[PATCH RFC v3 07/12] dataplane: allow virtio-1 devices

Cornelia Huck
2014-11-26T17:29:01Z

Handle endianness conversion for virtio-1 virtqueues correctly.

Note that dataplane now needs to be built per-target.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
---
hw/block/dataplane/virtio-blk.c | 4 +-
hw/scsi/virtio-scsi-dataplane.c | 2 +-
hw/virtio/Makefile.objs | 2 +-
hw/virtio/dataplane/Makefile.objs | 2 +-
hw/virtio/dataplane/vring.c | 86 ++++++++++++++-----------
include/hw/virtio/dataplane/vring-accessors.h | 75 +++++++++++++++++++++
include/hw/virtio/dataplane/vring.h | 14 +---
7 files changed, 131 insertions(+), 54 deletions(-)
create mode 100644 include/hw/virtio/dataplane/vring-accessors.h

diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c
index 1222a37..2d8cc15 100644
--- a/hw/block/dataplane/virtio-blk.c
+++ b/hw/block/dataplane/virtio-blk.c
@@ -16,7 +16,9 @@
#include "qemu/iov.h"
#include "qemu/thread.h"
#include "qemu/error-report.h"
+#include "hw/virtio/virtio-access.h"
#include "hw/virtio/dataplane/vring.h"
+#include "hw/virtio/dataplane/vring-accessors.h"
#include "sysemu/block-backend.h"
#include "hw/virtio/virtio-blk.h"
#include "virtio-blk.h"
@@ -75,7 +77,7 @@ static void complete_request_vring(VirtIOBlockReq *req, unsigned char status)
VirtIOBlockDataPlane *s = req->dev->dataplane;
stb_p(&req->in->status, status);

- vring_push(&req->dev->dataplane->vring, &req->elem,
+ vring_push(s->vdev, &req->dev->dataplane->vring, &req->elem,
req->qiov.size + sizeof(*req->in));

/* Suppress notification to guest by BH and its scheduled
diff --git a/hw/scsi/virtio-scsi-dataplane.c b/hw/scsi/virtio-scsi-dataplane.c
index 03a1e8c..418d73b 100644
--- a/hw/scsi/virtio-scsi-dataplane.c
+++ b/hw/scsi/virtio-scsi-dataplane.c
@@ -94,7 +94,7 @@ void virtio_scsi_vring_push_notify(VirtIOSCSIReq *req)
{
VirtIODevice *vdev = VIRTIO_DEVICE(req->vring->parent);

- vring_push(&req->vring->vring, &req->elem,
+ vring_push(vdev, &req->vring->vring, &req->elem,
req->qsgl.size + req->resp_iov.size);

if (vring_should_notify(vdev, &req->vring->vring)) {
diff --git a/hw/virtio/Makefile.objs b/hw/virtio/Makefile.objs
index d21c397..19b224a 100644
--- a/hw/virtio/Makefile.objs
+++ b/hw/virtio/Makefile.objs
@@ -2,7 +2,7 @@ common-obj-y += virtio-rng.o
common-obj-$(CONFIG_VIRTIO_PCI) += virtio-pci.o
common-obj-y += virtio-bus.o
common-obj-y += virtio-mmio.o
-common-obj-$(CONFIG_VIRTIO) += dataplane/
+obj-$(CONFIG_VIRTIO) += dataplane/

obj-y += virtio.o virtio-balloon.o
obj-$(CONFIG_LINUX) += vhost.o vhost-backend.o vhost-user.o
diff --git a/hw/virtio/dataplane/Makefile.objs b/hw/virtio/dataplane/Makefile.objs
index 9a8cfc0..753a9ca 100644
--- a/hw/virtio/dataplane/Makefile.objs
+++ b/hw/virtio/dataplane/Makefile.objs
@@ -1 +1 @@
-common-obj-y += vring.o
+obj-y += vring.o
diff --git a/hw/virtio/dataplane/vring.c b/hw/virtio/dataplane/vring.c
index a051775..0da8d6b 100644
--- a/hw/virtio/dataplane/vring.c
+++ b/hw/virtio/dataplane/vring.c
@@ -18,7 +18,9 @@
#include "hw/hw.h"
#include "exec/memory.h"
#include "exec/address-spaces.h"
+#include "hw/virtio/virtio-access.h"
#include "hw/virtio/dataplane/vring.h"
+#include "hw/virtio/dataplane/vring-accessors.h"
#include "qemu/error-report.h"

