From: Paolo Bonzini <pbonz...@redhat.com>
Allocate the arrays for in_addr/out_addr/in_sg/out_sg outside the
VirtQueueElement. For now, virtqueue_pop and vring_pop keep
allocating a very large VirtQueueElement.
Reviewed-by: Cornelia Huck <cornelia.h...@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Reviewed-by: Michael S. Tsirkin <m...@redhat.com>
Signed-off-by: Michael S. Tsirkin <m...@redhat.com>
---
include/hw/virtio/virtio.h | 9 ++--
hw/virtio/dataplane/vring.c | 3 +-
hw/virtio/virtio.c | 110 +++++++++++++++++++++++++++++++++++++++-----
3 files changed, 105 insertions(+), 17 deletions(-)
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index 44da9a8..108cdb0 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -46,10 +46,10 @@ typedef struct VirtQueueElement
unsigned int index;
unsigned int out_num;
unsigned int in_num;
- hwaddr in_addr[VIRTQUEUE_MAX_SIZE];
- hwaddr out_addr[VIRTQUEUE_MAX_SIZE];
- struct iovec in_sg[VIRTQUEUE_MAX_SIZE];
- struct iovec out_sg[VIRTQUEUE_MAX_SIZE];
+ hwaddr *in_addr;
+ hwaddr *out_addr;
+ struct iovec *in_sg;
+ struct iovec *out_sg;
} VirtQueueElement;
#define VIRTIO_QUEUE_MAX 1024
@@ -143,6 +143,7 @@ VirtQueue *virtio_add_queue(VirtIODevice *vdev, int
queue_size,
void virtio_del_queue(VirtIODevice *vdev, int n);
+void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned in_num);
void virtqueue_push(VirtQueue *vq, const VirtQueueElement *elem,
unsigned int len);
void virtqueue_flush(VirtQueue *vq, unsigned int count);
diff --git a/hw/virtio/dataplane/vring.c b/hw/virtio/dataplane/vring.c
index 4fb84bb..57ada3b 100644
--- a/hw/virtio/dataplane/vring.c
+++ b/hw/virtio/dataplane/vring.c
@@ -403,8 +403,7 @@ void *vring_pop(VirtIODevice *vdev, Vring *vring, size_t sz)
goto out;
}
- assert(sz >= sizeof(VirtQueueElement));
- elem = g_malloc(sz);
+ elem = virtqueue_alloc_element(sz, VIRTQUEUE_MAX_SIZE, VIRTQUEUE_MAX_SIZE);
/* Initialize elem so it can be safely unmapped */
elem->in_num = elem->out_num = 0;
diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 28fa7fe..661a1e1 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -494,11 +494,30 @@ static void virtqueue_map_iovec(struct iovec *sg, hwaddr
*addr,
void virtqueue_map(VirtQueueElement *elem)
{
virtqueue_map_iovec(elem->in_sg, elem->in_addr, &elem->in_num,
- MIN(ARRAY_SIZE(elem->in_sg),
ARRAY_SIZE(elem->in_addr)),
- 1);
+ VIRTQUEUE_MAX_SIZE, 1);
virtqueue_map_iovec(elem->out_sg, elem->out_addr, &elem->out_num,
- MIN(ARRAY_SIZE(elem->out_sg),
ARRAY_SIZE(elem->out_addr)),
- 0);
+ VIRTQUEUE_MAX_SIZE, 0);
+}
+
+void *virtqueue_alloc_element(size_t sz, unsigned out_num, unsigned in_num)
+{
+ VirtQueueElement *elem;
+ size_t in_addr_ofs = QEMU_ALIGN_UP(sz, __alignof__(elem->in_addr[0]));
+ size_t out_addr_ofs = in_addr_ofs + in_num * sizeof(elem->in_addr[0]);
+ size_t out_addr_end = out_addr_ofs + out_num * sizeof(elem->out_addr[0]);
+ size_t in_sg_ofs = QEMU_ALIGN_UP(out_addr_end,
__alignof__(elem->in_sg[0]));
+ size_t out_sg_ofs = in_sg_ofs + in_num * sizeof(elem->in_sg[0]);
+ size_t out_sg_end = out_sg_ofs + out_num * sizeof(elem->out_sg[0]);
+
+ assert(sz >= sizeof(VirtQueueElement));
+ elem = g_malloc(out_sg_end);
+ elem->out_num = out_num;
+ elem->in_num = in_num;
+ elem->in_addr = (void *)elem + in_addr_ofs;
+ elem->out_addr = (void *)elem + out_addr_ofs;
+ elem->in_sg = (void *)elem + in_sg_ofs;
+ elem->out_sg = (void *)elem + out_sg_ofs;
+ return elem;
}
void *virtqueue_pop(VirtQueue *vq, size_t sz)
@@ -513,8 +532,7 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz)
