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-rw-r--r--hw/block/dataplane/virtio-blk.c85
-rw-r--r--hw/virtio/dataplane/vring.c56
-rw-r--r--include/hw/virtio/dataplane/vring.h7
3 files changed, 72 insertions, 76 deletions
diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index 2b4a773f13..456d437ac3 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -35,7 +35,7 @@ enum {
typedef struct {
struct iocb iocb; /* Linux AIO control block */
QEMUIOVector *inhdr; /* iovecs for virtio_blk_inhdr */
- unsigned int head; /* vring descriptor index */
+ VirtQueueElement *elem; /* saved data from the virtqueue */
struct iovec *bounce_iov; /* used if guest buffers are unaligned */
QEMUIOVector *read_qiov; /* for read completion /w bounce buffer */
} VirtIOBlockRequest;
@@ -96,7 +96,7 @@ static void complete_request(struct iocb *iocb, ssize_t ret, void *opaque)
len = 0;
}
- trace_virtio_blk_data_plane_complete_request(s, req->head, ret);
+ trace_virtio_blk_data_plane_complete_request(s, req->elem->index, ret);
if (req->read_qiov) {
assert(req->bounce_iov);
@@ -118,12 +118,12 @@ static void complete_request(struct iocb *iocb, ssize_t ret, void *opaque)
* written to, but for virtio-blk it seems to be the number of bytes
* transferred plus the status bytes.
*/
- vring_push(&s->vring, req->head, len + sizeof(hdr));
-
+ vring_push(&s->vring, req->elem, len + sizeof(hdr));
+ req->elem = NULL;
s->num_reqs--;
}
-static void complete_request_early(VirtIOBlockDataPlane *s, unsigned int head,
+static void complete_request_early(VirtIOBlockDataPlane *s, VirtQueueElement *elem,
QEMUIOVector *inhdr, unsigned char status)
{
struct virtio_blk_inhdr hdr = {
@@ -134,26 +134,26 @@ static void complete_request_early(VirtIOBlockDataPlane *s, unsigned int head,
qemu_iovec_destroy(inhdr);
g_slice_free(QEMUIOVector, inhdr);
- vring_push(&s->vring, head, sizeof(hdr));
+ vring_push(&s->vring, elem, sizeof(hdr));
notify_guest(s);
}
/* Get disk serial number */
static void do_get_id_cmd(VirtIOBlockDataPlane *s,
struct iovec *iov, unsigned int iov_cnt,
- unsigned int head, QEMUIOVector *inhdr)
+ VirtQueueElement *elem, QEMUIOVector *inhdr)
{
char id[VIRTIO_BLK_ID_BYTES];
/* Serial number not NUL-terminated when shorter than buffer */
strncpy(id, s->blk->serial ? s->blk->serial : "", sizeof(id));
iov_from_buf(iov, iov_cnt, 0, id, sizeof(id));
- complete_request_early(s, head, inhdr, VIRTIO_BLK_S_OK);
+ complete_request_early(s, elem, inhdr, VIRTIO_BLK_S_OK);
}
static int do_rdwr_cmd(VirtIOBlockDataPlane *s, bool read,
- struct iovec *iov, unsigned int iov_cnt,
- long long offset, unsigned int head,
+ struct iovec *iov, unsigned iov_cnt,
+ long long offset, VirtQueueElement *elem,
QEMUIOVector *inhdr)
{
struct iocb *iocb;
@@ -186,19 +186,20 @@ static int do_rdwr_cmd(VirtIOBlockDataPlane *s, bool read,
/* Fill in virtio block metadata needed for completion */
VirtIOBlockRequest *req = container_of(iocb, VirtIOBlockRequest, iocb);
