* [Qemu-devel] [PATCH v2 1/4] vring: create a common function to parse descriptors
2013-12-10 12:26 [Qemu-devel] [PATCH v2 0/4] dataplane: use more of the generic virtio data structures, drop hostmem Paolo Bonzini
@ 2013-12-10 12:26 ` Paolo Bonzini
2013-12-10 12:26 ` [Qemu-devel] [PATCH v2 2/4] vring: factor common code for error exits Paolo Bonzini
` (4 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: Paolo Bonzini @ 2013-12-10 12:26 UTC (permalink / raw)
To: qemu-devel; +Cc: stefanha
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
hw/virtio/dataplane/vring.c | 113 ++++++++++++++++++++------------------------
1 file changed, 51 insertions(+), 62 deletions(-)
diff --git a/hw/virtio/dataplane/vring.c b/hw/virtio/dataplane/vring.c
index 351a343..8294f36 100644
--- a/hw/virtio/dataplane/vring.c
+++ b/hw/virtio/dataplane/vring.c
@@ -110,6 +110,47 @@ bool vring_should_notify(VirtIODevice *vdev, Vring *vring)
return vring_need_event(vring_used_event(&vring->vr), new, old);
}
+
+static int get_desc(Vring *vring,
+ struct iovec iov[], struct iovec *iov_end,
+ unsigned int *out_num, unsigned int *in_num,
+ struct vring_desc *desc)
+{
+ unsigned *num;
+
+ if (desc->flags & VRING_DESC_F_WRITE) {
+ num = in_num;
+ } else {
+ num = out_num;
+
+ /* If it's an output descriptor, they're all supposed
+ * to come before any input descriptors. */
+ if (unlikely(*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) {
+ return -ENOBUFS;
+ }
+
+ /* TODO handle non-contiguous memory across region boundaries */
+ iov->iov_base = hostmem_lookup(&vring->hostmem, desc->addr, desc->len,
+ desc->flags & VRING_DESC_F_WRITE);
+ if (!iov->iov_base) {
+ error_report("Failed to map descriptor addr %#" PRIx64 " len %u",
+ (uint64_t)desc->addr, desc->len);
+ return -EFAULT;
+ }
+
+ iov->iov_len = desc->len;
+ *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,
@@ -118,6 +159,7 @@ static int get_indirect(Vring *vring,
{
struct vring_desc desc;
unsigned int i = 0, count, found = 0;
+ int ret;
/* Sanity check */
if (unlikely(indirect->len % sizeof(desc))) {
@@ -170,36 +212,10 @@ static int get_indirect(Vring *vring,
return -EFAULT;
}
- /* Stop for now if there are not enough iovecs available. */
- if (iov >= iov_end) {
- return -ENOBUFS;
- }
-
- iov->iov_base = hostmem_lookup(&vring->hostmem, desc.addr, desc.len,
- desc.flags & VRING_DESC_F_WRITE);
- if (!iov->iov_base) {
- error_report("Failed to map indirect descriptor"
- "addr %#" PRIx64 " len %u",
- (uint64_t)desc.addr, desc.len);
- vring->broken = true;
- return -EFAULT;
- }
- iov->iov_len = desc.len;
- iov++;
-
- /* If this is an input descriptor, increment that count. */
- if (desc.flags & VRING_DESC_F_WRITE) {
- *in_num += 1;
- } else {
- /* If it's an output descriptor, they're all supposed
- * to come before any input descriptors. */
- if (unlikely(*in_num)) {
- error_report("Indirect descriptor "
- "has out after in: idx %u", i);
- vring->broken = true;
- return -EFAULT;
- }
- *out_num += 1;
+ ret = get_desc(vring, iov, iov_end, out_num, in_num, &desc);
+ if (ret < 0) {
+ vring->broken |= (ret == -EFAULT);
+ return ret;
}
i = desc.next;
} while (desc.flags & VRING_DESC_F_NEXT);
@@ -224,6 +240,7 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
struct vring_desc desc;
unsigned int i, head, found = 0, num = vring->vr.num;
uint16_t avail_idx, last_avail_idx;
+ int ret;
/* If there was a fatal error then refuse operation */
if (vring->broken) {
@@ -294,40 +311,12 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
continue;
}
- /* If there are not enough iovecs left, stop for now. The caller
- * should check if there are more descs available once they have dealt
- * with the current set.
