Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost

Pull virtio fixes from Michael Tsirkin:
 "This includes some fixes and cleanups in virtio and vhost code.

  Most notably, shadowing the index fixes the excessive cacheline
  bouncing observed on AMD platforms"

* tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost:
  virtio_ring: shadow available ring flags & index
  virtio: Do not drop __GFP_HIGH in alloc_indirect
  vhost: replace % with & on data path
  tools/virtio: fix byteswap logic
  tools/virtio: move list macro stubs
  virtio: fix memory leak of virtio ida cache layers
  vhost: relax log address alignment
  virtio-net: Stop doing DMA from the stack

7 files changed, 78 insertions, 45 deletions

diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c
index d8838dedb7a4..f94ab786088f 100644
--- a/drivers/net/virtio_net.c
+++ b/drivers/net/virtio_net.c
@@ -140,6 +140,12 @@ struct virtnet_info {
 
         /* CPU hot plug notifier */
         struct notifier_block nb;
+
+        /* Control VQ buffers: protected by the rtnl lock */
+        struct virtio_net_ctrl_hdr ctrl_hdr;
+        virtio_net_ctrl_ack ctrl_status;
+        u8 ctrl_promisc;
+        u8 ctrl_allmulti;
 };
 
 struct padded_vnet_hdr {
@@ -976,31 +982,30 @@ static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
                                  struct scatterlist *out)
 {
         struct scatterlist *sgs[4], hdr, stat;
-        struct virtio_net_ctrl_hdr ctrl;
-        virtio_net_ctrl_ack status = ~0;
         unsigned out_num = 0, tmp;
 
         /* Caller should know better */
         BUG_ON(!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_VQ));
 
-        ctrl.class = class;
-        ctrl.cmd = cmd;
+        vi->ctrl_status = ~0;
+        vi->ctrl_hdr.class = class;
+        vi->ctrl_hdr.cmd = cmd;
         /* Add header */
-        sg_init_one(&hdr, &ctrl, sizeof(ctrl));
+        sg_init_one(&hdr, &vi->ctrl_hdr, sizeof(vi->ctrl_hdr));
         sgs[out_num++] = &hdr;
 
         if (out)
                 sgs[out_num++] = out;
 
         /* Add return status. */
-        sg_init_one(&stat, &status, sizeof(status));
+        sg_init_one(&stat, &vi->ctrl_status, sizeof(vi->ctrl_status));
         sgs[out_num] = &stat;
 
         BUG_ON(out_num + 1 > ARRAY_SIZE(sgs));
         virtqueue_add_sgs(vi->cvq, sgs, out_num, 1, vi, GFP_ATOMIC);
 
         if (unlikely(!virtqueue_kick(vi->cvq)))
-                return status == VIRTIO_NET_OK;
+                return vi->ctrl_status == VIRTIO_NET_OK;
 
         /* Spin for a response, the kick causes an ioport write, trapping
          * into the hypervisor, so the request should be handled immediately.
@@ -1009,7 +1014,7 @@ static bool virtnet_send_command(struct virtnet_info *vi, u8 class, u8 cmd,
                !virtqueue_is_broken(vi->cvq))
                 cpu_relax();
 
-        return status == VIRTIO_NET_OK;
+        return vi->ctrl_status == VIRTIO_NET_OK;
 }
 
 static int virtnet_set_mac_address(struct net_device *dev, void *p)
@@ -1151,7 +1156,6 @@ static void virtnet_set_rx_mode(struct net_device *dev)
 {
         struct virtnet_info *vi = netdev_priv(dev);
         struct scatterlist sg[2];
-        u8 promisc, allmulti;
         struct virtio_net_ctrl_mac *mac_data;
         struct netdev_hw_addr *ha;
         int uc_count;
@@ -1163,22 +1167,22 @@ static void virtnet_set_rx_mode(struct net_device *dev)
         if (!virtio_has_feature(vi->vdev, VIRTIO_NET_F_CTRL_RX))
                 return;
 
-        promisc = ((dev->flags & IFF_PROMISC) != 0);
-        allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
+        vi->ctrl_promisc = ((dev->flags & IFF_PROMISC) != 0);
+        vi->ctrl_allmulti = ((dev->flags & IFF_ALLMULTI) != 0);
 
-        sg_init_one(sg, &promisc, sizeof(promisc));
+        sg_init_one(sg, &vi->ctrl_promisc, sizeof(vi->ctrl_promisc));
 
         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
                                   VIRTIO_NET_CTRL_RX_PROMISC, sg))
                 dev_warn(&dev->dev, "Failed to %sable promisc mode.\n",
-                         promisc ? "en" : "dis");
+                         vi->ctrl_promisc ? "en" : "dis");
 
