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-rw-r--r--drivers/virtio/virtio_ring.c2876
1 files changed, 2876 insertions, 0 deletions
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
new file mode 100644
index 000000000..7d320f799
--- /dev/null
+++ b/drivers/virtio/virtio_ring.c
@@ -0,0 +1,2876 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* Virtio ring implementation.
+ *
+ * Copyright 2007 Rusty Russell IBM Corporation
+ */
+#include <linux/virtio.h>
+#include <linux/virtio_ring.h>
+#include <linux/virtio_config.h>
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/hrtimer.h>
+#include <linux/dma-mapping.h>
+#include <linux/kmsan.h>
+#include <linux/spinlock.h>
+#include <xen/xen.h>
+
+#ifdef DEBUG
+/* For development, we want to crash whenever the ring is screwed. */
+#define BAD_RING(_vq, fmt, args...) \
+ do { \
+ dev_err(&(_vq)->vq.vdev->dev, \
+ "%s:"fmt, (_vq)->vq.name, ##args); \
+ BUG(); \
+ } while (0)
+/* Caller is supposed to guarantee no reentry. */
+#define START_USE(_vq) \
+ do { \
+ if ((_vq)->in_use) \
+ panic("%s:in_use = %i\n", \
+ (_vq)->vq.name, (_vq)->in_use); \
+ (_vq)->in_use = __LINE__; \
+ } while (0)
+#define END_USE(_vq) \
+ do { BUG_ON(!(_vq)->in_use); (_vq)->in_use = 0; } while(0)
+#define LAST_ADD_TIME_UPDATE(_vq) \
+ do { \
+ 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; \
+ } while (0)
+#define LAST_ADD_TIME_CHECK(_vq) \
+ do { \
+ if ((_vq)->last_add_time_valid) { \
+ WARN_ON(ktime_to_ms(ktime_sub(ktime_get(), \
+ (_vq)->last_add_time)) > 100); \
+ } \
+ } while (0)
+#define LAST_ADD_TIME_INVALID(_vq) \
+ ((_vq)->last_add_time_valid = false)
+#else
+#define BAD_RING(_vq, fmt, args...) \
+ do { \
+ dev_err(&_vq->vq.vdev->dev, \
+ "%s:"fmt, (_vq)->vq.name, ##args); \
+ (_vq)->broken = true; \
+ } while (0)
+#define START_USE(vq)
+#define END_USE(vq)
+#define LAST_ADD_TIME_UPDATE(vq)
+#define LAST_ADD_TIME_CHECK(vq)
+#define LAST_ADD_TIME_INVALID(vq)
+#endif
+
+struct vring_desc_state_split {
+ 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. */
+ u16 num; /* Descriptor list length. */
+ u16 last; /* The last desc state in a list. */
+};
+
+struct vring_desc_extra {
+ dma_addr_t addr; /* Descriptor DMA addr. */
+ u32 len; /* Descriptor length. */
+ u16 flags; /* Descriptor flags. */
+ u16 next; /* The next desc state in a list. */
+};
+
+struct vring_virtqueue_split {
+ /* 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;
+
+ /* Per-descriptor state. */
+ struct vring_desc_state_split *desc_state;
+ struct vring_desc_extra *desc_extra;
+
+ /* DMA address and size information */
+ dma_addr_t queue_dma_addr;
+ size_t queue_size_in_bytes;
+
+ /*
+ * The parameters for creating vrings are reserved for creating new
+ * vring.
+ */
+ u32 vring_align;
+ bool may_reduce_num;
+};
+
+struct vring_virtqueue_packed {
+ /* Actual memory layout for this queue. */
+ struct {
+ unsigned int num;
+ struct vring_packed_desc *desc;
+ struct vring_packed_desc_event *driver;
+ struct vring_packed_desc_event *device;
+ } vring;
+
+ /* Driver ring wrap counter. */
+ bool avail_wrap_counter;
+
+ /* Avail used flags. */
+ u16 avail_used_flags;
+
+ /* Index of the next avail descriptor. */
+ u16 next_avail_idx;
+
+ /*
+ * Last written value to driver->flags in
+ * guest byte order.
+ */
+ u16 event_flags_shadow;
+
+ /* Per-descriptor state. */
+ struct vring_desc_state_packed *desc_state;
+ struct vring_desc_extra *desc_extra;
+
+ /* DMA address and size information */
+ dma_addr_t ring_dma_addr;
+ dma_addr_t driver_event_dma_addr;
+ dma_addr_t device_event_dma_addr;
+ size_t ring_size_in_bytes;
+ size_t event_size_in_bytes;
+};
+
+struct vring_virtqueue {
+ struct virtqueue vq;
+
+ /* Is this a packed ring? */
+ bool packed_ring;
+
+ /* Is DMA API used? */
+ bool use_dma_api;
+
+ /* Can we use weak barriers? */
+ bool weak_barriers;
+
+ /* Other side has made a mess, don't try any more. */
+ bool broken;
+
+ /* Host supports indirect buffers */
+ bool indirect;
+
+ /* 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.
+ * for split ring, it just contains last used index
+ * for packed ring:
+ * bits up to VRING_PACKED_EVENT_F_WRAP_CTR include the last used index.
+ * bits from VRING_PACKED_EVENT_F_WRAP_CTR include the used wrap counter.
+ */
+ u16 last_used_idx;
+
+ /* Hint for event idx: already triggered no need to disable. */
+ bool event_triggered;
+
+ union {
+ /* Available for split ring */
+ struct vring_virtqueue_split split;
+
+ /* Available for packed ring */
+ struct vring_virtqueue_packed packed;
+ };
+
+ /* How to notify other side. FIXME: commonalize hcalls! */
+ bool (*notify)(struct virtqueue *vq);
+
+ /* DMA, allocation, and size information */
+ bool we_own_ring;
+
+#ifdef DEBUG
+ /* They're supposed to lock for us. */
+ unsigned int in_use;
+
+ /* Figure out if their kicks are too delayed. */
+ bool last_add_time_valid;
+ ktime_t last_add_time;
+#endif
+};
+
+static struct virtqueue *__vring_new_virtqueue(unsigned int index,
+ struct vring_virtqueue_split *vring_split,
+ struct virtio_device *vdev,
+ bool weak_barriers,
+ bool context,
+ bool (*notify)(struct virtqueue *),
+ void (*callback)(struct virtqueue *),
+ const char *name);
+static struct vring_desc_extra *vring_alloc_desc_extra(unsigned int num);
+static void vring_free(struct virtqueue *_vq);
+
+/*
+ * Helpers.
+ */
+
+#define to_vvq(_vq) container_of(_vq, struct vring_virtqueue, vq)
+
+static inline bool virtqueue_use_indirect(struct vring_virtqueue *vq,
+ unsigned int total_sg)
+{
+ /*
+ * If the host supports indirect descriptor tables, and we have multiple
+ * buffers, then go indirect. FIXME: tune this threshold
+ */
+ return (vq->indirect && total_sg > 1 && vq->vq.num_free);
+}
+
+/*
+ * Modern virtio devices have feature bits to specify whether they need a
+ * quirk and bypass the IOMMU. If not there, just use the DMA API.
+ *
+ * If there, the interaction between virtio and DMA API is messy.
+ *
+ * On most systems with virtio, physical addresses match bus addresses,
+ * and it doesn't particularly matter whether we use the DMA API.
+ *
+ * On some systems, including Xen and any system with a physical device
+ * that speaks virtio behind a physical IOMMU, we must use the DMA API
+ * for virtio DMA to work at all.
+ *
+ * On other systems, including SPARC and PPC64, virtio-pci devices are
+ * enumerated as though they are behind an IOMMU, but the virtio host
+ * ignores the IOMMU, so we must either pretend that the IOMMU isn't
+ * there or somehow map everything as the identity.
+ *
+ * For the time being, we preserve historic behavior and bypass the DMA
+ * API.
+ *
+ * TODO: install a per-device DMA ops structure that does the right thing
+ * taking into account all the above quirks, and use the DMA API
+ * unconditionally on data path.
+ */
+
+static bool vring_use_dma_api(struct virtio_device *vdev)
+{
+ if (!virtio_has_dma_quirk(vdev))
+ return true;
+
+ /* Otherwise, we are left to guess. */
+ /*
+ * In theory, it's possible to have a buggy QEMU-supposed
+ * emulated Q35 IOMMU and Xen enabled at the same time. On
+ * such a configuration, virtio has never worked and will
+ * not work without an even larger kludge. Instead, enable
+ * the DMA API if we're a Xen guest, which at least allows
+ * all of the sensible Xen configurations to work correctly.
+ */
+ if (xen_domain())
+ return true;
+
+ return false;
+}
+
+size_t virtio_max_dma_size(struct virtio_device *vdev)
+{
+ size_t max_segment_size = SIZE_MAX;
+
+ if (vring_use_dma_api(vdev))
+ max_segment_size = dma_max_mapping_size(vdev->dev.parent);
+
+ return max_segment_size;
+}
+EXPORT_SYMBOL_GPL(virtio_max_dma_size);
+
+static void *vring_alloc_queue(struct virtio_device *vdev, size_t size,
+ dma_addr_t *dma_handle, gfp_t flag)
+{
+ if (vring_use_dma_api(vdev)) {
+ return dma_alloc_coherent(vdev->dev.parent, size,
+ dma_handle, flag);
+ } else {
+ void *queue = alloc_pages_exact(PAGE_ALIGN(size), flag);
+
+ if (queue) {
+ phys_addr_t phys_addr = virt_to_phys(queue);
+ *dma_handle = (dma_addr_t)phys_addr;
+
+ /*
+ * Sanity check: make sure we dind't truncate
+ * the address. The only arches I can find that
+ * have 64-bit phys_addr_t but 32-bit dma_addr_t
+ * are certain non-highmem MIPS and x86
+ * configurations, but these configurations
+ * should never allocate physical pages above 32
+ * bits, so this is fine. Just in case, throw a
+ * warning and abort if we end up with an
+ * unrepresentable address.
