Hello everyone, This RFC implements a subset of packed ring which is described at https://github.com/oasis-tcs/virtio-docs/blob/master/virtio-v1.1-packed-wd08.pdf The code was tested with DPDK vhost (testpmd/vhost-PMD) implemented by Jens at http://dpdk.org/ml/archives/dev/2018-January/089417.html Minor changes are needed for the vhost code, e.g. to kick the guest. It's not a complete implementation, here is what's missing: - Device area and driver area - VIRTIO_RING_F_INDIRECT_DESC - VIRTIO_F_NOTIFICATION_DATA - Virtio devices except net are not tested - See FIXME in the code for more details Thanks! Best regards, Tiwei Bie Tiwei Bie (2): virtio: introduce packed ring defines virtio_ring: support packed ring drivers/virtio/virtio_ring.c | 699 ++++++++++++++++++++++++++++++++----- include/linux/virtio_ring.h | 8 +- include/uapi/linux/virtio_config.h | 18 +- include/uapi/linux/virtio_ring.h | 68 ++++ 4 files changed, 703 insertions(+), 90 deletions(-) -- 2.14.1
Signed-off-by: Tiwei Bie <tiwei.bie at intel.com>
---
include/uapi/linux/virtio_config.h | 18 +++++++++-
include/uapi/linux/virtio_ring.h | 68 ++++++++++++++++++++++++++++++++++++++
2 files changed, 85 insertions(+), 1 deletion(-)
diff --git a/include/uapi/linux/virtio_config.h
b/include/uapi/linux/virtio_config.h
index 308e2096291f..e3d077ef5207 100644
--- a/include/uapi/linux/virtio_config.h
+++ b/include/uapi/linux/virtio_config.h
@@ -49,7 +49,7 @@
* transport being used (eg. virtio_ring), the rest are per-device feature
* bits. */
#define VIRTIO_TRANSPORT_F_START 28
-#define VIRTIO_TRANSPORT_F_END 34
+#define VIRTIO_TRANSPORT_F_END 37
#ifndef VIRTIO_CONFIG_NO_LEGACY
/* Do we get callbacks when the ring is completely used, even if we've
@@ -71,4 +71,20 @@
* this is for compatibility with legacy systems.
*/
#define VIRTIO_F_IOMMU_PLATFORM 33
+
+/* This feature indicates support for the packed virtqueue layout. */
+#define VIRTIO_F_RING_PACKED 34
+
+/*
+ * This feature indicates that all buffers are used by the device
+ * in the same order in which they have been made available.
+ */
+#define VIRTIO_F_IN_ORDER 35
+
+/*
+ * This feature indicates that drivers pass extra data (besides
+ * identifying the Virtqueue) in their device notifications.
+ */
+#define VIRTIO_F_NOTIFICATION_DATA 36
+
#endif /* _UAPI_LINUX_VIRTIO_CONFIG_H */
diff --git a/include/uapi/linux/virtio_ring.h b/include/uapi/linux/virtio_ring.h
index 6d5d5faa989b..77b1d4aeef72 100644
--- a/include/uapi/linux/virtio_ring.h
+++ b/include/uapi/linux/virtio_ring.h
@@ -44,6 +44,9 @@
/* This means the buffer contains a list of buffer descriptors. */
#define VRING_DESC_F_INDIRECT 4
+#define VRING_DESC_F_AVAIL(b) ((b) << 7)
+#define VRING_DESC_F_USED(b) ((b) << 15)
+
/* The Host uses this in used->flags to advise the Guest: don't kick me
when
* you add a buffer. It's unreliable, so it's simply an optimization.
Guest
* will still kick if it's out of buffers. */
@@ -104,6 +107,36 @@ struct vring {
struct vring_used *used;
};
+struct vring_packed_desc_event {
+ /* Descriptor Event Offset */
+ __virtio16 desc_event_off : 15,
+ /* Descriptor Event Wrap Counter */
+ desc_event_wrap : 1;
+ /* Descriptor Event Flags */
+ __virtio16 desc_event_flags : 2;
+};
+
+struct vring_packed_desc {
+ /* Buffer Address. */
+ __virtio64 addr;
+ /* Buffer Length. */
+ __virtio32 len;
+ /* Buffer ID. */
+ __virtio16 id;
+ /* The flags depending on descriptor type. */
+ __virtio16 flags;
+};
+
+struct vring_packed {
+ unsigned int num;
+
+ struct vring_packed_desc *desc;
+
+ struct vring_packed_desc_event *driver;
+
+ struct vring_packed_desc_event *device;
+};
+
/* Alignment requirements for vring elements.
* When using pre-virtio 1.0 layout, these fall out naturally.
*/
@@ -171,4 +204,39 @@ static inline int vring_need_event(__u16 event_idx, __u16
new_idx, __u16 old)
return (__u16)(new_idx - event_idx - 1) < (__u16)(new_idx - old);
}
+/* The standard layout for the packed ring is a continuous chunk of memory
+ * which looks like this.
+ *
+ * struct vring_packed
+ * {
+ * // The actual descriptors (16 bytes each)
+ * struct vring_packed_desc desc[num];
+ *
+ * // Padding to the next align boundary.
+ * char pad[];
+ *
+ * // Driver Event Suppression
+ * struct vring_packed_desc_event driver;
+ *
+ * // Device Event Suppression
+ * struct vring_packed_desc_event device;
+ * };
+ */
+
+static inline void vring_packed_init(struct vring_packed *vr, unsigned int num,
+ void *p, unsigned long align)
+{
+ vr->num = num;
+ vr->desc = p;
+ vr->driver = (void *)(((uintptr_t)p + sizeof(struct vring_packed_desc)
+ * num + align - 1) & ~(align - 1));
+ vr->device = vr->driver + 1;
+}
+
+static inline unsigned vring_packed_size(unsigned int num, unsigned long align)
+{
+ return ((sizeof(struct vring_packed_desc) * num + align - 1)
+ & ~(align - 1)) + sizeof(struct vring_packed_desc_event) * 2;
+}
+
#endif /* _UAPI_LINUX_VIRTIO_RING_H */
--
2.14.1
Signed-off-by: Tiwei Bie <tiwei.bie at intel.com>
---
drivers/virtio/virtio_ring.c | 699 +++++++++++++++++++++++++++++++++++++------
include/linux/virtio_ring.h | 8 +-
2 files changed, 618 insertions(+), 89 deletions(-)
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index eb30f3e09a47..393778a2f809 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -58,14 +58,14 @@
struct vring_desc_state {
void *data; /* Data for callback. */
- struct vring_desc *indir_desc; /* Indirect descriptor, if any. */
+ void *indir_desc; /* Indirect descriptor, if any. */
+ int num; /* Descriptor list length. */
};
struct vring_virtqueue {
struct virtqueue vq;
- /* Actual memory layout for this queue */
- struct vring vring;
+ bool packed;
/* Can we use weak barriers? */
bool weak_barriers;
@@ -87,11 +87,28 @@ 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;
+ union {
+ /* Available for split ring */
+ struct {
+ /* Actual memory layout for this queue */
+ struct vring vring;
+
+ /* Last written value to avail->flags */
+ u16 avail_flags_shadow;
+
+ /* Last written value to avail->idx in
+ * guest byte order */
+ u16 avail_idx_shadow;
+ };
+
+ /* Available for packed ring */
+ struct {
+ /* Actual memory layout for this queue */
+ struct vring_packed vring_packed;
+ u8 wrap_counter : 1;
+ bool chaining;
+ };
+ };
/* How to notify other side. FIXME: commonalize hcalls! */
bool (*notify)(struct virtqueue *vq);
@@ -201,26 +218,37 @@ static dma_addr_t vring_map_single(const struct
vring_virtqueue *vq,
cpu_addr, size, direction);
}
-static void vring_unmap_one(const struct vring_virtqueue *vq,
- struct vring_desc *desc)
+static void vring_unmap_one(const struct vring_virtqueue *vq, void *_desc)
{
+ u64 addr;
+ u32 len;
u16 flags;
if (!vring_use_dma_api(vq->vq.vdev))
return;
- flags = virtio16_to_cpu(vq->vq.vdev, desc->flags);
+ if (vq->packed) {
+ struct vring_packed_desc *desc = _desc;
+
+ addr = virtio64_to_cpu(vq->vq.vdev, desc->addr);
+ len = virtio32_to_cpu(vq->vq.vdev, desc->len);
+ flags = virtio16_to_cpu(vq->vq.vdev, desc->flags);
+ } else {
+ struct vring_desc *desc = _desc;
+
+ addr = virtio64_to_cpu(vq->vq.vdev, desc->addr);
+ len = virtio32_to_cpu(vq->vq.vdev, desc->len);
+ flags = virtio16_to_cpu(vq->vq.vdev, desc->flags);
+ }
if (flags & VRING_DESC_F_INDIRECT) {
dma_unmap_single(vring_dma_dev(vq),
- virtio64_to_cpu(vq->vq.vdev, desc->addr),
- virtio32_to_cpu(vq->vq.vdev, desc->len),
+ addr, len,
(flags & VRING_DESC_F_WRITE) ?
DMA_FROM_DEVICE : DMA_TO_DEVICE);
} else {
dma_unmap_page(vring_dma_dev(vq),
- virtio64_to_cpu(vq->vq.vdev, desc->addr),
- virtio32_to_cpu(vq->vq.vdev, desc->len),
+ addr, len,
(flags & VRING_DESC_F_WRITE) ?
DMA_FROM_DEVICE : DMA_TO_DEVICE);
}
@@ -235,8 +263,9 @@ static int vring_mapping_error(const struct vring_virtqueue
*vq,
return dma_mapping_error(vring_dma_dev(vq), addr);
}
-static struct vring_desc *alloc_indirect(struct virtqueue *_vq,
- unsigned int total_sg, gfp_t gfp)
+static struct vring_desc *alloc_indirect_split(struct virtqueue *_vq,
+ unsigned int total_sg,
+ gfp_t gfp)
{
struct vring_desc *desc;
unsigned int i;
@@ -257,14 +286,32 @@ static struct vring_desc *alloc_indirect(struct virtqueue
*_vq,
return desc;
}
-static inline int virtqueue_add(struct virtqueue *_vq,
- struct scatterlist *sgs[],
- unsigned int total_sg,
- unsigned int out_sgs,
- unsigned int in_sgs,
- void *data,
- void *ctx,
- gfp_t gfp)
+static struct vring_packed_desc *alloc_indirect_packed(struct virtqueue *_vq,
+ unsigned int total_sg,
+ gfp_t gfp)
+{
+ struct vring_packed_desc *desc;
+
+ /*
+ * We require lowmem mappings for the descriptors because
+ * otherwise virt_to_phys will give us bogus addresses in the
+ * virtqueue.