-        sg_init_one(sg, &allmulti, sizeof(allmulti));
+        sg_init_one(sg, &vi->ctrl_allmulti, sizeof(vi->ctrl_allmulti));
 
         if (!virtnet_send_command(vi, VIRTIO_NET_CTRL_RX,
                                   VIRTIO_NET_CTRL_RX_ALLMULTI, sg))
                 dev_warn(&dev->dev, "Failed to %sable allmulti mode.\n",
-                         allmulti ? "en" : "dis");
+                         vi->ctrl_allmulti ? "en" : "dis");
 
         uc_count = netdev_uc_count(dev);
         mc_count = netdev_mc_count(dev);
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index eec2f11809ff..ad2146a9ab2d 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -819,7 +819,7 @@ long vhost_vring_ioctl(struct vhost_dev *d, int ioctl, void __user *argp)
                 BUILD_BUG_ON(__alignof__ *vq->used > VRING_USED_ALIGN_SIZE);
                 if ((a.avail_user_addr & (VRING_AVAIL_ALIGN_SIZE - 1)) ||
                     (a.used_user_addr & (VRING_USED_ALIGN_SIZE - 1)) ||
-                    (a.log_guest_addr & (sizeof(u64) - 1))) {
+                    (a.log_guest_addr & (VRING_USED_ALIGN_SIZE - 1))) {
                         r = -EINVAL;
                         break;
                 }
@@ -1369,7 +1369,7 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
         /* Grab the next descriptor number they're advertising, and increment
          * the index we've seen. */
         if (unlikely(__get_user(ring_head,
-                                &vq->avail->ring[last_avail_idx % vq->num]))) {
+                                &vq->avail->ring[last_avail_idx & (vq->num - 1)]))) {
                 vq_err(vq, "Failed to read head: idx %d address %p\n",
                        last_avail_idx,
                        &vq->avail->ring[last_avail_idx % vq->num]);
@@ -1489,7 +1489,7 @@ static int __vhost_add_used_n(struct vhost_virtqueue *vq,
         u16 old, new;
         int start;
 
-        start = vq->last_used_idx % vq->num;
+        start = vq->last_used_idx & (vq->num - 1);
         used = vq->used->ring + start;
         if (count == 1) {
                 if (__put_user(heads[0].id, &used->id)) {
@@ -1531,7 +1531,7 @@ int vhost_add_used_n(struct vhost_virtqueue *vq, struct vring_used_elem *heads,
 {
         int start, n, r;
 
-        start = vq->last_used_idx % vq->num;
+        start = vq->last_used_idx & (vq->num - 1);
         n = vq->num - start;
         if (n < count) {
                 r = __vhost_add_used_n(vq, heads, n);
diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c
index b1877d73fa56..7062bb0975a5 100644
--- a/drivers/virtio/virtio.c
+++ b/drivers/virtio/virtio.c
@@ -412,6 +412,7 @@ static int virtio_init(void)
 static void __exit virtio_exit(void)
 {
         bus_unregister(&virtio_bus);
+        ida_destroy(&virtio_index_ida);
 }
 core_initcall(virtio_init);
 module_exit(virtio_exit);
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 096b857e7b75..ee663c458b20 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -80,6 +80,12 @@ struct vring_virtqueue {
         /* Last used index we've seen. */
         u16 last_used_idx;
 
+        /* Last written value to avail->flags */
+        u16 avail_flags_shadow;
+
+        /* Last written value to avail->idx in guest byte order */
+        u16 avail_idx_shadow;
+
         /* How to notify other side. FIXME: commonalize hcalls! */
         bool (*notify)(struct virtqueue *vq);
 
@@ -109,7 +115,7 @@ static struct vring_desc *alloc_indirect(struct virtqueue *_vq,
          * otherwise virt_to_phys will give us bogus addresses in the
          * virtqueue.
          */
-        gfp &= ~(__GFP_HIGHMEM | __GFP_HIGH);
+        gfp &= ~__GFP_HIGHMEM;
 
         desc = kmalloc(total_sg * sizeof(struct vring_desc), gfp);
         if (!desc)
@@ -235,13 +241,14 @@ static inline int virtqueue_add(struct virtqueue *_vq,
 
         /* Put entry in available array (but don't update avail->idx until they
          * do sync). */
-        avail = virtio16_to_cpu(_vq->vdev, vq->vring.avail->idx) & (vq->vring.num - 1);
+        avail = vq->avail_idx_shadow & (vq->vring.num - 1);
         vq->vring.avail->ring[avail] = cpu_to_virtio16(_vq->vdev, head);
 
