On Thu, Jul 07, 2022 at 10:44:09AM +0800, Guo Zhi wrote:
> Prior implementation don't use indirection feature because there is only
> one descriptor for every io event, actually prior implementation don't
> support indirection because vhost can't translate and find the indirect
> descriptors. This commit enable virtio_test malloc indirect descriptors
> in a indirect buffer and map this buffer to vhost, thus resolve this
> problem.
>
> Signed-off-by: Guo Zhi <qtxuning1999@xxxxxxxxxxx>
> ---
> tools/virtio/virtio_test.c | 50 ++++++++++++++++++++++++++++++++------
> 1 file changed, 42 insertions(+), 8 deletions(-)
>
> diff --git a/tools/virtio/virtio_test.c b/tools/virtio/virtio_test.c
> index 363695b33..dca408a5c 100644
> --- a/tools/virtio/virtio_test.c
> +++ b/tools/virtio/virtio_test.c
> @@ -25,7 +25,7 @@
> #define RINGSIZE 256
> #define TEST_BUF_NUM 0x100000
> #define BUF_SIZE 1024
> -/* Unused */
> +#define INDIRECTS_SIZE (RINGSIZE * sizeof(struct vring_desc) * 8)
> void *__kmalloc_fake, *__kfree_ignore_start, *__kfree_ignore_end;
>
> struct vq_info {
> @@ -47,6 +47,8 @@ struct vdev_info {
> int nvqs;
> void *buf;
> size_t buf_size;
> + void *indirects;
> + size_t indirects_size;
What are these exactly?
> struct vhost_memory *mem;
> };
>
> @@ -131,6 +133,8 @@ static void vq_info_add(struct vdev_info *dev, int num)
> static void vdev_info_init(struct vdev_info* dev, unsigned long long features)
> {
> int r;
> + int nregions = 2;
> +
> memset(dev, 0, sizeof *dev);
> dev->vdev.features = features;
> INIT_LIST_HEAD(&dev->vdev.vqs);
> @@ -138,19 +142,25 @@ static void vdev_info_init(struct vdev_info* dev, unsigned long long features)
> dev->buf_size = BUF_SIZE;
> dev->buf = malloc(dev->buf_size);
> assert(dev->buf);
> - dev->control = open("/dev/vhost-test", O_RDWR);
> + dev->indirects_size = INDIRECTS_SIZE;
> + dev->indirects = malloc(dev->indirects_size);
> + assert(dev->indirects);
> + dev->control = open("/dev/vhost-test", O_RDWR);
> assert(dev->control >= 0);
> r = ioctl(dev->control, VHOST_SET_OWNER, NULL);
> assert(r >= 0);
> dev->mem = malloc(offsetof(struct vhost_memory, regions) +
> - sizeof dev->mem->regions[0]);
> + (sizeof(dev->mem->regions[0])) * nregions);
> assert(dev->mem);
> memset(dev->mem, 0, offsetof(struct vhost_memory, regions) +
> - sizeof dev->mem->regions[0]);
> - dev->mem->nregions = 1;
> + (sizeof(dev->mem->regions[0])) * nregions);
> + dev->mem->nregions = nregions;
> dev->mem->regions[0].guest_phys_addr = (long)dev->buf;
> dev->mem->regions[0].userspace_addr = (long)dev->buf;
> dev->mem->regions[0].memory_size = dev->buf_size;
> + dev->mem->regions[1].guest_phys_addr = (long)dev->indirects;
> + dev->mem->regions[1].userspace_addr = (long)dev->indirects;
> + dev->mem->regions[1].memory_size = dev->indirects_size;
> r = ioctl(dev->control, VHOST_SET_MEM_TABLE, dev->mem);
> assert(r >= 0);
> }
> @@ -170,6 +180,19 @@ static void wait_for_interrupt(struct vdev_info *dev)
> }
> }
>
> +static int test_virtqueue_add_outbuf(struct virtqueue *vq,
> + struct scatterlist *sg, unsigned int num,
> + void *data, void *indirects)
> +{
> + int r;
> +
> + __kmalloc_fake = indirects;
> + r = virtqueue_add_outbuf(vq, sg, num, data,
> + GFP_ATOMIC);
> + __kmalloc_fake = NULL;
> + return r;
> +}
> +
Quite a hack. Please add comments with documentation. Also - no way to
avoid hacks?
> static void run_test(struct vdev_info *dev, struct vq_info *vq,
> bool delayed, int batch, int reset_n, int bufs)
> {
> @@ -181,6 +204,7 @@ static void run_test(struct vdev_info *dev, struct vq_info *vq,
> unsigned len;
> long long spurious = 0;
> const bool random_batch = batch == RANDOM_BATCH;
> + void *indirects;
>
> r = ioctl(dev->control, VHOST_TEST_RUN, &test);
> assert(r >= 0);
> @@ -188,10 +212,15 @@ static void run_test(struct vdev_info *dev, struct vq_info *vq,
> next_reset = INT_MAX;
> }
>
> + /* Don't kfree indirects. */
> + __kfree_ignore_start = dev->indirects;
> + __kfree_ignore_end = dev->indirects + dev->indirects_size;
> +
> for (;;) {
> virtqueue_disable_cb(vq->vq);
> completed_before = completed;
> started_before = started;
> + indirects = dev->indirects;
> do {
> const bool reset = completed > next_reset;
> if (random_batch)
> @@ -203,9 +232,13 @@ static void run_test(struct vdev_info *dev, struct vq_info *vq,
> sg_init_table(sg, sg_size);
> for (int i = 0; i < sg_size; ++i)
> sg_set_buf(&sg[i], dev->buf + i, 0x1);
> - r = virtqueue_add_outbuf(vq->vq, sg, sg_size,
> - dev->buf + started,
> - GFP_ATOMIC);
> +
> + // use indirects buffer repeatedly
C style comments please.
> + if (indirects + sg_size * sizeof(struct vring_desc) >
> + dev->indirects + dev->indirects_size)
> + indirects = dev->indirects;
> + r = test_virtqueue_add_outbuf(vq->vq, sg, sg_size,
> + dev->buf + started, indirects);
> if (unlikely(r != 0)) {
> if (r == -ENOSPC &&
> started > started_before)
> @@ -216,6 +249,7 @@ static void run_test(struct vdev_info *dev, struct vq_info *vq,
> }
>
> ++started;
> + indirects += sg_size * sizeof(struct vring_desc);
> }
> if (unlikely(!virtqueue_kick(vq->vq))) {
> r = -1;
> --
> 2.17.1
_______________________________________________
Virtualization mailing list
Virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linuxfoundation.org/mailman/listinfo/virtualization
