AcoSail/kernel_optimize_test
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lguest: remove invalid interrupt forcing logic.

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2088761152 (lguest: notify on empty) introduced
lguest support for the VIRTIO_F_NOTIFY_ON_EMPTY flag, but in fact it turned on
interrupts all the time.

Because we always process one buffer at a time, the inflight count is always 0
when call trigger_irq and so we always ignore VRING_AVAIL_F_NO_INTERRUPT from
the Guest.

It should be looking to see if there are more buffers in the Guest's queue:
if it's empty, then we force an interrupt.

This makes little difference, since we usually have an empty queue; but
that's the subject of another patch.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This commit is contained in:
Rusty Russell 2009-06-12 22:27:01 -06:00
parent a6c372de6e
commit ebf9a5a99c
1 changed files with 1 additions and 7 deletions
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8
Documentation/lguest/lguest.c
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@ -172,9 +172,6 @@ struct virtqueue
/* The routine to call when the Guest pings us, or timeout. */
void (*handle_output)(struct virtqueue *me, bool timeout);
/* Outstanding buffers */
unsigned int inflight;
/* Is this blocked awaiting a timer? */
bool blocked;
};
@ -699,7 +696,6 @@ static unsigned get_vq_desc(struct virtqueue *vq,
errx(1, "Looped descriptor");
} while ((i = next_desc(vq, i)) != vq->vring.num);
vq->inflight++;
return head;
}
@ -717,7 +713,6 @@ static void add_used(struct virtqueue *vq, unsigned int head, int len)
/* Make sure buffer is written before we update index. */
wmb();
vq->vring.used->idx++;
vq->inflight--;
}
/* This actually sends the interrupt for this virtqueue */
@ -727,7 +722,7 @@ static void trigger_irq(struct virtqueue *vq)
/* If they don't want an interrupt, don't send one, unless empty. */
if ((vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
&& vq->inflight)
&& lg_last_avail(vq) != vq->vring.avail->idx)
return;
/* Send the Guest an interrupt tell them we used something up. */
@ -1171,7 +1166,6 @@ static void add_virtqueue(struct device *dev, unsigned int num_descs,
vq->next = NULL;
vq->last_avail_idx = 0;
vq->dev = dev;
vq->inflight = 0;
vq->blocked = false;
/* Initialize the configuration. */