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Message-Id: <20180425051550.24342-3-tiwei.bie@intel.com> Date: Wed, 25 Apr 2018 13:15:47 +0800 From: Tiwei Bie <tiwei.bie@...el.com> To: mst@...hat.com, jasowang@...hat.com, virtualization@...ts.linux-foundation.org, linux-kernel@...r.kernel.org, netdev@...r.kernel.org Cc: wexu@...hat.com, jfreimann@...hat.com, tiwei.bie@...el.com Subject: [RFC v3 2/5] virtio_ring: support creating packed ring This commit introduces the support for creating packed ring. All split ring specific functions are added _split suffix. Some necessary stubs for packed ring are also added. Signed-off-by: Tiwei Bie <tiwei.bie@...el.com> --- drivers/virtio/virtio_ring.c | 764 ++++++++++++++++++++++++++++--------------- include/linux/virtio_ring.h | 8 +- 2 files changed, 513 insertions(+), 259 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 71458f493cf8..e164822ca66e 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -64,8 +64,8 @@ struct vring_desc_state { 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 +79,45 @@ 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 +227,17 @@ 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 int vring_mapping_error(const struct vring_virtqueue *vq, + dma_addr_t addr) +{ + if (!vring_use_dma_api(vq->vq.vdev)) + return 0; + + return dma_mapping_error(vring_dma_dev(vq), addr); +} + +static void vring_unmap_one_split(const struct vring_virtqueue *vq, + struct vring_desc *desc) { u16 flags; @@ -226,17 +261,9 @@ static void vring_unmap_one(const struct vring_virtqueue *vq, } } -static int vring_mapping_error(const struct vring_virtqueue *vq, - dma_addr_t addr) -{ - if (!vring_use_dma_api(vq->vq.vdev)) - return 0; - - 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 +284,14 @@ 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 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 +330,7 @@ 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 +451,7 @@ 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 +462,355 @@ static inline int virtqueue_add(struct virtqueue *_vq, return -EIO; } +static bool virtqueue_kick_prepare_split(struct virtqueue *_vq) +{ + struct vring_virtqueue *vq = to_vvq(_vq); + u16 new, old; + bool needs_kick; + + START_USE(vq); + /* We need to expose available array entries before checking avail + * event. */ + virtio_mb(vq->weak_barriers); + + old = vq->avail_idx_shadow - vq->num_added; + new = vq->avail_idx_shadow; + 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 + + if (vq->event) { + needs_kick = vring_need_event(virtio16_to_cpu(_vq->vdev, vring_avail_event(&vq->vring)), + new, old); + } else { + needs_kick = !(vq->vring.used->flags & cpu_to_virtio16(_vq->vdev, VRING_USED_F_NO_NOTIFY)); + } + END_USE(vq); + return needs_kick; +} + +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); + + /* Clear data ptr. */ + vq->desc_state[head].data = NULL; + + /* Put back on free list: unmap first-level descriptors and find end */ + i = head; + + while (vq->vring.desc[i].flags & nextflag) { + 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_split(vq, &vq->vring.desc[i]); + vq->vring.desc[i].next = cpu_to_virtio16(vq->vq.vdev, vq->free_head); + vq->free_head = head; + + /* Plus final descriptor */ + vq->vq.num_free++; + + if (vq->indirect) { + struct vring_desc *indir_desc = vq->desc_state[head].indir_desc; + u32 len; + + /* Free the indirect table, if any, now that it's unmapped. */ + if (!indir_desc) + return; + + len = virtio32_to_cpu(vq->vq.vdev, vq->vring.desc[head].len); + + BUG_ON(!(vq->vring.desc[head].flags & + cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_INDIRECT))); + BUG_ON(len == 0 || len % sizeof(struct vring_desc)); + + for (j = 0; j < len / sizeof(struct vring_desc); j++) + vring_unmap_one_split(vq, &indir_desc[j]); + + kfree(indir_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); +} + +static 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_split(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; +} + +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 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 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_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 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; +} + +/* + * The 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_init_packed(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_size_packed(unsigned int num, unsigned long align) +{ + return ((sizeof(struct vring_packed_desc) * num + align - 1) + & ~(align - 1)) + sizeof(struct vring_packed_desc_event) * 2; +} + +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) +{ + return -EIO; +} + +static bool virtqueue_kick_prepare_packed(struct