/* vring_map can be coupled with vring_unmap or (if you still have the
@@ -83,7 +85,7 @@ bool vring_setup(Vring *vring, VirtIODevice *vdev, int n)
vring_init(&vring->vr, virtio_queue_get_num(vdev, n), vring_ptr, 4096);

vring->last_avail_idx = virtio_queue_get_last_avail_idx(vdev, n);
- vring->last_used_idx = vring->vr.used->idx;
+ vring->last_used_idx = vring_get_used_idx(vdev, vring);
vring->signalled_used = 0;
vring->signalled_used_valid = false;

@@ -104,7 +106,7 @@ void vring_teardown(Vring *vring, VirtIODevice *vdev, int n)
void vring_disable_notification(VirtIODevice *vdev, Vring *vring)
{
if (!(vdev->guest_features[0] & (1 << VIRTIO_RING_F_EVENT_IDX))) {
- vring->vr.used->flags |= VRING_USED_F_NO_NOTIFY;
+ vring_set_used_flags(vdev, vring, VRING_USED_F_NO_NOTIFY);
}
}

@@ -117,10 +119,10 @@ bool vring_enable_notification(VirtIODevice *vdev, Vring *vring)
if (vdev->guest_features[0] & (1 << VIRTIO_RING_F_EVENT_IDX)) {
vring_avail_event(&vring->vr) = vring->vr.avail->idx;
} else {
- vring->vr.used->flags &= ~VRING_USED_F_NO_NOTIFY;
+ vring_clear_used_flags(vdev, vring, VRING_USED_F_NO_NOTIFY);
}
smp_mb(); /* ensure update is seen before reading avail_idx */
- return !vring_more_avail(vring);
+ return !vring_more_avail(vdev, vring);
}

/* This is stolen from linux/drivers/vhost/vhost.c:vhost_notify() */
@@ -134,12 +136,13 @@ bool vring_should_notify(VirtIODevice *vdev, Vring *vring)
smp_mb();

if ((vdev->guest_features[0] & VIRTIO_F_NOTIFY_ON_EMPTY) &&
- unlikely(vring->vr.avail->idx == vring->last_avail_idx)) {
+ unlikely(!vring_more_avail(vdev, vring))) {
return true;
}

if (!(vdev->guest_features[0] & VIRTIO_RING_F_EVENT_IDX)) {
- return !(vring->vr.avail->flags & VRING_AVAIL_F_NO_INTERRUPT);
+ return !(vring_get_avail_flags(vdev, vring) &
+ VRING_AVAIL_F_NO_INTERRUPT);
}
old = vring->signalled_used;
v = vring->signalled_used_valid;
@@ -154,15 +157,18 @@ bool vring_should_notify(VirtIODevice *vdev, Vring *vring)
}

-static int get_desc(Vring *vring, VirtQueueElement *elem,
+static int get_desc(VirtIODevice *vdev, Vring *vring, VirtQueueElement *elem,
struct vring_desc *desc)
{
unsigned *num;
struct iovec *iov;
hwaddr *addr;
MemoryRegion *mr;
+ int is_write = virtio_tswap16(vdev, desc->flags) & VRING_DESC_F_WRITE;
+ uint32_t len = virtio_tswap32(vdev, desc->len);
+ uint64_t desc_addr = virtio_tswap64(vdev, desc->addr);

- if (desc->flags & VRING_DESC_F_WRITE) {
+ if (is_write) {
num = &elem->in_num;
iov = &elem->in_sg[*num];
addr = &elem->in_addr[*num];
@@ -186,44 +192,45 @@ static int get_desc(Vring *vring, VirtQueueElement *elem,
}

/* TODO handle non-contiguous memory across region boundaries */
- iov->iov_base = vring_map(&mr, desc->addr, desc->len,
- desc->flags & VRING_DESC_F_WRITE);
+ iov->iov_base = vring_map(&mr, desc_addr, len, is_write);
if (!iov->iov_base) {
error_report("Failed to map descriptor addr %#" PRIx64 " len %u",
- (uint64_t)desc->addr, desc->len);
+ (uint64_t)desc_addr, 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;
+ iov->iov_len = len;
+ *addr = desc_addr;
*num += 1;
return 0;
}

/* This is stolen from linux/drivers/vhost/vhost.c. */
-static int get_indirect(Vring *vring, VirtQueueElement *elem,
- struct vring_desc *indirect)
+static int get_indirect(VirtIODevice *vdev, Vring *vring,
+ VirtQueueElement *elem, struct vring_desc *indirect)
{
struct vring_desc desc;
unsigned int i = 0, count, found = 0;
int ret;
+ uint32_t len = virtio_tswap32(vdev, indirect->len);
+ uint64_t addr = virtio_tswap64(vdev, indirect->addr);

