Hello everyone, This RFC implements packed ring support for virtio driver.
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. TODO: - Refinements and bug fixes; - Split into small patches; - Test indirect descriptor support; - Test/fix event suppression support; - Test devices other than net; RFC v1 -> RFC v2: - Add indirect descriptor support - compile test only; - Add event suppression supprt - compile test only; - Move vring_packed_init() out of uapi (Jason, MST); - Merge two loops into one in virtqueue_add_packed() (Jason); - Split vring_unmap_one() for packed ring and split ring (Jason); - Avoid using '%' operator (Jason); - Rename free_head -> next_avail_idx (Jason); - Add comments for virtio_wmb() in virtqueue_add_packed() (Jason); - Some other refinements and bug fixes; Thanks! Signed-off-by: Tiwei Bie <tiwei....@intel.com> --- drivers/virtio/virtio_ring.c | 1094 +++++++++++++++++++++++++++++------- include/linux/virtio_ring.h | 8 +- include/uapi/linux/virtio_config.h | 12 +- include/uapi/linux/virtio_ring.h | 61 ++ 4 files changed, 980 insertions(+), 195 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 71458f493cf8..0515dca34d77 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -58,14 +58,15 @@ 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; + /* Is this a packed ring? */ + bool packed; /* Can we use weak barriers? */ bool weak_barriers; @@ -79,19 +80,45 @@ struct vring_virtqueue { /* Host publishes avail event idx */ bool event; - /* Head of free buffer list. */ - unsigned int free_head; /* Number we've added since last sync. */ unsigned int num_added; /* Last used index we've seen. */ u16 last_used_idx; - /* Last written value to avail->flags */ - u16 avail_flags_shadow; + union { + /* Available for split ring */ + struct { + /* Actual memory layout for this queue. */ + struct vring vring; - /* Last written value to avail->idx in guest byte order */ - u16 avail_idx_shadow; + /* Head of free buffer list. */ + unsigned int free_head; + + /* 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; + + /* Driver ring wrap counter. */ + u8 wrap_counter; + + /* Index of the next avail descriptor. */ + unsigned int next_avail_idx; + + /* Last written value to driver->flags in + * guest byte order. */ + u16 event_flags_shadow; + }; + }; /* How to notify other side. FIXME: commonalize hcalls! */ bool (*notify)(struct virtqueue *vq); @@ -201,8 +228,33 @@ 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_split(const struct vring_virtqueue *vq, + struct vring_desc *desc) +{ + u16 flags; + + if (!vring_use_dma_api(vq->vq.vdev)) + return; + + 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), + (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), + (flags & VRING_DESC_F_WRITE) ? + DMA_FROM_DEVICE : DMA_TO_DEVICE); + } +} + +static void vring_unmap_one_packed(const struct vring_virtqueue *vq, + struct vring_packed_desc *desc) { u16 flags; @@ -235,8 +287,9 @@ 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 +310,32 @@ 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 +374,7 @@ 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); @@ -424,7 +495,7 @@ static inline int virtqueue_add(struct virtqueue *_vq, for (n = 0; n < total_sg; n++) { if (i == err_idx) break; - vring_unmap_one(vq, &desc[i]); + vring_unmap_one_split(vq, &desc[i]); i = virtio16_to_cpu(_vq->vdev, vq->vring.desc[i].next); } @@ -435,6 +506,210 @@ 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; + } + +#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->next_avail_idx; + 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_packed.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 (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 + in_sgs; n++) { + for (sg = sgs[n]; sg; sg = sg_next(sg)) { + dma_addr_t addr = vring_map_one_sg(vq, sg, n < out_sgs ? + DMA_TO_DEVICE : DMA_FROM_DEVICE); + if (vring_mapping_error(vq, addr)) + goto unmap_release; + + flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT | + (n < out_sgs ? 