Signed-off-by: Jason Wang <jasow...@redhat.com>
---
 drivers/vhost/net.c   |  14 +-
 drivers/vhost/vhost.c | 351 ++++++++++++++++++++++++++++++++++++++++++++++----
 drivers/vhost/vhost.h |   6 +-
 3 files changed, 343 insertions(+), 28 deletions(-)

diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index c613d2e..65b27c9 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -67,7 +67,8 @@ enum {
        VHOST_NET_FEATURES = VHOST_FEATURES |
                         (1ULL << VHOST_NET_F_VIRTIO_NET_HDR) |
                         (1ULL << VIRTIO_NET_F_MRG_RXBUF) |
-                        (1ULL << VIRTIO_F_IOMMU_PLATFORM)
+                        (1ULL << VIRTIO_F_IOMMU_PLATFORM) |
+                        (1ULL << VIRTIO_F_RING_PACKED)
 };
 
 enum {
@@ -473,6 +474,7 @@ static void handle_tx(struct vhost_net *net)
        struct socket *sock;
        struct vhost_net_ubuf_ref *uninitialized_var(ubufs);
        bool zcopy, zcopy_used;
+       struct vring_used_elem used;
 
        mutex_lock(&vq->mutex);
        sock = vq->private_data;
@@ -494,6 +496,8 @@ static void handle_tx(struct vhost_net *net)
                        vhost_zerocopy_signal_used(net, vq);
 
 
+               used.idx = vq->last_avail_idx & (vq->num - 1);
+               used.wrap_counter = vq->used_wrap_counter;
                head = vhost_net_tx_get_vq_desc(net, vq, vq->iov,
                                                ARRAY_SIZE(vq->iov),
                                                &out, &in);
@@ -515,6 +519,8 @@ static void handle_tx(struct vhost_net *net)
                }
                /* Skip header. TODO: support TSO. */
                len = iov_length(vq->iov, out);
+               used.id = head;
+               used.len = 0;
                iov_iter_init(&msg.msg_iter, WRITE, vq->iov, out, len);
                iov_iter_advance(&msg.msg_iter, hdr_size);
                /* Sanity check */
@@ -576,7 +582,7 @@ static void handle_tx(struct vhost_net *net)
                        pr_debug("Truncated TX packet: "
                                 " len %d != %zd\n", err, len);
                if (!zcopy_used)
-                       vhost_add_used_and_signal(&net->dev, vq, head, 0);
+                       vhost_add_used_and_signal_n(&net->dev, vq, &used, 1);
                else
                        vhost_zerocopy_signal_used(net, vq);
                vhost_net_tx_packet(net);
@@ -691,6 +697,8 @@ static int get_rx_bufs(struct vhost_virtqueue *vq,
                        r = -ENOBUFS;
                        goto err;
                }
+               heads[headcount].idx = vq->last_avail_idx & (vq->num - 1);
+               heads[headcount].wrap_counter = vq->used_wrap_counter;
                r = vhost_get_vq_desc(vq, vq->iov + seg,
                                      ARRAY_SIZE(vq->iov) - seg, &out,
                                      &in, log, log_num);
@@ -780,6 +788,8 @@ static void handle_rx(struct vhost_net *net)
        vq_log = unlikely(vhost_has_feature(vq, VHOST_F_LOG_ALL)) ?
                vq->log : NULL;
        mergeable = vhost_has_feature(vq, VIRTIO_NET_F_MRG_RXBUF);
+       /* FIXME: workaround for current dpdk prototype */
+       mergeable = false;
 
        while ((sock_len = vhost_net_rx_peek_head_len(net, sock->sk))) {
                sock_len += sock_hlen;
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 2db5af8..5667d03 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -324,6 +324,7 @@ static void vhost_vq_reset(struct vhost_dev *dev,
        vhost_reset_is_le(vq);
        vhost_disable_cross_endian(vq);
        vq->busyloop_timeout = 0;
+       vq->used_wrap_counter = true;
        vq->umem = NULL;
        vq->iotlb = NULL;
        __vhost_vq_meta_reset(vq);
@@ -1136,10 +1137,22 @@ static int vhost_iotlb_miss(struct vhost_virtqueue *vq, 
u64 iova, int access)
        return 0;
 }
 