- */
- if (iov >= iov_end) {
- return -ENOBUFS;
+ ret = get_desc(vring, iov, iov_end, out_num, in_num, &desc);
+ if (ret < 0) {
+ vring->broken |= (ret == -EFAULT);
+ return ret;
}
- /* TODO handle non-contiguous memory across region boundaries */
- iov->iov_base = hostmem_lookup(&vring->hostmem, desc.addr, desc.len,
- desc.flags & VRING_DESC_F_WRITE);
- if (!iov->iov_base) {
- error_report("Failed to map vring desc addr %#" PRIx64 " len %u",
- (uint64_t)desc.addr, desc.len);
- vring->broken = true;
- return -EFAULT;
- }
- iov->iov_len = desc.len;
- iov++;
-
- if (desc.flags & VRING_DESC_F_WRITE) {
- /* If this is an input descriptor,
- * increment that count. */
- *in_num += 1;
- } else {
- /* If it's an output descriptor, they're all supposed
- * to come before any input descriptors. */
- if (unlikely(*in_num)) {
- error_report("Descriptor has out after in: idx %d", i);
- vring->broken = true;
- return -EFAULT;
- }
- *out_num += 1;
- }
i = desc.next;
} while (desc.flags & VRING_DESC_F_NEXT);
--
1.8.3.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* [Qemu-devel] [PATCH v2 2/4] vring: factor common code for error exits
2013-12-10 12:26 [Qemu-devel] [PATCH v2 0/4] dataplane: use more of the generic virtio data structures, drop hostmem Paolo Bonzini
2013-12-10 12:26 ` [Qemu-devel] [PATCH v2 1/4] vring: create a common function to parse descriptors Paolo Bonzini
@ 2013-12-10 12:26 ` Paolo Bonzini
2013-12-10 12:27 ` [Qemu-devel] [PATCH v2 3/4] dataplane: change vring API to use VirtQueueElement Paolo Bonzini
` (3 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: Paolo Bonzini @ 2013-12-10 12:26 UTC (permalink / raw)
To: qemu-devel; +Cc: stefanha
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
hw/block/dataplane/virtio-blk.c | 1 +
hw/virtio/dataplane/vring.c | 34 +++++++++++++++++++++-------------
2 files changed, 22 insertions(+), 13 deletions(-)
diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index 1e57f3a..2b4a773 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -308,6 +308,7 @@ static void handle_notify(EventNotifier *e)
if (process_request(&s->ioqueue, iov, out_num, in_num, head) < 0) {
vring_set_broken(&s->vring);
+ ret = -EFAULT;
break;
}
iov += out_num + in_num;
diff --git a/hw/virtio/dataplane/vring.c b/hw/virtio/dataplane/vring.c
index 8294f36..d81b653 100644
--- a/hw/virtio/dataplane/vring.c
+++ b/hw/virtio/dataplane/vring.c
@@ -244,7 +244,8 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
/* If there was a fatal error then refuse operation */
if (vring->broken) {
- return -EFAULT;
+ ret = -EFAULT;
+ goto out;
}
/* Check it isn't doing very strange things with descriptor numbers. */
@@ -255,13 +256,14 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
if (unlikely((uint16_t)(avail_idx - last_avail_idx) > num)) {
error_report("Guest moved used index from %u to %u",
last_avail_idx, avail_idx);
- vring->broken = true;
- return -EFAULT;
+ ret = -EFAULT;
+ goto out;
}
/* If there's nothing new since last we looked. */
if (avail_idx == last_avail_idx) {
- return -EAGAIN;
+ ret = -EAGAIN;
+ goto out;
}
/* Only get avail ring entries after they have been exposed by guest. */