- req->head = head;
+ req->elem = elem;
req->inhdr = inhdr;
req->bounce_iov = bounce_iov;
req->read_qiov = read_qiov;
return 0;
}
-static int process_request(IOQueue *ioq, struct iovec iov[],
- unsigned int out_num, unsigned int in_num,
- unsigned int head)
+static int process_request(IOQueue *ioq, VirtQueueElement *elem)
{
VirtIOBlockDataPlane *s = container_of(ioq, VirtIOBlockDataPlane, ioqueue);
- struct iovec *in_iov = &iov[out_num];
+ struct iovec *iov = elem->out_sg;
+ struct iovec *in_iov = elem->in_sg;
+ unsigned out_num = elem->out_num;
+ unsigned in_num = elem->in_num;
struct virtio_blk_outhdr outhdr;
QEMUIOVector *inhdr;
size_t in_size;
@@ -229,29 +230,29 @@ static int process_request(IOQueue *ioq, struct iovec iov[],
switch (outhdr.type) {
case VIRTIO_BLK_T_IN:
- do_rdwr_cmd(s, true, in_iov, in_num, outhdr.sector * 512, head, inhdr);
+ do_rdwr_cmd(s, true, in_iov, in_num, outhdr.sector * 512, elem, inhdr);
return 0;
case VIRTIO_BLK_T_OUT:
- do_rdwr_cmd(s, false, iov, out_num, outhdr.sector * 512, head, inhdr);
+ do_rdwr_cmd(s, false, iov, out_num, outhdr.sector * 512, elem, inhdr);
return 0;
case VIRTIO_BLK_T_SCSI_CMD:
/* TODO support SCSI commands */
- complete_request_early(s, head, inhdr, VIRTIO_BLK_S_UNSUPP);
+ complete_request_early(s, elem, inhdr, VIRTIO_BLK_S_UNSUPP);
return 0;
case VIRTIO_BLK_T_FLUSH:
/* TODO fdsync not supported by Linux AIO, do it synchronously here! */
if (qemu_fdatasync(s->fd) < 0) {
- complete_request_early(s, head, inhdr, VIRTIO_BLK_S_IOERR);
+ complete_request_early(s, elem, inhdr, VIRTIO_BLK_S_IOERR);
} else {
- complete_request_early(s, head, inhdr, VIRTIO_BLK_S_OK);
+ complete_request_early(s, elem, inhdr, VIRTIO_BLK_S_OK);
}
return 0;
case VIRTIO_BLK_T_GET_ID:
- do_get_id_cmd(s, in_iov, in_num, head, inhdr);
+ do_get_id_cmd(s, in_iov, in_num, elem, inhdr);
return 0;
default:
@@ -267,29 +268,8 @@ static void handle_notify(EventNotifier *e)
VirtIOBlockDataPlane *s = container_of(e, VirtIOBlockDataPlane,
host_notifier);
- /* There is one array of iovecs into which all new requests are extracted
- * from the vring. Requests are read from the vring and the translated
- * descriptors are written to the iovecs array. The iovecs do not have to
- * persist across handle_notify() calls because the kernel copies the
- * iovecs on io_submit().
- *
- * Handling io_submit() EAGAIN may require storing the requests across
- * handle_notify() calls until the kernel has sufficient resources to
- * accept more I/O. This is not implemented yet.
- */
- struct iovec iovec[VRING_MAX];
- struct iovec *end = &iovec[VRING_MAX];
- struct iovec *iov = iovec;
-
- /* When a request is read from the vring, the index of the first descriptor
- * (aka head) is returned so that the completed request can be pushed onto
- * the vring later.
- *
- * The number of hypervisor read-only iovecs is out_num. The number of
- * hypervisor write-only iovecs is in_num.