         /* Descriptors and available array need to be set before we expose the
          * new available array entries. */
         virtio_wmb(vq->weak_barriers);
-        vq->vring.avail->idx = cpu_to_virtio16(_vq->vdev, virtio16_to_cpu(_vq->vdev, vq->vring.avail->idx) + 1);
+        vq->avail_idx_shadow++;
+        vq->vring.avail->idx = cpu_to_virtio16(_vq->vdev, vq->avail_idx_shadow);
         vq->num_added++;
 
         pr_debug("Added buffer head %i to %p\n", head, vq);
@@ -354,8 +361,8 @@ bool virtqueue_kick_prepare(struct virtqueue *_vq)
          * event. */
         virtio_mb(vq->weak_barriers);
 
-        old = virtio16_to_cpu(_vq->vdev, vq->vring.avail->idx) - vq->num_added;
-        new = virtio16_to_cpu(_vq->vdev, vq->vring.avail->idx);
+        old = vq->avail_idx_shadow - vq->num_added;
+        new = vq->avail_idx_shadow;
         vq->num_added = 0;
 
 #ifdef DEBUG
@@ -510,7 +517,7 @@ void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len)
         /* If we expect an interrupt for the next entry, tell host
          * by writing event index and flush out the write before
          * the read in the next get_buf call. */
-        if (!(vq->vring.avail->flags & cpu_to_virtio16(_vq->vdev, VRING_AVAIL_F_NO_INTERRUPT))) {
+        if (!(vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) {
                 vring_used_event(&vq->vring) = cpu_to_virtio16(_vq->vdev, vq->last_used_idx);
                 virtio_mb(vq->weak_barriers);
         }
@@ -537,7 +544,11 @@ void virtqueue_disable_cb(struct virtqueue *_vq)
 {
         struct vring_virtqueue *vq = to_vvq(_vq);
 
-        vq->vring.avail->flags |= cpu_to_virtio16(_vq->vdev, VRING_AVAIL_F_NO_INTERRUPT);
+        if (!(vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) {
+                vq->avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT;
+                vq->vring.avail->flags = cpu_to_virtio16(_vq->vdev, vq->avail_flags_shadow);
+        }
+
 }
 EXPORT_SYMBOL_GPL(virtqueue_disable_cb);
 
@@ -565,7 +576,10 @@ unsigned virtqueue_enable_cb_prepare(struct virtqueue *_vq)
         /* Depending on the VIRTIO_RING_F_EVENT_IDX feature, we need to
          * either clear the flags bit or point the event index at the next
          * entry. Always do both to keep code simple. */
-        vq->vring.avail->flags &= cpu_to_virtio16(_vq->vdev, ~VRING_AVAIL_F_NO_INTERRUPT);
+        if (vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT) {
+                vq->avail_flags_shadow &= ~VRING_AVAIL_F_NO_INTERRUPT;
+                vq->vring.avail->flags = cpu_to_virtio16(_vq->vdev, vq->avail_flags_shadow);
+        }
         vring_used_event(&vq->vring) = cpu_to_virtio16(_vq->vdev, last_used_idx = vq->last_used_idx);
         END_USE(vq);
         return last_used_idx;
@@ -633,9 +647,12 @@ bool virtqueue_enable_cb_delayed(struct virtqueue *_vq)
         /* Depending on the VIRTIO_RING_F_USED_EVENT_IDX feature, we need to
          * either clear the flags bit or point the event index at the next
          * entry. Always do both to keep code simple. */
-        vq->vring.avail->flags &= cpu_to_virtio16(_vq->vdev, ~VRING_AVAIL_F_NO_INTERRUPT);
+        if (vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT) {
+                vq->avail_flags_shadow &= ~VRING_AVAIL_F_NO_INTERRUPT;
+                vq->vring.avail->flags = cpu_to_virtio16(_vq->vdev, vq->avail_flags_shadow);
+        }
         /* TODO: tune this threshold */
-        bufs = (u16)(virtio16_to_cpu(_vq->vdev, vq->vring.avail->idx) - vq->last_used_idx) * 3 / 4;
+        bufs = (u16)(vq->avail_idx_shadow - vq->last_used_idx) * 3 / 4;
         vring_used_event(&vq->vring) = cpu_to_virtio16(_vq->vdev, vq->last_used_idx + bufs);
         virtio_mb(vq->weak_barriers);
         if (unlikely((u16)(virtio16_to_cpu(_vq->vdev, vq->vring.used->idx) - vq->last_used_idx) > bufs)) {
@@ -670,7 +687,8 @@ void *virtqueue_detach_unused_buf(struct virtqueue *_vq)
                 /* detach_buf clears data, so grab it now. */
                 buf = vq->data[i];
                 detach_buf(vq, i);
-                vq->vring.avail->idx = cpu_to_virtio16(_vq->vdev, virtio16_to_cpu(_vq->vdev, vq->vring.avail->idx) - 1);
+                vq->avail_idx_shadow--;
+                vq->vring.avail->idx = cpu_to_virtio16(_vq->vdev, vq->avail_idx_shadow);
                 END_USE(vq);
                 return buf;
         }
@@ -735,6 +753,8 @@ struct virtqueue *vring_new_virtqueue(unsigned int index,
         vq->weak_barriers = weak_barriers;
         vq->broken = false;
         vq->last_used_idx = 0;
+        vq->avail_flags_shadow = 0;
+        vq->avail_idx_shadow = 0;
         vq->num_added = 0;
         list_add_tail(&vq->vq.list, &vdev->vqs);
 #ifdef DEBUG
@@ -746,8 +766,10 @@ struct virtqueue *vring_new_virtqueue(unsigned int index,
         vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
 