+ */
+ if (WARN_ON_ONCE(*dma_handle != phys_addr)) {
+ free_pages_exact(queue, PAGE_ALIGN(size));
+ return NULL;
+ }
+ }
+ return queue;
+ }
+}
+
+static void vring_free_queue(struct virtio_device *vdev, size_t size,
+ void *queue, dma_addr_t dma_handle)
+{
+ if (vring_use_dma_api(vdev))
+ dma_free_coherent(vdev->dev.parent, size, queue, dma_handle);
+ else
+ free_pages_exact(queue, PAGE_ALIGN(size));
+}
+
+/*
+ * The DMA ops on various arches are rather gnarly right now, and
+ * making all of the arch DMA ops work on the vring device itself
+ * is a mess. For now, we use the parent device for DMA ops.
+ */
+static inline struct device *vring_dma_dev(const struct vring_virtqueue *vq)
+{
+ return vq->vq.vdev->dev.parent;
+}
+
+/* Map one sg entry. */
+static dma_addr_t vring_map_one_sg(const struct vring_virtqueue *vq,
+ struct scatterlist *sg,
+ enum dma_data_direction direction)
+{
+ if (!vq->use_dma_api) {
+ /*
+ * If DMA is not used, KMSAN doesn't know that the scatterlist
+ * is initialized by the hardware. Explicitly check/unpoison it
+ * depending on the direction.
+ */
+ kmsan_handle_dma(sg_page(sg), sg->offset, sg->length, direction);
+ return (dma_addr_t)sg_phys(sg);
+ }
+
+ /*
+ * We can't use dma_map_sg, because we don't use scatterlists in
+ * the way it expects (we don't guarantee that the scatterlist
+ * will exist for the lifetime of the mapping).
+ */
+ return dma_map_page(vring_dma_dev(vq),
+ sg_page(sg), sg->offset, sg->length,
+ direction);
+}
+
+static dma_addr_t vring_map_single(const struct vring_virtqueue *vq,
+ void *cpu_addr, size_t size,
+ enum dma_data_direction direction)
+{
+ if (!vq->use_dma_api)
+ return (dma_addr_t)virt_to_phys(cpu_addr);
+
+ return dma_map_single(vring_dma_dev(vq),
+ cpu_addr, size, direction);
+}
+
+static int vring_mapping_error(const struct vring_virtqueue *vq,
+ dma_addr_t addr)
+{
+ if (!vq->use_dma_api)
+ return 0;
+
+ return dma_mapping_error(vring_dma_dev(vq), addr);
+}
+
+static void virtqueue_init(struct vring_virtqueue *vq, u32 num)
+{
+ vq->vq.num_free = num;
+
+ if (vq->packed_ring)
+ vq->last_used_idx = 0 | (1 << VRING_PACKED_EVENT_F_WRAP_CTR);
+ else
+ vq->last_used_idx = 0;
+
+ vq->event_triggered = false;
+ vq->num_added = 0;
+
+#ifdef DEBUG
+ vq->in_use = false;
+ vq->last_add_time_valid = false;
+#endif
+}
+
+
+/*
+ * Split ring specific functions - *_split().
+ */
+
+static void vring_unmap_one_split_indirect(const struct vring_virtqueue *vq,
+ struct vring_desc *desc)
+{
+ u16 flags;
+
+ if (!vq->use_dma_api)
+ return;
+
+ flags = virtio16_to_cpu(vq->vq.vdev, desc->flags);
+
+ 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 unsigned int vring_unmap_one_split(const struct vring_virtqueue *vq,
+ unsigned int i)
+{
+ struct vring_desc_extra *extra = vq->split.desc_extra;
+ u16 flags;
+
+ if (!vq->use_dma_api)
+ goto out;
+
+ flags = extra[i].flags;
+
+ if (flags & VRING_DESC_F_INDIRECT) {
+ dma_unmap_single(vring_dma_dev(vq),
+ extra[i].addr,
+ extra[i].len,
+ (flags & VRING_DESC_F_WRITE) ?
+ DMA_FROM_DEVICE : DMA_TO_DEVICE);
+ } else {
+ dma_unmap_page(vring_dma_dev(vq),
+ extra[i].addr,
+ extra[i].len,
+ (flags & VRING_DESC_F_WRITE) ?
+ DMA_FROM_DEVICE : DMA_TO_DEVICE);
+ }
+
+out:
+ return extra[i].next;
+}
+
+static struct vring_desc *alloc_indirect_split(struct virtqueue *_vq,
+ unsigned int total_sg,
+ gfp_t gfp)
+{
+ struct vring_desc *desc;
+ unsigned int i;
+
+ /*
+ * 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_array(total_sg, sizeof(struct vring_desc), gfp);
+ if (!desc)
+ return NULL;
+
+ for (i = 0; i < total_sg; i++)
+ desc[i].next = cpu_to_virtio16(_vq->vdev, i + 1);
+ return desc;
+}
+
+static inline unsigned int virtqueue_add_desc_split(struct virtqueue *vq,
+ struct vring_desc *desc,
+ unsigned int i,
+ dma_addr_t addr,
+ unsigned int len,
+ u16 flags,
+ bool indirect)
+{
+ struct vring_virtqueue *vring = to_vvq(vq);
+ struct vring_desc_extra *extra = vring->split.desc_extra;
+ u16 next;
+
+ desc[i].flags = cpu_to_virtio16(vq->vdev, flags);
+ desc[i].addr = cpu_to_virtio64(vq->vdev, addr);
+ desc[i].len = cpu_to_virtio32(vq->vdev, len);
+
+ if (!indirect) {
+ next = extra[i].next;
+ desc[i].next = cpu_to_virtio16(vq->vdev, next);
+
+ extra[i].addr = addr;
+ extra[i].len = len;
+ extra[i].flags = flags;
+ } else
+ next = virtio16_to_cpu(vq->vdev, desc[i].next);
+
+ return next;
+}
+
+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;
+ struct vring_desc *desc;
+ unsigned int i, n, avail, descs_used, prev, err_idx;
+ int head;
+ bool indirect;
+
+ START_USE(vq);
+
+ BUG_ON(data == NULL);
+ BUG_ON(ctx && vq->indirect);
+
+ if (unlikely(vq->broken)) {
+ END_USE(vq);
+ return -EIO;
+ }
+
+ LAST_ADD_TIME_UPDATE(vq);
+
+ BUG_ON(total_sg == 0);
+
+ head = vq->free_head;
+
+ if (virtqueue_use_indirect(vq, total_sg))
+ desc = alloc_indirect_split(_vq, total_sg, gfp);
+ else {
+ desc = NULL;
+ WARN_ON_ONCE(total_sg > vq->split.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->split.vring.desc;
+ i = head;
+ descs_used = total_sg;
+ }
+
+ if (unlikely(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;
+
+ prev = i;
+ /* Note that we trust indirect descriptor
+ * table since it use stream DMA mapping.
+ */
+ i = virtqueue_add_desc_split(_vq, desc, i, addr, sg->length,
+ VRING_DESC_F_NEXT,
+ indirect);
+ }
+ }
+ 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;
+
+ prev = i;
+ /* Note that we trust indirect descriptor
+ * table since it use stream DMA mapping.
+ */
+ i = virtqueue_add_desc_split(_vq, desc, i, addr,
+ sg->length,
+ VRING_DESC_F_NEXT |
+ VRING_DESC_F_WRITE,
+ indirect);
+ }
+ }
+ /* Last one doesn't continue. */
+ desc[prev].flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT);
+ if (!indirect && vq->use_dma_api)
+ vq->split.desc_extra[prev & (vq->split.vring.num - 1)].flags &=
+ ~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_desc),
+ DMA_TO_DEVICE);
+ if (vring_mapping_error(vq, addr))
+ goto unmap_release;
+
+ virtqueue_add_desc_split(_vq, vq->split.vring.desc,
+ head, addr,
+ total_sg * sizeof(struct vring_desc),
+ VRING_DESC_F_INDIRECT,
+ false);
+ }
+
+ /* We're using some buffers from the free list. */
+ vq->vq.num_free -= descs_used;
+
+ /* Update free pointer */
+ if (indirect)
+ vq->free_head = vq->split.desc_extra[head].next;
+ else
+ vq->free_head = i;
+
+ /* Store token and indirect buffer state. */
+ vq->split.desc_state[head].data = data;
+ if (indirect)
+ vq->split.desc_state[head].indir_desc = desc;
+ else
+ vq->split.desc_state[head].indir_desc = ctx;
+
+ /* Put entry in available array (but don't update avail->idx until they
+ * do sync). */
+ avail = vq->split.avail_idx_shadow & (vq->split.vring.num - 1);
+ vq->split.vring.avail->ring[avail] = cpu_to_virtio16(_vq->vdev, head);
+
+ /* Descriptors and available array need to be set before we expose the
+ * new available array entries. */
+ virtio_wmb(vq->weak_barriers);
+ vq->split.avail_idx_shadow++;
+ vq->split.vring.avail->idx = cpu_to_virtio16(_vq->vdev,
+ vq->split.avail_idx_shadow);
+ vq->num_added++;
+
+ pr_debug("Added buffer head %i to %p\n", head, vq);
+ END_USE(vq);
+
+ /* This is very unlikely, but theoretically possible. Kick
+ * just in case. */
+ if (unlikely(vq->num_added == (1 << 16) - 1))
+ virtqueue_kick(_vq);
+
+ return 0;
+
+unmap_release:
+ err_idx = i;
+
+ if (indirect)
+ i = 0;
+ else
+ i = head;
+
+ for (n = 0; n < total_sg; n++) {
+ if (i == err_idx)
+ break;
+ if (indirect) {
+ vring_unmap_one_split_indirect(vq, &desc[i]);
+ i = virtio16_to_cpu(_vq->vdev, desc[i].next);
+ } else
+ i = vring_unmap_one_split(vq, i);
+ }
+
+ if (indirect)
+ kfree(desc);
+
+ END_USE(vq);
+ return -ENOMEM;
+}
+
+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->split.avail_idx_shadow - vq->num_added;
+ new = vq->split.avail_idx_shadow;
+ vq->num_added = 0;
+
+ LAST_ADD_TIME_CHECK(vq);
+ LAST_ADD_TIME_INVALID(vq);
+
+ if (vq->event) {
+ needs_kick = vring_need_event(virtio16_to_cpu(_vq->vdev,
+ vring_avail_event(&vq->split.vring)),
+ new, old);
+ } else {
+ needs_kick = !(vq->split.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->split.desc_state[head].data = NULL;
+
+ /* Put back on free list: unmap first-level descriptors and find end */
+ i = head;
+
+ while (vq->split.vring.desc[i].flags & nextflag) {
+ vring_unmap_one_split(vq, i);
+ i = vq->split.desc_extra[i].next;
+ vq->vq.num_free++;
+ }
+
+ vring_unmap_one_split(vq, i);
+ vq->split.desc_extra[i].next = vq->free_head;
+ vq->free_head = head;
+
+ /* Plus final descriptor */
+ vq->vq.num_free++;
+
+ if (vq->indirect) {
+ struct vring_desc *indir_desc =
+ vq->split.desc_state[head].indir_desc;
+ u32 len;
+
+ /* Free the indirect table, if any, now that it's unmapped. */
+ if (!indir_desc)
+ return;
+
+ len = vq->split.desc_extra[head].len;
+
+ BUG_ON(!(vq->split.desc_extra[head].flags &
+ 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_indirect(vq, &indir_desc[j]);
+
+ kfree(indir_desc);
+ vq->split.desc_state[head].indir_desc = NULL;
+ } else if (ctx) {
+ *ctx = vq->split.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->split.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->split.vring.num - 1));
+ i = virtio32_to_cpu(_vq->vdev,
+ vq->split.vring.used->ring[last_used].id);
+ *len = virtio32_to_cpu(_vq->vdev,
+ vq->split.vring.used->ring[last_used].len);
+
+ if (unlikely(i >= vq->split.vring.num)) {
+ BAD_RING(vq, "id %u out of range\n", i);
+ return NULL;
+ }
+ if (unlikely(!vq->split.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->split.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->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT))
+ virtio_store_mb(vq->weak_barriers,
+ &vring_used_event(&vq->split.vring),
+ cpu_to_virtio16(_vq->vdev, vq->last_used_idx));
+
+ LAST_ADD_TIME_INVALID(vq);
+
+ END_USE(vq);
+ return ret;
+}
+
+static void virtqueue_disable_cb_split(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ if (!(vq->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT)) {
+ vq->split.avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT;
+
+ /*
+ * If device triggered an event already it won't trigger one again:
+ * no need to disable.