}
/* When we start there are none of either input nor output. */
- assert(sz >= sizeof(VirtQueueElement));
- elem = g_malloc(sz);
+ elem = virtqueue_alloc_element(sz, VIRTQUEUE_MAX_SIZE, VIRTQUEUE_MAX_SIZE);
elem->out_num = elem->in_num = 0;
max = vq->vring.num;
@@ -541,14 +559,14 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz)
struct iovec *sg;
if (vring_desc_flags(vdev, desc_pa, i) & VRING_DESC_F_WRITE) {
- if (elem->in_num >= ARRAY_SIZE(elem->in_sg)) {
+ if (elem->in_num >= VIRTQUEUE_MAX_SIZE) {
error_report("Too many write descriptors in indirect table");
exit(1);
}
elem->in_addr[elem->in_num] = vring_desc_addr(vdev, desc_pa, i);
sg = &elem->in_sg[elem->in_num++];
} else {
- if (elem->out_num >= ARRAY_SIZE(elem->out_sg)) {
+ if (elem->out_num >= VIRTQUEUE_MAX_SIZE) {
error_report("Too many read descriptors in indirect table");
exit(1);
}
@@ -576,17 +594,87 @@ void *virtqueue_pop(VirtQueue *vq, size_t sz)
return elem;
}
+/* Reading and writing a structure directly to QEMUFile is *awful*, but
+ * it is what QEMU has always done by mistake. We can change it sooner
+ * or later by bumping the version number of the affected vm states.
+ * In the meanwhile, since the in-memory layout of VirtQueueElement
+ * has changed, we need to marshal to and from the layout that was
+ * used before the change.
+ */
+typedef struct VirtQueueElementOld {
+ unsigned int index;
+ unsigned int out_num;
+ unsigned int in_num;
+ hwaddr in_addr[VIRTQUEUE_MAX_SIZE];
+ hwaddr out_addr[VIRTQUEUE_MAX_SIZE];
+ struct iovec in_sg[VIRTQUEUE_MAX_SIZE];
+ struct iovec out_sg[VIRTQUEUE_MAX_SIZE];
+} VirtQueueElementOld;
+
void *qemu_get_virtqueue_element(QEMUFile *f, size_t sz)
{
- VirtQueueElement *elem = g_malloc(sz);
- qemu_get_buffer(f, (uint8_t *)elem, sizeof(VirtQueueElement));
+ VirtQueueElement *elem;
+ VirtQueueElementOld data;
+ int i;
+
+ qemu_get_buffer(f, (uint8_t *)&data, sizeof(VirtQueueElementOld));
+
+ elem = virtqueue_alloc_element(sz, data.out_num, data.in_num);
+ elem->index = data.index;
+
+ for (i = 0; i < elem->in_num; i++) {
+ elem->in_addr[i] = data.in_addr[i];
+ }
+
+ for (i = 0; i < elem->out_num; i++) {
+ elem->out_addr[i] = data.out_addr[i];
+ }
+
+ for (i = 0; i < elem->in_num; i++) {
+ /* Base is overwritten by virtqueue_map. */
+ elem->in_sg[i].iov_base = 0;
+ elem->in_sg[i].iov_len = data.in_sg[i].iov_len;
+ }
+
+ for (i = 0; i < elem->out_num; i++) {
+ /* Base is overwritten by virtqueue_map. */
+ elem->out_sg[i].iov_base = 0;
+ elem->out_sg[i].iov_len = data.out_sg[i].iov_len;
+ }
+
virtqueue_map(elem);
return elem;
}
void qemu_put_virtqueue_element(QEMUFile *f, VirtQueueElement *elem)
{
- qemu_put_buffer(f, (uint8_t *)elem, sizeof(VirtQueueElement));
+ VirtQueueElementOld data;
+ int i;
+
+ memset(&data, 0, sizeof(data));
+ data.index = elem->index;
+ data.in_num = elem->in_num;
+ data.out_num = elem->out_num;
+
+ for (i = 0; i < elem->in_num; i++) {
+ data.in_addr[i] = elem->in_addr[i];
+ }
+
+ for (i = 0; i < elem->out_num; i++) {
+ data.out_addr[i] = elem->out_addr[i];
+ }
+
+ for (i = 0; i < elem->in_num; i++) {
+ /* Base is overwritten by virtqueue_map when loading. Do not
+ * save it, as it would leak the QEMU address space layout. */
+ data.in_sg[i].iov_len = elem->in_sg[i].iov_len;
+ }
+
+ for (i = 0; i < elem->out_num; i++) {
+ /* Do not save iov_base as above. */
+ data.out_sg[i].iov_len = elem->out_sg[i].iov_len;
+ }
+ qemu_put_buffer(f, (uint8_t *)&data, sizeof(VirtQueueElementOld));
}
/* virtio device */
--
MST
