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qemu-patch-raspberry4
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virtio: introduce virtqueue_alloc_element 

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.huck@de.ibm.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
stable-2.6
Paolo Bonzini 2016-01-31 11:29:00 +01:00 committed by Michael S. Tsirkin
parent ab281c1781
commit 3724650db0
3 changed files with 105 additions and 17 deletions
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3
hw/virtio/dataplane/vring.c
View File

@ -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;

110
hw/virtio/virtio.c
View File

@ -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 */

9
include/hw/virtio/virtio.h
View File

@ -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);