+ */
+ if (vq->event_triggered)
+ return;
+
+ if (vq->event)
+ /* TODO: this is a hack. Figure out a cleaner value to write. */
+ vring_used_event(&vq->split.vring) = 0x0;
+ else
+ vq->split.vring.avail->flags =
+ cpu_to_virtio16(_vq->vdev,
+ vq->split.avail_flags_shadow);
+ }
+}
+
+static unsigned int 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->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT) {
+ vq->split.avail_flags_shadow &= ~VRING_AVAIL_F_NO_INTERRUPT;
+ if (!vq->event)
+ vq->split.vring.avail->flags =
+ cpu_to_virtio16(_vq->vdev,
+ vq->split.avail_flags_shadow);
+ }
+ vring_used_event(&vq->split.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 int last_used_idx)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ return (u16)last_used_idx != virtio16_to_cpu(_vq->vdev,
+ vq->split.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->split.avail_flags_shadow & VRING_AVAIL_F_NO_INTERRUPT) {
+ vq->split.avail_flags_shadow &= ~VRING_AVAIL_F_NO_INTERRUPT;
+ if (!vq->event)
+ vq->split.vring.avail->flags =
+ cpu_to_virtio16(_vq->vdev,
+ vq->split.avail_flags_shadow);
+ }
+ /* TODO: tune this threshold */
+ bufs = (u16)(vq->split.avail_idx_shadow - vq->last_used_idx) * 3 / 4;
+
+ virtio_store_mb(vq->weak_barriers,
+ &vring_used_event(&vq->split.vring),
+ cpu_to_virtio16(_vq->vdev, vq->last_used_idx + bufs));
+
+ if (unlikely((u16)(virtio16_to_cpu(_vq->vdev, vq->split.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->split.vring.num; i++) {
+ if (!vq->split.desc_state[i].data)
+ continue;
+ /* detach_buf_split clears data, so grab it now. */
+ buf = vq->split.desc_state[i].data;
+ detach_buf_split(vq, i, NULL);
+ vq->split.avail_idx_shadow--;
+ vq->split.vring.avail->idx = cpu_to_virtio16(_vq->vdev,
+ vq->split.avail_idx_shadow);
+ END_USE(vq);
+ return buf;
+ }
+ /* That should have freed everything. */
+ BUG_ON(vq->vq.num_free != vq->split.vring.num);
+
+ END_USE(vq);
+ return NULL;
+}
+
+static void virtqueue_vring_init_split(struct vring_virtqueue_split *vring_split,
+ struct vring_virtqueue *vq)
+{
+ struct virtio_device *vdev;
+
+ vdev = vq->vq.vdev;
+
+ vring_split->avail_flags_shadow = 0;
+ vring_split->avail_idx_shadow = 0;
+
+ /* No callback? Tell other side not to bother us. */
+ if (!vq->vq.callback) {
+ vring_split->avail_flags_shadow |= VRING_AVAIL_F_NO_INTERRUPT;
+ if (!vq->event)
+ vring_split->vring.avail->flags = cpu_to_virtio16(vdev,
+ vring_split->avail_flags_shadow);
+ }
+}
+
+static void virtqueue_reinit_split(struct vring_virtqueue *vq)
+{
+ int num;
+
+ num = vq->split.vring.num;
+
+ vq->split.vring.avail->flags = 0;
+ vq->split.vring.avail->idx = 0;
+
+ /* reset avail event */
+ vq->split.vring.avail->ring[num] = 0;
+
+ vq->split.vring.used->flags = 0;
+ vq->split.vring.used->idx = 0;
+
+ /* reset used event */
+ *(__virtio16 *)&(vq->split.vring.used->ring[num]) = 0;
+
+ virtqueue_init(vq, num);
+
+ virtqueue_vring_init_split(&vq->split, vq);
+}
+
+static void virtqueue_vring_attach_split(struct vring_virtqueue *vq,
+ struct vring_virtqueue_split *vring_split)
+{
+ vq->split = *vring_split;
+
+ /* Put everything in free lists. */
+ vq->free_head = 0;
+}
+
+static int vring_alloc_state_extra_split(struct vring_virtqueue_split *vring_split)
+{
+ struct vring_desc_state_split *state;
+ struct vring_desc_extra *extra;
+ u32 num = vring_split->vring.num;
+
+ state = kmalloc_array(num, sizeof(struct vring_desc_state_split), GFP_KERNEL);
+ if (!state)
+ goto err_state;
+
+ extra = vring_alloc_desc_extra(num);
+ if (!extra)
+ goto err_extra;
+
+ memset(state, 0, num * sizeof(struct vring_desc_state_split));
+
+ vring_split->desc_state = state;
+ vring_split->desc_extra = extra;
+ return 0;
+
+err_extra:
+ kfree(state);
+err_state:
+ return -ENOMEM;
+}
+
+static void vring_free_split(struct vring_virtqueue_split *vring_split,
+ struct virtio_device *vdev)
+{
+ vring_free_queue(vdev, vring_split->queue_size_in_bytes,
+ vring_split->vring.desc,
+ vring_split->queue_dma_addr);
+
+ kfree(vring_split->desc_state);
+ kfree(vring_split->desc_extra);
+}
+
+static int vring_alloc_queue_split(struct vring_virtqueue_split *vring_split,
+ struct virtio_device *vdev,
+ u32 num,
+ unsigned int vring_align,
+ bool may_reduce_num)
+{
+ void *queue = NULL;
+ dma_addr_t dma_addr;
+
+ /* We assume num is a power of 2. */
+ if (num & (num - 1)) {
+ dev_warn(&vdev->dev, "Bad virtqueue length %u\n", num);
+ return -EINVAL;
+ }
+
+ /* 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),
+ &dma_addr,
+ GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO);
+ if (queue)
+ break;
+ if (!may_reduce_num)
+ return -ENOMEM;
+ }
+
+ if (!num)
+ return -ENOMEM;
+
+ if (!queue) {
+ /* Try to get a single page. You are my only hope! */
+ queue = vring_alloc_queue(vdev, vring_size(num, vring_align),
+ &dma_addr, GFP_KERNEL | __GFP_ZERO);
+ }
+ if (!queue)
+ return -ENOMEM;
+
+ vring_init(&vring_split->vring, num, queue, vring_align);
+
+ vring_split->queue_dma_addr = dma_addr;
+ vring_split->queue_size_in_bytes = vring_size(num, vring_align);
+
+ vring_split->vring_align = vring_align;
+ vring_split->may_reduce_num = may_reduce_num;
+
+ return 0;
+}
+
+static struct virtqueue *vring_create_virtqueue_split(
+ unsigned int index,
+ unsigned int num,
+ unsigned int vring_align,
+ struct virtio_device *vdev,
+ bool weak_barriers,
+ bool may_reduce_num,
+ bool context,
+ bool (*notify)(struct virtqueue *),
+ void (*callback)(struct virtqueue *),
+ const char *name)
+{
+ struct vring_virtqueue_split vring_split = {};
+ struct virtqueue *vq;
+ int err;
+
+ err = vring_alloc_queue_split(&vring_split, vdev, num, vring_align,
+ may_reduce_num);
+ if (err)
+ return NULL;
+
+ vq = __vring_new_virtqueue(index, &vring_split, vdev, weak_barriers,
+ context, notify, callback, name);
+ if (!vq) {
+ vring_free_split(&vring_split, vdev);
+ return NULL;
+ }
+
+ to_vvq(vq)->we_own_ring = true;
+
+ return vq;
+}
+
+static int virtqueue_resize_split(struct virtqueue *_vq, u32 num)
+{
+ struct vring_virtqueue_split vring_split = {};
+ struct vring_virtqueue *vq = to_vvq(_vq);
+ struct virtio_device *vdev = _vq->vdev;
+ int err;
+
+ err = vring_alloc_queue_split(&vring_split, vdev, num,
+ vq->split.vring_align,
+ vq->split.may_reduce_num);
+ if (err)
+ goto err;
+
+ err = vring_alloc_state_extra_split(&vring_split);
+ if (err)
+ goto err_state_extra;
+
+ vring_free(&vq->vq);
+
+ virtqueue_vring_init_split(&vring_split, vq);
+
+ virtqueue_init(vq, vring_split.vring.num);
+ virtqueue_vring_attach_split(vq, &vring_split);
+
+ return 0;
+
+err_state_extra:
+ vring_free_split(&vring_split, vdev);
+err:
+ virtqueue_reinit_split(vq);
+ return -ENOMEM;
+}
+
+
+/*
+ * Packed ring specific functions - *_packed().
