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virtio: Use physical addresses for buffers in virtio
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Have the higher level rpmsg_virtio handle the virt-to-phys and back
conversion. The rpmsg_virtio layer already has the shared buffer memory
metal IO. This removes the need to pass in the buffer region metal_io
struct down to the virtio layer, which otherwise does nothing with the
contents of the buffers.

Signed-off-by: Andrew Davis <[email protected]>
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@glneo
glneo committed Mar 19, 2024
1 parent 3dbbb25 commit 471ac44
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Showing 3 changed files with 28 additions and 48 deletions.
13 changes: 7 additions & 6 deletions lib/include/openamp/virtqueue.h
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Original file line number Diff line number Diff line change
Expand Up @@ -65,8 +65,8 @@ extern "C" {

/** @brief Buffer descriptor. */
struct virtqueue_buf {
/** Address of the buffer. */
void *buf;
/** Address (guest-physical) */
uint64_t buf;

/** Size of the buffer. */
int len;
Expand Down Expand Up @@ -285,12 +285,13 @@ void *virtqueue_get_buffer(struct virtqueue *vq, uint32_t *len, uint16_t *idx);
*
* @param vq Pointer to VirtIO queue control block
* @param avail_idx Pointer to index used in vring desc table
* @param buffer Physical address of buffer
* @param len Length of buffer
*
* @return Pointer to available buffer
* @return Function status
*/
void *virtqueue_get_available_buffer(struct virtqueue *vq, uint16_t *avail_idx,
uint32_t *len);
int virtqueue_get_available_buffer(struct virtqueue *vq, uint16_t *avail_idx,
uint64_t *buffer, uint32_t *len);

/**
* @internal
Expand Down Expand Up @@ -381,7 +382,7 @@ void virtqueue_notification(struct virtqueue *vq);
uint32_t virtqueue_get_desc_size(struct virtqueue *vq);

uint32_t virtqueue_get_buffer_length(struct virtqueue *vq, uint16_t idx);
void *virtqueue_get_buffer_addr(struct virtqueue *vq, uint16_t idx);
uint64_t virtqueue_get_buffer_addr(struct virtqueue *vq, uint16_t idx);

/**
* @brief Test if virtqueue is empty
Expand Down
28 changes: 13 additions & 15 deletions lib/rpmsg/rpmsg_virtio.c
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Original file line number Diff line number Diff line change
Expand Up @@ -120,7 +120,7 @@ static void rpmsg_virtio_return_buffer(struct rpmsg_virtio_device *rvdev,

(void)idx;
/* Initialize buffer node */
vqbuf.buf = buffer;
vqbuf.buf = metal_io_virt_to_phys(rvdev->shbuf_io, buffer);
vqbuf.len = len;
ret = virtqueue_add_buffer(rvdev->rvq, &vqbuf, 0, 1, buffer);
RPMSG_ASSERT(ret == VQUEUE_SUCCESS, "add buffer failed\r\n");
Expand Down Expand Up @@ -162,7 +162,7 @@ static int rpmsg_virtio_enqueue_buffer(struct rpmsg_virtio_device *rvdev,
(void)idx;

/* Initialize buffer node */
vqbuf.buf = buffer;
vqbuf.buf = metal_io_virt_to_phys(rvdev->shbuf_io, buffer);
vqbuf.len = len;
return virtqueue_add_buffer(rvdev->svq, &vqbuf, 1, 0, buffer);
}
Expand Down Expand Up @@ -224,7 +224,10 @@ static void *rpmsg_virtio_get_tx_buffer(struct rpmsg_virtio_device *rvdev,
#endif /*!VIRTIO_DEVICE_ONLY*/
#ifndef VIRTIO_DRIVER_ONLY
} else if (role == RPMSG_REMOTE) {
data = virtqueue_get_available_buffer(rvdev->svq, idx, len);
uint64_t phys_data;
int status = virtqueue_get_available_buffer(rvdev->svq, idx, &phys_data, len);
if (!status)

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lib/rpmsg/rpmsg_virtio.c:229  Missing a blank line after declarations
data = metal_io_phys_to_virt(rvdev->shbuf_io, phys_data);
#endif /*!VIRTIO_DRIVER_ONLY*/
}

Expand Down Expand Up @@ -254,10 +257,13 @@ static void *rpmsg_virtio_get_rx_buffer(struct rpmsg_virtio_device *rvdev,
}
#endif /*!VIRTIO_DEVICE_ONLY*/


#ifndef VIRTIO_DRIVER_ONLY
if (role == RPMSG_REMOTE) {
data =
virtqueue_get_available_buffer(rvdev->rvq, idx, len);
uint64_t phys_data;
int status = virtqueue_get_available_buffer(rvdev->rvq, idx, &phys_data, len);
if (!status)

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lib/rpmsg/rpmsg_virtio.c:265  Missing a blank line after declarations
data = metal_io_phys_to_virt(rvdev->shbuf_io, phys_data);
}
#endif /*!VIRTIO_DRIVER_ONLY*/