- */
- int head;
- unsigned int out_num = 0, in_num = 0;
+ VirtQueueElement *elem;
+ int ret;
unsigned int num_queued;
event_notifier_test_and_clear(&s->host_notifier);
@@ -298,30 +278,31 @@ static void handle_notify(EventNotifier *e)
vring_disable_notification(s->vdev, &s->vring);
for (;;) {
- head = vring_pop(s->vdev, &s->vring, iov, end, &out_num, &in_num);
- if (head < 0) {
+ ret = vring_pop(s->vdev, &s->vring, &elem);
+ if (ret < 0) {
+ assert(elem == NULL);
break; /* no more requests */
}
- trace_virtio_blk_data_plane_process_request(s, out_num, in_num,
- head);
+ trace_virtio_blk_data_plane_process_request(s, elem->out_num,
+ elem->in_num, elem->index);
- if (process_request(&s->ioqueue, iov, out_num, in_num, head) < 0) {
+ if (process_request(&s->ioqueue, elem) < 0) {
vring_set_broken(&s->vring);
+ vring_free_element(elem);
ret = -EFAULT;
break;
}
- iov += out_num + in_num;
}
- if (likely(head == -EAGAIN)) { /* vring emptied */
+ if (likely(ret == -EAGAIN)) { /* vring emptied */
/* Re-enable guest->host notifies and stop processing the vring.
* But if the guest has snuck in more descriptors, keep processing.
*/
if (vring_enable_notification(s->vdev, &s->vring)) {
break;
}
- } else { /* head == -ENOBUFS or fatal error, iovecs[] is depleted */
+ } else { /* ret == -ENOBUFS or fatal error, iovecs[] is depleted */
/* Since there are no iovecs[] left, stop processing for now. Do
* not re-enable guest->host notifies since the I/O completion
* handler knows to check for more vring descriptors anyway.
diff --git a/hw/virtio/dataplane/vring.c b/hw/virtio/dataplane/vring.c
index d81b653399..1bf9dd335a 100644
--- a/hw/virtio/dataplane/vring.c
+++ b/hw/virtio/dataplane/vring.c
@@ -111,29 +111,32 @@ bool vring_should_notify(VirtIODevice *vdev, Vring *vring)
}
-static int get_desc(Vring *vring,
- struct iovec iov[], struct iovec *iov_end,
- unsigned int *out_num, unsigned int *in_num,
+static int get_desc(Vring *vring, VirtQueueElement *elem,
struct vring_desc *desc)
{
unsigned *num;
+ struct iovec *iov;
+ hwaddr *addr;
if (desc->flags & VRING_DESC_F_WRITE) {
- num = in_num;
+ num = &elem->in_num;
+ iov = &elem->in_sg[*num];
+ addr = &elem->in_addr[*num];
} else {
- num = out_num;
+ num = &elem->out_num;
+ iov = &elem->out_sg[*num];
+ addr = &elem->out_addr[*num];
/* If it's an output descriptor, they're all supposed
* to come before any input descriptors. */
- if (unlikely(*in_num)) {
+ if (unlikely(elem->in_num)) {
error_report("Descriptor has out after in");
return -EFAULT;
}
}
/* Stop for now if there are not enough iovecs available. */
- iov += *in_num + *out_num;
- if (iov >= iov_end) {
+ if (*num >= VIRTQUEUE_MAX_SIZE) {
return -ENOBUFS;
}
@@ -147,14 +150,13 @@ static int get_desc(Vring *vring,
}
iov->iov_len = desc->len;
+ *addr = desc->addr;
*num += 1;
return 0;
}
/* This is stolen from linux/drivers/vhost/vhost.c. */
-static int get_indirect(Vring *vring,
- struct iovec iov[], struct iovec *iov_end,
- unsigned int *out_num, unsigned int *in_num,
+static int get_indirect(Vring *vring, VirtQueueElement *elem,
struct vring_desc *indirect)
{
struct vring_desc desc;
@@ -212,7 +214,7 @@ static int get_indirect(Vring *vring,
return -EFAULT;
}
- ret = get_desc(vring, iov, iov_end, out_num, in_num, &desc);
+ ret = get_desc(vring, elem, &desc);
if (ret < 0) {
vring->broken |= (ret == -EFAULT);
return ret;
@@ -222,6 +224,11 @@ static int get_indirect(Vring *vring,
return 0;
}
+void vring_free_element(VirtQueueElement *elem)
+{
+ g_slice_free(VirtQueueElement, elem);
+}
+
/* This looks in the virtqueue and for the first available buffer, and converts
* it to an iovec for convenient access. Since descriptors consist of some
* number of output then some number of input descriptors, it's actually two
@@ -234,12 +241,12 @@ static int get_indirect(Vring *vring,
* Stolen from linux/drivers/vhost/vhost.c.