+ */
+static inline bool packed_used_wrap_counter(u16 last_used_idx)
+{
+ return !!(last_used_idx & (1 << VRING_PACKED_EVENT_F_WRAP_CTR));
+}
+
+static inline u16 packed_last_used(u16 last_used_idx)
+{
+ return last_used_idx & ~(-(1 << VRING_PACKED_EVENT_F_WRAP_CTR));
+}
+
+static void vring_unmap_extra_packed(const struct vring_virtqueue *vq,
+ struct vring_desc_extra *extra)
+{
+ u16 flags;
+
+ if (!vq->use_dma_api)
+ return;
+
+ flags = extra->flags;
+
+ if (flags & VRING_DESC_F_INDIRECT) {
+ dma_unmap_single(vring_dma_dev(vq),
+ extra->addr, extra->len,
+ (flags & VRING_DESC_F_WRITE) ?
+ DMA_FROM_DEVICE : DMA_TO_DEVICE);
+ } else {
+ dma_unmap_page(vring_dma_dev(vq),
+ extra->addr, extra->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 (!vq->use_dma_api)
+ return;
+
+ flags = le16_to_cpu(desc->flags);
+
+ dma_unmap_page(vring_dma_dev(vq),
+ le64_to_cpu(desc->addr),
+ le32_to_cpu(desc->len),
+ (flags & VRING_DESC_F_WRITE) ?
+ DMA_FROM_DEVICE : DMA_TO_DEVICE);
+}
+
+static struct vring_packed_desc *alloc_indirect_packed(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_array(total_sg, sizeof(struct vring_packed_desc), gfp);
+
+ return desc;
+}
+
+static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
+ struct scatterlist *sgs[],
+ unsigned int total_sg,
+ unsigned int out_sgs,
+ unsigned int in_sgs,
+ void *data,
+ gfp_t gfp)
+{
+ struct vring_packed_desc *desc;
+ struct scatterlist *sg;
+ unsigned int i, n, err_idx;
+ u16 head, id;
+ dma_addr_t addr;
+
+ head = vq->packed.next_avail_idx;
+ desc = alloc_indirect_packed(total_sg, gfp);
+ if (!desc)
+ return -ENOMEM;
+
+ if (unlikely(vq->vq.num_free < 1)) {
+ pr_debug("Can't add buf len 1 - avail = 0\n");
+ kfree(desc);
+ END_USE(vq);
+ return -ENOSPC;
+ }
+
+ i = 0;
+ id = vq->free_head;
+ BUG_ON(id == vq->packed.vring.num);
+
+ for (n = 0; n < out_sgs + in_sgs; n++) {
+ for (sg = sgs[n]; sg; sg = sg_next(sg)) {
+ 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;
+
+ desc[i].flags = cpu_to_le16(n < out_sgs ?
+ 0 : VRING_DESC_F_WRITE);
+ desc[i].addr = cpu_to_le64(addr);
+ desc[i].len = cpu_to_le32(sg->length);
+ i++;
+ }
+ }
+
+ /* Now that the indirect table is filled in, map it. */
+ 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;
+
+ vq->packed.vring.desc[head].addr = cpu_to_le64(addr);
+ vq->packed.vring.desc[head].len = cpu_to_le32(total_sg *
+ sizeof(struct vring_packed_desc));
+ vq->packed.vring.desc[head].id = cpu_to_le16(id);
+
+ if (vq->use_dma_api) {
+ vq->packed.desc_extra[id].addr = addr;
+ vq->packed.desc_extra[id].len = total_sg *
+ sizeof(struct vring_packed_desc);
+ vq->packed.desc_extra[id].flags = VRING_DESC_F_INDIRECT |
+ vq->packed.avail_used_flags;
+ }
+
+ /*
+ * 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->packed.vring.desc[head].flags = cpu_to_le16(VRING_DESC_F_INDIRECT |
+ vq->packed.avail_used_flags);
+
+ /* We're using some buffers from the free list. */
+ vq->vq.num_free -= 1;
+
+ /* Update free pointer */
+ n = head + 1;
+ if (n >= vq->packed.vring.num) {
+ n = 0;
+ vq->packed.avail_wrap_counter ^= 1;
+ vq->packed.avail_used_flags ^=
+ 1 << VRING_PACKED_DESC_F_AVAIL |
+ 1 << VRING_PACKED_DESC_F_USED;
+ }
+ vq->packed.next_avail_idx = n;
+ vq->free_head = vq->packed.desc_extra[id].next;
+
+ /* Store token and indirect buffer state. */
+ vq->packed.desc_state[id].num = 1;
+ vq->packed.desc_state[id].data = data;
+ vq->packed.desc_state[id].indir_desc = desc;
+ vq->packed.desc_state[id].last = id;
+
+ vq->num_added += 1;
+
+ pr_debug("Added buffer head %i to %p\n", head, vq);
+ END_USE(vq);
+
+ return 0;
+
+unmap_release:
+ err_idx = i;
+
+ for (i = 0; i < err_idx; i++)
+ vring_unmap_desc_packed(vq, &desc[i]);
+
+ kfree(desc);
+
+ END_USE(vq);
+ return -ENOMEM;
+}
+
+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, c, descs_used, err_idx;
+ __le16 head_flags, flags;
+ u16 head, id, prev, curr, avail_used_flags;
+ int err;
+
+ START_USE(vq);
+
+ BUG_ON(data == NULL);
+ BUG_ON(ctx && vq->indirect);
+
+ if (unlikely(vq->broken)) {
+ END_USE(vq);
+ return -EIO;
+ }
+
+ LAST_ADD_TIME_UPDATE(vq);
+
+ BUG_ON(total_sg == 0);
+
+ if (virtqueue_use_indirect(vq, total_sg)) {
+ err = virtqueue_add_indirect_packed(vq, sgs, total_sg, out_sgs,
+ in_sgs, data, gfp);
+ if (err != -ENOMEM) {
+ END_USE(vq);
+ return err;
+ }
+
+ /* fall back on direct */
+ }
+
+ head = vq->packed.next_avail_idx;
+ avail_used_flags = vq->packed.avail_used_flags;
+
+ WARN_ON_ONCE(total_sg > vq->packed.vring.num && !vq->indirect);
+
+ desc = vq->packed.vring.desc;
+ i = head;
+ descs_used = total_sg;
+
+ if (unlikely(vq->vq.num_free < descs_used)) {
+ pr_debug("Can't add buf len %i - avail = %i\n",
+ descs_used, vq->vq.num_free);
+ END_USE(vq);
+ return -ENOSPC;
+ }
+
+ id = vq->free_head;
+ BUG_ON(id == vq->packed.vring.num);
+
+ curr = id;
+ c = 0;
+ 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_le16(vq->packed.avail_used_flags |
+ (++c == total_sg ? 0 : VRING_DESC_F_NEXT) |
+ (n < out_sgs ? 0 : VRING_DESC_F_WRITE));
+ if (i == head)
+ head_flags = flags;
+ else
+ desc[i].flags = flags;
+
+ desc[i].addr = cpu_to_le64(addr);
+ desc[i].len = cpu_to_le32(sg->length);
+ desc[i].id = cpu_to_le16(id);
+
+ if (unlikely(vq->use_dma_api)) {
+ vq->packed.desc_extra[curr].addr = addr;
+ vq->packed.desc_extra[curr].len = sg->length;
+ vq->packed.desc_extra[curr].flags =
+ le16_to_cpu(flags);
+ }
+ prev = curr;
+ curr = vq->packed.desc_extra[curr].next;
+
+ if ((unlikely(++i >= vq->packed.vring.num))) {
+ i = 0;
+ vq->packed.avail_used_flags ^=
+ 1 << VRING_PACKED_DESC_F_AVAIL |
+ 1 << VRING_PACKED_DESC_F_USED;
+ }
+ }
+ }
+
+ if (i <= head)
+ vq->packed.avail_wrap_counter ^= 1;
+
+ /* We're using some buffers from the free list. */
+ vq->vq.num_free -= descs_used;
+
+ /* Update free pointer */
+ vq->packed.next_avail_idx = i;
+ vq->free_head = curr;
+
+ /* Store token. */
+ vq->packed.desc_state[id].num = descs_used;
+ vq->packed.desc_state[id].data = data;
+ vq->packed.desc_state[id].indir_desc = ctx;
+ vq->packed.desc_state[id].last = prev;
+
+ /*
+ * 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->packed.vring.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;
+ curr = vq->free_head;
+
+ vq->packed.avail_used_flags = avail_used_flags;
+
+ for (n = 0; n < total_sg; n++) {
+ if (i == err_idx)
+ break;
+ vring_unmap_extra_packed(vq, &vq->packed.desc_extra[curr]);
+ curr = vq->packed.desc_extra[curr].next;
+ i++;
+ if (i >= vq->packed.vring.num)
+ i = 0;
+ }
+
+ END_USE(vq);
+ return -EIO;
+}
+
+static bool virtqueue_kick_prepare_packed(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+ u16 new, old, off_wrap, flags, wrap_counter, event_idx;
+ bool needs_kick;
+ union {
+ struct {
+ __le16 off_wrap;
+ __le16 flags;
+ };
+ u32 u32;
+ } snapshot;
+
+ START_USE(vq);
+
+ /*
+ * We need to expose the new flags value before checking notification
+ * suppressions.