0 : 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 (total_sg == 1) + 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) { + /* 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->next_avail_idx = n; + } else + vq->next_avail_idx = 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; + + /* A driver MUST NOT make the first descriptor in the list + * available before all subsequent descriptors comprising + * the list are made available. */ + 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_packed(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. @@ -537,18 +812,7 @@ int virtqueue_add_inbuf_ctx(struct virtqueue *vq, } EXPORT_SYMBOL_GPL(virtqueue_add_inbuf_ctx); -/** - * virtqueue_kick_prepare - first half of split virtqueue_kick call. - * @vq: the struct virtqueue - * - * Instead of virtqueue_kick(), you can do: - * if (virtqueue_kick_prepare(vq)) - * virtqueue_notify(vq); - * - * This is sometimes useful because the virtqueue_kick_prepare() needs - * to be serialized, but the actual virtqueue_notify() call does not. - */ -bool virtqueue_kick_prepare(struct virtqueue *_vq) +static bool virtqueue_kick_prepare_split(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); u16 new, old; @@ -580,6 +844,62 @@ bool virtqueue_kick_prepare(struct virtqueue *_vq) END_USE(vq); return needs_kick; } + +static bool virtqueue_kick_prepare_packed(struct virtqueue *_vq) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + u16 new, old, off_wrap; + bool needs_kick; + + START_USE(vq); + /* We need to expose the new flags value before checking notification + * suppressions. */ + virtio_mb(vq->weak_barriers); + + old = vq->next_avail_idx - vq->num_added; + new = vq->next_avail_idx; + vq->num_added = 0; + +#ifdef DEBUG + if (vq->last_add_time_valid) { + WARN_ON(ktime_to_ms(ktime_sub(ktime_get(), + vq->last_add_time)) > 100); + } + vq->last_add_time_valid = false; +#endif + + off_wrap = virtio16_to_cpu(_vq->vdev, vq->vring_packed.device->off_wrap); + + if (vq->event) { + // FIXME: fix this! + needs_kick = ((off_wrap >> 15) == vq->wrap_counter) && + vring_need_event(off_wrap & ~(1<<15), new, old); + } else { + needs_kick = (vq->vring_packed.device->flags != + cpu_to_virtio16(_vq->vdev, VRING_EVENT_F_DISABLE)); + } + END_USE(vq); + return needs_kick; +} + +/** + * virtqueue_kick_prepare - first half of split virtqueue_kick call. + * @vq: the struct virtqueue + * + * Instead of virtqueue_kick(), you can do: + * if (virtqueue_kick_prepare(vq)) + * virtqueue_notify(vq); + * + * This is sometimes useful because the virtqueue_kick_prepare() needs + * to be serialized, but the actual virtqueue_notify() call does not. + */ +bool virtqueue_kick_prepare(struct virtqueue *_vq) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + + return vq->packed ? virtqueue_kick_prepare_packed(_vq) : + virtqueue_kick_prepare_split(_vq); +} EXPORT_SYMBOL_GPL(virtqueue_kick_prepare); /** @@ -626,8 +946,8 @@ 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); @@ -639,12 +959,12 @@ static void detach_buf(struct vring_virtqueue *vq, unsigned int head, i = head; while (vq->vring.desc[i].flags & nextflag) { - vring_unmap_one(vq, &vq->vring.desc[i]); + vring_unmap_one_split(vq, &vq->vring.desc[i]); i = virtio16_to_cpu(vq->vq.vdev, vq->vring.desc[i].next); vq->vq.num_free++; } - vring_unmap_one(vq, &vq->vring.desc[i]); + vring_unmap_one_split(vq, &vq->vring.desc[i]); vq->vring.desc[i].next = cpu_to_virtio16(vq->vq.vdev, vq->free_head); vq->free_head = head; @@ -666,7 +986,7 @@ static void detach_buf(struct vring_virtqueue *vq, unsigned int head, BUG_ON(len == 0 || len % sizeof(struct vring_desc)); for (j = 0; j < len / sizeof(struct vring_desc); j++) - vring_unmap_one(vq, &indir_desc[j]); + vring_unmap_one_split(vq, &indir_desc[j]); kfree(indir_desc); vq->desc_state[head].indir_desc = NULL; @@ -675,11 +995,207 @@ static void detach_buf(struct vring_virtqueue *vq, unsigned int head, } } -static inline