*/
int vring_pop(VirtIODevice *vdev, Vring *vring,
- struct iovec iov[], struct iovec *iov_end,
- unsigned int *out_num, unsigned int *in_num)
+ VirtQueueElement **p_elem)
{
struct vring_desc desc;
unsigned int i, head, found = 0, num = vring->vr.num;
uint16_t avail_idx, last_avail_idx;
+ VirtQueueElement *elem = NULL;
int ret;
/* If there was a fatal error then refuse operation */
@@ -273,6 +280,10 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
* the index we've seen. */
head = vring->vr.avail->ring[last_avail_idx % num];
+ elem = g_slice_new(VirtQueueElement);
+ elem->index = head;
+ elem->in_num = elem->out_num = 0;
+
/* If their number is silly, that's an error. */
if (unlikely(head >= num)) {
error_report("Guest says index %u > %u is available", head, num);
@@ -284,9 +295,6 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
vring_avail_event(&vring->vr) = vring->vr.avail->idx;
}
- /* When we start there are none of either input nor output. */
- *out_num = *in_num = 0;
-
i = head;
do {
if (unlikely(i >= num)) {
@@ -306,14 +314,14 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
barrier();
if (desc.flags & VRING_DESC_F_INDIRECT) {
- int ret = get_indirect(vring, iov, iov_end, out_num, in_num, &desc);
+ int ret = get_indirect(vring, elem, &desc);
if (ret < 0) {
goto out;
}
continue;
}
- ret = get_desc(vring, iov, iov_end, out_num, in_num, &desc);
+ ret = get_desc(vring, elem, &desc);
if (ret < 0) {
goto out;
}
@@ -323,6 +331,7 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
/* On success, increment avail index. */
vring->last_avail_idx++;
+ *p_elem = elem;
return head;
out:
@@ -330,6 +339,10 @@ out:
if (ret == -EFAULT) {
vring->broken = true;
}
+ if (elem) {
+ vring_free_element(elem);
+ }
+ *p_elem = NULL;
return ret;
}
@@ -337,11 +350,14 @@ out:
*
* Stolen from linux/drivers/vhost/vhost.c.
*/
-void vring_push(Vring *vring, unsigned int head, int len)
+void vring_push(Vring *vring, VirtQueueElement *elem, int len)
{
struct vring_used_elem *used;
+ unsigned int head = elem->index;
uint16_t new;
+ vring_free_element(elem);
+
/* Don't touch vring if a fatal error occurred */
if (vring->broken) {
return;
diff --git a/include/hw/virtio/dataplane/vring.h b/include/hw/virtio/dataplane/vring.h
index c0b69ff18f..3d6c0dfc76 100644
--- a/include/hw/virtio/dataplane/vring.h
+++ b/include/hw/virtio/dataplane/vring.h
@@ -54,9 +54,8 @@ void vring_teardown(Vring *vring, VirtIODevice *vdev, int n);
void vring_disable_notification(VirtIODevice *vdev, Vring *vring);
bool vring_enable_notification(VirtIODevice *vdev, Vring *vring);
bool vring_should_notify(VirtIODevice *vdev, Vring *vring);
-int vring_pop(VirtIODevice *vdev, Vring *vring,
- struct iovec iov[], struct iovec *iov_end,
- unsigned int *out_num, unsigned int *in_num);
-void vring_push(Vring *vring, unsigned int head, int len);
+int vring_pop(VirtIODevice *vdev, Vring *vring, VirtQueueElement **elem);
+void vring_push(Vring *vring, VirtQueueElement *elem, int len);
+void vring_free_element(VirtQueueElement *elem);
#endif /* VRING_H */
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-16 07:24:34 +0000