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-rw-r--r--drivers/vhost/net.c6
-rw-r--r--drivers/vhost/vhost.c120
-rw-r--r--drivers/vhost/vhost.h8
3 files changed, 109 insertions, 25 deletions
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 7cbfc7d718b3..4f9c67f17b49 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -374,7 +374,8 @@ static void vhost_zerocopy_signal_used(struct vhost_net *net,
while (j) {
add = min(UIO_MAXIOV - nvq->done_idx, j);
vhost_add_used_and_signal_n(vq->dev, vq,
- &vq->heads[nvq->done_idx], add);
+ &vq->heads[nvq->done_idx],
+ NULL, add);
nvq->done_idx = (nvq->done_idx + add) % UIO_MAXIOV;
j -= add;
}
@@ -457,7 +458,8 @@ static void vhost_net_signal_used(struct vhost_net_virtqueue *nvq)
if (!nvq->done_idx)
return;
- vhost_add_used_and_signal_n(dev, vq, vq->heads, nvq->done_idx);
+ vhost_add_used_and_signal_n(dev, vq, vq->heads, NULL,
+ nvq->done_idx);
nvq->done_idx = 0;
}
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index b38e39242fb9..a4873d116df1 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -372,6 +372,7 @@ static void vhost_vq_reset(struct vhost_dev *dev,
vq->avail = NULL;
vq->used = NULL;
vq->last_avail_idx = 0;
+ vq->next_avail_head = 0;
vq->avail_idx = 0;
vq->last_used_idx = 0;
vq->signalled_used = 0;
@@ -501,6 +502,8 @@ static void vhost_vq_free_iovecs(struct vhost_virtqueue *vq)
vq->log = NULL;
kfree(vq->heads);
vq->heads = NULL;
+ kfree(vq->nheads);
+ vq->nheads = NULL;
}
/* Helper to allocate iovec buffers for all vqs. */
@@ -518,7 +521,9 @@ static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
GFP_KERNEL);
vq->heads = kmalloc_array(dev->iov_limit, sizeof(*vq->heads),
GFP_KERNEL);
- if (!vq->indirect || !vq->log || !vq->heads)
+ vq->nheads = kmalloc_array(dev->iov_limit, sizeof(*vq->nheads),
+ GFP_KERNEL);
+ if (!vq->indirect || !vq->log || !vq->heads || !vq->nheads)
goto err_nomem;
}
return 0;
@@ -2159,14 +2164,15 @@ long vhost_vring_ioctl(struct vhost_dev *d, unsigned int ioctl, void __user *arg
break;
}
if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED)) {
- vq->last_avail_idx = s.num & 0xffff;
+ vq->next_avail_head = vq->last_avail_idx =
+ s.num & 0xffff;
vq->last_used_idx = (s.num >> 16) & 0xffff;
} else {
if (s.num > 0xffff) {
r = -EINVAL;
break;
}
- vq->last_avail_idx = s.num;
+ vq->next_avail_head = vq->last_avail_idx = s.num;
}
/* Forget the cached index value. */
vq->avail_idx = vq->last_avail_idx;
@@ -2798,11 +2804,12 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
unsigned int *out_num, unsigned int *in_num,
struct vhost_log *log, unsigned int *log_num)
{
+ bool in_order = vhost_has_feature(vq, VIRTIO_F_IN_ORDER);
struct vring_desc desc;
unsigned int i, head, found = 0;
u16 last_avail_idx = vq->last_avail_idx;
__virtio16 ring_head;
- int ret, access;
+ int ret, access, c = 0;
if (vq->avail_idx == vq->last_avail_idx) {
ret = vhost_get_avail_idx(vq);
@@ -2813,17 +2820,21 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
return vq->num;
}
- /* Grab the next descriptor number they're advertising, and increment
- * the index we've seen. */
- if (unlikely(vhost_get_avail_head(vq, &ring_head, last_avail_idx))) {
- vq_err(vq, "Failed to read head: idx %d address %p\n",
- last_avail_idx,
- &vq->avail->ring[last_avail_idx % vq->num]);
- return -EFAULT;
+ if (in_order)
+ head = vq->next_avail_head & (vq->num - 1);
+ else {
+ /* Grab the next descriptor number they're
+ * advertising, and increment the index we've seen. */
+ if (unlikely(vhost_get_avail_head(vq, &ring_head,
+ last_avail_idx))) {
+ vq_err(vq, "Failed to read head: idx %d address %p\n",
+ last_avail_idx,
+ &vq->avail->ring[last_avail_idx % vq->num]);
+ return -EFAULT;
+ }
+ head = vhost16_to_cpu(vq, ring_head);
}
- head = vhost16_to_cpu(vq, ring_head);
-
/* If their number is silly, that's an error. */
if (unlikely(head >= vq->num)) {
vq_err(vq, "Guest says index %u > %u is available",
@@ -2866,6 +2877,7 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
"in indirect descriptor at idx %d\n", i);
return ret;
}
+ ++c;
continue;
}
@@ -2901,10 +2913,12 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
}
*out_num += ret;
}
+ ++c;
} while ((i = next_desc(vq, &desc)) != -1);
/* On success, increment avail index. */
vq->last_avail_idx++;
+ vq->next_avail_head += c;
/* Assume notifications from guest are disabled at this point,
* if they aren't we would need to update avail_event index. */
@@ -2928,8 +2942,9 @@ int vhost_add_used(struct vhost_virtqueue *vq, unsigned int head, int len)
cpu_to_vhost32(vq, head),
cpu_to_vhost32(vq, len)