+ */
+ gfp &= ~__GFP_HIGHMEM;
+
+ desc = kmalloc(total_sg * sizeof(struct vring_packed_desc), gfp);
+
+ return desc;
+}
+
+static inline int virtqueue_add_split(struct virtqueue *_vq,
+ struct scatterlist *sgs[],
+ unsigned int total_sg,
+ unsigned int out_sgs,
+ unsigned int in_sgs,
+ void *data,
+ void *ctx,
+ gfp_t gfp)
{
struct vring_virtqueue *vq = to_vvq(_vq);
struct scatterlist *sg;
@@ -303,7 +350,7 @@ static inline int virtqueue_add(struct virtqueue *_vq,
/* If the host supports indirect descriptor tables, and we have multiple
* buffers, then go indirect. FIXME: tune this threshold */
if (vq->indirect && total_sg > 1 && vq->vq.num_free)
- desc = alloc_indirect(_vq, total_sg, gfp);
+ desc = alloc_indirect_split(_vq, total_sg, gfp);
else {
desc = NULL;
WARN_ON_ONCE(total_sg > vq->vring.num && !vq->indirect);
@@ -437,6 +484,243 @@ static inline int virtqueue_add(struct virtqueue *_vq,
return -EIO;
}
+static inline int virtqueue_add_packed(struct virtqueue *_vq,
+ struct scatterlist *sgs[],
+ unsigned int total_sg,
+ unsigned int out_sgs,
+ unsigned int in_sgs,
+ void *data,
+ void *ctx,
+ gfp_t gfp)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+ struct vring_packed_desc *desc;
+ struct scatterlist *sg;
+ unsigned int i, n, descs_used, uninitialized_var(prev), err_idx;
+ __virtio16 uninitialized_var(head_flags), flags;
+ int head, wrap_counter;
+ bool indirect;
+
+ START_USE(vq);
+
+ BUG_ON(data == NULL);
+ BUG_ON(ctx && vq->indirect);
+
+ if (unlikely(vq->broken)) {
+ END_USE(vq);
+ return -EIO;
+ }
+
+ if (total_sg > 1 && !vq->chaining && !vq->indirect) {
+ END_USE(vq);
+ return -ENOTSUPP;
+ }
+
+#ifdef DEBUG
+ {
+ ktime_t now = ktime_get();
+
+ /* No kick or get, with .1 second between? Warn. */
+ if (vq->last_add_time_valid)
+ WARN_ON(ktime_to_ms(ktime_sub(now, vq->last_add_time))
+ > 100);
+ vq->last_add_time = now;
+ vq->last_add_time_valid = true;
+ }
+#endif
+
+ BUG_ON(total_sg == 0);
+
+ head = vq->free_head;
+ wrap_counter = vq->wrap_counter;
+
+ /* If the host supports indirect descriptor tables, and we have multiple
+ * buffers, then go indirect. FIXME: tune this threshold */
+ if (vq->indirect && total_sg > 1 && vq->vq.num_free)
+ desc = alloc_indirect_packed(_vq, total_sg, gfp);
+ else {
+ desc = NULL;
+ WARN_ON_ONCE(total_sg > vq->vring.num && !vq->indirect);
+ }
+
+ if (desc) {
+ /* Use a single buffer which doesn't continue */
+ indirect = true;
+ /* Set up rest to use this indirect table. */
+ i = 0;
+ descs_used = 1;
+ } else {
+ indirect = false;
+ desc = vq->vring_packed.desc;
+ i = head;
+ descs_used = total_sg;
+
+ if (total_sg > 1 && !vq->chaining) {
+ END_USE(vq);
+ return -ENOTSUPP;
+ }
+ }
+
+ if (vq->vq.num_free < descs_used) {
+ pr_debug("Can't add buf len %i - avail = %i\n",
+ descs_used, vq->vq.num_free);
+ /* FIXME: for historical reasons, we force a notify here if
+ * there are outgoing parts to the buffer. Presumably the
+ * host should service the ring ASAP. */
+ if (out_sgs)
+ vq->notify(&vq->vq);
+ if (indirect)
+ kfree(desc);
+ END_USE(vq);
+ return -ENOSPC;
+ }
+
+ for (n = 0; n < out_sgs; n++) {
+ for (sg = sgs[n]; sg; sg = sg_next(sg)) {
+ dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_TO_DEVICE);
+ if (vring_mapping_error(vq, addr))
+ goto unmap_release;
+
+ flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT |
+ VRING_DESC_F_AVAIL(vq->wrap_counter) |
+ VRING_DESC_F_USED(!vq->wrap_counter));
+ if (!indirect && i == head)
+ head_flags = flags;
+ else
+ desc[i].flags = flags;
+
+ desc[i].addr = cpu_to_virtio64(_vq->vdev, addr);
+ desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length);
+ desc[i].id = cpu_to_virtio32(_vq->vdev, head);
+ prev = i;
+ i++;
+ if (!indirect && i >= vq->vring_packed.num) {
+ i = 0;
+ vq->wrap_counter ^= 1;
+ }
+ }
+ }
+ for (; n < (out_sgs + in_sgs); n++) {
+ for (sg = sgs[n]; sg; sg = sg_next(sg)) {
+ dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_FROM_DEVICE);
+ if (vring_mapping_error(vq, addr))
+ goto unmap_release;
+
+ flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT |
+ VRING_DESC_F_WRITE |
+ VRING_DESC_F_AVAIL(vq->wrap_counter) |
+ VRING_DESC_F_USED(!vq->wrap_counter));
+ if (!indirect && i == head)
+ head_flags = flags;
+ else
+ desc[i].flags = flags;
+
+ desc[i].addr = cpu_to_virtio64(_vq->vdev, addr);
+ desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length);
+ desc[i].id = cpu_to_virtio32(_vq->vdev, head);
+ prev = i;
+ i++;
+ if (!indirect && i >= vq->vring_packed.num) {
+ i = 0;
+ vq->wrap_counter ^= 1;
+ }
+ }
+ }
+ /* Last one doesn't continue. */
+ if (!indirect && (head + 1) % vq->vring_packed.num == i)
+ head_flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT);
+ else
+ desc[prev].flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT);
+
+ if (indirect) {
+ /* FIXME: to be implemented */
+
+ /* Now that the indirect table is filled in, map it. */
+ dma_addr_t addr = vring_map_single(
+ vq, desc, total_sg * sizeof(struct vring_packed_desc),
+ DMA_TO_DEVICE);
+ if (vring_mapping_error(vq, addr))
+ goto unmap_release;
+
+ head_flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_INDIRECT |
+ VRING_DESC_F_AVAIL(wrap_counter) |
+ VRING_DESC_F_USED(!wrap_counter));
+ vq->vring_packed.desc[head].addr = cpu_to_virtio64(_vq->vdev, addr);
+ vq->vring_packed.desc[head].len = cpu_to_virtio32(_vq->vdev,
+ total_sg * sizeof(struct vring_packed_desc));
+ vq->vring_packed.desc[head].id = cpu_to_virtio32(_vq->vdev, head);
+ }
+
+ /* We're using some buffers from the free list. */
+ vq->vq.num_free -= descs_used;
+
+ /* Update free pointer */
+ if (indirect) {
+ n = head + 1;
+ if (n >= vq->vring_packed.num) {
+ n = 0;
+ vq->wrap_counter ^= 1;
+ }
+ vq->free_head = n;
+ } else
+ vq->free_head = i;
+
+ /* Store token and indirect buffer state. */
+ vq->desc_state[head].num = descs_used;
+ vq->desc_state[head].data = data;
+ if (indirect)
+ vq->desc_state[head].indir_desc = desc;
+ else
+ vq->desc_state[head].indir_desc = ctx;
+
+ virtio_wmb(vq->weak_barriers);
+ vq->vring_packed.desc[head].flags = head_flags;
+ vq->num_added++;
+
+ pr_debug("Added buffer head %i to %p\n", head, vq);
+ END_USE(vq);
+
+ return 0;
+
+unmap_release:
+ err_idx = i;
+ i = head;
+
+ for (n = 0; n < total_sg; n++) {
+ if (i == err_idx)
+ break;
+ vring_unmap_one(vq, &desc[i]);
+ i++;
+ if (!indirect && i >= vq->vring_packed.num)
+ i = 0;
+ }
+
+ vq->wrap_counter = wrap_counter;
+
+ if (indirect)
+ kfree(desc);
+
+ END_USE(vq);
+ return -EIO;
+}
+
+static inline int virtqueue_add(struct virtqueue *_vq,
+ struct scatterlist *sgs[],
+ unsigned int total_sg,
+ unsigned int out_sgs,
+ unsigned int in_sgs,
+ void *data,
+ void *ctx,
+ gfp_t gfp)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ return vq->packed ? virtqueue_add_packed(_vq, sgs, total_sg, out_sgs,
+ in_sgs, data, ctx, gfp) :
+ virtqueue_add_split(_vq, sgs, total_sg, out_sgs,
+ in_sgs, data, ctx, gfp);
+}
+
/**
* virtqueue_add_sgs - expose buffers to other end
* @vq: the struct virtqueue we're talking about.
@@ -561,6 +845,12 @@ bool virtqueue_kick_prepare(struct virtqueue *_vq)
* event. */
virtio_mb(vq->weak_barriers);
+ if (vq->packed) {
+ /* FIXME: to be implemented */
+ needs_kick = true;
+ goto out;
+ }
+
old = vq->avail_idx_shadow - vq->num_added;
new = vq->avail_idx_shadow;
vq->num_added = 0;
@@ -579,6 +869,8 @@ bool virtqueue_kick_prepare(struct virtqueue *_vq)
} else {
needs_kick = !(vq->vring.used->flags &
cpu_to_virtio16(_vq->vdev, VRING_USED_F_NO_NOTIFY));
}
+
+out:
END_USE(vq);
return needs_kick;
}
@@ -628,8 +920,8 @@ bool virtqueue_kick(struct virtqueue *vq)
}
EXPORT_SYMBOL_GPL(virtqueue_kick);
-static void detach_buf(struct vring_virtqueue *vq, unsigned int head,
- void **ctx)
+static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head,
+ void **ctx)
{
unsigned int i, j;
__virtio16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT);
@@ -677,29 +969,81 @@ static void detach_buf(struct vring_virtqueue *vq,
unsigned int head,
}
}
-static inline bool more_used(const struct vring_virtqueue *vq)
+static void detach_buf_packed(struct vring_virtqueue *vq, unsigned int head,
+ void **ctx)
+{
+ struct vring_packed_desc *desc;
+ unsigned int i, j;
+
+ /* Clear data ptr. */
+ vq->desc_state[head].data = NULL;
+
+ i = head;
+
+ for (j = 0; j < vq->desc_state[head].num; j++) {
+ desc = &vq->vring_packed.desc[i];
+ vring_unmap_one(vq, desc);
+ i++;
+ if (i >= vq->vring_packed.num)
+ i = 0;
+ }
+
+ vq->vq.num_free += vq->desc_state[head].num;
+
+ if (vq->indirect) {
+ u32 len;
+
+ desc = vq->desc_state[head].indir_desc;
+ /* Free the indirect table, if any, now that it's unmapped. */
+ if (!desc)
+ return;
+
+ len = virtio32_to_cpu(vq->vq.vdev,
+ vq->vring_packed.desc[head].len);
+
+ BUG_ON(!(vq->vring_packed.desc[head].flags &
+ cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_INDIRECT)));
+ BUG_ON(len == 0 || len % sizeof(struct vring_packed_desc));
+
+ for (j = 0; j < len / sizeof(struct vring_packed_desc); j++)
+ vring_unmap_one(vq, &desc[j]);
+
+ kfree(desc);
+ vq->desc_state[head].indir_desc = NULL;
+ } else if (ctx) {
+ *ctx = vq->desc_state[head].indir_desc;
+ }
+}
+
+static inline bool more_used_split(const struct vring_virtqueue *vq)
{
return vq->last_used_idx != virtio16_to_cpu(vq->vq.vdev,
vq->vring.used->idx);
}
-/**
- * virtqueue_get_buf - get the next used buffer
- * @vq: the struct virtqueue we're talking about.
- * @len: the length written into the buffer
- *
- * If the device wrote data into the buffer, @len will be set to the
- * amount written. This means you don't need to clear the buffer
- * beforehand to ensure there's no data leakage in the case of short
- * writes.
- *
- * Caller must ensure we don't call this with other virtqueue
- * operations at the same time (except where noted).
- *
- * Returns NULL if there are no used buffers, or the "data" token
- * handed to virtqueue_add_*().
- */
-void *virtqueue_get_buf_ctx(struct virtqueue *_vq, unsigned int *len,
- void **ctx)
+static inline bool more_used_packed(const struct vring_virtqueue *vq)
+{
+ u16 last_used, flags;
+ bool avail, used;
+
+ if (vq->vq.num_free == vq->vring.num)
+ return false;
+
+ last_used = vq->last_used_idx;
+ flags = virtio16_to_cpu(vq->vq.vdev,
+ vq->vring_packed.desc[last_used].flags);
+ avail = flags & VRING_DESC_F_AVAIL(1);
+ used = flags & VRING_DESC_F_USED(1);
+
+ return avail == used;
+}
+
+static inline bool more_used(const struct vring_virtqueue *vq)
+{
+ return vq->packed ? more_used_packed(vq) : more_used_split(vq);
+}
+
+void *virtqueue_get_buf_ctx_split(struct virtqueue *_vq, unsigned int *len,
+ void **ctx)
{
struct vring_virtqueue *vq = to_vvq(_vq);
void *ret;
@@ -735,9 +1079,9 @@ void *virtqueue_get_buf_ctx(struct virtqueue *_vq, unsigned
int *len,
return NULL;
}
- /* detach_buf clears data, so grab it now. */
+ /* detach_buf_split clears data, so grab it now. */
ret = vq->desc_state[i].data;
- detach_buf(vq, i, ctx);
+ detach_buf_split(vq, i, ctx);
vq->last_used_idx++;
/* If we expect an interrupt for the next entry, tell host
* by writing event index and flush out the write before
@@ -754,6 +1098,87 @@ void *virtqueue_get_buf_ctx(struct virtqueue *_vq,
unsigned int *len,
END_USE(vq);
return ret;
}
+
+void *virtqueue_get_buf_ctx_packed(struct virtqueue *_vq, unsigned int *len,
+ void **ctx)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+ void *ret;
+ unsigned int i;
+ u16 last_used;
+
+ START_USE(vq);
+
+ if (unlikely(vq->broken)) {
+ END_USE(vq);
+ return NULL;
+ }
+
+ if (!more_used(vq)) {
+ pr_debug("No more buffers in queue\n");
+ END_USE(vq);
+ return NULL;
+ }
+
+ /* Only get used array entries after they have been exposed by host. */
+ virtio_rmb(vq->weak_barriers);
+
+ last_used = vq->last_used_idx;
+
+ i = virtio32_to_cpu(_vq->vdev, vq->vring_packed.desc[last_used].id);
+ *len = virtio32_to_cpu(_vq->vdev, vq->vring_packed.desc[last_used].len);
+
+ if (unlikely(i >= vq->vring_packed.num)) {
+ BAD_RING(vq, "id %u out of range\n", i);
+ return NULL;
+ }
+ if (unlikely(!vq->desc_state[i].data)) {
+ BAD_RING(vq, "id %u is not a head!\n", i);
+ return NULL;
+ }
+
+ /* detach_buf_packed clears data, so grab it now. */
+ ret = vq->desc_state[i].data;
+ detach_buf_packed(vq, i, ctx);
+
+ vq->last_used_idx += vq->desc_state[i].num;
+ if (vq->last_used_idx >= vq->vring_packed.num)
+ vq->last_used_idx %= vq->vring_packed.num;
+
+ // FIXME: implement the desc event support
+
+#ifdef DEBUG
+ vq->last_add_time_valid = false;
+#endif
+
+ END_USE(vq);
+ return ret;
+}
+
+/**
+ * virtqueue_get_buf - get the next used buffer
+ * @vq: the struct virtqueue we're talking about.
+ * @len: the length written into the buffer
+ *
+ * If the device wrote data into the buffer, @len will be set to the
+ * amount written. This means you don't need to clear the buffer
+ * beforehand to ensure there's no data leakage in the case of short
+ * writes.
+ *
+ * Caller must ensure we don't call this with other virtqueue
+ * operations at the same time (except where noted).
+ *
+ * Returns NULL if there are no used buffers, or the "data" token
+ * handed to virtqueue_add_*().
+ */
+void *virtqueue_get_buf_ctx(struct virtqueue *_vq, unsigned int *len,
+ void **ctx)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ return vq->packed ? virtqueue_get_buf_ctx_packed(_vq, len, ctx) :
+ virtqueue_get_buf_ctx_split(_vq, len, ctx);
+}
EXPORT_SYMBOL_GPL(virtqueue_get_buf_ctx);
void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len)
@@ -761,6 +1186,24 @@ void *virtqueue_get_buf(struct virtqueue *_vq, unsigned
int *len)
return virtqueue_get_buf_ctx(_vq, len, NULL);
}
EXPORT_SYMBOL_GPL(virtqueue_get_buf);
+
+static void virtqueue_disable_cb_split(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ if (!(vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) {
+ vq->avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT;
+ if (!vq->event)
+ vq->vring.avail->flags = cpu_to_virtio16(_vq->vdev,
+ vq->avail_flags_shadow);
+ }
+}
+
+static void virtqueue_disable_cb_packed(struct virtqueue *_vq)
+{
+ // FIXME: to be implemented
+}
+
/**
* virtqueue_disable_cb - disable callbacks
* @vq: the struct virtqueue we're talking about.
