From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tiwei Bie Subject: [PATCH net-next v2 3/5] virtio_ring: add packed ring support Date: Wed, 11 Jul 2018 10:27:09 +0800 Message-ID: <20180711022711.7090-4-tiwei.bie__5935.23180946267$1531276162$gmane$org@intel.com> References: <20180711022711.7090-1-tiwei.bie@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20180711022711.7090-1-tiwei.bie@intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: mst@redhat.com, jasowang@redhat.com, virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, virtio-dev@lists.oasis-open.org Cc: wexu@redhat.com List-Id: virtualization@lists.linuxfoundation.org This commit introduces the support (without EVENT_IDX) for packed ring. Signed-off-by: Tiwei Bie --- drivers/virtio/virtio_ring.c | 495 ++++++++++++++++++++++++++++++++++- 1 file changed, 487 insertions(+), 8 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index c4f8abc7445a..f317b485ba54 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -55,12 +55,21 @@ #define END_USE(vq) #endif +#define _VRING_DESC_F_AVAIL(b) ((__u16)(b) << 7) +#define _VRING_DESC_F_USED(b) ((__u16)(b) << 15) + struct vring_desc_state { void *data; /* Data for callback. */ struct vring_desc *indir_desc; /* Indirect descriptor, if any. */ }; struct vring_desc_state_packed { + void *data; /* Data for callback. */ + struct vring_packed_desc *indir_desc; /* Indirect descriptor, if any. */ + int num; /* Descriptor list length. */ + dma_addr_t addr; /* Buffer DMA addr. */ + u32 len; /* Buffer length. */ + u16 flags; /* Descriptor flags. */ int next; /* The next desc state. */ }; @@ -660,7 +669,6 @@ 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); } @@ -757,6 +765,72 @@ static inline unsigned vring_size_packed(unsigned int num, unsigned long align) & ~(align - 1)) + sizeof(struct vring_packed_desc_event) * 2; } +static void vring_unmap_state_packed(const struct vring_virtqueue *vq, + struct vring_desc_state_packed *state) +{ + u16 flags; + + if (!vring_use_dma_api(vq->vq.vdev)) + return; + + flags = state->flags; + + if (flags & VRING_DESC_F_INDIRECT) { + dma_unmap_single(vring_dma_dev(vq), + state->addr, state->len, + (flags & VRING_DESC_F_WRITE) ? + DMA_FROM_DEVICE : DMA_TO_DEVICE); + } else { + dma_unmap_page(vring_dma_dev(vq), + state->addr, state->len, + (flags & VRING_DESC_F_WRITE) ? + DMA_FROM_DEVICE : DMA_TO_DEVICE); + } +} + +static void vring_unmap_desc_packed(const struct vring_virtqueue *vq, + struct vring_packed_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 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_packed(struct virtqueue *_vq, struct scatterlist *sgs[], unsigned int total_sg, @@ -766,47 +840,449 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq, 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; + u16 head, avail_wrap_counter, id, curr; + 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; + avail_wrap_counter = vq->avail_wrap_counter; + + if (virtqueue_use_indirect(_vq, total_sg)) + 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; + } + + id = vq->free_head; + BUG_ON(id == vq->vring_packed.num); + + curr = id; + 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->avail_wrap_counter) | + _VRING_DESC_F_USED(!vq->avail_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); + i++; + if (!indirect) { + if (vring_use_dma_api(_vq->vdev)) { + vq->desc_state_packed[curr].addr = addr; + vq->desc_state_packed[curr].len = + sg->length; + vq->desc_state_packed[curr].flags = + virtio16_to_cpu(_vq->vdev, + flags); + } + curr = vq->desc_state_packed[curr].next; + + if (i >= vq->vring_packed.num) { + i = 0; + vq->avail_wrap_counter ^= 1; + } + } + } + } + + prev = (i > 0 ? i : vq->vring_packed.num) - 1; + desc[prev].id = cpu_to_virtio16(_vq->vdev, id); + + /* 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(avail_wrap_counter) | + _VRING_DESC_F_USED(!avail_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_virtio16(_vq->vdev, id); + + if (vring_use_dma_api(_vq->vdev)) { + vq->desc_state_packed[id].addr = addr; + vq->desc_state_packed[id].len = total_sg * + sizeof(struct vring_packed_desc); + vq->desc_state_packed[id].flags = + virtio16_to_cpu(_vq->vdev, head_flags); + } + } + + /* 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->avail_wrap_counter ^= 1; + } + vq->next_avail_idx = n; + vq->free_head = vq->desc_state_packed[id].next; + } else { + vq->next_avail_idx = i; + vq->free_head = curr; + } + + /* Store token and indirect buffer state. */ + vq->desc_state_packed[id].num = descs_used; + vq->desc_state_packed[id].data = data; + if (indirect) + vq->desc_state_packed[id].indir_desc = desc; + else + vq->desc_state_packed[id].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 += descs_used; + + 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_desc_packed(vq, &desc[i]); + i++; + if (!indirect && i >= vq->vring_packed.num) + i = 0; + } + + vq->avail_wrap_counter = avail_wrap_counter; + + if (indirect) + kfree(desc); + + END_USE(vq); return -EIO; } static bool virtqueue_kick_prepare_packed(struct virtqueue *_vq) { - return false; + struct vring_virtqueue *vq = to_vvq(_vq); + u16 flags; + bool needs_kick; + u32 snapshot; + + START_USE(vq); + /* We need to expose the new flags value before checking notification + * suppressions. */ + virtio_mb(vq->weak_barriers); + + snapshot = READ_ONCE(*(u32 *)vq->vring_packed.device); + flags = virtio16_to_cpu(_vq->vdev, (__virtio16)(snapshot >> 16)) & 0x3; + +#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 + + needs_kick = (flags != VRING_EVENT_F_DISABLE); + END_USE(vq); + return needs_kick; +} + +static void detach_buf_packed(struct vring_virtqueue *vq, + unsigned int id, void **ctx) +{ + struct vring_desc_state_packed *state = NULL; + struct vring_packed_desc *desc; + unsigned int curr, i; + + /* Clear data ptr. */ + vq->desc_state_packed[id].data = NULL; + + curr = id; + for (i = 0; i < vq->desc_state_packed[id].num; i++) { + state = &vq->desc_state_packed[curr]; + vring_unmap_state_packed(vq, state); + curr = state->next; + } + + BUG_ON(state == NULL); + vq->vq.num_free += vq->desc_state_packed[id].num; + state->next = vq->free_head; + vq->free_head = id; + + if (vq->indirect) { + u32 len; + + /* Free the indirect table, if any, now that it's unmapped. */ + desc = vq->desc_state_packed[id].indir_desc; + if (!desc) + return; + + if (vring_use_dma_api(vq->vq.vdev)) { + len = vq->desc_state_packed[id].len; + for (i = 0; i < len / sizeof(struct vring_packed_desc); + i++) + vring_unmap_desc_packed(vq, &desc[i]); + } + kfree(desc); + vq->desc_state_packed[id].indir_desc = NULL; + } else if (ctx) { + *ctx = vq->desc_state_packed[id].indir_desc; + } +} + +static inline bool is_used_desc_packed(const struct vring_virtqueue *vq, + u16 idx, bool used_wrap_counter) +{ + u16 flags; + bool avail, used; + + flags = virtio16_to_cpu(vq->vq.vdev, + vq->vring_packed.desc[idx].flags); + avail = !!(flags & VRING_DESC_F_AVAIL); + used = !!