};
+ u16 nheads = 1;
- return vhost_add_used_n(vq, &heads, 1);
+ return vhost_add_used_n(vq, &heads, &nheads, 1);
}
EXPORT_SYMBOL_GPL(vhost_add_used);
@@ -2965,10 +2980,9 @@ static int __vhost_add_used_n(struct vhost_virtqueue *vq,
return 0;
}
-/* After we've used one of their buffers, we tell them about it. We'll then
- * want to notify the guest, using eventfd. */
-int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
- unsigned count)
+static int vhost_add_used_n_ooo(struct vhost_virtqueue *vq,
+ struct vring_used_elem *heads,
+ unsigned count)
{
int start, n, r;
@@ -2981,7 +2995,69 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
heads += n;
count -= n;
}
- r = __vhost_add_used_n(vq, heads, count);
+ return __vhost_add_used_n(vq, heads, count);
+}
+
+static int vhost_add_used_n_in_order(struct vhost_virtqueue *vq,
+ struct vring_used_elem *heads,
+ const u16 *nheads,
+ unsigned count)
+{
+ vring_used_elem_t __user *used;
+ u16 old, new = vq->last_used_idx;
+ int start, i;
+
+ if (!nheads)
+ return -EINVAL;
+
+ start = vq->last_used_idx & (vq->num - 1);
+ used = vq->used->ring + start;
+
+ for (i = 0; i < count; i++) {
+ if (vhost_put_used(vq, &heads[i], start, 1)) {
+ vq_err(vq, "Failed to write used");
+ return -EFAULT;
+ }
+ start += nheads[i];
+ new += nheads[i];
+ if (start >= vq->num)
+ start -= vq->num;
+ }
+
+ if (unlikely(vq->log_used)) {
+ /* Make sure data is seen before log. */
+ smp_wmb();
+ /* Log used ring entry write. */
+ log_used(vq, ((void __user *)used - (void __user *)vq->used),
+ (vq->num - start) * sizeof *used);
+ if (start + count > vq->num)
+ log_used(vq, 0,
+ (start + count - vq->num) * sizeof *used);
+ }
+
+ old = vq->last_used_idx;
+ vq->last_used_idx = new;
+ /* If the driver never bothers to signal in a very long while,
+ * used index might wrap around. If that happens, invalidate
+ * signalled_used index we stored. TODO: make sure driver
+ * signals at least once in 2^16 and remove this. */
+ if (unlikely((u16)(new - vq->signalled_used) < (u16)(new - old)))
+ vq->signalled_used_valid = false;
+ return 0;
+}
+
+/* After we've used one of their buffers, we tell them about it. We'll then
+ * want to notify the guest, using eventfd. */
+int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
+ u16 *nheads, unsigned count)
+{
+ bool in_order = vhost_has_feature(vq, VIRTIO_F_IN_ORDER);
+ int r;
+
+ if (!in_order || !nheads)
+ r = vhost_add_used_n_ooo(vq, heads, count);
+ else
+ r = vhost_add_used_n_in_order(vq, heads, nheads, count);
if (r < 0)
return r;
@@ -3064,9 +3140,11 @@ EXPORT_SYMBOL_GPL(vhost_add_used_and_signal);
/* multi-buffer version of vhost_add_used_and_signal */
void vhost_add_used_and_signal_n(struct vhost_dev *dev,
struct vhost_virtqueue *vq,
- struct vring_used_elem *heads, unsigned count)
+ struct vring_used_elem *heads,
+ u16 *nheads,
+ unsigned count)
{
- vhost_add_used_n(vq, heads, count);
+ vhost_add_used_n(vq, heads, nheads, count);
vhost_signal(dev, vq);
}
EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index ab704d84fb34..24f3540b08a2 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -115,6 +115,8 @@ struct vhost_virtqueue {
* Values are limited to 0x7fff, and the high bit is used as
* a wrap counter when using VIRTIO_F_RING_PACKED. */
u16 last_avail_idx;
+ /* Next avail ring head when VIRTIO_F_IN_ORDER is negoitated */
+ u16 next_avail_head;
/* Caches available index value from user. */
u16 avail_idx;
@@ -141,6 +143,7 @@ struct vhost_virtqueue {
struct iovec iotlb_iov[64];
struct iovec *indirect;
struct vring_used_elem *heads;
+ u16 *nheads;
/* Protected by virtqueue mutex. */
struct vhost_iotlb *umem;
struct vhost_iotlb *iotlb;
@@ -235,11 +238,12 @@ bool vhost_vq_is_setup(struct vhost_virtqueue *vq);
int vhost_vq_init_access(struct vhost_virtqueue *);
int vhost_add_used(struct vhost_virtqueue *, unsigned int head, int len);
int vhost_add_used_n(struct vhost_virtqueue *, struct vring_used_elem *heads,
- unsigned count);
+ u16 *nheads, unsigned count);
void vhost_add_used_and_signal(struct vhost_dev *, struct vhost_virtqueue *,
unsigned int id, int len);
void vhost_add_used_and_signal_n(struct vhost_dev *, struct vhost_virtqueue *,
- struct vring_used_elem *heads, unsigned count);
+ struct vring_used_elem *heads, u16 *nheads,
+ unsigned count);
void vhost_signal(struct vhost_dev *, struct vhost_virtqueue *);
void vhost_disable_notify(struct vhost_dev *, struct vhost_virtqueue *);
bool vhost_vq_avail_empty(struct vhost_dev *, struct vhost_virtqueue *);
generated by cgit (git 2.34.1) at 2025-10-01 13:05:27 +0000