bool more_used(const struct vring_virtqueue *vq) +static int 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_packed(vq, desc); + desc->flags = 0x0; + 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) + goto out; + + 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_packed(vq, &desc[j]); + + kfree(desc); + vq->desc_state[head].indir_desc = NULL; + } else if (ctx) { + *ctx = vq->desc_state[head].indir_desc; + } + +out: + return vq->desc_state[head].num; +} + +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); } +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_packed.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; + 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 & (vq->vring.num - 1)); + i = virtio32_to_cpu(_vq->vdev, vq->vring.used->ring[last_used].id); + *len = virtio32_to_cpu(_vq->vdev, vq->vring.used->ring[last_used].len); + + if (unlikely(i >= vq->vring.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_split clears data, so grab it now. */ + ret = vq->desc_state[i].data; + 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 + * the read in the next get_buf call. */ + if (!(vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) + virtio_store_mb(vq->weak_barriers, + &vring_used_event(&vq->vring), + cpu_to_virtio16(_vq->vdev, vq->last_used_idx)); + +#ifdef DEBUG + vq->last_add_time_valid = false; +#endif + + 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); + uint16_t wrap_counter; + 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 elements 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; + + wrap_counter = vq->wrap_counter; + if (vq->last_used_idx > vq->next_avail_idx) + wrap_counter ^= 1; + + /* 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->event_flags_shadow == VRING_EVENT_F_DESC) + virtio_store_mb(vq->weak_barriers, + &vq->vring_packed.driver->off_wrap, + cpu_to_virtio16(_vq->vdev, vq->last_used_idx | + wrap_counter << 15)); + +#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. @@ -700,57 +1216,9 @@ void *virtqueue_get_buf_ctx(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 & (vq->vring.num - 1)); - i = virtio32_to_cpu(_vq->vdev, vq->vring.used->ring[last_used].id); - *len = virtio32_to_cpu(_vq->vdev, vq->vring.used->ring[last_used].len); - - if (unlikely(i >= vq->vring.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 clears data, so grab it now. */ - ret = vq->desc_state[i].data; - detach_buf(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 - * the read in the next get_buf call. */ - if (!(vq->avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) - virtio_store_mb(vq->weak_barriers, - &vring_used_event(&vq->vring), - cpu_to_virtio16(_vq->vdev, vq->last_used_idx)); - -#ifdef DEBUG - vq->last_add_time_valid = false; -#endif - - END_USE(vq); - return ret; + 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); @@ -759,6 +1227,29 @@ 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) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + + if (vq->event_flags_shadow != VRING_EVENT_F_DISABLE) { + vq->event_flags_shadow = VRING_EVENT_F_DISABLE; + vq->vring_packed.driver->flags = cpu_to_virtio16(_vq->vdev, + vq->event_flags_shadow); + } +} + /** * virtqueue_disable_cb - disable callbacks * @vq: the struct virtqueue we're talking about. @@ -772,15 +1263,66 @@ 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); +static unsigned virtqueue_enable_cb_prepare_split(struct virtqueue *_vq) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + u16 last_used_idx; + + START_USE(vq); + + /* 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 + * either clear the flags bit or point the event index at the next + * entry. Always do both to keep code simple. */ + 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); + } + vring_used_event(&vq->vring) = cpu_to_virtio16(_vq->vdev, last_used_idx = vq->last_used_idx); + END_USE(vq); + return last_used_idx; +} + +static unsigned virtqueue_enable_cb_prepare_packed(struct