/* Sanity check */
- if (unlikely(indirect->len % sizeof(desc))) {
+ if (unlikely(len % sizeof(desc))) {
error_report("Invalid length in indirect descriptor: "
"len %#x not multiple of %#zx",
- indirect->len, sizeof(desc));
+ len, sizeof(desc));
vring->broken = true;
return -EFAULT;
}

- count = indirect->len / sizeof(desc);
+ count = len / sizeof(desc);
/* Buffers are chained via a 16 bit next field, so
* we can have at most 2^16 of these. */
if (unlikely(count > USHRT_MAX + 1)) {
- error_report("Indirect buffer length too big: %d", indirect->len);
+ error_report("Indirect buffer length too big: %d", len);
vring->broken = true;
return -EFAULT;
}
@@ -234,12 +241,12 @@ static int get_indirect(Vring *vring, VirtQueueElement *elem,

/* Translate indirect descriptor */
desc_ptr = vring_map(&mr,
- indirect->addr + found * sizeof(desc),
+ addr + found * sizeof(desc),
sizeof(desc), false);
if (!desc_ptr) {
error_report("Failed to map indirect descriptor "
"addr %#" PRIx64 " len %zu",
- (uint64_t)indirect->addr + found * sizeof(desc),
+ (uint64_t)addr + found * sizeof(desc),
sizeof(desc));
vring->broken = true;
return -EFAULT;
@@ -257,19 +264,20 @@ static int get_indirect(Vring *vring, VirtQueueElement *elem,
return -EFAULT;
}

- if (unlikely(desc.flags & VRING_DESC_F_INDIRECT)) {
+ if (unlikely(virtio_tswap16(vdev, desc.flags)
+ & VRING_DESC_F_INDIRECT)) {
error_report("Nested indirect descriptor");
vring->broken = true;
return -EFAULT;
}

- ret = get_desc(vring, elem, &desc);
+ ret = get_desc(vdev, vring, elem, &desc);
if (ret < 0) {
vring->broken |= (ret == -EFAULT);
return ret;
}
- i = desc.next;
- } while (desc.flags & VRING_DESC_F_NEXT);
+ i = virtio_tswap16(vdev, desc.next);
+ } while (virtio_tswap16(vdev, desc.flags) & VRING_DESC_F_NEXT);
return 0;
}

@@ -320,7 +328,7 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,

/* Check it isn't doing very strange things with descriptor numbers. */
last_avail_idx = vring->last_avail_idx;
- avail_idx = vring->vr.avail->idx;
+ avail_idx = vring_get_avail_idx(vdev, vring);
barrier(); /* load indices now and not again later */

if (unlikely((uint16_t)(avail_idx - last_avail_idx) > num)) {
@@ -341,7 +349,7 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,

/* Grab the next descriptor number they're advertising, and increment
* the index we've seen. */
- head = vring->vr.avail->ring[last_avail_idx % num];
+ head = vring_get_avail_ring(vdev, vring, last_avail_idx % num);

elem->index = head;

@@ -370,21 +378,21 @@ int vring_pop(VirtIODevice *vdev, Vring *vring,
/* Ensure descriptor is loaded before accessing fields */
barrier();

- if (desc.flags & VRING_DESC_F_INDIRECT) {
- ret = get_indirect(vring, elem, &desc);
+ if (virtio_tswap16(vdev, desc.flags) & VRING_DESC_F_INDIRECT) {
+ ret = get_indirect(vdev, vring, elem, &desc);
if (ret < 0) {
goto out;
}
continue;
}

- ret = get_desc(vring, elem, &desc);
+ ret = get_desc(vdev, vring, elem, &desc);
if (ret < 0) {
goto out;
}

- i = desc.next;
- } while (desc.flags & VRING_DESC_F_NEXT);
+ i = virtio_tswap16(vdev, desc.next);
+ } while (virtio_tswap16(vdev, desc.flags) & VRING_DESC_F_NEXT);

/* On success, increment avail index. */
vring->last_avail_idx++;
@@ -407,9 +415,9 @@ out:
*
* Stolen from linux/drivers/vhost/vhost.c.
*/
-void vring_push(Vring *vring, VirtQueueElement *elem, int len)
+void vring_push(VirtIODevice *vdev, Vring *vring, VirtQueueElement *elem,
+ int len)
{
- struct vring_used_elem *used;
unsigned int head = elem->index;
uint16_t new;

@@ -422,14 +430,16 @@ void vring_push(Vring *vring, VirtQueueElement *elem, int len)

/* The virtqueue contains a ring of used buffers. Get a pointer to the
* next entry in that used ring. */
- used = &vring->vr.used->ring[vring->last_used_idx % vring->vr.num];
- used->id = head;
- used->len = len;
+ vring_set_used_ring_id(vdev, vring, vring->last_used_idx % vring->vr.num,
+ head);
+ vring_set_used_ring_len(vdev, vring, vring->last_used_idx % vring->vr.num,
+ len);