-static int vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
-                       struct vring_desc __user *desc,
-                       struct vring_avail __user *avail,
-                       struct vring_used __user *used)
+static int vq_access_ok_packed(struct vhost_virtqueue *vq, unsigned int num,
+                              struct vring_desc __user *desc,
+                              struct vring_avail __user *avail,
+                              struct vring_used __user *used)
+{
+       struct vring_desc_packed *packed = (struct vring_desc_packed *)desc;
+
+       /* FIXME: check device area and driver area */
+       return access_ok(VERIFY_READ, packed, num * sizeof(*packed)) &&
+              access_ok(VERIFY_WRITE, packed, num * sizeof(*packed));
+}
+
+static int vq_access_ok_split(struct vhost_virtqueue *vq, unsigned int num,
+                             struct vring_desc __user *desc,
+                             struct vring_avail __user *avail,
+                             struct vring_used __user *used)
 
 {
        size_t s = vhost_has_feature(vq, VIRTIO_RING_F_EVENT_IDX) ? 2 : 0;
@@ -1151,6 +1164,17 @@ static int vq_access_ok(struct vhost_virtqueue *vq, 
unsigned int num,
                        sizeof *used + num * sizeof *used->ring + s);
 }
 
+static int vq_access_ok(struct vhost_virtqueue *vq, unsigned int num,
+                       struct vring_desc __user *desc,
+                       struct vring_avail __user *avail,
+                       struct vring_used __user *used)
+{
+       if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
+               return vq_access_ok_packed(vq, num, desc, avail, used);
+       else
+               return vq_access_ok_split(vq, num, desc, avail, used);
+}
+
 static void vhost_vq_meta_update(struct vhost_virtqueue *vq,
                                 const struct vhost_umem_node *node,
                                 int type)
@@ -1763,6 +1787,9 @@ int vhost_vq_init_access(struct vhost_virtqueue *vq)
 
        vhost_init_is_le(vq);
 
+       if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
+               return 0;
+
        r = vhost_update_used_flags(vq);
        if (r)
                goto err;
@@ -1947,18 +1974,136 @@ static int get_indirect(struct vhost_virtqueue *vq,
        return 0;
 }
 