virtqueue *_vq) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + u16 last_used_idx, wrap_counter, off_wrap; + + START_USE(vq); + + last_used_idx = vq->last_used_idx; + wrap_counter = vq->wrap_counter; + + if (last_used_idx > vq->next_avail_idx) + wrap_counter ^= 1; + + off_wrap = last_used_idx | (wrap_counter << 15); + + /* 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 + * either clear the flags bit or point the event index at the next + * entry. Always do both to keep code simple. */ + if (vq->event_flags_shadow == VRING_EVENT_F_DISABLE) { + vq->event_flags_shadow = vq->event ? VRING_EVENT_F_DESC: + VRING_EVENT_F_ENABLE; + vq->vring_packed.driver->flags = cpu_to_virtio16(_vq->vdev, + vq->event_flags_shadow); + } + vq->vring_packed.driver->off_wrap = cpu_to_virtio16(_vq->vdev, off_wrap); + END_USE(vq); + return last_used_idx; +} + /** * virtqueue_enable_cb_prepare - restart callbacks after disable_cb * @vq: the struct virtqueue we're talking about. @@ -796,26 +1338,34 @@ EXPORT_SYMBOL_GPL(virtqueue_disable_cb); unsigned virtqueue_enable_cb_prepare(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); - u16 last_used_idx; - START_USE(vq); - - /* 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 - * either clear the flags bit or point the event index at the next - * entry. Always do both to keep code simple. */ - 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); - } - vring_used_event(&vq->vring) = cpu_to_virtio16(_vq->vdev, last_used_idx = vq->last_used_idx); - END_USE(vq); - return last_used_idx; + return vq->packed ? virtqueue_enable_cb_prepare_packed(_vq) : + virtqueue_enable_cb_prepare_split(_vq); } EXPORT_SYMBOL_GPL(virtqueue_enable_cb_prepare); +static bool virtqueue_poll_split(struct virtqueue *_vq, unsigned last_used_idx) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + + virtio_mb(vq->weak_barriers); + return (u16)last_used_idx != virtio16_to_cpu(_vq->vdev, vq->vring.used->idx); +} + +static bool virtqueue_poll_packed(struct virtqueue *_vq, unsigned last_used_idx) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + bool avail, used; + u16 flags; + + virtio_mb(vq->weak_barriers); + flags = virtio16_to_cpu(vq->vq.vdev, + vq->vring_packed.desc[last_used_idx].flags); + avail = flags & VRING_DESC_F_AVAIL(1); + used = flags & VRING_DESC_F_USED(1); + return avail == used; +} + /** * virtqueue_poll - query pending used buffers * @vq: the struct virtqueue we're talking about. @@ -829,8 +1379,8 @@ bool virtqueue_poll(struct virtqueue *_vq, unsigned last_used_idx) { struct vring_virtqueue *vq = to_vvq(_vq); - virtio_mb(vq->weak_barriers); - return (u16)last_used_idx != virtio16_to_cpu(_vq->vdev, vq->vring.used->idx); + return vq->packed ? virtqueue_poll_packed(_vq, last_used_idx) : + virtqueue_poll_split(_vq, last_used_idx); } EXPORT_SYMBOL_GPL(virtqueue_poll); @@ -852,6 +1402,83 @@ bool virtqueue_enable_cb(struct virtqueue *_vq) } EXPORT_SYMBOL_GPL(virtqueue_enable_cb); +static bool virtqueue_enable_cb_delayed_split(struct virtqueue *_vq) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + u16 bufs; + + START_USE(vq); + + /* 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 + * either clear the flags bit or point the event index at the next + * entry. Always update the event index to keep code simple. */ + 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); + } + /* TODO: tune this threshold */ + bufs = (u16)(vq->avail_idx_shadow - vq->last_used_idx) * 3 / 4; + + virtio_store_mb(vq->weak_barriers, + &vring_used_event(&vq->vring), + cpu_to_virtio16(_vq->vdev, vq->last_used_idx + bufs)); + + if (unlikely((u16)(virtio16_to_cpu(_vq->vdev, vq->vring.used->idx) - vq->last_used_idx) > bufs)) { + END_USE(vq); + return false; + } + + END_USE(vq); + return true; +} + +static bool virtqueue_enable_cb_delayed_packed(struct virtqueue *_vq) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + u16 bufs, off_wrap, used_idx, wrap_counter; + + START_USE(vq); + + /* 