+ */
+ virtio_mb(vq->weak_barriers);
+
+ old = vq->packed.next_avail_idx - vq->num_added;
+ new = vq->packed.next_avail_idx;
+ vq->num_added = 0;
+
+ snapshot.u32 = *(u32 *)vq->packed.vring.device;
+ flags = le16_to_cpu(snapshot.flags);
+
+ LAST_ADD_TIME_CHECK(vq);
+ LAST_ADD_TIME_INVALID(vq);
+
+ if (flags != VRING_PACKED_EVENT_FLAG_DESC) {
+ needs_kick = (flags != VRING_PACKED_EVENT_FLAG_DISABLE);
+ goto out;
+ }
+
+ off_wrap = le16_to_cpu(snapshot.off_wrap);
+
+ wrap_counter = off_wrap >> VRING_PACKED_EVENT_F_WRAP_CTR;
+ event_idx = off_wrap & ~(1 << VRING_PACKED_EVENT_F_WRAP_CTR);
+ if (wrap_counter != vq->packed.avail_wrap_counter)
+ event_idx -= vq->packed.vring.num;
+
+ needs_kick = vring_need_event(event_idx, new, old);
+out:
+ 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 i, curr;
+
+ state = &vq->packed.desc_state[id];
+
+ /* Clear data ptr. */
+ state->data = NULL;
+
+ vq->packed.desc_extra[state->last].next = vq->free_head;
+ vq->free_head = id;
+ vq->vq.num_free += state->num;
+
+ if (unlikely(vq->use_dma_api)) {
+ curr = id;
+ for (i = 0; i < state->num; i++) {
+ vring_unmap_extra_packed(vq,
+ &vq->packed.desc_extra[curr]);
+ curr = vq->packed.desc_extra[curr].next;
+ }
+ }
+
+ if (vq->indirect) {
+ u32 len;
+
+ /* Free the indirect table, if any, now that it's unmapped. */
+ desc = state->indir_desc;
+ if (!desc)
+ return;
+
+ if (vq->use_dma_api) {
+ len = vq->packed.desc_extra[id].len;
+ for (i = 0; i < len / sizeof(struct vring_packed_desc);
+ i++)
+ vring_unmap_desc_packed(vq, &desc[i]);
+ }
+ kfree(desc);
+ state->indir_desc = NULL;
+ } else if (ctx) {
+ *ctx = state->indir_desc;
+ }
+}
+
+static inline bool is_used_desc_packed(const struct vring_virtqueue *vq,
+ u16 idx, bool used_wrap_counter)
+{
+ bool avail, used;
+ u16 flags;
+
+ flags = le16_to_cpu(vq->packed.vring.desc[idx].flags);
+ avail = !!(flags & (1 << VRING_PACKED_DESC_F_AVAIL));
+ used = !!(flags & (1 << VRING_PACKED_DESC_F_USED));
+
+ return avail == used && used == used_wrap_counter;
+}
+
+static inline bool more_used_packed(const struct vring_virtqueue *vq)
+{
+ u16 last_used;
+ u16 last_used_idx;
+ bool used_wrap_counter;
+
+ last_used_idx = READ_ONCE(vq->last_used_idx);
+ last_used = packed_last_used(last_used_idx);
+ used_wrap_counter = packed_used_wrap_counter(last_used_idx);
+ return is_used_desc_packed(vq, last_used, used_wrap_counter);
+}
+
+static void *virtqueue_get_buf_ctx_packed(struct virtqueue *_vq,
+ unsigned int *len,
+ void **ctx)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+ u16 last_used, id, last_used_idx;
+ bool used_wrap_counter;
+ 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_idx = READ_ONCE(vq->last_used_idx);
+ used_wrap_counter = packed_used_wrap_counter(last_used_idx);
+ last_used = packed_last_used(last_used_idx);
+ id = le16_to_cpu(vq->packed.vring.desc[last_used].id);
+ *len = le32_to_cpu(vq->packed.vring.desc[last_used].len);
+
+ if (unlikely(id >= vq->packed.vring.num)) {
+ BAD_RING(vq, "id %u out of range\n", id);
+ return NULL;
+ }
+ if (unlikely(!vq->packed.desc_state[id].data)) {
+ BAD_RING(vq, "id %u is not a head!\n", id);
+ return NULL;
+ }
+
+ /* detach_buf_packed clears data, so grab it now. */
+ ret = vq->packed.desc_state[id].data;
+ detach_buf_packed(vq, id, ctx);
+
+ last_used += vq->packed.desc_state[id].num;
+ if (unlikely(last_used >= vq->packed.vring.num)) {
+ last_used -= vq->packed.vring.num;
+ used_wrap_counter ^= 1;
+ }
+
+ last_used = (last_used | (used_wrap_counter << VRING_PACKED_EVENT_F_WRAP_CTR));
+ WRITE_ONCE(vq->last_used_idx, last_used);
+
+ /*
+ * 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->packed.event_flags_shadow == VRING_PACKED_EVENT_FLAG_DESC)
+ virtio_store_mb(vq->weak_barriers,
+ &vq->packed.vring.driver->off_wrap,
+ cpu_to_le16(vq->last_used_idx));
+
+ LAST_ADD_TIME_INVALID(vq);
+
+ END_USE(vq);
+ return ret;
+}
+
+static void virtqueue_disable_cb_packed(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ if (vq->packed.event_flags_shadow != VRING_PACKED_EVENT_FLAG_DISABLE) {
+ vq->packed.event_flags_shadow = VRING_PACKED_EVENT_FLAG_DISABLE;
+
+ /*
+ * If device triggered an event already it won't trigger one again:
+ * no need to disable.
+ */
+ if (vq->event_triggered)
+ return;
+
+ vq->packed.vring.driver->flags =
+ cpu_to_le16(vq->packed.event_flags_shadow);
+ }
+}
+
+static unsigned int virtqueue_enable_cb_prepare_packed(struct virtqueue *_vq)
+{
+ 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) {
+ vq->packed.vring.driver->off_wrap =
+ cpu_to_le16(vq->last_used_idx);
+ /*
+ * We need to update event offset and event wrap
+ * counter first before updating event flags.
+ */
+ virtio_wmb(vq->weak_barriers);
+ }
+
+ if (vq->packed.event_flags_shadow == VRING_PACKED_EVENT_FLAG_DISABLE) {
+ vq->packed.event_flags_shadow = vq->event ?
+ VRING_PACKED_EVENT_FLAG_DESC :
+ VRING_PACKED_EVENT_FLAG_ENABLE;
+ vq->packed.vring.driver->flags =
+ cpu_to_le16(vq->packed.event_flags_shadow);
+ }
+
+ END_USE(vq);
+ return vq->last_used_idx;
+}
+
+static bool virtqueue_poll_packed(struct virtqueue *_vq, u16 off_wrap)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+ bool wrap_counter;
+ u16 used_idx;
+
+ wrap_counter = off_wrap >> VRING_PACKED_EVENT_F_WRAP_CTR;
+ used_idx = off_wrap & ~(1 << VRING_PACKED_EVENT_F_WRAP_CTR);
+
+ return is_used_desc_packed(vq, used_idx, wrap_counter);
+}
+
+static bool virtqueue_enable_cb_delayed_packed(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+ u16 used_idx, wrap_counter, last_used_idx;
+ u16 bufs;
+
+ START_USE(vq);
+
+ /*
+ * We optimistically turn back on interrupts, then check if there was
+ * more to do.
+ */
+
+ if (vq->event) {
+ /* TODO: tune this threshold */
+ bufs = (vq->packed.vring.num - vq->vq.num_free) * 3 / 4;
+ last_used_idx = READ_ONCE(vq->last_used_idx);
+ wrap_counter = packed_used_wrap_counter(last_used_idx);
+
+ used_idx = packed_last_used(last_used_idx) + bufs;
+ if (used_idx >= vq->packed.vring.num) {
+ used_idx -= vq->packed.vring.num;
+ wrap_counter ^= 1;
+ }
+
+ vq->packed.vring.driver->off_wrap = cpu_to_le16(used_idx |
+ (wrap_counter << VRING_PACKED_EVENT_F_WRAP_CTR));
+
+ /*
+ * We need to update event offset and event wrap
+ * counter first before updating event flags.
+ */
+ virtio_wmb(vq->weak_barriers);
+ }
+
+ if (vq->packed.event_flags_shadow == VRING_PACKED_EVENT_FLAG_DISABLE) {
+ vq->packed.event_flags_shadow = vq->event ?
+ VRING_PACKED_EVENT_FLAG_DESC :
+ VRING_PACKED_EVENT_FLAG_ENABLE;
+ vq->packed.vring.driver->flags =
+ cpu_to_le16(vq->packed.event_flags_shadow);
+ }
+
+ /*
+ * We need to update event suppression structure first
+ * before re-checking for more used buffers.