/* Make sure buffer is written before we update index. */
smp_wmb();

- new = vring->vr.used->idx = ++vring->last_used_idx;
+ new = ++vring->last_used_idx;
+ vring_set_used_idx(vdev, vring, new);
if (unlikely((int16_t)(new - vring->signalled_used) < (uint16_t)1)) {
vring->signalled_used_valid = false;
}
diff --git a/include/hw/virtio/dataplane/vring-accessors.h b/include/hw/virtio/dataplane/vring-accessors.h
new file mode 100644
index 0000000..b508b87
--- /dev/null
+++ b/include/hw/virtio/dataplane/vring-accessors.h
@@ -0,0 +1,75 @@
+#ifndef VRING_ACCESSORS_H
+#define VRING_ACCESSORS_H
+
+#include "hw/virtio/virtio_ring.h"
+#include "hw/virtio/virtio.h"
+#include "hw/virtio/virtio-access.h"
+
+static inline uint16_t vring_get_used_idx(VirtIODevice *vdev, Vring *vring)
+{
+ return virtio_tswap16(vdev, vring->vr.used->idx);
+}
+
+static inline void vring_set_used_idx(VirtIODevice *vdev, Vring *vring,
+ uint16_t idx)
+{
+ vring->vr.used->idx = virtio_tswap16(vdev, idx);
+}
+
+static inline uint16_t vring_get_avail_idx(VirtIODevice *vdev, Vring *vring)
+{
+ return virtio_tswap16(vdev, vring->vr.avail->idx);
+}
+
+static inline uint16_t vring_get_avail_ring(VirtIODevice *vdev, Vring *vring,
+ int i)
+{
+ return virtio_tswap16(vdev, vring->vr.avail->ring[i]);
+}
+
+static inline void vring_set_used_ring_id(VirtIODevice *vdev, Vring *vring,
+ int i, uint32_t id)
+{
+ vring->vr.used->ring[i].id = virtio_tswap32(vdev, id);
+}
+
+static inline void vring_set_used_ring_len(VirtIODevice *vdev, Vring *vring,
+ int i, uint32_t len)
+{
+ vring->vr.used->ring[i].len = virtio_tswap32(vdev, len);
+}
+
+static inline uint16_t vring_get_used_flags(VirtIODevice *vdev, Vring *vring)
+{
+ return virtio_tswap16(vdev, vring->vr.used->flags);
+}
+
+static inline uint16_t vring_get_avail_flags(VirtIODevice *vdev, Vring *vring)
+{
+ return virtio_tswap16(vdev, vring->vr.avail->flags);
+}
+
+static inline void vring_set_used_flags(VirtIODevice *vdev, Vring *vring,
+ uint16_t flags)
+{
+ vring->vr.used->flags |= virtio_tswap16(vdev, flags);
+}
+
+static inline void vring_clear_used_flags(VirtIODevice *vdev, Vring *vring,
+ uint16_t flags)
+{
+ vring->vr.used->flags &= virtio_tswap16(vdev, ~flags);
+}
+
+static inline unsigned int vring_get_num(Vring *vring)
+{
+ return vring->vr.num;
+}
+
+/* Are there more descriptors available? */
+static inline bool vring_more_avail(VirtIODevice *vdev, Vring *vring)
+{
+ return vring_get_avail_idx(vdev, vring) != vring->last_avail_idx;
+}
+
+#endif
diff --git a/include/hw/virtio/dataplane/vring.h b/include/hw/virtio/dataplane/vring.h
index d3e086a..e42c0fc 100644
--- a/include/hw/virtio/dataplane/vring.h
+++ b/include/hw/virtio/dataplane/vring.h
@@ -31,17 +31,6 @@ typedef struct {
bool broken; /* was there a fatal error? */
} Vring;

-static inline unsigned int vring_get_num(Vring *vring)
-{
- return vring->vr.num;
-}
-
-/* Are there more descriptors available? */
-static inline bool vring_more_avail(Vring *vring)
-{
- return vring->vr.avail->idx != vring->last_avail_idx;
-}
-
/* Fail future vring_pop() and vring_push() calls until reset */
static inline void vring_set_broken(Vring *vring)
{
@@ -54,6 +43,7 @@ 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, VirtQueueElement *elem);
-void vring_push(Vring *vring, VirtQueueElement *elem, int len);
+void vring_push(VirtIODevice *vdev, Vring *vring, VirtQueueElement *elem,
+ int len);

#endif /* VRING_H */
--
1.7.9.5