-/* This looks in the virtqueue and for the first available buffer, and converts
- * it to an iovec for convenient access.  Since descriptors consist of some
- * number of output then some number of input descriptors, it's actually two
- * iovecs, but we pack them into one and note how many of each there were.
- *
- * This function returns the descriptor number found, or vq->num (which is
- * never a valid descriptor number) if none was found.  A negative code is
- * returned on error. */
-int vhost_get_vq_desc(struct vhost_virtqueue *vq,
-                     struct iovec iov[], unsigned int iov_size,
-                     unsigned int *out_num, unsigned int *in_num,
-                     struct vhost_log *log, unsigned int *log_num)
+#define DESC_AVAIL (1 << VRING_DESC_F_AVAIL)
+#define DESC_USED  (1 << VRING_DESC_F_USED)
+static bool desc_is_avail(struct vhost_virtqueue *vq,
+                         struct vring_desc_packed *desc)
+{
+       if (vq->used_wrap_counter)
+               if ((desc->flags & DESC_AVAIL) && !(desc->flags & DESC_USED))
+                       return true;
+       if (vq->used_wrap_counter == false)
+               if (!(desc->flags & DESC_AVAIL) && (desc->flags & DESC_USED))
+                       return true;
+
+       return false;
+}
+
+static void set_desc_used(struct vhost_virtqueue *vq,
+                         struct vring_desc_packed *desc, bool wrap_counter)
+{
+       __virtio16 flags = desc->flags;
+
+       if (wrap_counter) {
+               desc->flags |= cpu_to_vhost16(vq, DESC_AVAIL);
+               desc->flags |= cpu_to_vhost16(vq, DESC_USED);
+       } else {
+               desc->flags &= ~cpu_to_vhost16(vq, DESC_AVAIL);
+               desc->flags &= ~cpu_to_vhost16(vq, DESC_USED);
+       }
+
+       desc->flags = flags;
+}
+
+static int vhost_get_vq_desc_packed(struct vhost_virtqueue *vq,
+                                   struct iovec iov[], unsigned int iov_size,
+                                   unsigned int *out_num, unsigned int *in_num,
+                                   struct vhost_log *log,
+                                   unsigned int *log_num)
+{
+       struct vring_desc_packed desc;
+       int ret, access, i;
+       u16 avail_idx = vq->last_avail_idx;
+
+       /* When we start there are none of either input nor output. */
+       *out_num = *in_num = 0;
+       if (unlikely(log))
+               *log_num = 0;
+
+       do {
+               unsigned int iov_count = *in_num + *out_num;
+
+               i = vq->last_avail_idx & (vq->num - 1);
+               ret = vhost_copy_from_user(vq, &desc, vq->desc_packed + i,
+                                          sizeof(desc));
+               if (unlikely(ret)) {
+                       vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
+                               i, vq->desc_packed + i);
+                       return -EFAULT;
+               }
+
+               if (!desc_is_avail(vq, &desc)) {
+                       /* If there's nothing new since last we looked, return
+                        * invalid.
+                        */
+                       if (likely(avail_idx == vq->last_avail_idx))
+                               return vq->num;
+               }
+
+               /* Only start to read descriptor after we're sure it was
+                * available.
+                */
+               smp_rmb();
+
+               /* FIXME: support indirect */
+               if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_INDIRECT)) {
+                       vq_err(vq, "Indirect descriptor is not supported\n");
+                       return -EFAULT;
+               }
+
+               if (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_WRITE))
+                       access = VHOST_ACCESS_WO;
+               else
+                       access = VHOST_ACCESS_RO;
+               ret = translate_desc(vq, vhost64_to_cpu(vq, desc.addr),
+                                    vhost32_to_cpu(vq, desc.len),
+                                    iov + iov_count, iov_size - iov_count,
+                                    access);
+               if (unlikely(ret < 0)) {
+                       if (ret != -EAGAIN)
+                               vq_err(vq, "Translation failure %d idx %d\n",
+                                       ret, i);
+                       return ret;
+               }
+
+               if (access == VHOST_ACCESS_WO) {
+                       /* If this is an input descriptor,
+                        * increment that count.
+                        */
+                       *in_num += ret;
+                       if (unlikely(log)) {
+                               log[*log_num].addr =
+                                       vhost64_to_cpu(vq, desc.addr);
+                               log[*log_num].len =
+                                       vhost32_to_cpu(vq, desc.len);
+                               ++*log_num;
+                       }
+               } else {
+                       /* If it's an output descriptor, they're all supposed
+                        * to come before any input descriptors.
+                        */
+                       if (unlikely(*in_num)) {
+                               vq_err(vq, "Desc out after in: idx %d\n",
+                                      i);
+                               return -EINVAL;
+                       }
+                       *out_num += ret;
+               }
+
+               /* On success, increment avail index. */
+               if ((++vq->last_avail_idx & (vq->num - 1)) == 0)
+                       vq->used_wrap_counter ^= 1;
+
+       /* If this descriptor says it doesn't chain, we're done. */
+       } while (desc.flags & cpu_to_vhost16(vq, VRING_DESC_F_NEXT));
+
+       return desc.id;
+}
+
+static int vhost_get_vq_desc_split(struct vhost_virtqueue *vq,
+                                  struct iovec iov[], unsigned int iov_size,
+                                  unsigned int *out_num, unsigned int *in_num,
+                                  struct vhost_log *log, unsigned int *log_num)
 {
        struct vring_desc desc;
        unsigned int i, head, found = 0;
@@ -2096,6 +2241,30 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
        BUG_ON(!(vq->used_flags & VRING_USED_F_NO_NOTIFY));
        return head;
 }
+
+/* This looks in the virtqueue and for the first available buffer, and converts
+ * it to an iovec for convenient access.  Since descriptors consist of some
+ * number of output then some number of input descriptors, it's actually two
+ * iovecs, but we pack them into one and note how many of each there were.
+ *
+ * This function returns the descriptor number found, or vq->num (which is
+ * never a valid descriptor number) if none was found.  A negative code is
+ * returned on error.
+ */
+int vhost_get_vq_desc(struct vhost_virtqueue *vq,
+                     struct iovec iov[], unsigned int iov_size,
+                     unsigned int *out_num, unsigned int *in_num,
+                     struct vhost_log *log, unsigned int *log_num)
+{
+       if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
+               return vhost_get_vq_desc_packed(vq, iov, iov_size,
+                                               out_num, in_num,
+                                               log, log_num);
+       else
+               return vhost_get_vq_desc_split(vq, iov, iov_size,
+                                              out_num, in_num,
+                                              log, log_num);
+}
 EXPORT_SYMBOL_GPL(vhost_get_vq_desc);
 
