diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
index cab9f3f63a38929b0634ae05fc3bc7d2ce4a3dd4..77590320d44ce218f31ba09b4420f6ee9e412561 100644
--- a/drivers/virtio/Kconfig
+++ b/drivers/virtio/Kconfig
@@ -60,7 +60,7 @@ config VIRTIO_INPUT
config VIRTIO_MMIO
tristate "Platform bus driver for memory mapped virtio devices"
- depends on HAS_IOMEM
+ depends on HAS_IOMEM && HAS_DMA
select VIRTIO
---help---
This drivers provides support for memory mapped virtio
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index ab0be6c084f60c540fdbf580d0d0aaa60ba9dbe1..9abc008ff7ea84d0fecffb11e69ebf73cc936c12 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -24,6 +24,7 @@
#include <linux/module.h>
#include <linux/hrtimer.h>
#include <linux/kmemleak.h>
+#include <linux/dma-mapping.h>
#ifdef DEBUG
/* For development, we want to crash whenever the ring is screwed. */
@@ -54,6 +55,11 @@
#define END_USE(vq)
#endif
+struct vring_desc_state {
+ void *data; /* Data for callback. */
+ struct vring_desc *indir_desc; /* Indirect descriptor, if any. */
+};
+
struct vring_virtqueue {
struct virtqueue vq;
@@ -98,8 +104,8 @@ struct vring_virtqueue {
ktime_t last_add_time;
#endif
- /* Tokens for callbacks. */
- void *data[];
+ /* Per-descriptor state. */
+ struct vring_desc_state desc_state[];
};
#define to_vvq(_vq) container_of(_vq, struct vring_virtqueue, vq)
@@ -128,6 +134,79 @@ static bool vring_use_dma_api(struct virtio_device *vdev)
return false;
}
+/*
+ * 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.
+ */
+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 (!vring_use_dma_api(vq->vq.vdev))
+ 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 (!vring_use_dma_api(vq->vq.vdev))
+ return (dma_addr_t)virt_to_phys(cpu_addr);
+
+ return dma_map_single(vring_dma_dev(vq),
+ cpu_addr, size, direction);
+}
+
+static void vring_unmap_one(const struct vring_virtqueue *vq,
+ struct vring_desc *desc)
+{
+ u16 flags;
+
+ if (!vring_use_dma_api(vq->vq.vdev))
+ return;
+
+ flags = virtio16_to_cpu(vq->vq.vdev, desc->flags);
+
+ if (flags & VRING_DESC_F_INDIRECT) {
+ dma_unmap_single(vring_dma_dev(vq),
+ virtio64_to_cpu(vq->vq.vdev, desc->addr),
+ virtio32_to_cpu(vq->vq.vdev, desc->len),
+ (flags & VRING_DESC_F_WRITE) ?
+ DMA_FROM_DEVICE : DMA_TO_DEVICE);
+ } else {
+ dma_unmap_page(vring_dma_dev(vq),
+ virtio64_to_cpu(vq->vq.vdev, desc->addr),
+ virtio32_to_cpu(vq->vq.vdev, desc->len),
+ (flags & VRING_DESC_F_WRITE) ?