@@ -274,8 +276,8 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
/* If their number is silly, that's an error. */
if (unlikely(head >= num)) {
error_report("Guest says index %u > %u is available", head, num);
- vring->broken = true;
- return -EFAULT;
+ ret = -EFAULT;
+ goto out;
}
if (vdev->guest_features & (1 << VIRTIO_RING_F_EVENT_IDX)) {
@@ -289,14 +291,14 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
do {
if (unlikely(i >= num)) {
error_report("Desc index is %u > %u, head = %u", i, num, head);
- vring->broken = true;
- return -EFAULT;
+ ret = -EFAULT;
+ goto out;
}
if (unlikely(++found > num)) {
error_report("Loop detected: last one at %u vq size %u head %u",
i, num, head);
- vring->broken = true;
- return -EFAULT;
+ ret = -EFAULT;
+ goto out;
}
desc = vring->vr.desc[i];
@@ -306,15 +308,14 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
if (desc.flags & VRING_DESC_F_INDIRECT) {
int ret = get_indirect(vring, iov, iov_end, out_num, in_num, &desc);
if (ret < 0) {
- return ret;
+ goto out;
}
continue;
}
ret = get_desc(vring, iov, iov_end, out_num, in_num, &desc);
if (ret < 0) {
- vring->broken |= (ret == -EFAULT);
- return ret;
+ goto out;
}
i = desc.next;
@@ -323,6 +324,13 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
/* On success, increment avail index. */
vring->last_avail_idx++;
return head;
+
+out:
+ assert(ret < 0);
+ if (ret == -EFAULT) {
+ vring->broken = true;
+ }
+ return ret;
}
/* After we've used one of their buffers, we tell them about it.
--
1.8.3.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* [Qemu-devel] [PATCH v2 3/4] dataplane: change vring API to use VirtQueueElement
2013-12-10 12:26 [Qemu-devel] [PATCH v2 0/4] dataplane: use more of the generic virtio data structures, drop hostmem Paolo Bonzini
2013-12-10 12:26 ` [Qemu-devel] [PATCH v2 1/4] vring: create a common function to parse descriptors Paolo Bonzini
2013-12-10 12:26 ` [Qemu-devel] [PATCH v2 2/4] vring: factor common code for error exits Paolo Bonzini
@ 2013-12-10 12:27 ` Paolo Bonzini
2013-12-10 12:27 ` [Qemu-devel] [PATCH v2 4/4] dataplane: replace hostmem with memory_region_find Paolo Bonzini
` (2 subsequent siblings)
5 siblings, 0 replies; 7+ messages in thread
From: Paolo Bonzini @ 2013-12-10 12:27 UTC (permalink / raw)
To: qemu-devel; +Cc: stefanha
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
hw/block/dataplane/virtio-blk.c | 85 ++++++++++++++-----------------------
hw/virtio/dataplane/vring.c | 56 +++++++++++++++---------
include/hw/virtio/dataplane/vring.h | 7 ++-
3 files changed, 72 insertions(+), 76 deletions(-)
diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index 2b4a773..3242c30 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 d81b653..1bf9dd3 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 c0b69ff..3d6c0df 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 */
--
1.8.3.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* [Qemu-devel] [PATCH v2 4/4] dataplane: replace hostmem with memory_region_find
2013-12-10 12:26 [Qemu-devel] [PATCH v2 0/4] dataplane: use more of the generic virtio data structures, drop hostmem Paolo Bonzini
` (2 preceding siblings ...)