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 + * either clear the flags bit or point the event index at the next + * entry. Always update the event index to keep code simple. */ + if (vq->event_flags_shadow == VRING_EVENT_F_DISABLE) { + vq->event_flags_shadow = vq->event ? VRING_EVENT_F_DESC: + VRING_EVENT_F_ENABLE; + vq->vring_packed.driver->flags = cpu_to_virtio16(_vq->vdev, + vq->event_flags_shadow); + } + + /* TODO: tune this threshold */ + bufs = (u16)(vq->next_avail_idx - vq->last_used_idx) * 3 / 4; + + used_idx = vq->last_used_idx + bufs; + if (used_idx >= vq->vring_packed.num) + used_idx -= vq->vring_packed.num; + + wrap_counter = vq->wrap_counter; + if (used_idx > vq->next_avail_idx) + wrap_counter ^= 1; + + off_wrap = used_idx | (wrap_counter << 15); + + virtio_store_mb(vq->weak_barriers, &vq->vring_packed.driver->off_wrap, + cpu_to_virtio16(_vq->vdev, off_wrap)); + + if (more_used_packed(vq)) { + END_USE(vq); + return false; + } + + END_USE(vq); + return true; +} + /** * virtqueue_enable_cb_delayed - restart callbacks after disable_cb. * @vq: the struct virtqueue we're talking about. @@ -868,37 +1495,69 @@ EXPORT_SYMBOL_GPL(virtqueue_enable_cb); bool virtqueue_enable_cb_delayed(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); - u16 bufs; - START_USE(vq); - - /* 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 - * either clear the flags bit or point the event index at the next - * entry. Always update the event index to keep code simple. */ - 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); - } - /* TODO: tune this threshold */ - bufs = (u16)(vq->avail_idx_shadow - vq->last_used_idx) * 3 / 4; - - virtio_store_mb(vq->weak_barriers, - &vring_used_event(&vq->vring), - cpu_to_virtio16(_vq->vdev, vq->last_used_idx + bufs)); - - if (unlikely((u16)(virtio16_to_cpu(_vq->vdev, vq->vring.used->idx) - vq->last_used_idx) > bufs)) { - END_USE(vq); - return false; - } - - END_USE(vq); - return true; + return vq->packed ? virtqueue_enable_cb_delayed_packed(_vq) : + virtqueue_enable_cb_delayed_split(_vq); } EXPORT_SYMBOL_GPL(virtqueue_enable_cb_delayed); +static void *virtqueue_detach_unused_buf_split(struct virtqueue *_vq) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + unsigned int i; + void *buf; + + START_USE(vq); + + for (i = 0; i < vq->vring.num; i++) { + if (!vq->desc_state[i].data) + continue; + /* detach_buf clears data, so grab it now. */ + buf = vq->desc_state[i].data; + 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); + + END_USE(vq); + return NULL; +} + +static void *virtqueue_detach_unused_buf_packed(struct virtqueue *_vq) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + unsigned int i, num; + void *buf; + + START_USE(vq); + + for (i = 0; i < vq->vring_packed.num; i++) { + if (!vq->desc_state[i].data) + continue; + /* detach_buf clears data, so grab it now. */ + buf = vq->desc_state[i].data; + num = detach_buf_packed(vq, i, NULL); + if (vq->next_avail_idx < num) { + vq->next_avail_idx = vq->vring_packed.num - + (num - vq->next_avail_idx); + vq->wrap_counter ^= 1; + } else { + vq->next_avail_idx -= num; + } + END_USE(vq); + return buf; + } + /* That should have freed everything. */ + BUG_ON(vq->vq.num_free != vq->vring_packed.num); + + END_USE(vq); + return NULL; +} + /** * virtqueue_detach_unused_buf - detach first unused buffer * @vq: the struct virtqueue we're talking about. @@ -910,27 +1569,9 @@ EXPORT_SYMBOL_GPL(virtqueue_enable_cb_delayed); void *virtqueue_detach_unused_buf(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); - unsigned int i; - void *buf; - START_USE(vq); - - for (i = 0; i < vq->vring.num; i++) { - if (!vq->desc_state[i].data) - 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); - END_USE(vq); - return buf; - } - /* That should have freed everything. */ - BUG_ON(vq->vq.num_free != vq->vring.num); - - END_USE(vq); - return NULL; + return vq->packed ? virtqueue_detach_unused_buf_packed(_vq) : + virtqueue_detach_unused_buf_split(_vq); } EXPORT_SYMBOL_GPL(virtqueue_detach_unused_buf); @@ -955,7 +1596,8 @@ 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, @@ -963,19 +1605,20 @@ 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; @@ -984,9 +1627,8 @@ 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; @@ -997,18 +1639,37 @@ 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->next_avail_idx = 0; + vq->wrap_counter = 1; + vq->event_flags_shadow = 0; + } 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) { + vq->event_flags_shadow = VRING_EVENT_F_DISABLE; + vq->vring_packed.driver->flags = cpu_to_virtio16(vdev, + vq->event_flags_shadow); + } 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; } @@ -1056,6 +1717,22 @@ 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) +{ + return packed ? vring_packed_size(num, align) : vring_size(num, align); +} + +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; +} + struct virtqueue *vring_create_virtqueue( unsigned int index, unsigned int num, @@ -1072,7 +1749,8 @@ 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)) { @@ -1080,9 +1758,13 @@ 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) @@ -1094,17 +1776,21 @@ 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); @@ -1130,10 +1816,17 @@ 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); @@ -1143,7 +1836,9 @@ 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); @@ -1157,14 +1852,18 @@ void vring_transport_features(struct virtio_device *vdev) for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) { switch (i) { - case VIRTIO_RING_F_INDIRECT_DESC: +#if 0 + case VIRTIO_RING_F_INDIRECT_DESC: // FIXME not tested yet. break; - case VIRTIO_RING_F_EVENT_IDX: + case VIRTIO_RING_F_EVENT_IDX: // FIXME probably not work. break; +#endif 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); @@ -1185,7 +1884,7 @@ 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); @@ -1228,6 +1927,10 @@ dma_addr_t virtqueue_get_avail_addr(struct virtqueue *_vq) BUG_ON(!vq->we_own_ring); + if (vq->packed) + return vq->queue_dma_addr + ((char *)vq->vring_packed.driver - + (char *)vq->vring_packed.desc); + return vq->queue_dma_addr + ((char *)vq->vring.avail - (char *)vq->vring.desc); } @@ -1239,11 +1942,16 @@ dma_addr_t virtqueue_get_used_addr(struct virtqueue *_vq) BUG_ON(!vq->we_own_ring); + if (vq->packed) + return vq->queue_dma_addr + ((char *)vq->vring_packed.device - + (char *)vq->vring_packed.desc); + return vq->queue_dma_addr + ((char *)vq->vring.used - (char *)vq->vring.desc); } 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, diff --git a/include/uapi/linux/virtio_config.h b/include/uapi/linux/virtio_config.h index 308e2096291f..a6e392325e3a 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 36 #ifndef VIRTIO_CONFIG_NO_LEGACY /* Do we get callbacks when the ring is completely used, even if we've @@ -71,4 +71,14 @@ * 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 + #endif /* _UAPI_LINUX_VIRTIO_CONFIG_H */ diff --git a/include/uapi/linux/virtio_ring.h b/include/uapi/linux/virtio_ring.h index 6d5d5faa989b..735d4207c988 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. */ @@ -53,6 +56,10 @@ * optimization. */ #define VRING_AVAIL_F_NO_INTERRUPT 1 +#define VRING_EVENT_F_ENABLE 0x0 +#define VRING_EVENT_F_DISABLE 0x1 +#define VRING_EVENT_F_DESC 0x2 + /* We support indirect buffer descriptors */ #define VIRTIO_RING_F_INDIRECT_DESC 28 @@ -171,4 +178,58 @@ 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); } +struct vring_packed_desc_event { + /* __virtio16 off : 15; // Descriptor Event Offset + * __virtio16 wrap : 1; // Descriptor Event Wrap Counter */ + __virtio16 off_wrap; + /* __virtio16 flags : 2; // Descriptor Event Flags */ + __virtio16 flags; +}; + +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; +}; + +/* 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 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 */ -- 2.11.0 _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization
