lguest: notify on empty
This is the lguest implementation of the VIRTIO_F_NOTIFY_ON_EMPTY feature. It is currently only published for network devices, but it is turned on for everyone. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
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@ -157,6 +157,9 @@ struct virtqueue
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/* The routine to call when the Guest pings us. */
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/* The routine to call when the Guest pings us. */
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void (*handle_output)(int fd, struct virtqueue *me);
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void (*handle_output)(int fd, struct virtqueue *me);
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/* Outstanding buffers */
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unsigned int inflight;
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};
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};
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/* Remember the arguments to the program so we can "reboot" */
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/* Remember the arguments to the program so we can "reboot" */
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@ -702,6 +705,7 @@ static unsigned get_vq_desc(struct virtqueue *vq,
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errx(1, "Looped descriptor");
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errx(1, "Looped descriptor");
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} while ((i = next_desc(vq, i)) != vq->vring.num);
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} while ((i = next_desc(vq, i)) != vq->vring.num);
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vq->inflight++;
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return head;
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return head;
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}
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}
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@ -719,6 +723,7 @@ static void add_used(struct virtqueue *vq, unsigned int head, int len)
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/* Make sure buffer is written before we update index. */
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/* Make sure buffer is written before we update index. */
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wmb();
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wmb();
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vq->vring.used->idx++;
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vq->vring.used->idx++;
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vq->inflight--;
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}
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}
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/* This actually sends the interrupt for this virtqueue */
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/* This actually sends the interrupt for this virtqueue */
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@ -726,8 +731,9 @@ static void trigger_irq(int fd, struct virtqueue *vq)
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{
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{
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unsigned long buf[] = { LHREQ_IRQ, vq->config.irq };
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unsigned long buf[] = { LHREQ_IRQ, vq->config.irq };
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/* If they don't want an interrupt, don't send one. */
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/* If they don't want an interrupt, don't send one, unless empty. */
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if (vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
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if ((vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
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&& vq->inflight)
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return;
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return;
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/* Send the Guest an interrupt tell them we used something up. */
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/* Send the Guest an interrupt tell them we used something up. */
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@ -1107,6 +1113,7 @@ static void add_virtqueue(struct device *dev, unsigned int num_descs,
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vq->next = NULL;
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vq->next = NULL;
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vq->last_avail_idx = 0;
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vq->last_avail_idx = 0;
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vq->dev = dev;
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vq->dev = dev;
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vq->inflight = 0;
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/* Initialize the configuration. */
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/* Initialize the configuration. */
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vq->config.num = num_descs;
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vq->config.num = num_descs;
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@ -1368,6 +1375,7 @@ static void setup_tun_net(const char *arg)
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/* Tell Guest what MAC address to use. */
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/* Tell Guest what MAC address to use. */
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add_feature(dev, VIRTIO_NET_F_MAC);
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add_feature(dev, VIRTIO_NET_F_MAC);
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add_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY);
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set_config(dev, sizeof(conf), &conf);
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set_config(dev, sizeof(conf), &conf);
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/* We don't need the socket any more; setup is done. */
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/* We don't need the socket any more; setup is done. */
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