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,