From 3724650db07057333879484c8bc7d900b5c1bf8e Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Sun, 31 Jan 2016 11:29:00 +0100 Subject: 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 Signed-off-by: Paolo Bonzini Reviewed-by: Michael S. Tsirkin Signed-off-by: Michael S. Tsirkin --- hw/virtio/dataplane/vring.c | 3 +- hw/virtio/virtio.c | 110 +++++++++++++++++++++++++++++++++++++++----- 2 files changed, 100 insertions(+), 13 deletions(-) (limited to 'hw/virtio') 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 */ -- cgit v1.1