@@ -774,12 +1217,10 @@ void virtqueue_disable_cb(struct virtqueue *_vq)
{
struct vring_virtqueue *vq = to_vvq(_vq);
- if (!(vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) {
- vq->avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT;
- if (!vq->event)
- vq->vring.avail->flags = cpu_to_virtio16(_vq->vdev,
vq->avail_flags_shadow);
- }
-
+ if (vq->packed)
+ virtqueue_disable_cb_packed(_vq);
+ else
+ virtqueue_disable_cb_split(_vq);
}
EXPORT_SYMBOL_GPL(virtqueue_disable_cb);
@@ -802,6 +1243,12 @@ unsigned virtqueue_enable_cb_prepare(struct virtqueue
*_vq)
START_USE(vq);
+ if (vq->packed) {
+ // FIXME: to be implemented
+ last_used_idx = vq->last_used_idx;
+ goto out;
+ }
+
/* We optimistically turn back on interrupts, then check if there was
* more to do. */
/* Depending on the VIRTIO_RING_F_EVENT_IDX feature, we need to
@@ -813,6 +1260,7 @@ unsigned virtqueue_enable_cb_prepare(struct virtqueue *_vq)
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);
+out:
END_USE(vq);
return last_used_idx;
}
@@ -832,6 +1280,12 @@ bool virtqueue_poll(struct virtqueue *_vq, unsigned
last_used_idx)
struct vring_virtqueue *vq = to_vvq(_vq);
virtio_mb(vq->weak_barriers);
+ if (vq->packed) {
+ u16 flags = virtio16_to_cpu(vq->vq.vdev,
+ vq->vring_packed.desc[last_used_idx].flags);
+ return !(flags & VRING_DESC_F_AVAIL(1)) =+ !(flags &
VRING_DESC_F_USED(1));
+ }
return (u16)last_used_idx != virtio16_to_cpu(_vq->vdev,
vq->vring.used->idx);
}
EXPORT_SYMBOL_GPL(virtqueue_poll);
@@ -874,6 +1328,11 @@ bool virtqueue_enable_cb_delayed(struct virtqueue *_vq)
START_USE(vq);
+ if (vq->packed) {
+ // FIXME: to be implemented
+ goto out;
+ }
+
/* We optimistically turn back on interrupts, then check if there was
* more to do. */
/* Depending on the VIRTIO_RING_F_USED_EVENT_IDX feature, we need to
@@ -896,6 +1355,7 @@ bool virtqueue_enable_cb_delayed(struct virtqueue *_vq)
return false;
}
+out:
END_USE(vq);
return true;
}
@@ -922,14 +1382,20 @@ void *virtqueue_detach_unused_buf(struct virtqueue *_vq)
continue;
/* detach_buf clears data, so grab it now. */
buf = vq->desc_state[i].data;
- detach_buf(vq, i, NULL);
- vq->avail_idx_shadow--;
- vq->vring.avail->idx = cpu_to_virtio16(_vq->vdev,
vq->avail_idx_shadow);
+ if (vq->packed)
+ detach_buf_packed(vq, i, NULL);
+ else {
+ detach_buf_split(vq, i, NULL);
+ vq->avail_idx_shadow--;
+ vq->vring.avail->idx = cpu_to_virtio16(_vq->vdev,
+ vq->avail_idx_shadow);
+ }
END_USE(vq);
return buf;
}
/* That should have freed everything. */
- BUG_ON(vq->vq.num_free != vq->vring.num);
+ BUG_ON(vq->vq.num_free != (vq->packed ? vq->vring_packed.num :
+ vq->vring.num));
END_USE(vq);
return NULL;
@@ -957,7 +1423,8 @@ irqreturn_t vring_interrupt(int irq, void *_vq)
EXPORT_SYMBOL_GPL(vring_interrupt);
struct virtqueue *__vring_new_virtqueue(unsigned int index,
- struct vring vring,
+ union vring_union vring,
+ bool packed,
struct virtio_device *vdev,
bool weak_barriers,
bool context,
@@ -965,19 +1432,20 @@ struct virtqueue *__vring_new_virtqueue(unsigned int
index,
void (*callback)(struct virtqueue *),
const char *name)
{
- unsigned int i;
+ unsigned int num, i;
struct vring_virtqueue *vq;
- vq = kmalloc(sizeof(*vq) + vring.num * sizeof(struct vring_desc_state),
+ num = packed ? vring.vring_packed.num : vring.vring_split.num;
+
+ vq = kmalloc(sizeof(*vq) + num * sizeof(struct vring_desc_state),
GFP_KERNEL);
if (!vq)
return NULL;
- vq->vring = vring;
vq->vq.callback = callback;
vq->vq.vdev = vdev;
vq->vq.name = name;
- vq->vq.num_free = vring.num;
+ vq->vq.num_free = num;
vq->vq.index = index;
vq->we_own_ring = false;
vq->queue_dma_addr = 0;
@@ -986,9 +1454,8 @@ 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;
+ vq->packed = packed;
list_add_tail(&vq->vq.list, &vdev->vqs);
#ifdef DEBUG
vq->in_use = false;
@@ -999,18 +1466,41 @@ struct virtqueue *__vring_new_virtqueue(unsigned int
index,
!context;
vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
+ if (vq->packed) {
+ vq->vring_packed = vring.vring_packed;
+ vq->free_head = 0;
+ vq->wrap_counter = 1;
+
+#if 0
+ vq->chaining = virtio_has_feature(vdev,
+ VIRTIO_RING_F_LIST_DESC);
+#else
+ vq->chaining = true;
+#endif
+ } else {
+ vq->vring = vring.vring_split;
+ vq->avail_flags_shadow = 0;
+ vq->avail_idx_shadow = 0;
+
+ /* Put everything in free lists. */
+ vq->free_head = 0;
+ for (i = 0; i < num-1; i++)
+ vq->vring.desc[i].next = cpu_to_virtio16(vdev, i + 1);
+ }
+
/* No callback? Tell other side not to bother us. */
if (!callback) {
- vq->avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT;
- if (!vq->event)
- vq->vring.avail->flags = cpu_to_virtio16(vdev,
vq->avail_flags_shadow);
+ if (packed) {
+ // FIXME: to be implemented
+ } else {
+ vq->avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT;
+ if (!vq->event)
+ vq->vring.avail->flags = cpu_to_virtio16(vdev,
+ vq->avail_flags_shadow);
+ }
}
- /* Put everything in free lists. */
- vq->free_head = 0;
- for (i = 0; i < vring.num-1; i++)
- vq->vring.desc[i].next = cpu_to_virtio16(vdev, i + 1);
- memset(vq->desc_state, 0, vring.num * sizeof(struct vring_desc_state));
+ memset(vq->desc_state, 0, num * sizeof(struct vring_desc_state));
return &vq->vq;
}
@@ -1058,6 +1548,14 @@ static void vring_free_queue(struct virtio_device *vdev,
size_t size,
}
}
+static inline int
+__vring_size(unsigned int num, unsigned long align, bool packed)
+{
+ if (packed)
+ return vring_packed_size(num, align);
+ return vring_size(num, align);
+}
+
struct virtqueue *vring_create_virtqueue(
unsigned int index,
unsigned int num,
@@ -1074,7 +1572,8 @@ struct virtqueue *vring_create_virtqueue(
void *queue = NULL;
dma_addr_t dma_addr;
size_t queue_size_in_bytes;
- struct vring vring;
+ union vring_union vring;
+ bool packed;
/* We assume num is a power of 2. */
if (num & (num - 1)) {
@@ -1082,9 +1581,13 @@ struct virtqueue *vring_create_virtqueue(
return NULL;
}
+ packed = virtio_has_feature(vdev, VIRTIO_F_RING_PACKED);
+
/* TODO: allocate each queue chunk individually */
- for (; num && vring_size(num, vring_align) > PAGE_SIZE; num /= 2) {
- queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
+ for (; num && __vring_size(num, vring_align, packed) > PAGE_SIZE;
+ num /= 2) {
+ queue = vring_alloc_queue(vdev, __vring_size(num, vring_align,
+ packed),
&dma_addr,
GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO);
if (queue)
@@ -1096,17 +1599,21 @@ struct virtqueue *vring_create_virtqueue(
if (!queue) {
/* Try to get a single page. You are my only hope! */
- queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
+ queue = vring_alloc_queue(vdev, __vring_size(num, vring_align,
+ packed),
&dma_addr, GFP_KERNEL|__GFP_ZERO);
}
if (!queue)
return NULL;
- queue_size_in_bytes = vring_size(num, vring_align);
- vring_init(&vring, num, queue, vring_align);
+ queue_size_in_bytes = __vring_size(num, vring_align, packed);
+ if (packed)
+ vring_packed_init(&vring.vring_packed, num, queue, vring_align);
+ else
+ vring_init(&vring.vring_split, num, queue, vring_align);
- vq = __vring_new_virtqueue(index, vring, vdev, weak_barriers, context,
- notify, callback, name);
+ vq = __vring_new_virtqueue(index, vring, packed, vdev, weak_barriers,
+ context, notify, callback, name);
if (!vq) {
vring_free_queue(vdev, queue_size_in_bytes, queue,
dma_addr);
@@ -1132,10 +1639,17 @@ struct virtqueue *vring_new_virtqueue(unsigned int
index,
void (*callback)(struct virtqueue *vq),
const char *name)
{
- struct vring vring;
- vring_init(&vring, num, pages, vring_align);
- return __vring_new_virtqueue(index, vring, vdev, weak_barriers, context,
- notify, callback, name);
+ union vring_union vring;
+ bool packed;
+
+ packed = virtio_has_feature(vdev, VIRTIO_F_RING_PACKED);
+ if (packed)
+ vring_packed_init(&vring.vring_packed, num, pages, vring_align);
+ else
+ vring_init(&vring.vring_split, num, pages, vring_align);
+
+ return __vring_new_virtqueue(index, vring, packed, vdev, weak_barriers,
+ context, notify, callback, name);
}
EXPORT_SYMBOL_GPL(vring_new_virtqueue);
@@ -1145,7 +1659,9 @@ void vring_del_virtqueue(struct virtqueue *_vq)
if (vq->we_own_ring) {
vring_free_queue(vq->vq.vdev, vq->queue_size_in_bytes,
- vq->vring.desc, vq->queue_dma_addr);
+ vq->packed ? (void *)vq->vring_packed.desc :
+ (void *)vq->vring.desc,
+ vq->queue_dma_addr);
}
list_del(&_vq->list);
kfree(vq);
@@ -1159,14 +1675,18 @@ void vring_transport_features(struct virtio_device
*vdev)
for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) {
switch (i) {
+#if 0 // FIXME: to be implemented
case VIRTIO_RING_F_INDIRECT_DESC:
break;
+#endif
case VIRTIO_RING_F_EVENT_IDX:
break;
case VIRTIO_F_VERSION_1:
break;
case VIRTIO_F_IOMMU_PLATFORM:
break;
+ case VIRTIO_F_RING_PACKED:
+ break;
default:
/* We don't understand this bit. */
__virtio_clear_bit(vdev, i);
@@ -1187,7 +1707,7 @@ unsigned int virtqueue_get_vring_size(struct virtqueue
*_vq)
struct vring_virtqueue *vq = to_vvq(_vq);
- return vq->vring.num;
+ return vq->packed ? vq->vring_packed.num : vq->vring.num;
}
EXPORT_SYMBOL_GPL(virtqueue_get_vring_size);