 /* Reverse the effect of vhost_get_vq_desc. Useful for error handling. */
@@ -2161,10 +2330,48 @@ 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_packed(struct vhost_virtqueue *vq,
+                                  struct vring_used_elem *heads,
+                                  unsigned int count)
+{
+       struct vring_desc_packed desc = {
+               .addr = 0,
+               .flags = 0,
+       };
+       int i, ret;
+
+       for (i = 0; i < count; i++) {
+               desc.id = heads[i].id;
+               desc.len = heads[i].len;
+               set_desc_used(vq, &desc, heads[i].wrap_counter);
+
+               /* Update flags etc before desc is written */
+               smp_mb();
+
+               ret = vhost_copy_to_user(vq, vq->desc_packed + heads[i].idx,
+                                        &desc, sizeof(desc));
+               if (unlikely(ret)) {
+                       vq_err(vq, "Failed to set descriptor: idx %d addr %p\n",
+                              heads[i].idx, vq->desc_packed + heads[i].idx);
+                       return -EFAULT;
+               }
+               if (unlikely(vq->log_used)) {
+                       /* Make sure desc is written before update log. */
+                       smp_wmb();
+                       log_write(vq->log_base,
+                                 vq->log_addr + heads[i].idx * sizeof(desc),
+                                 sizeof(desc));
+                       if (vq->log_ctx)
+                               eventfd_signal(vq->log_ctx, 1);
+               }
+       }
+
+       return 0;
+}
+
+static int vhost_add_used_n_split(struct vhost_virtqueue *vq,
+                                 struct vring_used_elem *heads,
+                                 unsigned int count)
 {
        int start, n, r;
 
@@ -2196,6 +2403,19 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct 
vring_used_elem *heads,
        }
        return r;
 }
+
+/* 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 int count)
+{
+       if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
+               return vhost_add_used_n_packed(vq, heads, count);
+       else
+               return vhost_add_used_n_split(vq, heads, count);
+}
 EXPORT_SYMBOL_GPL(vhost_add_used_n);
 
 static bool vhost_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
@@ -2203,6 +2423,11 @@ static bool vhost_notify(struct vhost_dev *dev, struct 
vhost_virtqueue *vq)
        __u16 old, new;
        __virtio16 event;
        bool v;
+
+       /* FIXME: check driver area */
+       if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
+               return false;
+
        /* Flush out used index updates. This is paired
         * with the barrier that the Guest executes when enabling
         * interrupts. */
@@ -2265,7 +2490,8 @@ void vhost_add_used_and_signal_n(struct vhost_dev *dev,
 EXPORT_SYMBOL_GPL(vhost_add_used_and_signal_n);
 
 /* return true if we're sure that avaiable ring is empty */
-bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
+static bool vhost_vq_avail_empty_split(struct vhost_dev *dev,
+                                      struct vhost_virtqueue *vq)
 {
        __virtio16 avail_idx;
        int r;
@@ -2280,10 +2506,61 @@ bool vhost_vq_avail_empty(struct vhost_dev *dev, struct 
vhost_virtqueue *vq)
 