2013-12-10 12:27 ` [Qemu-devel] [PATCH v2 3/4] dataplane: change vring API to use VirtQueueElement Paolo Bonzini
@ 2013-12-10 12:27 ` Paolo Bonzini
2013-12-11 8:49 ` [Qemu-devel] [PATCH v2 0/4] dataplane: use more of the generic virtio data structures, drop hostmem Stefan Hajnoczi
2013-12-16 16:16 ` Stefan Hajnoczi
5 siblings, 0 replies; 7+ messages in thread
From: Paolo Bonzini @ 2013-12-10 12:27 UTC (permalink / raw)
To: qemu-devel; +Cc: stefanha
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
hw/virtio/dataplane/Makefile.objs | 2 +-
hw/virtio/dataplane/hostmem.c | 183 ----------------------------------
hw/virtio/dataplane/vring.c | 78 +++++++++++++--
include/hw/virtio/dataplane/hostmem.h | 58 -----------
include/hw/virtio/dataplane/vring.h | 3 +-
5 files changed, 72 insertions(+), 252 deletions(-)
delete mode 100644 hw/virtio/dataplane/hostmem.c
delete mode 100644 include/hw/virtio/dataplane/hostmem.h
diff --git a/hw/virtio/dataplane/Makefile.objs b/hw/virtio/dataplane/Makefile.objs
index a91bf33..9a8cfc0 100644
--- a/hw/virtio/dataplane/Makefile.objs
+++ b/hw/virtio/dataplane/Makefile.objs
@@ -1 +1 @@
-common-obj-y += hostmem.o vring.o
+common-obj-y += vring.o
diff --git a/hw/virtio/dataplane/hostmem.c b/hw/virtio/dataplane/hostmem.c
deleted file mode 100644
index 901d98b..0000000
--- a/hw/virtio/dataplane/hostmem.c
+++ /dev/null
@@ -1,183 +0,0 @@
-/*
- * Thread-safe guest to host memory mapping
- *
- * Copyright 2012 Red Hat, Inc. and/or its affiliates
- *
- * Authors:
- * Stefan Hajnoczi <stefanha@redhat.com>
- *
- * This work is licensed under the terms of the GNU GPL, version 2 or later.
- * See the COPYING file in the top-level directory.
- *
- */
-
-#include "exec/address-spaces.h"
-#include "hw/virtio/dataplane/hostmem.h"
-
-static int hostmem_lookup_cmp(const void *phys_, const void *region_)
-{
- hwaddr phys = *(const hwaddr *)phys_;
- const HostMemRegion *region = region_;
-
- if (phys < region->guest_addr) {
- return -1;
- } else if (phys >= region->guest_addr + region->size) {
- return 1;
- } else {
- return 0;
- }
-}
-
-/**
- * Map guest physical address to host pointer
- */
-void *hostmem_lookup(HostMem *hostmem, hwaddr phys, hwaddr len, bool is_write)
-{
- HostMemRegion *region;
- void *host_addr = NULL;
- hwaddr offset_within_region;
-
- qemu_mutex_lock(&hostmem->current_regions_lock);
- region = bsearch(&phys, hostmem->current_regions,
- hostmem->num_current_regions,
- sizeof(hostmem->current_regions[0]),
- hostmem_lookup_cmp);
- if (!region) {
- goto out;
- }
- if (is_write && region->readonly) {
- goto out;
- }
- offset_within_region = phys - region->guest_addr;
- if (len <= region->size - offset_within_region) {
- host_addr = region->host_addr + offset_within_region;
- }
-out:
- qemu_mutex_unlock(&hostmem->current_regions_lock);
-
- return host_addr;
-}
-
-/**
- * Install new regions list
- */
-static void hostmem_listener_commit(MemoryListener *listener)
-{
- HostMem *hostmem = container_of(listener, HostMem, listener);
- int i;
-
- qemu_mutex_lock(&hostmem->current_regions_lock);
- for (i = 0; i < hostmem->num_current_regions; i++) {
- memory_region_unref(hostmem->current_regions[i].mr);
- }
- g_free(hostmem->current_regions);
- hostmem->current_regions = hostmem->new_regions;
- hostmem->num_current_regions = hostmem->num_new_regions;
- qemu_mutex_unlock(&hostmem->current_regions_lock);
-
- /* Reset new regions list */
- hostmem->new_regions = NULL;
- hostmem->num_new_regions = 0;
-}
-
-/**