virtqueue *_vq) +{ + return false; +} + +static inline bool more_used_packed(const struct vring_virtqueue *vq) +{ + return false; +} + +static void *virtqueue_get_buf_ctx_packed(struct virtqueue *_vq, + unsigned int *len, + void **ctx) +{ + return NULL; +} + +static void virtqueue_disable_cb_packed(struct virtqueue *_vq) +{ +} + +static unsigned virtqueue_enable_cb_prepare_packed(struct virtqueue *_vq) +{ + return 0; +} + +static bool virtqueue_poll_packed(struct virtqueue *_vq, unsigned last_used_idx) +{ + return false; +} + +static bool virtqueue_enable_cb_delayed_packed(struct virtqueue *_vq) +{ + return false; +} + +static void *virtqueue_detach_unused_buf_packed(struct virtqueue *_vq) +{ + return NULL; +} + +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. @@ -551,34 +927,9 @@ EXPORT_SYMBOL_GPL(virtqueue_add_inbuf_ctx); bool virtqueue_kick_prepare(struct virtqueue *_vq) { struct vring_virtqueue *vq = to_vvq(_vq); - u16 new, old; - bool needs_kick; - START_USE(vq); - /* We need to expose available array entries before checking avail - * event. */ - virtio_mb(vq->weak_barriers); - - old = vq->avail_idx_shadow - vq->num_added; - new = vq->avail_idx_shadow; - 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 - - if (vq->event) { - needs_kick = vring_need_event(virtio16_to_cpu(_vq->vdev, vring_avail_event(&vq->vring)), - new, old); - } else { - needs_kick = !(vq->vring.used->flags & cpu_to_virtio16(_vq->vdev, VRING_USED_F_NO_NOTIFY)); - } - END_USE(vq); - return needs_kick; + return vq->packed ? virtqueue_kick_prepare_packed(_vq) : + virtqueue_kick_prepare_split(_vq); } EXPORT_SYMBOL_GPL(virtqueue_kick_prepare); @@ -626,58 +977,9 @@ bool virtqueue_kick(struct virtqueue *vq) } EXPORT_SYMBOL_GPL(virtqueue_kick); -static void detach_buf(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); - - /* Clear data ptr. */ - vq->desc_state[head].data = NULL; - - /* Put back on free list: unmap first-level descriptors and find end */ - i = head; - - while (vq->vring.desc[i].flags & nextflag) { - vring_unmap_one(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]); - vq->vring.desc[i].next = cpu_to_virtio16(vq->vq.vdev, vq->free_head); - vq->free_head = head; - - /* Plus final descriptor */ - vq->vq.num_free++; - - if (vq->indirect) { - struct vring_desc *indir_desc = vq->desc_state[head].indir_desc; - u32 len; - - /* Free the indirect table, if any, now that it's unmapped. */ - if (!indir_desc) - return; - - len = virtio32_to_cpu(vq->vq.vdev, vq->vring.desc[head].len); - - BUG_ON(!(vq->vring.desc[head].flags & - cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_INDIRECT))); - 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]); - - kfree(indir_desc); - vq->desc_state[head].indir_desc = NULL; - } else if (ctx) { - *ctx = vq->desc_state[head].indir_desc; - } -} - static inline bool more_used(const struct vring_virtqueue *vq) { - return vq->last_used_idx != virtio16_to_cpu(vq->vq.vdev, vq->vring.used->idx); + return vq->packed ? more_used_packed(vq) : more_used_split(vq); } /** @@ -700,57 +1002,9 @@ 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); @@ -772,12 +1026,10 @@ 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); @@ -796,23 +1048,9 @@ 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); @@ -829,8 +1067,8 @@ 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); @@ -868,34 +1106,9 @@ 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); @@ -910,27 +1123,9 @@ 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 +1150,8 @@ 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 +1159,20 @@ 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 +1181,8 @@ 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 +1193,37 @@ 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 +1271,12 @@ 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_size_packed(num, align) : vring_size(num, align); +} + struct virtqueue *vring_create_virtqueue( unsigned int index, unsigned int num, @@ -1072,7 +1293,8 @@ 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 +1302,13 @@ 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 +1320,21 @@ 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_init_packed(&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 +1360,17 @@ 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_init_packed(&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 +1380,9 @@ 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); @@ -1185,7 +1424,7 @@ 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 +1467,10 @@ 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 +1482,16 @@ 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, -- 2.11.0
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