+ */
+ virtio_mb(vq->weak_barriers);
+
+ last_used_idx = READ_ONCE(vq->last_used_idx);
+ wrap_counter = packed_used_wrap_counter(last_used_idx);
+ used_idx = packed_last_used(last_used_idx);
+ if (is_used_desc_packed(vq, used_idx, wrap_counter)) {
+ 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->packed.vring.num; i++) {
+ if (!vq->packed.desc_state[i].data)
+ continue;
+ /* detach_buf clears data, so grab it now. */
+ buf = vq->packed.desc_state[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->packed.vring.num);
+
+ END_USE(vq);
+ return NULL;
+}
+
+static struct vring_desc_extra *vring_alloc_desc_extra(unsigned int num)
+{
+ struct vring_desc_extra *desc_extra;
+ unsigned int i;
+
+ desc_extra = kmalloc_array(num, sizeof(struct vring_desc_extra),
+ GFP_KERNEL);
+ if (!desc_extra)
+ return NULL;
+
+ memset(desc_extra, 0, num * sizeof(struct vring_desc_extra));
+
+ for (i = 0; i < num - 1; i++)
+ desc_extra[i].next = i + 1;
+
+ return desc_extra;
+}
+
+static void vring_free_packed(struct vring_virtqueue_packed *vring_packed,
+ struct virtio_device *vdev)
+{
+ if (vring_packed->vring.desc)
+ vring_free_queue(vdev, vring_packed->ring_size_in_bytes,
+ vring_packed->vring.desc,
+ vring_packed->ring_dma_addr);
+
+ if (vring_packed->vring.driver)
+ vring_free_queue(vdev, vring_packed->event_size_in_bytes,
+ vring_packed->vring.driver,
+ vring_packed->driver_event_dma_addr);
+
+ if (vring_packed->vring.device)
+ vring_free_queue(vdev, vring_packed->event_size_in_bytes,
+ vring_packed->vring.device,
+ vring_packed->device_event_dma_addr);
+
+ kfree(vring_packed->desc_state);
+ kfree(vring_packed->desc_extra);
+}
+
+static int vring_alloc_queue_packed(struct vring_virtqueue_packed *vring_packed,
+ struct virtio_device *vdev,
+ u32 num)
+{
+ struct vring_packed_desc *ring;
+ struct vring_packed_desc_event *driver, *device;
+ dma_addr_t ring_dma_addr, driver_event_dma_addr, device_event_dma_addr;
+ size_t ring_size_in_bytes, event_size_in_bytes;
+
+ ring_size_in_bytes = num * sizeof(struct vring_packed_desc);
+
+ ring = vring_alloc_queue(vdev, ring_size_in_bytes,
+ &ring_dma_addr,
+ GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO);
+ if (!ring)
+ goto err;
+
+ vring_packed->vring.desc = ring;
+ vring_packed->ring_dma_addr = ring_dma_addr;
+ vring_packed->ring_size_in_bytes = ring_size_in_bytes;
+
+ event_size_in_bytes = sizeof(struct vring_packed_desc_event);
+
+ driver = vring_alloc_queue(vdev, event_size_in_bytes,
+ &driver_event_dma_addr,
+ GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO);
+ if (!driver)
+ goto err;
+
+ vring_packed->vring.driver = driver;
+ vring_packed->event_size_in_bytes = event_size_in_bytes;
+ vring_packed->driver_event_dma_addr = driver_event_dma_addr;
+
+ device = vring_alloc_queue(vdev, event_size_in_bytes,
+ &device_event_dma_addr,
+ GFP_KERNEL | __GFP_NOWARN | __GFP_ZERO);
+ if (!device)
+ goto err;
+
+ vring_packed->vring.device = device;
+ vring_packed->device_event_dma_addr = device_event_dma_addr;
+
+ vring_packed->vring.num = num;
+
+ return 0;
+
+err:
+ vring_free_packed(vring_packed, vdev);
+ return -ENOMEM;
+}
+
+static int vring_alloc_state_extra_packed(struct vring_virtqueue_packed *vring_packed)
+{
+ struct vring_desc_state_packed *state;
+ struct vring_desc_extra *extra;
+ u32 num = vring_packed->vring.num;
+
+ state = kmalloc_array(num, sizeof(struct vring_desc_state_packed), GFP_KERNEL);
+ if (!state)
+ goto err_desc_state;
+
+ memset(state, 0, num * sizeof(struct vring_desc_state_packed));
+
+ extra = vring_alloc_desc_extra(num);
+ if (!extra)
+ goto err_desc_extra;
+
+ vring_packed->desc_state = state;
+ vring_packed->desc_extra = extra;
+
+ return 0;
+
+err_desc_extra:
+ kfree(state);
+err_desc_state:
+ return -ENOMEM;
+}
+
+static void virtqueue_vring_init_packed(struct vring_virtqueue_packed *vring_packed,
+ bool callback)
+{
+ vring_packed->next_avail_idx = 0;
+ vring_packed->avail_wrap_counter = 1;
+ vring_packed->event_flags_shadow = 0;
+ vring_packed->avail_used_flags = 1 << VRING_PACKED_DESC_F_AVAIL;
+
+ /* No callback? Tell other side not to bother us. */
+ if (!callback) {
+ vring_packed->event_flags_shadow = VRING_PACKED_EVENT_FLAG_DISABLE;
+ vring_packed->vring.driver->flags =
+ cpu_to_le16(vring_packed->event_flags_shadow);
+ }
+}
+
+static void virtqueue_vring_attach_packed(struct vring_virtqueue *vq,
+ struct vring_virtqueue_packed *vring_packed)
+{
+ vq->packed = *vring_packed;
+
+ /* Put everything in free lists. */
+ vq->free_head = 0;
+}
+
+static void virtqueue_reinit_packed(struct vring_virtqueue *vq)
+{
+ memset(vq->packed.vring.device, 0, vq->packed.event_size_in_bytes);
+ memset(vq->packed.vring.driver, 0, vq->packed.event_size_in_bytes);
+
+ /* we need to reset the desc.flags. For more, see is_used_desc_packed() */
+ memset(vq->packed.vring.desc, 0, vq->packed.ring_size_in_bytes);
+
+ virtqueue_init(vq, vq->packed.vring.num);
+ virtqueue_vring_init_packed(&vq->packed, !!vq->vq.callback);
+}
+
+static struct virtqueue *vring_create_virtqueue_packed(
+ unsigned int index,
+ unsigned int num,
+ unsigned int vring_align,
+ struct virtio_device *vdev,
+ bool weak_barriers,
+ bool may_reduce_num,
+ bool context,
+ bool (*notify)(struct virtqueue *),
+ void (*callback)(struct virtqueue *),
+ const char *name)
+{
+ struct vring_virtqueue_packed vring_packed = {};
+ struct vring_virtqueue *vq;
+ int err;
+
+ if (vring_alloc_queue_packed(&vring_packed, vdev, num))
+ goto err_ring;
+
+ vq = kmalloc(sizeof(*vq), GFP_KERNEL);
+ if (!vq)
+ goto err_vq;
+
+ vq->vq.callback = callback;
+ vq->vq.vdev = vdev;
+ vq->vq.name = name;
+ vq->vq.index = index;
+ vq->vq.reset = false;
+ vq->we_own_ring = true;
+ vq->notify = notify;
+ vq->weak_barriers = weak_barriers;
+#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION
+ vq->broken = true;
+#else
+ vq->broken = false;
+#endif
+ vq->packed_ring = true;
+ vq->use_dma_api = vring_use_dma_api(vdev);
+
+ vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) &&
+ !context;
+ vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
+
+ if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
+ vq->weak_barriers = false;
+
+ err = vring_alloc_state_extra_packed(&vring_packed);
+ if (err)
+ goto err_state_extra;
+
+ virtqueue_vring_init_packed(&vring_packed, !!callback);
+
+ virtqueue_init(vq, num);
+ virtqueue_vring_attach_packed(vq, &vring_packed);
+
+ spin_lock(&vdev->vqs_list_lock);
+ list_add_tail(&vq->vq.list, &vdev->vqs);
+ spin_unlock(&vdev->vqs_list_lock);
+ return &vq->vq;
+
+err_state_extra:
+ kfree(vq);
+err_vq:
+ vring_free_packed(&vring_packed, vdev);
+err_ring:
+ return NULL;
+}
+
+static int virtqueue_resize_packed(struct virtqueue *_vq, u32 num)
+{
+ struct vring_virtqueue_packed vring_packed = {};
+ struct vring_virtqueue *vq = to_vvq(_vq);
+ struct virtio_device *vdev = _vq->vdev;
+ int err;
+
+ if (vring_alloc_queue_packed(&vring_packed, vdev, num))
+ goto err_ring;
+
+ err = vring_alloc_state_extra_packed(&vring_packed);
+ if (err)
+ goto err_state_extra;
+
+ vring_free(&vq->vq);
+
+ virtqueue_vring_init_packed(&vring_packed, !!vq->vq.callback);
+
+ virtqueue_init(vq, vring_packed.vring.num);
+ virtqueue_vring_attach_packed(vq, &vring_packed);
+
+ return 0;
+
+err_state_extra:
+ vring_free_packed(&vring_packed, vdev);
+err_ring:
+ virtqueue_reinit_packed(vq);
+ return -ENOMEM;
+}
+
+
+/*
+ * Generic functions and exported symbols.
+ */
+
+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_ring ? 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.
+ * @sgs: array of terminated scatterlists.
+ * @out_sgs: the number of scatterlists readable by other side
+ * @in_sgs: the number of scatterlists which are writable (after readable ones)
+ * @data: the token identifying the buffer.
+ * @gfp: how to do memory allocations (if necessary).
+ *
+ * Caller must ensure we don't call this with other virtqueue operations
+ * at the same time (except where noted).
+ *
+ * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
+ */
+int virtqueue_add_sgs(struct virtqueue *_vq,
+ struct scatterlist *sgs[],
+ unsigned int out_sgs,
+ unsigned int in_sgs,
+ void *data,
+ gfp_t gfp)
+{
+ unsigned int i, total_sg = 0;
+
+ /* Count them first. */
+ for (i = 0; i < out_sgs + in_sgs; i++) {
+ struct scatterlist *sg;
+
+ for (sg = sgs[i]; sg; sg = sg_next(sg))
+ total_sg++;
+ }
+ return virtqueue_add(_vq, sgs, total_sg, out_sgs, in_sgs,
+ data, NULL, gfp);
+}
+EXPORT_SYMBOL_GPL(virtqueue_add_sgs);
+
+/**
+ * virtqueue_add_outbuf - expose output buffers to other end
+ * @vq: the struct virtqueue we're talking about.
+ * @sg: scatterlist (must be well-formed and terminated!)
+ * @num: the number of entries in @sg readable by other side
+ * @data: the token identifying the buffer.
+ * @gfp: how to do memory allocations (if necessary).
+ *
+ * Caller must ensure we don't call this with other virtqueue operations
+ * at the same time (except where noted).
+ *
+ * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
+ */
+int virtqueue_add_outbuf(struct virtqueue *vq,
+ struct scatterlist *sg, unsigned int num,
+ void *data,
+ gfp_t gfp)
+{
+ return virtqueue_add(vq, &sg, num, 1, 0, data, NULL, gfp);
+}
+EXPORT_SYMBOL_GPL(virtqueue_add_outbuf);
+
+/**
+ * virtqueue_add_inbuf - expose input buffers to other end
+ * @vq: the struct virtqueue we're talking about.
+ * @sg: scatterlist (must be well-formed and terminated!)
+ * @num: the number of entries in @sg writable by other side
+ * @data: the token identifying the buffer.
+ * @gfp: how to do memory allocations (if necessary).
+ *
+ * Caller must ensure we don't call this with other virtqueue operations
+ * at the same time (except where noted).
+ *
+ * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
+ */
+int virtqueue_add_inbuf(struct virtqueue *vq,
+ struct scatterlist *sg, unsigned int num,
+ void *data,
+ gfp_t gfp)
+{
+ return virtqueue_add(vq, &sg, num, 0, 1, data, NULL, gfp);
+}
+EXPORT_SYMBOL_GPL(virtqueue_add_inbuf);
+
+/**
+ * virtqueue_add_inbuf_ctx - expose input buffers to other end
+ * @vq: the struct virtqueue we're talking about.
+ * @sg: scatterlist (must be well-formed and terminated!)
+ * @num: the number of entries in @sg writable by other side
+ * @data: the token identifying the buffer.
+ * @ctx: extra context for the token
+ * @gfp: how to do memory allocations (if necessary).
+ *
+ * Caller must ensure we don't call this with other virtqueue operations
+ * at the same time (except where noted).
+ *
+ * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
+ */
+int virtqueue_add_inbuf_ctx(struct virtqueue *vq,
+ struct scatterlist *sg, unsigned int num,
+ void *data,
+ void *ctx,
+ gfp_t gfp)
+{
+ return virtqueue_add(vq, &sg, num, 0, 1, data, ctx, gfp);
+}
+EXPORT_SYMBOL_GPL(virtqueue_add_inbuf_ctx);
+
+/**
+ * virtqueue_kick_prepare - first half of split virtqueue_kick call.