- * Add a MemoryRegionSection to the new regions list
- */
-static void hostmem_append_new_region(HostMem *hostmem,
- MemoryRegionSection *section)
-{
- void *ram_ptr = memory_region_get_ram_ptr(section->mr);
- size_t num = hostmem->num_new_regions;
- size_t new_size = (num + 1) * sizeof(hostmem->new_regions[0]);
-
- hostmem->new_regions = g_realloc(hostmem->new_regions, new_size);
- hostmem->new_regions[num] = (HostMemRegion){
- .host_addr = ram_ptr + section->offset_within_region,
- .guest_addr = section->offset_within_address_space,
- .size = int128_get64(section->size),
- .readonly = section->readonly,
- .mr = section->mr,
- };
- hostmem->num_new_regions++;
-
- memory_region_ref(section->mr);
-}
-
-static void hostmem_listener_append_region(MemoryListener *listener,
- MemoryRegionSection *section)
-{
- HostMem *hostmem = container_of(listener, HostMem, listener);
-
- /* Ignore non-RAM regions, we may not be able to map them */
- if (!memory_region_is_ram(section->mr)) {
- return;
- }
-
- /* Ignore regions with dirty logging, we cannot mark them dirty */
- if (memory_region_is_logging(section->mr)) {
- return;
- }
-
- hostmem_append_new_region(hostmem, section);
-}
-
-/* We don't implement most MemoryListener callbacks, use these nop stubs */
-static void hostmem_listener_dummy(MemoryListener *listener)
-{
-}
-
-static void hostmem_listener_section_dummy(MemoryListener *listener,
- MemoryRegionSection *section)
-{
-}
-
-static void hostmem_listener_eventfd_dummy(MemoryListener *listener,
- MemoryRegionSection *section,
- bool match_data, uint64_t data,
- EventNotifier *e)
-{
-}
-
-static void hostmem_listener_coalesced_mmio_dummy(MemoryListener *listener,
- MemoryRegionSection *section,
- hwaddr addr, hwaddr len)
-{
-}
-
-void hostmem_init(HostMem *hostmem)
-{
- memset(hostmem, 0, sizeof(*hostmem));
-
- qemu_mutex_init(&hostmem->current_regions_lock);
-
- hostmem->listener = (MemoryListener){
- .begin = hostmem_listener_dummy,
- .commit = hostmem_listener_commit,
- .region_add = hostmem_listener_append_region,
- .region_del = hostmem_listener_section_dummy,
- .region_nop = hostmem_listener_append_region,
- .log_start = hostmem_listener_section_dummy,
- .log_stop = hostmem_listener_section_dummy,
- .log_sync = hostmem_listener_section_dummy,
- .log_global_start = hostmem_listener_dummy,
- .log_global_stop = hostmem_listener_dummy,
- .eventfd_add = hostmem_listener_eventfd_dummy,
- .eventfd_del = hostmem_listener_eventfd_dummy,
- .coalesced_mmio_add = hostmem_listener_coalesced_mmio_dummy,
- .coalesced_mmio_del = hostmem_listener_coalesced_mmio_dummy,
- .priority = 10,
- };
-
- memory_listener_register(&hostmem->listener, &address_space_memory);
- if (hostmem->num_new_regions > 0) {
- hostmem_listener_commit(&hostmem->listener);
- }
-}
-
-void hostmem_finalize(HostMem *hostmem)
-{
- memory_listener_unregister(&hostmem->listener);
- g_free(hostmem->new_regions);
- g_free(hostmem->current_regions);
- qemu_mutex_destroy(&hostmem->current_regions_lock);
-}
diff --git a/hw/virtio/dataplane/vring.c b/hw/virtio/dataplane/vring.c
index 1bf9dd3..250d45e 100644
--- a/hw/virtio/dataplane/vring.c
+++ b/hw/virtio/dataplane/vring.c
@@ -15,9 +15,53 @@
*/
#include "trace.h"
+#include "hw/hw.h"
+#include "exec/memory.h"
+#include "exec/address-spaces.h"
#include "hw/virtio/dataplane/vring.h"
#include "qemu/error-report.h"
+/* vring_map can be coupled with vring_unmap or (if you still have the
+ * value returned in *mr) memory_region_unref.
