> +	struct vring_virtqueue *vq = to_vvq(_vq);
>> +
>> +	/* Pairs with READ_ONCE() in virtqueue_is_broken(). */
>> +	WRITE_ONCE(vq->broken, true);
>> +}
>> +EXPORT_SYMBOL_GPL(__virtqueue_break);
>> +
>> +/*
>> + * This function should only be called by the core, not directly by the driver.
>> + */
>> +void __virtqueue_unbreak(struct virtqueue *_vq)
>> +{
>> +	struct vring_virtqueue *vq = to_vvq(_vq);
>> +
>> +	/* Pairs with READ_ONCE() in virtqueue_is_broken(). */
>> +	WRITE_ONCE(vq->broken, false);
>> +}
> I don't think these "Pairs" comments have any value.
>
>
>> +EXPORT_SYMBOL_GPL(__virtqueue_unbreak);
>> +
>>   bool virtqueue_is_broken(struct virtqueue *_vq)
>>   {
>>   	struct vring_virtqueue *vq = to_vvq(_vq);
>> diff --git a/include/linux/virtio.h b/include/linux/virtio.h
>> index 1272566adec6..dc474a0d48d1 100644
>> --- a/include/linux/virtio.h
>> +++ b/include/linux/virtio.h
>> @@ -138,6 +138,9 @@ bool is_virtio_device(struct device *dev);
>>   void virtio_break_device(struct virtio_device *dev);
>>   void __virtio_unbreak_device(struct virtio_device *dev);
>>   
>> +void __virtqueue_break(struct virtqueue *_vq);
>> +void __virtqueue_unbreak(struct virtqueue *_vq);
>> +
>>   void virtio_config_changed(struct virtio_device *dev);
>>   #ifdef CONFIG_PM_SLEEP
>>   int virtio_device_freeze(struct virtio_device *dev);
>> -- 
>> 2.31.0