+ * @_vq: the struct virtqueue
+ *
+ * Instead of virtqueue_kick(), you can do:
+ * if (virtqueue_kick_prepare(vq))
+ * virtqueue_notify(vq);
+ *
+ * This is sometimes useful because the virtqueue_kick_prepare() needs
+ * to be serialized, but the actual virtqueue_notify() call does not.
+ */
+bool virtqueue_kick_prepare(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ return vq->packed_ring ? virtqueue_kick_prepare_packed(_vq) :
+ virtqueue_kick_prepare_split(_vq);
+}
+EXPORT_SYMBOL_GPL(virtqueue_kick_prepare);
+
+/**
+ * virtqueue_notify - second half of split virtqueue_kick call.
+ * @_vq: the struct virtqueue
+ *
+ * This does not need to be serialized.
+ *
+ * Returns false if host notify failed or queue is broken, otherwise true.
+ */
+bool virtqueue_notify(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ if (unlikely(vq->broken))
+ return false;
+
+ /* Prod other side to tell it about changes. */
+ if (!vq->notify(_vq)) {
+ vq->broken = true;
+ return false;
+ }
+ return true;
+}
+EXPORT_SYMBOL_GPL(virtqueue_notify);
+
+/**
+ * virtqueue_kick - update after add_buf
+ * @vq: the struct virtqueue
+ *
+ * After one or more virtqueue_add_* calls, invoke this to kick
+ * the other side.
+ *
+ * Caller must ensure we don't call this with other virtqueue
+ * operations at the same time (except where noted).
+ *
+ * Returns false if kick failed, otherwise true.
+ */
+bool virtqueue_kick(struct virtqueue *vq)
+{
+ if (virtqueue_kick_prepare(vq))
+ return virtqueue_notify(vq);
+ return true;
+}
+EXPORT_SYMBOL_GPL(virtqueue_kick);
+
+/**
+ * virtqueue_get_buf_ctx - get the next used buffer
+ * @_vq: the struct virtqueue we're talking about.
+ * @len: the length written into the buffer
+ * @ctx: extra context for the token
+ *
+ * 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_ring ? 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)
+{
+ return virtqueue_get_buf_ctx(_vq, len, NULL);
+}
+EXPORT_SYMBOL_GPL(virtqueue_get_buf);
+/**
+ * virtqueue_disable_cb - disable callbacks
+ * @_vq: the struct virtqueue we're talking about.
+ *
+ * Note that this is not necessarily synchronous, hence unreliable and only
+ * useful as an optimization.
+ *
+ * Unlike other operations, this need not be serialized.
+ */
+void virtqueue_disable_cb(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ if (vq->packed_ring)
+ virtqueue_disable_cb_packed(_vq);
+ else
+ virtqueue_disable_cb_split(_vq);
+}
+EXPORT_SYMBOL_GPL(virtqueue_disable_cb);
+
+/**
+ * virtqueue_enable_cb_prepare - restart callbacks after disable_cb
+ * @_vq: the struct virtqueue we're talking about.
+ *
+ * This re-enables callbacks; it returns current queue state
+ * in an opaque unsigned value. This value should be later tested by
+ * virtqueue_poll, to detect a possible race between the driver checking for
+ * more work, and enabling callbacks.
+ *
+ * Caller must ensure we don't call this with other virtqueue
+ * operations at the same time (except where noted).
+ */
+unsigned int virtqueue_enable_cb_prepare(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ if (vq->event_triggered)
+ vq->event_triggered = false;
+
+ return vq->packed_ring ? virtqueue_enable_cb_prepare_packed(_vq) :
+ virtqueue_enable_cb_prepare_split(_vq);
+}
+EXPORT_SYMBOL_GPL(virtqueue_enable_cb_prepare);
+
+/**
+ * virtqueue_poll - query pending used buffers
+ * @_vq: the struct virtqueue we're talking about.
+ * @last_used_idx: virtqueue state (from call to virtqueue_enable_cb_prepare).
+ *
+ * Returns "true" if there are pending used buffers in the queue.
+ *
+ * This does not need to be serialized.
+ */
+bool virtqueue_poll(struct virtqueue *_vq, unsigned int last_used_idx)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ if (unlikely(vq->broken))
+ return false;
+
+ virtio_mb(vq->weak_barriers);
+ return vq->packed_ring ? virtqueue_poll_packed(_vq, last_used_idx) :
+ virtqueue_poll_split(_vq, last_used_idx);
+}
+EXPORT_SYMBOL_GPL(virtqueue_poll);
+
+/**
+ * virtqueue_enable_cb - restart callbacks after disable_cb.
+ * @_vq: the struct virtqueue we're talking about.
+ *
+ * This re-enables callbacks; it returns "false" if there are pending
+ * buffers in the queue, to detect a possible race between the driver
+ * checking for more work, and enabling callbacks.
+ *
+ * Caller must ensure we don't call this with other virtqueue
+ * operations at the same time (except where noted).
+ */
+bool virtqueue_enable_cb(struct virtqueue *_vq)
+{
+ unsigned int last_used_idx = virtqueue_enable_cb_prepare(_vq);
+
+ return !virtqueue_poll(_vq, last_used_idx);
+}
+EXPORT_SYMBOL_GPL(virtqueue_enable_cb);
+
+/**
+ * virtqueue_enable_cb_delayed - restart callbacks after disable_cb.
+ * @_vq: the struct virtqueue we're talking about.
+ *
+ * This re-enables callbacks but hints to the other side to delay
+ * interrupts until most of the available buffers have been processed;
+ * it returns "false" if there are many pending buffers in the queue,
+ * to detect a possible race between the driver checking for more work,
+ * and enabling callbacks.
+ *
+ * Caller must ensure we don't call this with other virtqueue
+ * operations at the same time (except where noted).
+ */
+bool virtqueue_enable_cb_delayed(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ if (vq->event_triggered)
+ vq->event_triggered = false;
+
+ return vq->packed_ring ? virtqueue_enable_cb_delayed_packed(_vq) :
+ virtqueue_enable_cb_delayed_split(_vq);
+}
+EXPORT_SYMBOL_GPL(virtqueue_enable_cb_delayed);
+
+/**
+ * virtqueue_detach_unused_buf - detach first unused buffer
+ * @_vq: the struct virtqueue we're talking about.
+ *
+ * Returns NULL or the "data" token handed to virtqueue_add_*().
+ * This is not valid on an active queue; it is useful for device
+ * shutdown or the reset queue.
+ */
+void *virtqueue_detach_unused_buf(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ return vq->packed_ring ? virtqueue_detach_unused_buf_packed(_vq) :
+ virtqueue_detach_unused_buf_split(_vq);
+}
+EXPORT_SYMBOL_GPL(virtqueue_detach_unused_buf);
+
+static inline bool more_used(const struct vring_virtqueue *vq)
+{
+ return vq->packed_ring ? more_used_packed(vq) : more_used_split(vq);
+}
+
+/**
+ * vring_interrupt - notify a virtqueue on an interrupt
+ * @irq: the IRQ number (ignored)
+ * @_vq: the struct virtqueue to notify
+ *
+ * Calls the callback function of @_vq to process the virtqueue
+ * notification.
+ */
+irqreturn_t vring_interrupt(int irq, void *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ if (!more_used(vq)) {
+ pr_debug("virtqueue interrupt with no work for %p\n", vq);
+ return IRQ_NONE;
+ }
+
+ if (unlikely(vq->broken)) {
+#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION
+ dev_warn_once(&vq->vq.vdev->dev,
+ "virtio vring IRQ raised before DRIVER_OK");
+ return IRQ_NONE;
+#else
+ return IRQ_HANDLED;
+#endif
+ }
+
+ /* Just a hint for performance: so it's ok that this can be racy! */
+ if (vq->event)
+ vq->event_triggered = true;
+
+ pr_debug("virtqueue callback for %p (%p)\n", vq, vq->vq.callback);
+ if (vq->vq.callback)
+ vq->vq.callback(&vq->vq);
+
+ return IRQ_HANDLED;
+}
+EXPORT_SYMBOL_GPL(vring_interrupt);
+
+/* Only available for split ring */
+static struct virtqueue *__vring_new_virtqueue(unsigned int index,
+ struct vring_virtqueue_split *vring_split,
+ struct virtio_device *vdev,
+ bool weak_barriers,
+ bool context,
+ bool (*notify)(struct virtqueue *),
+ void (*callback)(struct virtqueue *),
+ const char *name)
+{
+ struct vring_virtqueue *vq;
+ int err;
+
+ if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED))
+ return NULL;
+
+ vq = kmalloc(sizeof(*vq), GFP_KERNEL);
+ if (!vq)
+ return NULL;
+
+ vq->packed_ring = false;
+ vq->vq.callback = callback;
+ vq->vq.vdev = vdev;
+ vq->vq.name = name;
+ vq->vq.index = index;
+ vq->vq.reset = false;
+ vq->we_own_ring = false;
+ vq->notify = notify;
+ vq->weak_barriers = weak_barriers;
+#ifdef CONFIG_VIRTIO_HARDEN_NOTIFICATION
+ vq->broken = true;
+#else
+ vq->broken = false;
+#endif
+ vq->use_dma_api = vring_use_dma_api(vdev);
+
+ vq->indirect = virtio_has_feature(vdev, VIRTIO_RING_F_INDIRECT_DESC) &&
+ !context;
+ vq->event = virtio_has_feature(vdev, VIRTIO_RING_F_EVENT_IDX);
+
+ if (virtio_has_feature(vdev, VIRTIO_F_ORDER_PLATFORM))
+ vq->weak_barriers = false;
+
+ err = vring_alloc_state_extra_split(vring_split);
+ if (err) {
+ kfree(vq);
+ return NULL;
+ }
+
+ virtqueue_vring_init_split(vring_split, vq);
+
+ virtqueue_init(vq, vring_split->vring.num);
+ virtqueue_vring_attach_split(vq, vring_split);
+
+ spin_lock(&vdev->vqs_list_lock);
+ list_add_tail(&vq->vq.list, &vdev->vqs);
+ spin_unlock(&vdev->vqs_list_lock);
+ return &vq->vq;
+}
+
+struct virtqueue *vring_create_virtqueue(
+ unsigned int index,
+ unsigned int num,
+ unsigned int vring_align,
+ struct virtio_device *vdev,
+ bool weak_barriers,
+ bool may_reduce_num,
+ bool context,
+ bool (*notify)(struct virtqueue *),
+ void (*callback)(struct virtqueue *),
+ const char *name)
+{
+
+ if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED))
+ return vring_create_virtqueue_packed(index, num, vring_align,
+ vdev, weak_barriers, may_reduce_num,
+ context, notify, callback, name);
+
+ return vring_create_virtqueue_split(index, num, vring_align,
+ vdev, weak_barriers, may_reduce_num,
+ context, notify, callback, name);
+}
+EXPORT_SYMBOL_GPL(vring_create_virtqueue);
+
+/**
+ * virtqueue_resize - resize the vring of vq
+ * @_vq: the struct virtqueue we're talking about.