+ */
+static void *vring_map(MemoryRegion **mr, hwaddr phys, hwaddr len,
+ bool is_write)
+{
+ MemoryRegionSection section = memory_region_find(get_system_memory(), phys, len);
+
+ if (!section.mr || int128_get64(section.size) < len) {
+ goto out;
+ }
+ if (is_write && section.readonly) {
+ goto out;
+ }
+ if (!memory_region_is_ram(section.mr)) {
+ goto out;
+ }
+
+ /* Ignore regions with dirty logging, we cannot mark them dirty */
+ if (memory_region_is_logging(section.mr)) {
+ goto out;
+ }
+
+ *mr = section.mr;
+ return memory_region_get_ram_ptr(section.mr) + section.offset_within_region;
+
+out:
+ memory_region_unref(section.mr);
+ *mr = NULL;
+ return NULL;
+}
+
+static void vring_unmap(void *buffer, bool is_write)
+{
+ ram_addr_t addr;
+ MemoryRegion *mr;
+
+ mr = qemu_ram_addr_from_host(buffer, &addr);
+ memory_region_unref(mr);
+}
+
/* Map the guest's vring to host memory */
bool vring_setup(Vring *vring, VirtIODevice *vdev, int n)
{
@@ -27,8 +71,7 @@ bool vring_setup(Vring *vring, VirtIODevice *vdev, int n)
vring->broken = false;
- hostmem_init(&vring->hostmem);
- vring_ptr = hostmem_lookup(&vring->hostmem, vring_addr, vring_size, true);
+ vring_ptr = vring_map(&vring->mr, vring_addr, vring_size, true);
if (!vring_ptr) {
error_report("Failed to map vring "
"addr %#" HWADDR_PRIx " size %" HWADDR_PRIu,
@@ -54,7 +97,7 @@ void vring_teardown(Vring *vring, VirtIODevice *vdev, int n)
virtio_queue_set_last_avail_idx(vdev, n, vring->last_avail_idx);
virtio_queue_invalidate_signalled_used(vdev, n);
- hostmem_finalize(&vring->hostmem);
+ memory_region_unref(vring->mr);
}
/* Disable guest->host notifies */
@@ -117,6 +160,7 @@ static int get_desc(Vring *vring, VirtQueueElement *elem,
unsigned *num;
struct iovec *iov;
hwaddr *addr;
+ MemoryRegion *mr;
if (desc->flags & VRING_DESC_F_WRITE) {
num = &elem->in_num;
@@ -141,14 +185,16 @@ static int get_desc(Vring *vring, VirtQueueElement *elem,
}
/* TODO handle non-contiguous memory across region boundaries */
- iov->iov_base = hostmem_lookup(&vring->hostmem, desc->addr, desc->len,
- desc->flags & VRING_DESC_F_WRITE);
+ iov->iov_base = vring_map(&mr, desc->addr, desc->len,
+ desc->flags & VRING_DESC_F_WRITE);
if (!iov->iov_base) {
error_report("Failed to map descriptor addr %#" PRIx64 " len %u",
(uint64_t)desc->addr, desc->len);
return -EFAULT;
}
+ /* The MemoryRegion is looked up again and unref'ed later, leave the
+ * ref in place. */
iov->iov_len = desc->len;
*addr = desc->addr;
*num += 1;
@@ -183,11 +229,12 @@ static int get_indirect(Vring *vring, VirtQueueElement *elem,
do {
struct vring_desc *desc_ptr;
+ MemoryRegion *mr;
/* Translate indirect descriptor */
- desc_ptr = hostmem_lookup(&vring->hostmem,
- indirect->addr + found * sizeof(desc),
- sizeof(desc), false);
+ desc_ptr = vring_map(&mr,
+ indirect->addr + found * sizeof(desc),
+ sizeof(desc), false);
if (!desc_ptr) {
error_report("Failed to map indirect descriptor "
"addr %#" PRIx64 " len %zu",
@@ -197,6 +244,7 @@ static int get_indirect(Vring *vring, VirtQueueElement *elem,
return -EFAULT;
}
desc = *desc_ptr;
+ memory_region_unref(mr);
/* Ensure descriptor has been loaded before accessing fields */
barrier(); /* read_barrier_depends(); */
@@ -226,6 +274,20 @@ static int get_indirect(Vring *vring, VirtQueueElement *elem,
void vring_free_element(VirtQueueElement *elem)
{
+ int i;
+
+ /* This assumes that the iovecs, if changed, are never moved past
+ * the end of the valid area. This is true if iovec manipulations
+ * are done with iov_discard_front and iov_discard_back.
