Re: [Qemu-devel] [PATCH 8/8] virtio: queue pop support for packed ring

2018-06-04 Thread Wei Xu 
On Wed, Apr 11, 2018 at 10:43:40AM +0800, Jason Wang wrote:
> 
> 
> On 2018年04月04日 20:54, w...@redhat.com wrote:
> >From: Wei Xu 
> >
> >cloned from split ring pop, a global static length array
> >and the inside-element length array are introduced to
> >easy prototype, this consumes more memory and it is valuable
> >to move to dynamic allocation as the out/in sg does.
> 
> To ease the reviewer, I suggest to reorder this patch to patch 4.

OK.

> 
> >
> >Signed-off-by: Wei Xu 
> >---
> >  hw/virtio/virtio.c | 154 
> > -
> >  1 file changed, 153 insertions(+), 1 deletion(-)
> >
> >diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
> >index cf726f3..0eafb38 100644
> >--- a/hw/virtio/virtio.c
> >+++ b/hw/virtio/virtio.c
> >@@ -1221,7 +1221,7 @@ static void *virtqueue_alloc_element(size_t sz, 
> >unsigned out_num, unsigned in_nu
> >  return elem;
> >  }
> >-void *virtqueue_pop(VirtQueue *vq, size_t sz)
> >+static void *virtqueue_pop_split(VirtQueue *vq, size_t sz)
> >  {
> >  unsigned int i, head, max;
> >  VRingMemoryRegionCaches *caches;
> >@@ -1356,6 +1356,158 @@ err_undo_map:
> >  goto done;
> >  }
> >+static uint16_t dma_len[VIRTQUEUE_MAX_SIZE];
> 
> This looks odd.

This has been removed.

> 
> >+static void *virtqueue_pop_packed(VirtQueue *vq, size_t sz)
> >+{
> >+unsigned int i, head, max;
> >+VRingMemoryRegionCaches *caches;
> >+MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
> >+MemoryRegionCache *cache;
> >+int64_t len;
> >+VirtIODevice *vdev = vq->vdev;
> >+VirtQueueElement *elem = NULL;
> >+unsigned out_num, in_num, elem_entries;
> >+hwaddr addr[VIRTQUEUE_MAX_SIZE];
> >+struct iovec iov[VIRTQUEUE_MAX_SIZE];
> >+VRingDescPacked desc;
> >+uint8_t wrap_counter;
> >+
> >+if (unlikely(vdev->broken)) {
> >+return NULL;
> >+}
> >+
> >+vq->last_avail_idx %= vq->packed.num;
> 
> Queue size could not be a power of 2.

Has replaced it with subtraction.

> 
> >+
> >+rcu_read_lock();
> >+if (virtio_queue_empty_packed_rcu(vq)) {
> >+goto done;
> >+}
> >+
> >+/* When we start there are none of either input nor output. */
> >+out_num = in_num = elem_entries = 0;
> >+
> >+max = vq->vring.num;
> >+
> >+if (vq->inuse >= vq->vring.num) {
> >+virtio_error(vdev, "Virtqueue size exceeded");
> >+goto done;
> >+}
> >+
> >+if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
> >+/* FIXME: TBD */
> >+}
> >+
> >+head = vq->last_avail_idx;
> >+i = head;
> >+
> >+caches = vring_get_region_caches(vq);
> >+cache = >desc_packed;
> >+vring_desc_read_packed(vdev, , cache, i);
> >+if (desc.flags & VRING_DESC_F_INDIRECT) {
> >+if (desc.len % sizeof(VRingDescPacked)) {
> >+virtio_error(vdev, "Invalid size for indirect buffer table");
> >+goto done;
> >+}
> >+
> >+/* loop over the indirect descriptor table */
> >+len = address_space_cache_init(_desc_cache, vdev->dma_as,
> >+   desc.addr, desc.len, false);
> >+cache = _desc_cache;
> >+if (len < desc.len) {
> >+virtio_error(vdev, "Cannot map indirect buffer");
> >+goto done;
> >+}
> >+
> >+max = desc.len / sizeof(VRingDescPacked);
> >+i = 0;
> >+vring_desc_read_packed(vdev, , cache, i);
> >+}
> >+
> >+wrap_counter = vq->wrap_counter;
> >+/* Collect all the descriptors */
> >+while (1) {
> >+bool map_ok;
> >+
> >+if (desc.flags & VRING_DESC_F_WRITE) {
> >+map_ok = virtqueue_map_desc(vdev, _num, addr + out_num,
> >+iov + out_num,
> >+VIRTQUEUE_MAX_SIZE - out_num, true,
> >+desc.addr, desc.len);
> >+} else {
> >+if (in_num) {
> >+virtio_error(vdev, "Incorrect order for descriptors");
> >+goto err_undo_map;
> >+}
> >+map_ok = virtqueue_map_desc(vdev, _num, addr, iov,
> >+VIRTQUEUE_MAX_SIZE, false,
> >+desc.addr, desc.len);
> >+}
> >+if (!map_ok) {
> >+goto err_undo_map;
> >+}
> >+
> >+/* If we've got too many, that implies a descriptor loop. */
> >+if (++elem_entries > max) {
> >+virtio_error(vdev, "Looped descriptor");
> >+goto err_undo_map;
> >+}
> >+
> >+dma_len[i++] = desc.len;
> >+/* Toggle wrap_counter for non indirect desc */
> >+if ((i == vq->packed.num) && (cache != _desc_cache)) {
> >+vq->wrap_counter ^= 1;
> >+}
> >+
> >+if (desc.flags & VRING_DESC_F_NEXT) {
> >+vring_desc_read_packed(vq->vdev, ,

Re: [Qemu-devel] [PATCH 8/8] virtio: queue pop support for packed ring

2018-04-10 Thread Jason Wang 



On 2018年04月04日 20:54, w...@redhat.com wrote:

From: Wei Xu 

cloned from split ring pop, a global static length array
and the inside-element length array are introduced to
easy prototype, this consumes more memory and it is valuable
to move to dynamic allocation as the out/in sg does.


To ease the reviewer, I suggest to reorder this patch to patch 4.



Signed-off-by: Wei Xu 
---
  hw/virtio/virtio.c | 154 -
  1 file changed, 153 insertions(+), 1 deletion(-)

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index cf726f3..0eafb38 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -1221,7 +1221,7 @@ static void *virtqueue_alloc_element(size_t sz, unsigned 
out_num, unsigned in_nu
  return elem;
  }
  
-void *virtqueue_pop(VirtQueue *vq, size_t sz)

+static void *virtqueue_pop_split(VirtQueue *vq, size_t sz)
  {
  unsigned int i, head, max;
  VRingMemoryRegionCaches *caches;
@@ -1356,6 +1356,158 @@ err_undo_map:
  goto done;
  }
  
+static uint16_t dma_len[VIRTQUEUE_MAX_SIZE];


This looks odd.


+static void *virtqueue_pop_packed(VirtQueue *vq, size_t sz)
+{
+unsigned int i, head, max;
+VRingMemoryRegionCaches *caches;
+MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
+MemoryRegionCache *cache;
+int64_t len;
+VirtIODevice *vdev = vq->vdev;
+VirtQueueElement *elem = NULL;
+unsigned out_num, in_num, elem_entries;
+hwaddr addr[VIRTQUEUE_MAX_SIZE];
+struct iovec iov[VIRTQUEUE_MAX_SIZE];
+VRingDescPacked desc;
+uint8_t wrap_counter;
+
+if (unlikely(vdev->broken)) {
+return NULL;
+}
+
+vq->last_avail_idx %= vq->packed.num;


Queue size could not be a power of 2.


+
+rcu_read_lock();
+if (virtio_queue_empty_packed_rcu(vq)) {
+goto done;
+}
+
+/* When we start there are none of either input nor output. */
+out_num = in_num = elem_entries = 0;
+
+max = vq->vring.num;
+
+if (vq->inuse >= vq->vring.num) {
+virtio_error(vdev, "Virtqueue size exceeded");
+goto done;
+}
+
+if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
+/* FIXME: TBD */
+}
+
+head = vq->last_avail_idx;
+i = head;
+
+caches = vring_get_region_caches(vq);
+cache = >desc_packed;
+vring_desc_read_packed(vdev, , cache, i);
+if (desc.flags & VRING_DESC_F_INDIRECT) {
+if (desc.len % sizeof(VRingDescPacked)) {
+virtio_error(vdev, "Invalid size for indirect buffer table");
+goto done;
+}
+
+/* loop over the indirect descriptor table */
+len = address_space_cache_init(_desc_cache, vdev->dma_as,
+   desc.addr, desc.len, false);
+cache = _desc_cache;
+if (len < desc.len) {
+virtio_error(vdev, "Cannot map indirect buffer");
+goto done;
+}
+
+max = desc.len / sizeof(VRingDescPacked);
+i = 0;
+vring_desc_read_packed(vdev, , cache, i);
+}
+
+wrap_counter = vq->wrap_counter;
+/* Collect all the descriptors */
+while (1) {
+bool map_ok;
+
+if (desc.flags & VRING_DESC_F_WRITE) {
+map_ok = virtqueue_map_desc(vdev, _num, addr + out_num,
+iov + out_num,
+VIRTQUEUE_MAX_SIZE - out_num, true,
+desc.addr, desc.len);
+} else {
+if (in_num) {
+virtio_error(vdev, "Incorrect order for descriptors");
+goto err_undo_map;
+}
+map_ok = virtqueue_map_desc(vdev, _num, addr, iov,
+VIRTQUEUE_MAX_SIZE, false,
+desc.addr, desc.len);
+}
+if (!map_ok) {
+goto err_undo_map;
+}
+
+/* If we've got too many, that implies a descriptor loop. */
+if (++elem_entries > max) {
+virtio_error(vdev, "Looped descriptor");
+goto err_undo_map;
+}
+
+dma_len[i++] = desc.len;
+/* Toggle wrap_counter for non indirect desc */
+if ((i == vq->packed.num) && (cache != _desc_cache)) {
+vq->wrap_counter ^= 1;
+}
+
+if (desc.flags & VRING_DESC_F_NEXT) {
+vring_desc_read_packed(vq->vdev, , cache, i % vq->packed.num);
+} else {
+break;
+}
+}
+
+/* Now copy what we have collected and mapped */
+elem = virtqueue_alloc_element(sz, out_num, in_num);
+elem->index = head;


This seems wrong, we could not assume buffer id is last_avail_idx.


+elem->wrap_counter = wrap_counter;
+elem->count = (cache == _desc_cache) ? 1 : out_num + in_num;
+for (i = 0; i < out_num; i++) {
+/* DMA Done by marking the length as 0 */


This seems

[Qemu-devel] [PATCH 8/8] virtio: queue pop support for packed ring

2018-04-04 Thread wexu 
From: Wei Xu 

cloned from split ring pop, a global static length array
and the inside-element length array are introduced to
easy prototype, this consumes more memory and it is valuable
to move to dynamic allocation as the out/in sg does.

Signed-off-by: Wei Xu 
---
 hw/virtio/virtio.c | 154 -
 1 file changed, 153 insertions(+), 1 deletion(-)

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index cf726f3..0eafb38 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -1221,7 +1221,7 @@ static void *virtqueue_alloc_element(size_t sz, unsigned 
out_num, unsigned in_nu
 return elem;
 }
 
-void *virtqueue_pop(VirtQueue *vq, size_t sz)
+static void *virtqueue_pop_split(VirtQueue *vq, size_t sz)
 {
 unsigned int i, head, max;
 VRingMemoryRegionCaches *caches;
@@ -1356,6 +1356,158 @@ err_undo_map:
 goto done;
 }
 
+static uint16_t dma_len[VIRTQUEUE_MAX_SIZE];
+static void *virtqueue_pop_packed(VirtQueue *vq, size_t sz)
+{
+unsigned int i, head, max;
+VRingMemoryRegionCaches *caches;
+MemoryRegionCache indirect_desc_cache = MEMORY_REGION_CACHE_INVALID;
+MemoryRegionCache *cache;
+int64_t len;
+VirtIODevice *vdev = vq->vdev;
+VirtQueueElement *elem = NULL;
+unsigned out_num, in_num, elem_entries;
+hwaddr addr[VIRTQUEUE_MAX_SIZE];
+struct iovec iov[VIRTQUEUE_MAX_SIZE];
+VRingDescPacked desc;
+uint8_t wrap_counter;
+
+if (unlikely(vdev->broken)) {
+return NULL;
+}
+
+vq->last_avail_idx %= vq->packed.num;
+
+rcu_read_lock();
+if (virtio_queue_empty_packed_rcu(vq)) {
+goto done;
+}
+
+/* When we start there are none of either input nor output. */
+out_num = in_num = elem_entries = 0;
+
+max = vq->vring.num;
+
+if (vq->inuse >= vq->vring.num) {
+virtio_error(vdev, "Virtqueue size exceeded");
+goto done;
+}
+
+if (virtio_vdev_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX)) {
+/* FIXME: TBD */
+}
+
+head = vq->last_avail_idx;
+i = head;
+
+caches = vring_get_region_caches(vq);
+cache = >desc_packed;
+vring_desc_read_packed(vdev, , cache, i);
+if (desc.flags & VRING_DESC_F_INDIRECT) {
+if (desc.len % sizeof(VRingDescPacked)) {
+virtio_error(vdev, "Invalid size for indirect buffer table");
+goto done;
+}
+
+/* loop over the indirect descriptor table */
+len = address_space_cache_init(_desc_cache, vdev->dma_as,
+   desc.addr, desc.len, false);
+cache = _desc_cache;
+if (len < desc.len) {
+virtio_error(vdev, "Cannot map indirect buffer");
+goto done;
+}
+
+max = desc.len / sizeof(VRingDescPacked);
+i = 0;
+vring_desc_read_packed(vdev, , cache, i);
+}
+
+wrap_counter = vq->wrap_counter;
+/* Collect all the descriptors */
+while (1) {
+bool map_ok;
+
+if (desc.flags & VRING_DESC_F_WRITE) {
+map_ok = virtqueue_map_desc(vdev, _num, addr + out_num,
+iov + out_num,
+VIRTQUEUE_MAX_SIZE - out_num, true,
+desc.addr, desc.len);
+} else {
+if (in_num) {
+virtio_error(vdev, "Incorrect order for descriptors");
+goto err_undo_map;
+}
+map_ok = virtqueue_map_desc(vdev, _num, addr, iov,
+VIRTQUEUE_MAX_SIZE, false,
+desc.addr, desc.len);
+}
+if (!map_ok) {
+goto err_undo_map;
+}
+
+/* If we've got too many, that implies a descriptor loop. */
+if (++elem_entries > max) {
+virtio_error(vdev, "Looped descriptor");
+goto err_undo_map;
+}
+
+dma_len[i++] = desc.len;
+/* Toggle wrap_counter for non indirect desc */
+if ((i == vq->packed.num) && (cache != _desc_cache)) {
+vq->wrap_counter ^= 1;
+}
+
+if (desc.flags & VRING_DESC_F_NEXT) {
+vring_desc_read_packed(vq->vdev, , cache, i % vq->packed.num);
+} else {
+break;
+}
+}
+
+/* Now copy what we have collected and mapped */
+elem = virtqueue_alloc_element(sz, out_num, in_num);
+elem->index = head;
+elem->wrap_counter = wrap_counter;
+elem->count = (cache == _desc_cache) ? 1 : out_num + in_num;
+for (i = 0; i < out_num; i++) {
+/* DMA Done by marking the length as 0 */
+elem->len[i] = 0;
+elem->out_addr[i] = addr[i];
+elem->out_sg[i] = iov[i];
+}
+for (i = 0; i < in_num; i++) {
+elem->len[out_num + i] = dma_len[head + out_num + i];
+elem->in_addr[i] = addr[out_num + i];
+elem->in_sg[i] =