@@ -1224,6 +1744,7 @@ dma_addr_t virtqueue_get_desc_addr(struct virtqueue *_vq)
}
EXPORT_SYMBOL_GPL(virtqueue_get_desc_addr);
+/* Only available for split ring */
dma_addr_t virtqueue_get_avail_addr(struct virtqueue *_vq)
{
struct vring_virtqueue *vq = to_vvq(_vq);
@@ -1235,6 +1756,7 @@ dma_addr_t virtqueue_get_avail_addr(struct virtqueue *_vq)
}
EXPORT_SYMBOL_GPL(virtqueue_get_avail_addr);
+/* Only available for split ring */
dma_addr_t virtqueue_get_used_addr(struct virtqueue *_vq)
{
struct vring_virtqueue *vq = to_vvq(_vq);
@@ -1246,6 +1768,7 @@ dma_addr_t virtqueue_get_used_addr(struct virtqueue *_vq)
}
EXPORT_SYMBOL_GPL(virtqueue_get_used_addr);
+/* Only available for split ring */
const struct vring *virtqueue_get_vring(struct virtqueue *vq)
{
return &to_vvq(vq)->vring;
diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h
index bbf32524ab27..a0075894ad16 100644
--- a/include/linux/virtio_ring.h
+++ b/include/linux/virtio_ring.h
@@ -60,6 +60,11 @@ static inline void virtio_store_mb(bool weak_barriers,
struct virtio_device;
struct virtqueue;
+union vring_union {
+ struct vring vring_split;
+ struct vring_packed vring_packed;
+};
+
/*
* Creates a virtqueue and allocates the descriptor ring. If
* may_reduce_num is set, then this may allocate a smaller ring than
@@ -79,7 +84,8 @@ struct virtqueue *vring_create_virtqueue(unsigned int index,
/* Creates a virtqueue with a custom layout. */
struct virtqueue *__vring_new_virtqueue(unsigned int index,
- struct vring vring,
+ union vring_union vring,
+ bool packed,
struct virtio_device *vdev,
bool weak_barriers,
bool ctx,
--
2.14.1
On Fri, Feb 23, 2018 at 07:18:00PM +0800, Tiwei Bie wrote:>Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> >--- > include/uapi/linux/virtio_config.h | 18 +++++++++- > include/uapi/linux/virtio_ring.h | 68 ++++++++++++++++++++++++++++++++++++++ > 2 files changed, 85 insertions(+), 1 deletion(-) > >diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h >index 308e2096291f..e3d077ef5207 100644 >--- a/include/uapi/linux/virtio_config.h >+++ b/include/uapi/linux/virtio_config.h >@@ -49,7 +49,7 @@ > * transport being used (eg. virtio_ring), the rest are per-device feature > * bits. */ > #define VIRTIO_TRANSPORT_F_START 28 >-#define VIRTIO_TRANSPORT_F_END 34 >+#define VIRTIO_TRANSPORT_F_END 37 > > #ifndef VIRTIO_CONFIG_NO_LEGACY > /* Do we get callbacks when the ring is completely used, even if we've >@@ -71,4 +71,20 @@ > * this is for compatibility with legacy systems. > */ > #define VIRTIO_F_IOMMU_PLATFORM 33 >+ >+/* This feature indicates support for the packed virtqueue layout. */ >+#define VIRTIO_F_RING_PACKED 34Spec says VIRTIO_F_PACKED_RING not RING_PACKED>+ >+/* >+ * This feature indicates that all buffers are used by the device >+ * in the same order in which they have been made available. >+ */ >+#define VIRTIO_F_IN_ORDER 35 >+ >+/* >+ * This feature indicates that drivers pass extra data (besides >+ * identifying the Virtqueue) in their device notifications. >+ */ >+#define VIRTIO_F_NOTIFICATION_DATA 36 >+ > #endif /* _UAPI_LINUX_VIRTIO_CONFIG_H */ >diff --git a/include/uapi/linux/virtio_ring.h b/include/uapi/linux/virtio_ring.h >index 6d5d5faa989b..77b1d4aeef72 100644 >--- a/include/uapi/linux/virtio_ring.h >+++ b/include/uapi/linux/virtio_ring.h >@@ -44,6 +44,9 @@ > /* This means the buffer contains a list of buffer descriptors. */ > #define VRING_DESC_F_INDIRECT 4 > >+#define VRING_DESC_F_AVAIL(b) ((b) << 7) >+#define VRING_DESC_F_USED(b) ((b) << 15) >+ > /* The Host uses this in used->flags to advise the Guest: don't kick me when > * you add a buffer. It's unreliable, so it's simply an optimization. Guest > * will still kick if it's out of buffers. */ >@@ -104,6 +107,36 @@ struct vring { > struct vring_used *used; > }; > >+struct vring_packed_desc_event { >+ /* Descriptor Event Offset */ >+ __virtio16 desc_event_off : 15, >+ /* Descriptor Event Wrap Counter */ >+ desc_event_wrap : 1; >+ /* Descriptor Event Flags */ >+ __virtio16 desc_event_flags : 2; >+};Where would the virtqueue number go in driver notifications? regards, Jens
From: Tiwei Bie> Sent: 23 February 2018 11:18...> +struct vring_packed_desc_event { > + /* Descriptor Event Offset */ > + __virtio16 desc_event_off : 15, > + /* Descriptor Event Wrap Counter */ > + desc_event_wrap : 1; > + /* Descriptor Event Flags */ > + __virtio16 desc_event_flags : 2; > +};This looks like you are assuming that a bit-field has a defined layout and can be used to map a 'hardware' structure. The don't, don't use them like that. David
On 2018?02?23? 19:18, Tiwei Bie wrote:> Signed-off-by: Tiwei Bie <tiwei.bie at intel.com> > --- > drivers/virtio/virtio_ring.c | 699 +++++++++++++++++++++++++++++++++++++------ > include/linux/virtio_ring.h | 8 +- > 2 files changed, 618 insertions(+), 89 deletions(-) > > diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c > index eb30f3e09a47..393778a2f809 100644 > --- a/drivers/virtio/virtio_ring.c > +++ b/drivers/virtio/virtio_ring.c > @@ -58,14 +58,14 @@ > > struct vring_desc_state { > void *data; /* Data for callback. */ > - struct vring_desc *indir_desc; /* Indirect descriptor, if any. */ > + void *indir_desc; /* Indirect descriptor, if any. */ > + int num; /* Descriptor list length. */ > }; > > struct vring_virtqueue { > struct virtqueue vq; > > - /* Actual memory layout for this queue */ > - struct vring vring; > + bool packed; > > /* Can we use weak barriers? */ > bool weak_barriers; > @@ -87,11 +87,28 @@ 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; > + union { > + /* Available for split ring */ > + struct { > + /* Actual memory layout for this queue */ > + struct vring vring; > + > + /* Last written value to avail->flags */ > + u16 avail_flags_shadow; > + > + /* Last written value to avail->idx in > + * guest byte order */ > + u16 avail_idx_shadow; > + }; > + > + /* Available for packed ring */ > + struct { > + /* Actual memory layout for this queue */ > + struct vring_packed vring_packed; > + u8 wrap_counter : 1; > + bool chaining; > + }; > + }; > > /* How to notify other side. FIXME: commonalize hcalls! */ > bool (*notify)(struct virtqueue *vq); > @@ -201,26 +218,37 @@ static dma_addr_t vring_map_single(const struct vring_virtqueue *vq, > cpu_addr, size, direction); > } > > -static void vring_unmap_one(const struct vring_virtqueue *vq, > - struct vring_desc *desc) > +static void vring_unmap_one(const struct vring_virtqueue *vq, void *_desc) > {Let's split the helpers to packed/split version like other helpers? (Consider the caller has already known the type of vq).> + u64 addr; > + u32 len; > u16 flags; > > if (!vring_use_dma_api(vq->vq.vdev)) > return; > > - flags = virtio16_to_cpu(vq->vq.vdev, desc->flags); > + if (vq->packed) { > + struct vring_packed_desc *desc = _desc; > + > + addr = virtio64_to_cpu(vq->vq.vdev, desc->addr); > + len = virtio32_to_cpu(vq->vq.vdev, desc->len); > + flags = virtio16_to_cpu(vq->vq.vdev, desc->flags); > + } else { > + struct vring_desc *desc = _desc; > + > + addr = virtio64_to_cpu(vq->vq.vdev, desc->addr); > + len = virtio32_to_cpu(vq->vq.vdev, desc->len); > + flags = virtio16_to_cpu(vq->vq.vdev, desc->flags); > + } > > if (flags & VRING_DESC_F_INDIRECT) { > dma_unmap_single(vring_dma_dev(vq), > - virtio64_to_cpu(vq->vq.vdev, desc->addr), > - virtio32_to_cpu(vq->vq.vdev, desc->len), > + addr, len, > (flags & VRING_DESC_F_WRITE) ? > DMA_FROM_DEVICE : DMA_TO_DEVICE); > } else { > dma_unmap_page(vring_dma_dev(vq), > - virtio64_to_cpu(vq->vq.vdev, desc->addr), > - virtio32_to_cpu(vq->vq.vdev, desc->len), > + addr, len, > (flags & VRING_DESC_F_WRITE) ? > DMA_FROM_DEVICE : DMA_TO_DEVICE); > } > @@ -235,8 +263,9 @@ static int vring_mapping_error(const struct vring_virtqueue *vq, > return dma_mapping_error(vring_dma_dev(vq), addr); > } > > -static struct vring_desc *alloc_indirect(struct virtqueue *_vq, > - unsigned int total_sg, gfp_t gfp) > +static struct vring_desc *alloc_indirect_split(struct virtqueue *_vq, > + unsigned int total_sg, > + gfp_t gfp) > { > struct vring_desc *desc; > unsigned int i; > @@ -257,14 +286,32 @@ static struct vring_desc *alloc_indirect(struct virtqueue *_vq, > return desc; > } > > -static inline int virtqueue_add(struct virtqueue *_vq, > - struct scatterlist *sgs[], > - unsigned int total_sg, > - unsigned int out_sgs, > - unsigned int in_sgs, > - void *data, > - void *ctx, > - gfp_t gfp) > +static struct vring_packed_desc *alloc_indirect_packed(struct virtqueue *_vq, > + unsigned int total_sg, > + gfp_t gfp) > +{ > + struct vring_packed_desc *desc; > + > + /* > + * We require lowmem mappings for the descriptors because > + * otherwise virt_to_phys will give us bogus addresses in the > + * virtqueue. > + */ > + gfp &= ~__GFP_HIGHMEM; > + > + desc = kmalloc(total_sg * sizeof(struct vring_packed_desc), gfp); > + > + return desc; > +} > + > +static inline int virtqueue_add_split(struct virtqueue *_vq, > + struct scatterlist *sgs[], > + unsigned int total_sg, > + unsigned int out_sgs, > + unsigned int in_sgs, > + void *data, > + void *ctx, > + gfp_t gfp) > { > struct vring_virtqueue *vq = to_vvq(_vq); > struct scatterlist *sg; > @@ -303,7 +350,7 @@ static inline int virtqueue_add(struct virtqueue *_vq, > /* If the host supports indirect descriptor tables, and we have multiple > * buffers, then go indirect. FIXME: tune this threshold */ > if (vq->indirect && total_sg > 1 && vq->vq.num_free) > - desc = alloc_indirect(_vq, total_sg, gfp); > + desc = alloc_indirect_split(_vq, total_sg, gfp); > else { > desc = NULL; > WARN_ON_ONCE(total_sg > vq->vring.num && !vq->indirect); > @@ -437,6 +484,243 @@ static inline int virtqueue_add(struct virtqueue *_vq, > return -EIO; > } > > +static inline int virtqueue_add_packed(struct virtqueue *_vq, > + struct scatterlist *sgs[], > + unsigned int total_sg, > + unsigned int out_sgs, > + unsigned int in_sgs, > + void *data, > + void *ctx, > + gfp_t gfp) > +{ > + struct vring_virtqueue *vq = to_vvq(_vq); > + struct vring_packed_desc *desc; > + struct scatterlist *sg; > + unsigned int i, n, descs_used, uninitialized_var(prev), err_idx; > + __virtio16 uninitialized_var(head_flags), flags; > + int head, wrap_counter; > + bool indirect; > + > + START_USE(vq); > + > + BUG_ON(data == NULL); > + BUG_ON(ctx && vq->indirect); > + > + if (unlikely(vq->broken)) { > + END_USE(vq); > + return -EIO; > + } > + > + if (total_sg > 1 && !vq->chaining && !vq->indirect) { > + END_USE(vq); > + return -ENOTSUPP; > + } > + > +#ifdef DEBUG > + { > + ktime_t now = ktime_get(); > + > + /* No kick or get, with .1 second between? Warn. */ > + if (vq->last_add_time_valid) > + WARN_ON(ktime_to_ms(ktime_sub(now, vq->last_add_time)) > + > 100); > + vq->last_add_time = now; > + vq->last_add_time_valid = true; > + } > +#endif > + > + BUG_ON(total_sg == 0); > + > + head = vq->free_head; > + wrap_counter = vq->wrap_counter; > + > + /* If the host supports indirect descriptor tables, and we have multiple > + * buffers, then go indirect. FIXME: tune this threshold */ > + if (vq->indirect && total_sg > 1 && vq->vq.num_free) > + desc = alloc_indirect_packed(_vq, total_sg, gfp); > + else { > + desc = NULL; > + WARN_ON_ONCE(total_sg > vq->vring.num && !vq->indirect); > + } > + > + if (desc) { > + /* Use a single buffer which doesn't continue */ > + indirect = true; > + /* Set up rest to use this indirect table. */ > + i = 0; > + descs_used = 1; > + } else { > + indirect = false; > + desc = vq->vring_packed.desc; > + i = head; > + descs_used = total_sg; > + > + if (total_sg > 1 && !vq->chaining) { > + END_USE(vq); > + return -ENOTSUPP; > + } > + } > + > + if (vq->vq.num_free < descs_used) { > + pr_debug("Can't add buf len %i - avail = %i\n", > + descs_used, vq->vq.num_free); > + /* FIXME: for historical reasons, we force a notify here if > + * there are outgoing parts to the buffer. Presumably the > + * host should service the ring ASAP. */ > + if (out_sgs) > + vq->notify(&vq->vq); > + if (indirect) > + kfree(desc); > + END_USE(vq); > + return -ENOSPC; > + } > + > + for (n = 0; n < out_sgs; n++) { > + for (sg = sgs[n]; sg; sg = sg_next(sg)) { > + dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_TO_DEVICE); > + if (vring_mapping_error(vq, addr)) > + goto unmap_release; > + > + flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT | > + VRING_DESC_F_AVAIL(vq->wrap_counter) | > + VRING_DESC_F_USED(!vq->wrap_counter)); > + if (!indirect && i == head) > + head_flags = flags; > + else > + desc[i].flags = flags; > + > + desc[i].addr = cpu_to_virtio64(_vq->vdev, addr); > + desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length); > + desc[i].id = cpu_to_virtio32(_vq->vdev, head);If it's a part of chain, we only need to do this for last buffer I think.> + prev = i; > + i++;It looks to me prev is always i - 1?> + if (!indirect && i >= vq->vring_packed.num) { > + i = 0; > + vq->wrap_counter ^= 1; > + } > + } > + } > + for (; n < (out_sgs + in_sgs); n++) { > + for (sg = sgs[n]; sg; sg = sg_next(sg)) { > + dma_addr_t addr = vring_map_one_sg(vq, sg, DMA_FROM_DEVICE); > + if (vring_mapping_error(vq, addr)) > + goto unmap_release; > + > + flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT | > + VRING_DESC_F_WRITE | > + VRING_DESC_F_AVAIL(vq->wrap_counter) | > + VRING_DESC_F_USED(!vq->wrap_counter)); > + if (!indirect && i == head) > + head_flags = flags; > + else > + desc[i].flags = flags; > + > + desc[i].addr = cpu_to_virtio64(_vq->vdev, addr); > + desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length); > + desc[i].id = cpu_to_virtio32(_vq->vdev, head); > + prev = i; > + i++; > + if (!indirect && i >= vq->vring_packed.num) { > + i = 0; > + vq->wrap_counter ^= 1; > + } > + } > + } > + /* Last one doesn't continue. */ > + if (!indirect && (head + 1) % vq->vring_packed.num == i) > + head_flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT);I can't get the why we need this here.> + else > + desc[prev].flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT); > + > + if (indirect) { > + /* FIXME: to be implemented */ > + > + /* Now that the indirect table is filled in, map it. */ > + dma_addr_t addr = vring_map_single( > + vq, desc, total_sg * sizeof(struct vring_packed_desc), > + DMA_TO_DEVICE); > + if (vring_mapping_error(vq, addr)) > + goto unmap_release; > + > + head_flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_INDIRECT | > + VRING_DESC_F_AVAIL(wrap_counter) | > + VRING_DESC_F_USED(!wrap_counter)); > + vq->vring_packed.desc[head].addr = cpu_to_virtio64(_vq->vdev, addr); > + vq->vring_packed.desc[head].len = cpu_to_virtio32(_vq->vdev, > + total_sg * sizeof(struct vring_packed_desc)); > + vq->vring_packed.desc[head].id = cpu_to_virtio32(_vq->vdev, head); > + } > + > + /* We're using some buffers from the free list. */ > + vq->vq.num_free -= descs_used; > + > + /* Update free pointer */ > + if (indirect) { > + n = head + 1; > + if (n >= vq->vring_packed.num) { > + n = 0; > + vq->wrap_counter ^= 1; > + } > + vq->free_head = n;detach_buf_packed() does not even touch free_head here, so need to explain its meaning for packed ring.> + } else > + vq->free_head = i;ID is only valid in the last descriptor in the list, so head + 1 should be ok too?> + > + /* Store token and indirect buffer state. */ > + vq->desc_state[head].num = descs_used; > + vq->desc_state[head].data = data; > + if (indirect) > + vq->desc_state[head].indir_desc = desc; > + else > + vq->desc_state[head].indir_desc = ctx; > + > + virtio_wmb(vq->weak_barriers);Let's add a comment to explain the barrier here.> + vq->vring_packed.desc[head].flags = head_flags; > + vq->num_added++; > + > + pr_debug("Added buffer head %i to %p\n", head, vq); > + END_USE(vq); > + > + return 0; > + > +unmap_release: > + err_idx = i; > + i = head; > + > + for (n = 0; n < total_sg; n++) { > + if (i == err_idx) > + break; > + vring_unmap_one(vq, &desc[i]); > + i++; > + if (!indirect && i >= vq->vring_packed.num) > + i = 0; > + } > + > + vq->wrap_counter = wrap_counter; > + > + if (indirect) > + kfree(desc); > + > + END_USE(vq); > + return -EIO; > +} > + > +static inline int virtqueue_add(struct virtqueue *_vq, > + struct scatterlist *sgs[], > + unsigned int total_sg, > + unsigned int out_sgs, > + unsigned int in_sgs, > + void *data, > + void *ctx, > + gfp_t gfp) > +{ > + struct vring_virtqueue *vq = to_vvq(_vq); > + > + return vq->packed ? virtqueue_add_packed(_vq, sgs, total_sg, out_sgs, > + in_sgs, data, ctx, gfp) : > + virtqueue_add_split(_vq, sgs, total_sg, out_sgs, > + in_sgs, data, ctx, gfp); > +} > + > /** > * virtqueue_add_sgs - expose buffers to other end > * @vq: the struct virtqueue we're talking about. > @@ -561,6 +845,12 @@ bool virtqueue_kick_prepare(struct virtqueue *_vq) > * event. */ > virtio_mb(vq->weak_barriers); > > + if (vq->packed) { > + /* FIXME: to be implemented */ > + needs_kick = true; > + goto out; > + } > + > old = vq->avail_idx_shadow - vq->num_added; > new = vq->avail_idx_shadow; > vq->num_added = 0; > @@ -579,6 +869,8 @@ bool virtqueue_kick_prepare(struct virtqueue *_vq) > } else { > needs_kick = !(vq->vring.used->flags & cpu_to_virtio16(_vq->vdev, VRING_USED_F_NO_NOTIFY)); > } > + > +out: > END_USE(vq); > return needs_kick; > } > @@ -628,8 +920,8 @@ bool virtqueue_kick(struct virtqueue *vq) > } > EXPORT_SYMBOL_GPL(virtqueue_kick); > > -static void detach_buf(struct vring_virtqueue *vq, unsigned int head, > - void **ctx) > +static void detach_buf_split(struct vring_virtqueue *vq, unsigned int head, > + void **ctx) > { > unsigned int i, j; > __virtio16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT); > @@ -677,29 +969,81 @@ static void detach_buf(struct vring_virtqueue *vq, unsigned int head, > } > } > > -static inline bool more_used(const struct vring_virtqueue *vq) > +static void detach_buf_packed(struct vring_virtqueue *vq, unsigned int head, > + void **ctx) > +{ > + struct vring_packed_desc *desc; > + unsigned int i, j; > + > + /* Clear data ptr. */ > + vq->desc_state[head].data = NULL; > + > + i = head; > + > + for (j = 0; j < vq->desc_state[head].num; j++) { > + desc = &vq->vring_packed.desc[i]; > + vring_unmap_one(vq, desc); > + i++; > + if (i >= vq->vring_packed.num) > + i = 0; > + } > + > + vq->vq.num_free += vq->desc_state[head].num;It looks to me vq->free_head grows always, how can we make sure it does not exceeds vq.num here?