         /* No callback?  Tell other side not to bother us. */
-        if (!callback)
-                vq->vring.avail->flags |= cpu_to_virtio16(vdev, VRING_AVAIL_F_NO_INTERRUPT);
+        if (!callback) {
+                vq->avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT;
+                vq->vring.avail->flags = cpu_to_virtio16(vdev, vq->avail_flags_shadow);
+        }
 
         /* Put everything in free lists. */
         vq->free_head = 0;
diff --git a/tools/virtio/linux/kernel.h b/tools/virtio/linux/kernel.h
index 0a3da64638ce..4db7d5691ba7 100644
--- a/tools/virtio/linux/kernel.h
+++ b/tools/virtio/linux/kernel.h
@@ -110,4 +110,10 @@ static inline void free_page(unsigned long addr)
         (void) (&_min1 == &_min2);              \
         _min1 < _min2 ? _min1 : _min2; })
 
+/* TODO: empty stubs for now. Broken but enough for virtio_ring.c */
+#define list_add_tail(a, b) do {} while (0)
+#define list_del(a) do {} while (0)
+#define list_for_each_entry(a, b, c) while (0)
+/* end of stubs */
+
 #endif /* KERNEL_H */
diff --git a/tools/virtio/linux/virtio.h b/tools/virtio/linux/virtio.h
index a3e07016a440..ee125e714053 100644
--- a/tools/virtio/linux/virtio.h
+++ b/tools/virtio/linux/virtio.h
@@ -3,12 +3,6 @@
 #include <linux/scatterlist.h>
 #include <linux/kernel.h>
 
-/* TODO: empty stubs for now. Broken but enough for virtio_ring.c */
-#define list_add_tail(a, b) do {} while (0)
-#define list_del(a) do {} while (0)
-#define list_for_each_entry(a, b, c) while (0)
-/* end of stubs */
-
 struct virtio_device {
         void *dev;
         u64 features;
diff --git a/tools/virtio/linux/virtio_config.h b/tools/virtio/linux/virtio_config.h
index 806d683ab107..57a6964a1e35 100644
--- a/tools/virtio/linux/virtio_config.h
+++ b/tools/virtio/linux/virtio_config.h
@@ -40,33 +40,39 @@ static inline void __virtio_clear_bit(struct virtio_device *vdev,
 #define virtio_has_feature(dev, feature) \
         (__virtio_test_bit((dev), feature))
 
+static inline bool virtio_is_little_endian(struct virtio_device *vdev)
+{
+        return virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
+                virtio_legacy_is_little_endian();
+}
+
+/* Memory accessors */
 static inline u16 virtio16_to_cpu(struct virtio_device *vdev, __virtio16 val)
 {
-        return __virtio16_to_cpu(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
+        return __virtio16_to_cpu(virtio_is_little_endian(vdev), val);
 }
 
 static inline __virtio16 cpu_to_virtio16(struct virtio_device *vdev, u16 val)
 {
-        return __cpu_to_virtio16(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
+        return __cpu_to_virtio16(virtio_is_little_endian(vdev), val);
 }
 
 static inline u32 virtio32_to_cpu(struct virtio_device *vdev, __virtio32 val)
 {
-        return __virtio32_to_cpu(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
+        return __virtio32_to_cpu(virtio_is_little_endian(vdev), val);
 }
 
 static inline __virtio32 cpu_to_virtio32(struct virtio_device *vdev, u32 val)
 {
-        return __cpu_to_virtio32(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
+        return __cpu_to_virtio32(virtio_is_little_endian(vdev), val);
 }
 
 static inline u64 virtio64_to_cpu(struct virtio_device *vdev, __virtio64 val)
 {
-        return __virtio64_to_cpu(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
+        return __virtio64_to_cpu(virtio_is_little_endian(vdev), val);
 }
 
 static inline __virtio64 cpu_to_virtio64(struct virtio_device *vdev, u64 val)
 {
-        return __cpu_to_virtio64(virtio_has_feature(vdev, VIRTIO_F_VERSION_1), val);
+        return __cpu_to_virtio64(virtio_is_little_endian(vdev), val);
 }
-