+ */
+ for (i = 0; i < elem->out_num; i++) {
+ vring_unmap(elem->out_sg[i].iov_base, false);
+ }
+
+ for (i = 0; i < elem->in_num; i++) {
+ vring_unmap(elem->in_sg[i].iov_base, true);
+ }
+
g_slice_free(VirtQueueElement, elem);
}
diff --git a/include/hw/virtio/dataplane/hostmem.h b/include/hw/virtio/dataplane/hostmem.h
deleted file mode 100644
index 2810f4b..0000000
--- a/include/hw/virtio/dataplane/hostmem.h
+++ /dev/null
@@ -1,58 +0,0 @@
-/*
- * Thread-safe guest to host memory mapping
- *
- * Copyright 2012 Red Hat, Inc. and/or its affiliates
- *
- * Authors:
- * Stefan Hajnoczi <stefanha@redhat.com>
- *
- * This work is licensed under the terms of the GNU GPL, version 2 or later.
- * See the COPYING file in the top-level directory.
- *
- */
-
-#ifndef HOSTMEM_H
-#define HOSTMEM_H
-
-#include "exec/memory.h"
-#include "qemu/thread.h"
-
-typedef struct {
- MemoryRegion *mr;
- void *host_addr;
- hwaddr guest_addr;
- uint64_t size;
- bool readonly;
-} HostMemRegion;
-
-typedef struct {
- /* The listener is invoked when regions change and a new list of regions is
- * built up completely before they are installed.
- */
- MemoryListener listener;
- HostMemRegion *new_regions;
- size_t num_new_regions;
-
- /* Current regions are accessed from multiple threads either to lookup
- * addresses or to install a new list of regions. The lock protects the
- * pointer and the regions.
- */
- QemuMutex current_regions_lock;
- HostMemRegion *current_regions;
- size_t num_current_regions;
-} HostMem;
-
-void hostmem_init(HostMem *hostmem);
-void hostmem_finalize(HostMem *hostmem);
-
-/**
- * Map a guest physical address to a pointer
- *
- * Note that there is map/unmap mechanism here. The caller must ensure that
- * mapped memory is no longer used across events like hot memory unplug. This
- * can be done with other mechanisms like bdrv_drain_all() that quiesce
- * in-flight I/O.
- */
-void *hostmem_lookup(HostMem *hostmem, hwaddr phys, hwaddr len, bool is_write);
-
-#endif /* HOSTMEM_H */
diff --git a/include/hw/virtio/dataplane/vring.h b/include/hw/virtio/dataplane/vring.h
index 3d6c0df..63e7bf4 100644
--- a/include/hw/virtio/dataplane/vring.h
+++ b/include/hw/virtio/dataplane/vring.h
@@ -19,11 +19,10 @@
#include <linux/virtio_ring.h>
#include "qemu-common.h"
-#include "hostmem.h"
#include "hw/virtio/virtio.h"
typedef struct {
- HostMem hostmem; /* guest memory mapper */
+ MemoryRegion *mr; /* memory region containing the vring */
struct vring vr; /* virtqueue vring mapped to host memory */
uint16_t last_avail_idx; /* last processed avail ring index */
uint16_t last_used_idx; /* last processed used ring index */
--
1.8.3.1
^ permalink raw reply related [flat|nested] 7+ messages in thread* Re: [Qemu-devel] [PATCH v2 0/4] dataplane: use more of the generic virtio data structures, drop hostmem
2013-12-10 12:26 [Qemu-devel] [PATCH v2 0/4] dataplane: use more of the generic virtio data structures, drop hostmem Paolo Bonzini
` (3 preceding siblings ...)
2013-12-10 12:27 ` [Qemu-devel] [PATCH v2 4/4] dataplane: replace hostmem with memory_region_find Paolo Bonzini
@ 2013-12-11 8:49 ` Stefan Hajnoczi
2013-12-16 16:16 ` Stefan Hajnoczi
5 siblings, 0 replies; 7+ messages in thread
From: Stefan Hajnoczi @ 2013-12-11 8:49 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: qemu-devel
On Tue, Dec 10, 2013 at 01:26:57PM +0100, Paolo Bonzini wrote:
> Now that the memory API is thread-safe, we can use it in
> virtio-blk-dataplane and replace hostmem.[ch]. This series does this,
> and also changes the vring API to use VirtQueueElement (with an eye
> towards migration). With this change, virtio-blk-dataplane is also safe
> against memory hot-unplug.