> + > + if (vq->indirect) { > + u32 len; > + > + desc = vq->desc_state[head].indir_desc; > + /* Free the indirect table, if any, now that it's unmapped. */ > + if (!desc) > + return; > + > + len = virtio32_to_cpu(vq->vq.vdev, > + vq->vring_packed.desc[head].len); > + > + BUG_ON(!(vq->vring_packed.desc[head].flags & > + cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_INDIRECT))); > + BUG_ON(len == 0 || len % sizeof(struct vring_packed_desc)); > + > + for (j = 0; j < len / sizeof(struct vring_packed_desc); j++) > + vring_unmap_one(vq, &desc[j]); > + > + kfree(desc); > + vq->desc_state[head].indir_desc = NULL; > + } else if (ctx) { > + *ctx = vq->desc_state[head].indir_desc; > + } > +} > + > +static inline bool more_used_split(const struct vring_virtqueue *vq) > { > return vq->last_used_idx != virtio16_to_cpu(vq->vq.vdev, vq->vring.used->idx); > } > > -/** > - * virtqueue_get_buf - get the next used buffer > - * @vq: the struct virtqueue we're talking about. > - * @len: the length written into the buffer > - * > - * If the device wrote data into the buffer, @len will be set to the > - * amount written. This means you don't need to clear the buffer > - * beforehand to ensure there's no data leakage in the case of short > - * writes. > - * > - * Caller must ensure we don't call this with other virtqueue > - * operations at the same time (except where noted). > - * > - * Returns NULL if there are no used buffers, or the "data" token > - * handed to virtqueue_add_*(). > - */ > -void *virtqueue_get_buf_ctx(struct virtqueue *_vq, unsigned int *len, > - void **ctx) > +static inline bool more_used_packed(const struct vring_virtqueue *vq) > +{ > + u16 last_used, flags; > + bool avail, used; > + > + if (vq->vq.num_free == vq->vring.num) > + return false; > + > + last_used = vq->last_used_idx; > + flags = virtio16_to_cpu(vq->vq.vdev, > + vq->vring_packed.desc[last_used].flags); > + avail = flags & VRING_DESC_F_AVAIL(1); > + used = flags & VRING_DESC_F_USED(1); > + > + return avail == used; > +} > + > +static inline bool more_used(const struct vring_virtqueue *vq) > +{ > + return vq->packed ? more_used_packed(vq) : more_used_split(vq); > +} > + > +void *virtqueue_get_buf_ctx_split(struct virtqueue *_vq, unsigned int *len, > + void **ctx) > { > struct vring_virtqueue *vq = to_vvq(_vq); > void *ret; > @@ -735,9 +1079,9 @@ void *virtqueue_get_buf_ctx(struct virtqueue *_vq, unsigned int *len, > return NULL; > } > > - /* detach_buf clears data, so grab it now. */ > + /* detach_buf_split clears data, so grab it now. */ > ret = vq->desc_state[i].data; > - detach_buf(vq, i, ctx); > + detach_buf_split(vq, i, ctx); > vq->last_used_idx++; > /* If we expect an interrupt for the next entry, tell host > * by writing event index and flush out the write before > @@ -754,6 +1098,87 @@ void *virtqueue_get_buf_ctx(struct virtqueue *_vq, unsigned int *len, > END_USE(vq); > return ret; > } > + > +void *virtqueue_get_buf_ctx_packed(struct virtqueue *_vq, unsigned int *len, > + void **ctx) > +{ > + struct vring_virtqueue *vq = to_vvq(_vq); > + void *ret; > + unsigned int i; > + u16 last_used; > + > + START_USE(vq); > + > + if (unlikely(vq->broken)) { > + END_USE(vq); > + return NULL; > + } > + > + if (!more_used(vq)) { > + pr_debug("No more buffers in queue\n"); > + END_USE(vq); > + return NULL; > + } > + > + /* Only get used array entries after they have been exposed by host. */ > + virtio_rmb(vq->weak_barriers); > + > + last_used = vq->last_used_idx; > + > + i = virtio32_to_cpu(_vq->vdev, vq->vring_packed.desc[last_used].id); > + *len = virtio32_to_cpu(_vq->vdev, vq->vring_packed.desc[last_used].len); > + > + if (unlikely(i >= vq->vring_packed.num)) { > + BAD_RING(vq, "id %u out of range\n", i); > + return NULL; > + } > + if (unlikely(!vq->desc_state[i].data)) { > + BAD_RING(vq, "id %u is not a head!\n", i); > + return NULL; > + } > + > + /* detach_buf_packed clears data, so grab it now. */ > + ret = vq->desc_state[i].data; > + detach_buf_packed(vq, i, ctx); > + > + vq->last_used_idx += vq->desc_state[i].num; > + if (vq->last_used_idx >= vq->vring_packed.num) > + vq->last_used_idx %= vq->vring_packed.num;'-=' should be sufficient here?> + > + // FIXME: implement the desc event support > + > +#ifdef DEBUG > + vq->last_add_time_valid = false; > +#endif > + > + END_USE(vq); > + return ret; > +} > + > +/** > + * virtqueue_get_buf - get the next used buffer > + * @vq: the struct virtqueue we're talking about. > + * @len: the length written into the buffer > + * > + * If the device wrote data into the buffer, @len will be set to the > + * amount written. This means you don't need to clear the buffer > + * beforehand to ensure there's no data leakage in the case of short > + * writes. > + * > + * Caller must ensure we don't call this with other virtqueue > + * operations at the same time (except where noted). > + * > + * Returns NULL if there are no used buffers, or the "data" token > + * handed to virtqueue_add_*(). > + */ > +void *virtqueue_get_buf_ctx(struct virtqueue *_vq, unsigned int *len, > + void **ctx) > +{ > + struct vring_virtqueue *vq = to_vvq(_vq); > + > + return vq->packed ? virtqueue_get_buf_ctx_packed(_vq, len, ctx) : > + virtqueue_get_buf_ctx_split(_vq, len, ctx); > +} > EXPORT_SYMBOL_GPL(virtqueue_get_buf_ctx); > > void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len) > @@ -761,6 +1186,24 @@ void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len) > return virtqueue_get_buf_ctx(_vq, len, NULL); > } > EXPORT_SYMBOL_GPL(virtqueue_get_buf); > + > +static void virtqueue_disable_cb_split(struct virtqueue *_vq) > +{ > + struct vring_virtqueue *vq = to_vvq(_vq); > + > + if (!(vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) { > + vq->avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT; > + if (!vq->event) > + vq->vring.avail->flags = cpu_to_virtio16(_vq->vdev, > + vq->avail_flags_shadow); > + } > +} > + > +static void virtqueue_disable_cb_packed(struct virtqueue *_vq) > +{ > + // FIXME: to be implemented > +} > + > /** > * virtqueue_disable_cb - disable callbacks > * @vq: the struct virtqueue we're talking about. > @@ -774,12 +1217,10 @@ void virtqueue_disable_cb(struct virtqueue *_vq) > { > struct vring_virtqueue *vq = to_vvq(_vq); > > - if (!(vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) { > - vq->avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT; > - if (!vq->event) > - vq->vring.avail->flags = cpu_to_virtio16(_vq->vdev, vq->avail_flags_shadow); > - } > - > + if (vq->packed) > + virtqueue_disable_cb_packed(_vq); > + else > + virtqueue_disable_cb_split(_vq); > } > EXPORT_SYMBOL_GPL(virtqueue_disable_cb); > > @@ -802,6 +1243,12 @@ unsigned virtqueue_enable_cb_prepare(struct virtqueue *_vq) > > START_USE(vq); > > + if (vq->packed) { > + // FIXME: to be implemented > + last_used_idx = vq->last_used_idx; > + goto out; > + } > + > /* We optimistically turn back on interrupts, then check if there was > * more to do. */ > /* Depending on the VIRTIO_RING_F_EVENT_IDX feature, we need to > @@ -813,6 +1260,7 @@ unsigned virtqueue_enable_cb_prepare(struct virtqueue *_vq) > 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); > +out: > END_USE(vq); > return last_used_idx; > } > @@ -832,6 +1280,12 @@ bool virtqueue_poll(struct virtqueue *_vq, unsigned last_used_idx) > struct vring_virtqueue *vq = to_vvq(_vq); > > virtio_mb(vq->weak_barriers); > + if (vq->packed) { > + u16 flags = virtio16_to_cpu(vq->vq.vdev, > + vq->vring_packed.desc[last_used_idx].flags); > + return !(flags & VRING_DESC_F_AVAIL(1)) => + !(flags & VRING_DESC_F_USED(1)); > + } > return (u16)last_used_idx != virtio16_to_cpu(_vq->vdev, vq->vring.used->idx); > } > EXPORT_SYMBOL_GPL(virtqueue_poll); > @@ -874,6 +1328,11 @@ bool virtqueue_enable_cb_delayed(struct virtqueue *_vq) > > START_USE(vq); > > + if (vq->packed) { > + // FIXME: to be implemented > + goto out; > + } > + > /* We optimistically turn back on interrupts, then check if there was > * more to do. */ > /* Depending on the VIRTIO_RING_F_USED_EVENT_IDX feature, we need to > @@ -896,6 +1355,7 @@ bool virtqueue_enable_cb_delayed(struct virtqueue *_vq) > return false; > } > > +out: > END_USE(vq); > return true; > } > @@ -922,14 +1382,20 @@ void *virtqueue_detach_unused_buf(struct virtqueue *_vq) > continue; > /* detach_buf clears data, so grab it now. */ > buf = vq->desc_state[i].data; > - detach_buf(vq, i, NULL); > - vq->avail_idx_shadow--; > - vq->vring.avail->idx = cpu_to_virtio16(_vq->vdev, vq->avail_idx_shadow); > + if (vq->packed) > + detach_buf_packed(vq, i, NULL); > + else { > + detach_buf_split(vq, i, NULL); > + vq->avail_idx_shadow--; > + vq->vring.avail->idx = cpu_to_virtio16(_vq->vdev, > + vq->avail_idx_shadow); > + } > END_USE(vq); > return buf; > } > /* That should have freed everything. */ > - BUG_ON(vq->vq.num_free != vq->vring.num); > + BUG_ON(vq->vq.num_free != (vq->packed ? vq->vring_packed.num : > + vq->vring.num)); > > END_USE(vq); > return NULL; > @@ -957,7 +1423,8 @@ irqreturn_t vring_interrupt(int irq, void *_vq) > EXPORT_SYMBOL_GPL(vring_interrupt); > > struct virtqueue *__vring_new_virtqueue(unsigned int index, > - struct vring vring, > + union vring_union vring, > + bool packed, > struct virtio_device *vdev, > bool weak_barriers, > bool context, > @@ -965,19 +1432,20 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index, > void (*callback)(struct virtqueue *), > const char *name) > { > - unsigned int i; > + unsigned int num, i; > struct vring_virtqueue *vq; > > - vq = kmalloc(sizeof(*vq) + vring.num * sizeof(struct vring_desc_state), > + num = packed ? vring.vring_packed.num : vring.vring_split.num; > + > + vq = kmalloc(sizeof(*vq) + num * sizeof(struct vring_desc_state), > GFP_KERNEL); > if (!vq) > return NULL; > > - vq->vring = vring; > vq->vq.callback = callback; > vq->vq.vdev = vdev; > vq->vq.name = name; > - vq->vq.num_free = vring.num; > + vq->vq.num_free = num; > vq->vq.index = index; > vq->we_own_ring = false; > vq->queue_dma_addr = 0; > @@ -986,9 +1454,8 @@ 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; > + vq->packed = packed; > list_add_tail(&vq->vq.list, &vdev->vqs); > #ifdef DEBUG > vq->in_use = false; > @@ -999,18 +1466,41 @@ struct virtqueue *__vring_new_virtqueue(unsigned int index, > !context; > vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX); > > + if (vq->packed) { > + vq->vring_packed = vring.vring_packed; > + vq->free_head = 0; > + vq->wrap_counter = 1; > + > +#if 0 > + vq->chaining = virtio_has_feature(vdev, > + VIRTIO_RING_F_LIST_DESC); > +#else > + vq->chaining = true;Looks like in V10 there's no F_LIST_DESC.> +#endif > + } else { > + vq->vring = vring.vring_split; > + vq->avail_flags_shadow = 0; > + vq->avail_idx_shadow = 0; > + > + /* Put everything in free lists. */ > + vq->free_head = 0; > + for (i = 0; i < num-1; i++) > + vq->vring.desc[i].next = cpu_to_virtio16(vdev, i + 1); > + } > + > /* No callback? Tell other side not to bother us. */ > if (!callback) { > - vq->avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT; > - if (!vq->event) > - vq->vring.avail->flags = cpu_to_virtio16(vdev, vq->avail_flags_shadow); > + if (packed) { > + // FIXME: to be implemented > + } else { > + vq->avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT; > + if (!vq->event) > + vq->vring.avail->flags = cpu_to_virtio16(vdev, > + vq->avail_flags_shadow); > + } > } > > - /* Put everything in free lists. */ > - vq->free_head = 0; > - for (i = 0; i < vring.num-1; i++) > - vq->vring.desc[i].next = cpu_to_virtio16(vdev, i + 1); > - memset(vq->desc_state, 0, vring.num * sizeof(struct vring_desc_state)); > + memset(vq->desc_state, 0, num * sizeof(struct vring_desc_state)); > > return &vq->vq; > } > @@ -1058,6 +1548,14 @@ static void vring_free_queue(struct virtio_device *vdev, size_t size, > } > } > > +static inline int > +__vring_size(unsigned int num, unsigned long align, bool packed) > +{ > + if (packed) > + return vring_packed_size(num, align); > + return vring_size(num, align); > +} > + > struct virtqueue *vring_create_virtqueue( > unsigned int index, > unsigned int num, > @@ -1074,7 +1572,8 @@ struct virtqueue *vring_create_virtqueue( > void *queue = NULL; > dma_addr_t dma_addr; > size_t queue_size_in_bytes; > - struct vring vring; > + union vring_union vring; > + bool packed; > > /* We assume num is a power of 2. */ > if (num & (num - 1)) { > @@ -1082,9 +1581,13 @@ struct virtqueue *vring_create_virtqueue( > return NULL; > } > > + packed = virtio_has_feature(vdev, VIRTIO_F_RING_PACKED); > + > /* TODO: allocate each queue chunk individually */ > - for (; num && vring_size(num, vring_align) > PAGE_SIZE; num /= 2) { > - queue = vring_alloc_queue(vdev, vring_size(num, vring_align), > + for (; num && __vring_size(num, vring_align, packed) > PAGE_SIZE; > + num /= 2) { > + queue = vring_alloc_queue(vdev, __vring_size(num, vring_align, > + packed), > &dma_addr, > GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO); > if (queue) > @@ -1096,17 +1599,21 @@ struct virtqueue *vring_create_virtqueue( > > if (!queue) { > /* Try to get a single page. You are my only hope! */ > - queue = vring_alloc_queue(vdev, vring_size(num, vring_align), > + queue = vring_alloc_queue(vdev, __vring_size(num, vring_align, > + packed), > &dma_addr, GFP_KERNEL|__GFP_ZERO); > } > if (!queue) > return NULL; > > - queue_size_in_bytes = vring_size(num, vring_align); > - vring_init(&vring, num, queue, vring_align); > + queue_size_in_bytes = __vring_size(num, vring_align, packed); > + if (packed) > + vring_packed_init(&vring.vring_packed, num, queue, vring_align); > + else > + vring_init(&vring.vring_split, num, queue, vring_align);Let's rename vring_init to vring_init_split() like other helpers?> > - vq = __vring_new_virtqueue(index, vring, vdev, weak_barriers, context, > - notify, callback, name); > + vq = __vring_new_virtqueue(index, vring, packed, vdev, weak_barriers, > + context, notify, callback, name); > if (!vq) { > vring_free_queue(vdev, queue_size_in_bytes, queue, > dma_addr); > @@ -1132,10 +1639,17 @@ struct virtqueue *vring_new_virtqueue(unsigned int index, > void (*callback)(struct virtqueue *vq), > const char *name) > { > - struct vring vring; > - vring_init(&vring, num, pages, vring_align); > - return __vring_new_virtqueue(index, vring, vdev, weak_barriers, context, > - notify, callback, name); > + union vring_union vring; > + bool packed; > + > + packed = virtio_has_feature(vdev, VIRTIO_F_RING_PACKED); > + if (packed) > + vring_packed_init(&vring.vring_packed, num, pages, vring_align); > + else > + vring_init(&vring.vring_split, num, pages, vring_align); > + > + return __vring_new_virtqueue(index, vring, packed, vdev, weak_barriers, > + context, notify, callback, name); > } > EXPORT_SYMBOL_GPL(vring_new_virtqueue); > > @@ -1145,7 +1659,9 @@ void vring_del_virtqueue(struct virtqueue *_vq) > > if (vq->we_own_ring) { > vring_free_queue(vq->vq.vdev, vq->queue_size_in_bytes, > - vq->vring.desc, vq->queue_dma_addr); > + vq->packed ? (void *)vq->vring_packed.desc : > + (void *)vq->vring.desc, > + vq->queue_dma_addr); > } > list_del(&_vq->list); > kfree(vq); > @@ -1159,14 +1675,18 @@ void vring_transport_features(struct virtio_device *vdev) > > for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) { > switch (i) { > +#if 0 // FIXME: to be implemented > case VIRTIO_RING_F_INDIRECT_DESC: > break; > +#endif > case VIRTIO_RING_F_EVENT_IDX: > break; > case VIRTIO_F_VERSION_1: > break; > case VIRTIO_F_IOMMU_PLATFORM: > break; > + case VIRTIO_F_RING_PACKED: > + break; > default: > /* We don't understand this bit. */ > __virtio_clear_bit(vdev, i); > @@ -1187,7 +1707,7 @@ unsigned int virtqueue_get_vring_size(struct virtqueue *_vq) > > struct vring_virtqueue *vq = to_vvq(_vq); > > - return vq->vring.num; > + return vq->packed ? vq->vring_packed.num : vq->vring.num; > } > EXPORT_SYMBOL_GPL(virtqueue_get_vring_size); > > @@ -1224,6 +1744,7 @@ dma_addr_t virtqueue_get_desc_addr(struct virtqueue *_vq) > } > EXPORT_SYMBOL_GPL(virtqueue_get_desc_addr); > > +/* Only available for split ring */Interesting, I think we need this for correctly configure pci. e.g in setup_vq()?> dma_addr_t virtqueue_get_avail_addr(struct virtqueue *_vq) > { > struct vring_virtqueue *vq = to_vvq(_vq); > @@ -1235,6 +1756,7 @@ dma_addr_t virtqueue_get_avail_addr(struct virtqueue *_vq) > } > EXPORT_SYMBOL_GPL(virtqueue_get_avail_addr); > > +/* Only available for split ring */ > dma_addr_t virtqueue_get_used_addr(struct virtqueue *_vq)Maybe it's better to rename this to get_device_addr(). Thanks> { > struct vring_virtqueue *vq = to_vvq(_vq); > @@ -1246,6 +1768,7 @@ dma_addr_t virtqueue_get_used_addr(struct virtqueue *_vq) > } > EXPORT_SYMBOL_GPL(virtqueue_get_used_addr); > > +/* Only available for split ring */ > const struct vring *virtqueue_get_vring(struct virtqueue *vq) > { > return &to_vvq(vq)->vring; > diff --git a/include/linux/virtio_ring.h b/include/linux/virtio_ring.h > index bbf32524ab27..a0075894ad16 100644 > --- a/include/linux/virtio_ring.h > +++ b/include/linux/virtio_ring.h > @@ -60,6 +60,11 @@ static inline void virtio_store_mb(bool weak_barriers, > struct virtio_device; > struct virtqueue; > > +union vring_union { > + struct vring vring_split; > + struct vring_packed vring_packed; > +}; > + > /* > * Creates a virtqueue and allocates the descriptor ring. If > * may_reduce_num is set, then this may allocate a smaller ring than > @@ -79,7 +84,8 @@ struct virtqueue *vring_create_virtqueue(unsigned int index, > > /* Creates a virtqueue with a custom layout. */ > struct virtqueue *__vring_new_virtqueue(unsigned int index, > - struct vring vring, > + union vring_union vring, > + bool packed, > struct virtio_device *vdev, > bool weak_barriers, > bool ctx,
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