        return vq->avail_idx == vq->last_avail_idx;
 }
+
+/* FIXME: unify codes with vhost_enable_notify_packed() */
+static bool vhost_vq_avail_empty_packed(struct vhost_dev *dev,
+                                       struct vhost_virtqueue *vq)
+{
+       struct vring_desc_packed desc;
+       int ret, i = vq->last_avail_idx & (vq->num - 1);
+
+       ret = vhost_copy_from_user(vq, &desc, vq->desc_packed + i,
+                                  sizeof(desc));
+       if (unlikely(ret)) {
+               vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
+                       i, vq->desc_packed + i);
+               return -EFAULT;
+       }
+
+       /* Read flag after desc is read */
+       smp_mb();
+
+       return desc_is_avail(vq, &desc);
+}
+
+bool vhost_vq_avail_empty(struct vhost_dev *dev, struct vhost_virtqueue *vq)
+{
+       if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
+               return vhost_vq_avail_empty_packed(dev, vq);
+       else
+               return vhost_vq_avail_empty_split(dev, vq);
+}
 EXPORT_SYMBOL_GPL(vhost_vq_avail_empty);
 
-/* OK, now we need to know about added descriptors. */
-bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
+static bool vhost_enable_notify_packed(struct vhost_dev *dev,
+                                      struct vhost_virtqueue *vq)
+{
+       struct vring_desc_packed desc;
+       int ret, i = vq->last_avail_idx & (vq->num - 1);
+
+       /* FIXME: disable notification through device area */
+
+       ret = vhost_copy_from_user(vq, &desc, vq->desc_packed + i,
+                                  sizeof(desc));
+       if (unlikely(ret)) {
+               vq_err(vq, "Failed to get descriptor: idx %d addr %p\n",
+                       i, vq->desc_packed + i);
+               return -EFAULT;
+       }
+
+       /* Read flag after desc is read */
+       smp_mb();
+
+       return desc_is_avail(vq, &desc);
+}
+
+static bool vhost_enable_notify_split(struct vhost_dev *dev,
+                                     struct vhost_virtqueue *vq)
 {
        __virtio16 avail_idx;
        int r;
@@ -2318,10 +2595,25 @@ bool vhost_enable_notify(struct vhost_dev *dev, struct 
vhost_virtqueue *vq)
 
        return vhost16_to_cpu(vq, avail_idx) != vq->avail_idx;
 }
+
+/* OK, now we need to know about added descriptors. */
+bool vhost_enable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
+{
+       if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
+               return vhost_enable_notify_packed(dev, vq);
+       else
+               return vhost_enable_notify_split(dev, vq);
+}
 EXPORT_SYMBOL_GPL(vhost_enable_notify);
 
-/* We don't need to be notified again. */
-void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
+static void vhost_disable_notify_packed(struct vhost_dev *dev,
+                                       struct vhost_virtqueue *vq)
+{
+       /* FIXME: disable notification through device area */
+}
+
+static void vhost_disable_notify_split(struct vhost_dev *dev,
+                                      struct vhost_virtqueue *vq)
 {
        int r;
 
@@ -2335,6 +2627,15 @@ void vhost_disable_notify(struct vhost_dev *dev, struct 
vhost_virtqueue *vq)
                               &vq->used->flags, r);
        }
 }
+
+/* We don't need to be notified again. */
+void vhost_disable_notify(struct vhost_dev *dev, struct vhost_virtqueue *vq)
+{
+       if (vhost_has_feature(vq, VIRTIO_F_RING_PACKED))
+               return vhost_disable_notify_packed(dev, vq);
+       else
+               return vhost_disable_notify_split(dev, vq);
+}
 EXPORT_SYMBOL_GPL(vhost_disable_notify);
 
 /* Create a new message. */
diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
index ac4b605..cf6533a 100644
--- a/drivers/vhost/vhost.h
+++ b/drivers/vhost/vhost.h
@@ -87,7 +87,10 @@ struct vhost_virtqueue {
        /* The actual ring of buffers. */
        struct mutex mutex;
        unsigned int num;
-       struct vring_desc __user *desc;
+       union {
+               struct vring_desc __user *desc;
+               struct vring_desc_packed __user *desc_packed;
+       };
        struct vring_avail __user *avail;
        struct vring_used __user *used;
        const struct vhost_umem_node *meta_iotlb[VHOST_NUM_ADDRS];
@@ -144,6 +147,7 @@ struct vhost_virtqueue {
        bool user_be;
 #endif
        u32 busyloop_timeout;
+       bool used_wrap_counter;
 };
 
 struct vhost_msg_node {
-- 
2.7.4

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