>
> The next step would be to replace memory_region_find with
> address_space_{map,unmap}, which handle dirtying of memory correctly.
> However these APIs are not thread-safe yet, and neither is the handling
> of dirty memory (Juan's patches may be a start here).
>
> Also, the usage of iov_discard_{front,back} may cause some complication
> when we use address_space_{map,unmap}. We may have to change a bit the
> logic in virtio-blk-dataplane to switch to address_space_{map,unmap}.
>
> v1->v2: introduce vring_free_element
>
> Paolo Bonzini (4):
> vring: create a common function to parse descriptors
> vring: factor common code for error exits
> dataplane: change vring API to use VirtQueueElement
> dataplane: replace hostmem with memory_region_find
>
> hw/block/dataplane/virtio-blk.c | 86 +++++-------
> hw/virtio/dataplane/Makefile.objs | 2 +-
> hw/virtio/dataplane/hostmem.c | 183 ------------------------
> hw/virtio/dataplane/vring.c | 253 ++++++++++++++++++++++------------
> include/hw/virtio/dataplane/hostmem.h | 58 --------
> include/hw/virtio/dataplane/vring.h | 10 +-
> 6 files changed, 203 insertions(+), 389 deletions(-)
> delete mode 100644 hw/virtio/dataplane/hostmem.c
> delete mode 100644 include/hw/virtio/dataplane/hostmem.h
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
^ permalink raw reply [flat|nested] 7+ messages in thread* Re: [Qemu-devel] [PATCH v2 0/4] dataplane: use more of the generic virtio data structures, drop hostmem
2013-12-10 12:26 [Qemu-devel] [PATCH v2 0/4] dataplane: use more of the generic virtio data structures, drop hostmem Paolo Bonzini
` (4 preceding siblings ...)
2013-12-11 8:49 ` [Qemu-devel] [PATCH v2 0/4] dataplane: use more of the generic virtio data structures, drop hostmem Stefan Hajnoczi
@ 2013-12-16 16:16 ` Stefan Hajnoczi
5 siblings, 0 replies; 7+ messages in thread
From: Stefan Hajnoczi @ 2013-12-16 16:16 UTC (permalink / raw)
To: Paolo Bonzini; +Cc: qemu-devel, stefanha
On Tue, Dec 10, 2013 at 01:26:57PM +0100, Paolo Bonzini wrote:
> Now that the memory API is thread-safe, we can use it in
> virtio-blk-dataplane and replace hostmem.[ch]. This series does this,
> and also changes the vring API to use VirtQueueElement (with an eye
> towards migration). With this change, virtio-blk-dataplane is also safe
> against memory hot-unplug.
>
> The next step would be to replace memory_region_find with
> address_space_{map,unmap}, which handle dirtying of memory correctly.
> However these APIs are not thread-safe yet, and neither is the handling
> of dirty memory (Juan's patches may be a start here).
>
> Also, the usage of iov_discard_{front,back} may cause some complication
> when we use address_space_{map,unmap}. We may have to change a bit the
> logic in virtio-blk-dataplane to switch to address_space_{map,unmap}.
>
> v1->v2: introduce vring_free_element
>
> Paolo Bonzini (4):
> vring: create a common function to parse descriptors
> vring: factor common code for error exits
> dataplane: change vring API to use VirtQueueElement
> dataplane: replace hostmem with memory_region_find
>
> hw/block/dataplane/virtio-blk.c | 86 +++++-------
> hw/virtio/dataplane/Makefile.objs | 2 +-
> hw/virtio/dataplane/hostmem.c | 183 ------------------------
> hw/virtio/dataplane/vring.c | 253 ++++++++++++++++++++++------------
> include/hw/virtio/dataplane/hostmem.h | 58 --------
> include/hw/virtio/dataplane/vring.h | 10 +-
> 6 files changed, 203 insertions(+), 389 deletions(-)
> delete mode 100644 hw/virtio/dataplane/hostmem.c
> delete mode 100644 include/hw/virtio/dataplane/hostmem.h
Thanks, applied to my block tree:
https://github.com/stefanha/qemu/commits/block
Stefan
^ permalink raw reply [flat|nested] 7+ messages in thread