(flags & VRING_DESC_F_USED); + + return avail == used && used == used_wrap_counter; } static inline bool more_used_packed(const struct vring_virtqueue *vq) { - return false; + return is_used_desc_packed(vq, vq->last_used_idx, + vq->used_wrap_counter); } static void *virtqueue_get_buf_ctx_packed(struct virtqueue *_vq, unsigned int *len, void **ctx) { - return NULL; + struct vring_virtqueue *vq = to_vvq(_vq); + u16 last_used, id; + void *ret; + + START_USE(vq); + + if (unlikely(vq->broken)) { + END_USE(vq); + return NULL; + } + + if (!more_used_packed(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; + id = virtio16_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(id >= vq->vring_packed.num)) { + BAD_RING(vq, "id %u out of range\n", id); + return NULL; + } + if (unlikely(!vq->desc_state_packed[id].data)) { + BAD_RING(vq, "id %u is not a head!\n", id); + return NULL; + } + + vq->last_used_idx += vq->desc_state_packed[id].num; + if (vq->last_used_idx >= vq->vring_packed.num) { + vq->last_used_idx -= vq->vring_packed.num; + vq->used_wrap_counter ^= 1; + } + + /* detach_buf_packed clears data, so grab it now. */ + ret = vq->desc_state_packed[id].data; + detach_buf_packed(vq, id, ctx); + +#ifdef DEBUG + vq->last_add_time_valid = false; +#endif + + END_USE(vq); + return ret; } 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); + } } static unsigned virtqueue_enable_cb_prepare_packed(struct virtqueue *_vq) { - return 0; + struct vring_virtqueue *vq = to_vvq(_vq); + + START_USE(vq); + + /* We optimistically turn back on interrupts, then check if there was + * more to do. */ + + if (vq->event_flags_shadow == VRING_EVENT_F_DISABLE) { + vq->event_flags_shadow = VRING_EVENT_F_ENABLE; + vq->vring_packed.driver->flags = cpu_to_virtio16(_vq->vdev, + vq->event_flags_shadow); + } + + END_USE(vq); + return vq->last_used_idx | ((u16)vq->used_wrap_counter << 15); } -static bool virtqueue_poll_packed(struct virtqueue *_vq, unsigned last_used_idx) +static bool virtqueue_poll_packed(struct virtqueue *_vq, unsigned off_wrap) { - return false; + struct vring_virtqueue *vq = to_vvq(_vq); + bool wrap_counter; + u16 used_idx; + + wrap_counter = off_wrap >> 15; + used_idx = off_wrap & ~(1 << 15); + + return is_used_desc_packed(vq, used_idx, wrap_counter); } static bool virtqueue_enable_cb_delayed_packed(struct virtqueue *_vq) { - return false; + struct vring_virtqueue *vq = to_vvq(_vq); + + START_USE(vq); + + /* We optimistically turn back on interrupts, then check if there was + * more to do. */ + + if (vq->event_flags_shadow == VRING_EVENT_F_DISABLE) { + vq->event_flags_shadow = VRING_EVENT_F_ENABLE; + vq->vring_packed.driver->flags = cpu_to_virtio16(_vq->vdev, + vq->event_flags_shadow); + /* We need to enable interrupts first before re-checking + * for more used buffers. */ + virtio_mb(vq->weak_barriers); + } + + if (more_used_packed(vq)) { + END_USE(vq); + return false; + } + + END_USE(vq); + return true; } static void *virtqueue_detach_unused_buf_packed(struct virtqueue *_vq) { + struct vring_virtqueue *vq = to_vvq(_vq); + unsigned int i; + void *buf; + + START_USE(vq); + + for (i = 0; i < vq->vring_packed.num; i++) { + if (!vq->desc_state_packed[i].data) + continue; + /* detach_buf clears data, so grab it now. */ + buf = vq->desc_state_packed[i].data; + detach_buf_packed(vq, i, NULL); + 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; } @@ -1083,6 +1559,9 @@ bool virtqueue_poll(struct virtqueue *_vq, unsigned last_used_idx) { struct vring_virtqueue *vq = to_vvq(_vq); + /* We need to enable interrupts first before re-checking + * for more used buffers. */ + virtio_mb(vq->weak_barriers); return vq->packed ? virtqueue_poll_packed(_vq, last_used_idx) : virtqueue_poll_split(_vq, last_used_idx); } -- 2.18.0