+ DMA_FROM_DEVICE : DMA_TO_DEVICE);
+ }
+}
+
+static 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)
{
@@ -161,7 +240,7 @@ static inline int virtqueue_add(struct virtqueue *_vq,
struct vring_virtqueue *vq = to_vvq(_vq);
struct scatterlist *sg;
struct vring_desc *desc;
- unsigned int i, n, avail, descs_used, uninitialized_var(prev);
+ unsigned int i, n, avail, descs_used, uninitialized_var(prev), err_idx;
int head;
bool indirect;
@@ -201,21 +280,15 @@ static inline int virtqueue_add(struct virtqueue *_vq,
if (desc) {
/* Use a single buffer which doesn't continue */
- vq->vring.desc[head].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_INDIRECT);
- vq->vring.desc[head].addr = cpu_to_virtio64(_vq->vdev, virt_to_phys(desc));
- /* avoid kmemleak false positive (hidden by virt_to_phys) */
- kmemleak_ignore(desc);
- vq->vring.desc[head].len = cpu_to_virtio32(_vq->vdev, total_sg * sizeof(struct vring_desc));
-
+ indirect = true;
/* Set up rest to use this indirect table. */
i = 0;
descs_used = 1;
- indirect = true;
} else {
+ indirect = false;
desc = vq->vring.desc;
i = head;
descs_used = total_sg;
- indirect = false;
}
if (vq->vq.num_free < descs_used) {
@@ -230,13 +303,14 @@ static inline int virtqueue_add(struct virtqueue *_vq,
return -ENOSPC;
}
- /* We're about to use some buffers from the free list. */
- vq->vq.num_free -= descs_used;
-
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;
+
desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT);
- desc[i].addr = cpu_to_virtio64(_vq->vdev, sg_phys(sg));
+ desc[i].addr = cpu_to_virtio64(_vq->vdev, addr);
desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length);
prev = i;
i = virtio16_to_cpu(_vq->vdev, desc[i].next);
@@ -244,8 +318,12 @@ static inline int virtqueue_add(struct virtqueue *_vq,
}
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;
+
desc[i].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_NEXT | VRING_DESC_F_WRITE);
- desc[i].addr = cpu_to_virtio64(_vq->vdev, sg_phys(sg));
+ desc[i].addr = cpu_to_virtio64(_vq->vdev, addr);
desc[i].len = cpu_to_virtio32(_vq->vdev, sg->length);
prev = i;
i = virtio16_to_cpu(_vq->vdev, desc[i].next);
@@ -254,14 +332,33 @@ static inline int virtqueue_add(struct virtqueue *_vq,
/* Last one doesn't continue. */
desc[prev].flags &= cpu_to_virtio16(_vq->vdev, ~VRING_DESC_F_NEXT);
+ if (indirect) {
+ /* Now that the indirect table is filled in, map it. */
+ dma_addr_t addr = vring_map_single(
+ vq, desc, total_sg * sizeof(struct vring_desc),
+ DMA_TO_DEVICE);
+ if (vring_mapping_error(vq, addr))
+ goto unmap_release;
+
+ vq->vring.desc[head].flags = cpu_to_virtio16(_vq->vdev, VRING_DESC_F_INDIRECT);
+ vq->vring.desc[head].addr = cpu_to_virtio64(_vq->vdev, addr);
+
+ vq->vring.desc[head].len = cpu_to_virtio32(_vq->vdev, total_sg * sizeof(struct vring_desc));
+ }
+
+ /* We're using some buffers from the free list. */
+ vq->vq.num_free -= descs_used;
+
/* Update free pointer */
if (indirect)
vq->free_head = virtio16_to_cpu(_vq->vdev, vq->vring.desc[head].next);
else
vq->free_head = i;
- /* Set token. */
- vq->data[head] = data;
+ /* Store token and indirect buffer state. */
+ vq->desc_state[head].data = data;
+ if (indirect)
+ vq->desc_state[head].indir_desc = desc;
/* Put entry in available array (but don't update avail->idx until they
* do sync). */
@@ -284,6 +381,24 @@ static inline int virtqueue_add(struct virtqueue *_vq,
virtqueue_kick(_vq);
return 0;
+
+unmap_release:
+ err_idx = i;
+ i = head;
+
+ for (n = 0; n < total_sg; n++) {
+ if (i == err_idx)
+ break;
+ vring_unmap_one(vq, &desc[i]);
+ i = vq->vring.desc[i].next;
+ }
+
+ vq->vq.num_free += total_sg;
+
+ if (indirect)
+ kfree(desc);
+
+ return -EIO;
}
/**
@@ -454,27 +569,43 @@ EXPORT_SYMBOL_GPL(virtqueue_kick);
static void detach_buf(struct vring_virtqueue *vq, unsigned int head)
{
- unsigned int i;
+ unsigned int i, j;
+ u16 nextflag = cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT);
/* Clear data ptr. */
- vq->data[head] = NULL;
+ vq->desc_state[head].data = NULL;
- /* Put back on free list: find end */
+ /* Put back on free list: unmap first-level descriptors and find end */
i = head;
- /* Free the indirect table */
- if (vq->vring.desc[i].flags & cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_INDIRECT))
- kfree(phys_to_virt(virtio64_to_cpu(vq->vq.vdev, vq->vring.desc[i].addr)));
-
- while (vq->vring.desc[i].flags & cpu_to_virtio16(vq->vq.vdev, VRING_DESC_F_NEXT)) {
+ 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++;
+
+ /* Free the indirect table, if any, now that it's unmapped. */
+ if (vq->desc_state[head].indir_desc) {
+ struct vring_desc *indir_desc = vq->desc_state[head].indir_desc;
+ u32 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(vq->desc_state[head].indir_desc);
+ vq->desc_state[head].indir_desc = NULL;
+ }
}
static inline bool more_used(const struct vring_virtqueue *vq)
@@ -529,13 +660,13 @@ void *virtqueue_get_buf(struct virtqueue *_vq, unsigned int *len)
BAD_RING(vq, "id %u out of range\n", i);
return NULL;
}
- if (unlikely(!vq->data[i])) {
+ 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->data[i];
+ ret = vq->desc_state[i].data;
detach_buf(vq, i);
vq->last_used_idx++;
/* If we expect an interrupt for the next entry, tell host
@@ -709,10 +840,10 @@ void *virtqueue_detach_unused_buf(struct virtqueue *_vq)
START_USE(vq);
for (i = 0; i < vq->vring.num; i++) {
- if (!vq->data[i])
+ if (!vq->desc_state[i].data)
continue;
/* detach_buf clears data, so grab it now. */
- buf = vq->data[i];
+ buf = vq->desc_state[i].data;
detach_buf(vq, i);
vq->avail_idx_shadow--;
vq->vring.avail->idx = cpu_to_virtio16(_vq->vdev, vq->avail_idx_shadow);
@@ -766,7 +897,8 @@ struct virtqueue *vring_new_virtqueue(unsigned int index,
return NULL;
}
- vq = kmalloc(sizeof(*vq) + sizeof(void *)*num, GFP_KERNEL);
+ vq = kmalloc(sizeof(*vq) + num * sizeof(struct vring_desc_state),
+ GFP_KERNEL);
if (!vq)
return NULL;
@@ -800,11 +932,9 @@ struct virtqueue *vring_new_virtqueue(unsigned int index,
/* Put everything in free lists. */
vq->free_head = 0;
- for (i = 0; i < num-1; i++) {
+ for (i = 0; i < num-1; i++)
vq->vring.desc[i].next = cpu_to_virtio16(vdev, i + 1);
- vq->data[i] = NULL;
- }
- vq->data[i] = NULL;
+ memset(vq->desc_state, 0, num * sizeof(struct vring_desc_state));
return &vq->vq;
}
diff --git a/tools/virtio/linux/dma-mapping.h b/tools/virtio/linux/dma-mapping.h
new file mode 100644
index 0000000000000000000000000000000000000000..4f93af89ae165af7f82ced48e57c00460e6ce34d
--- /dev/null
+++ b/tools/virtio/linux/dma-mapping.h
@@ -0,0 +1,17 @@
+#ifndef _LINUX_DMA_MAPPING_H
+#define _LINUX_DMA_MAPPING_H
+
+#ifdef CONFIG_HAS_DMA
+# error Virtio userspace code does not support CONFIG_HAS_DMA
+#endif
+
+#define PCI_DMA_BUS_IS_PHYS 1
+
+enum dma_data_direction {
+ DMA_BIDIRECTIONAL = 0,
+ DMA_TO_DEVICE = 1,
+ DMA_FROM_DEVICE = 2,
+ DMA_NONE = 3,
+};
+
+#endif