+ * @num: new ring num
+ * @recycle: callback for recycle the useless buffer
+ *
+ * When it is really necessary to create a new vring, it will set the current vq
+ * into the reset state. Then call the passed callback to recycle the buffer
+ * that is no longer used. Only after the new vring is successfully created, the
+ * old vring will be released.
+ *
+ * Caller must ensure we don't call this with other virtqueue operations
+ * at the same time (except where noted).
+ *
+ * Returns zero or a negative error.
+ * 0: success.
+ * -ENOMEM: Failed to allocate a new ring, fall back to the original ring size.
+ * vq can still work normally
+ * -EBUSY: Failed to sync with device, vq may not work properly
+ * -ENOENT: Transport or device not supported
+ * -E2BIG/-EINVAL: num error
+ * -EPERM: Operation not permitted
+ *
+ */
+int virtqueue_resize(struct virtqueue *_vq, u32 num,
+ void (*recycle)(struct virtqueue *vq, void *buf))
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+ struct virtio_device *vdev = vq->vq.vdev;
+ void *buf;
+ int err;
+
+ if (!vq->we_own_ring)
+ return -EPERM;
+
+ if (num > vq->vq.num_max)
+ return -E2BIG;
+
+ if (!num)
+ return -EINVAL;
+
+ if ((vq->packed_ring ? vq->packed.vring.num : vq->split.vring.num) == num)
+ return 0;
+
+ if (!vdev->config->disable_vq_and_reset)
+ return -ENOENT;
+
+ if (!vdev->config->enable_vq_after_reset)
+ return -ENOENT;
+
+ err = vdev->config->disable_vq_and_reset(_vq);
+ if (err)
+ return err;
+
+ while ((buf = virtqueue_detach_unused_buf(_vq)) != NULL)
+ recycle(_vq, buf);
+
+ if (vq->packed_ring)
+ err = virtqueue_resize_packed(_vq, num);
+ else
+ err = virtqueue_resize_split(_vq, num);
+
+ if (vdev->config->enable_vq_after_reset(_vq))
+ return -EBUSY;
+
+ return err;
+}
+EXPORT_SYMBOL_GPL(virtqueue_resize);
+
+/* Only available for split ring */
+struct virtqueue *vring_new_virtqueue(unsigned int index,
+ unsigned int num,
+ unsigned int vring_align,
+ struct virtio_device *vdev,
+ bool weak_barriers,
+ bool context,
+ void *pages,
+ bool (*notify)(struct virtqueue *vq),
+ void (*callback)(struct virtqueue *vq),
+ const char *name)
+{
+ struct vring_virtqueue_split vring_split = {};
+
+ if (virtio_has_feature(vdev, VIRTIO_F_RING_PACKED))
+ return NULL;
+
+ vring_init(&vring_split.vring, num, pages, vring_align);
+ return __vring_new_virtqueue(index, &vring_split, vdev, weak_barriers,
+ context, notify, callback, name);
+}
+EXPORT_SYMBOL_GPL(vring_new_virtqueue);
+
+static void vring_free(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ if (vq->we_own_ring) {
+ if (vq->packed_ring) {
+ vring_free_queue(vq->vq.vdev,
+ vq->packed.ring_size_in_bytes,
+ vq->packed.vring.desc,
+ vq->packed.ring_dma_addr);
+
+ vring_free_queue(vq->vq.vdev,
+ vq->packed.event_size_in_bytes,
+ vq->packed.vring.driver,
+ vq->packed.driver_event_dma_addr);
+
+ vring_free_queue(vq->vq.vdev,
+ vq->packed.event_size_in_bytes,
+ vq->packed.vring.device,
+ vq->packed.device_event_dma_addr);
+
+ kfree(vq->packed.desc_state);
+ kfree(vq->packed.desc_extra);
+ } else {
+ vring_free_queue(vq->vq.vdev,
+ vq->split.queue_size_in_bytes,
+ vq->split.vring.desc,
+ vq->split.queue_dma_addr);
+ }
+ }
+ if (!vq->packed_ring) {
+ kfree(vq->split.desc_state);
+ kfree(vq->split.desc_extra);
+ }
+}
+
+void vring_del_virtqueue(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ spin_lock(&vq->vq.vdev->vqs_list_lock);
+ list_del(&_vq->list);
+ spin_unlock(&vq->vq.vdev->vqs_list_lock);
+
+ vring_free(_vq);
+
+ kfree(vq);
+}
+EXPORT_SYMBOL_GPL(vring_del_virtqueue);
+
+/* Manipulates transport-specific feature bits. */
+void vring_transport_features(struct virtio_device *vdev)
+{
+ unsigned int i;
+
+ for (i = VIRTIO_TRANSPORT_F_START; i < VIRTIO_TRANSPORT_F_END; i++) {
+ switch (i) {
+ case VIRTIO_RING_F_INDIRECT_DESC:
+ break;
+ case VIRTIO_RING_F_EVENT_IDX:
+ break;
+ case VIRTIO_F_VERSION_1:
+ break;
+ case VIRTIO_F_ACCESS_PLATFORM:
+ break;
+ case VIRTIO_F_RING_PACKED:
+ break;
+ case VIRTIO_F_ORDER_PLATFORM:
+ break;
+ default:
+ /* We don't understand this bit. */
+ __virtio_clear_bit(vdev, i);
+ }
+ }
+}
+EXPORT_SYMBOL_GPL(vring_transport_features);
+
+/**
+ * virtqueue_get_vring_size - return the size of the virtqueue's vring
+ * @_vq: the struct virtqueue containing the vring of interest.
+ *
+ * Returns the size of the vring. This is mainly used for boasting to
+ * userspace. Unlike other operations, this need not be serialized.
+ */
+unsigned int virtqueue_get_vring_size(struct virtqueue *_vq)
+{
+
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ return vq->packed_ring ? vq->packed.vring.num : vq->split.vring.num;
+}
+EXPORT_SYMBOL_GPL(virtqueue_get_vring_size);
+
+/*
+ * This function should only be called by the core, not directly by the driver.
+ */
+void __virtqueue_break(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ /* Pairs with READ_ONCE() in virtqueue_is_broken(). */
+ WRITE_ONCE(vq->broken, true);
+}
+EXPORT_SYMBOL_GPL(__virtqueue_break);
+
+/*
+ * This function should only be called by the core, not directly by the driver.
+ */
+void __virtqueue_unbreak(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ /* Pairs with READ_ONCE() in virtqueue_is_broken(). */
+ WRITE_ONCE(vq->broken, false);
+}
+EXPORT_SYMBOL_GPL(__virtqueue_unbreak);
+
+bool virtqueue_is_broken(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ return READ_ONCE(vq->broken);
+}
+EXPORT_SYMBOL_GPL(virtqueue_is_broken);
+
+/*
+ * This should prevent the device from being used, allowing drivers to
+ * recover. You may need to grab appropriate locks to flush.
+ */
+void virtio_break_device(struct virtio_device *dev)
+{
+ struct virtqueue *_vq;
+
+ spin_lock(&dev->vqs_list_lock);
+ list_for_each_entry(_vq, &dev->vqs, list) {
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ /* Pairs with READ_ONCE() in virtqueue_is_broken(). */
+ WRITE_ONCE(vq->broken, true);
+ }
+ spin_unlock(&dev->vqs_list_lock);
+}
+EXPORT_SYMBOL_GPL(virtio_break_device);
+
+/*
+ * This should allow the device to be used by the driver. You may
+ * need to grab appropriate locks to flush the write to
+ * vq->broken. This should only be used in some specific case e.g
+ * (probing and restoring). This function should only be called by the
+ * core, not directly by the driver.
+ */
+void __virtio_unbreak_device(struct virtio_device *dev)
+{
+ struct virtqueue *_vq;
+
+ spin_lock(&dev->vqs_list_lock);
+ list_for_each_entry(_vq, &dev->vqs, list) {
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ /* Pairs with READ_ONCE() in virtqueue_is_broken(). */
+ WRITE_ONCE(vq->broken, false);
+ }
+ spin_unlock(&dev->vqs_list_lock);
+}
+EXPORT_SYMBOL_GPL(__virtio_unbreak_device);
+
+dma_addr_t virtqueue_get_desc_addr(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ BUG_ON(!vq->we_own_ring);
+
+ if (vq->packed_ring)
+ return vq->packed.ring_dma_addr;
+
+ return vq->split.queue_dma_addr;
+}
+EXPORT_SYMBOL_GPL(virtqueue_get_desc_addr);
+
+dma_addr_t virtqueue_get_avail_addr(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ BUG_ON(!vq->we_own_ring);
+
+ if (vq->packed_ring)
+ return vq->packed.driver_event_dma_addr;
+
+ return vq->split.queue_dma_addr +
+ ((char *)vq->split.vring.avail - (char *)vq->split.vring.desc);
+}
+EXPORT_SYMBOL_GPL(virtqueue_get_avail_addr);
+
+dma_addr_t virtqueue_get_used_addr(struct virtqueue *_vq)
+{
+ struct vring_virtqueue *vq = to_vvq(_vq);
+
+ BUG_ON(!vq->we_own_ring);
+
+ if (vq->packed_ring)
+ return vq->packed.device_event_dma_addr;
+
+ return vq->split.queue_dma_addr +
+ ((char *)vq->split.vring.used - (char *)vq->split.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)->split.vring;
+}
+EXPORT_SYMBOL_GPL(virtqueue_get_vring);
+
+MODULE_LICENSE("GPL");