Expand Down Expand Up @@ -815,7 +821,7 @@ int rpmsg_init_vdev_with_config(struct rpmsg_virtio_device *rvdev,
const char *vq_names[RPMSG_NUM_VRINGS];
vq_callback callback[RPMSG_NUM_VRINGS];
int status;
unsigned int i, role;
unsigned int role;

if (!rvdev || !vdev || !shm_io)
return RPMSG_ERR_PARAM;
Expand Down Expand Up @@ -918,14 +924,6 @@ int rpmsg_init_vdev_with_config(struct rpmsg_virtio_device *rvdev,
*/
virtqueue_disable_cb(rvdev->svq);

/* TODO: can have a virtio function to set the shared memory I/O */
for (i = 0; i < RPMSG_NUM_VRINGS; i++) {
struct virtqueue *vq;

vq = vdev->vrings_info[i].vq;
vq->shm_io = shm_io;
}

#ifndef VIRTIO_DEVICE_ONLY
if (role == RPMSG_HOST) {
struct virtqueue_buf vqbuf;
Expand All @@ -943,7 +941,7 @@ int rpmsg_init_vdev_with_config(struct rpmsg_virtio_device *rvdev,
goto err;
}

vqbuf.buf = buffer;
vqbuf.buf = metal_io_virt_to_phys(shm_io, buffer);

metal_io_block_set(shm_io,
metal_io_virt_to_offset(shm_io,
Expand Down
35 changes: 8 additions & 27 deletions lib/virtio/virtqueue.c
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Original file line number Diff line number Diff line change
Expand Up @@ -28,24 +28,6 @@ static int virtqueue_nused(struct virtqueue *vq);
static int virtqueue_navail(struct virtqueue *vq);
#endif

/* Default implementation of P2V based on libmetal */
static inline void *virtqueue_phys_to_virt(struct virtqueue *vq,
metal_phys_addr_t phys)
{
struct metal_io_region *io = vq->shm_io;

return metal_io_phys_to_virt(io, phys);
}

/* Default implementation of V2P based on libmetal */
static inline metal_phys_addr_t virtqueue_virt_to_phys(struct virtqueue *vq,
void *buf)
{
struct metal_io_region *io = vq->shm_io;

return metal_io_virt_to_phys(io, buf);
}

int virtqueue_create(struct virtio_device *virt_dev, unsigned short id,
const char *name, struct vring_alloc_info *ring,
void (*callback)(struct virtqueue *vq),
Expand Down Expand Up @@ -182,11 +164,11 @@ uint32_t virtqueue_get_buffer_length(struct virtqueue *vq, uint16_t idx)
return vq->vq_ring.desc[idx].len;
}

void *virtqueue_get_buffer_addr(struct virtqueue *vq, uint16_t idx)
uint64_t virtqueue_get_buffer_addr(struct virtqueue *vq, uint16_t idx)
{
VRING_INVALIDATE(&vq->vq_ring.desc[idx].addr,
sizeof(vq->vq_ring.desc[idx].addr));
return virtqueue_phys_to_virt(vq, vq->vq_ring.desc[idx].addr);
return vq->vq_ring.desc[idx].addr;
}

void virtqueue_free(struct virtqueue *vq)
Expand All @@ -202,18 +184,17 @@ void virtqueue_free(struct virtqueue *vq)
}
}

void *virtqueue_get_available_buffer(struct virtqueue *vq, uint16_t *avail_idx,
uint32_t *len)
int virtqueue_get_available_buffer(struct virtqueue *vq, uint16_t *avail_idx,
uint64_t *buffer, uint32_t *len)
{
uint16_t head_idx = 0;
void *buffer;

atomic_thread_fence(memory_order_seq_cst);

/* Avail.idx is updated by driver, invalidate it */
VRING_INVALIDATE(&vq->vq_ring.avail->idx, sizeof(vq->vq_ring.avail->idx));
if (vq->vq_available_idx == vq->vq_ring.avail->idx) {
return NULL;
return ERROR_VRING_NO_BUFF;
}

VQUEUE_BUSY(vq);
Expand All @@ -228,12 +209,12 @@ void *virtqueue_get_available_buffer(struct virtqueue *vq, uint16_t *avail_idx,
/* Invalidate the desc entry written by driver before accessing it */
VRING_INVALIDATE(&vq->vq_ring.desc[*avail_idx],
sizeof(vq->vq_ring.desc[*avail_idx]));
buffer = virtqueue_phys_to_virt(vq, vq->vq_ring.desc[*avail_idx].addr);
*buffer = vq->vq_ring.desc[*avail_idx].addr;
*len = vq->vq_ring.desc[*avail_idx].len;

VQUEUE_IDLE(vq);

return buffer;
return 0;
}

int virtqueue_add_consumed_buffer(struct virtqueue *vq, uint16_t head_idx,
Expand Down Expand Up @@ -414,7 +395,7 @@ static uint16_t vq_ring_add_buffer(struct virtqueue *vq,

/* CACHE: No need to invalidate desc because it is only written by driver */
dp = &desc[idx];
dp->addr = virtqueue_virt_to_phys(vq, buf_list[i].buf);
dp->addr = buf_list[i].buf;
dp->len = buf_list[i].len;
dp->flags = 0;

Expand Down

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