linux/tools/virtio/vringh_test.c
Heinz Graalfs 46f9c2b925 virtio_ring: change host notification API
Currently a host kick error is silently ignored and not reflected in
the virtqueue of a particular virtio device.

Changing the notify API for guest->host notification seems to be one
prerequisite in order to be able to handle such errors in the context
where the kick is triggered.

This patch changes the notify API. The notify function must return a
bool return value. It returns false if the host notification failed.

Signed-off-by: Heinz Graalfs <graalfs@linux.vnet.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2013-10-29 11:28:11 +10:30

747 lines
20 KiB
C

/* Simple test of virtio code, entirely in userpsace. */
#define _GNU_SOURCE
#include <sched.h>
#include <err.h>
#include <linux/kernel.h>
#include <linux/err.h>
#include <linux/virtio.h>
#include <linux/vringh.h>
#include <linux/virtio_ring.h>
#include <linux/uaccess.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include <fcntl.h>
#define USER_MEM (1024*1024)
void *__user_addr_min, *__user_addr_max;
void *__kmalloc_fake, *__kfree_ignore_start, *__kfree_ignore_end;
static u64 user_addr_offset;
#define RINGSIZE 256
#define ALIGN 4096
static bool never_notify_host(struct virtqueue *vq)
{
abort();
}
static void never_callback_guest(struct virtqueue *vq)
{
abort();
}
static bool getrange_iov(struct vringh *vrh, u64 addr, struct vringh_range *r)
{
if (addr < (u64)(unsigned long)__user_addr_min - user_addr_offset)
return false;
if (addr >= (u64)(unsigned long)__user_addr_max - user_addr_offset)
return false;
r->start = (u64)(unsigned long)__user_addr_min - user_addr_offset;
r->end_incl = (u64)(unsigned long)__user_addr_max - 1 - user_addr_offset;
r->offset = user_addr_offset;
return true;
}
/* We return single byte ranges. */
static bool getrange_slow(struct vringh *vrh, u64 addr, struct vringh_range *r)
{
if (addr < (u64)(unsigned long)__user_addr_min - user_addr_offset)
return false;
if (addr >= (u64)(unsigned long)__user_addr_max - user_addr_offset)
return false;
r->start = addr;
r->end_incl = r->start;
r->offset = user_addr_offset;
return true;
}
struct guest_virtio_device {
struct virtio_device vdev;
int to_host_fd;
unsigned long notifies;
};
static bool parallel_notify_host(struct virtqueue *vq)
{
int rc;
struct guest_virtio_device *gvdev;
gvdev = container_of(vq->vdev, struct guest_virtio_device, vdev);
rc = write(gvdev->to_host_fd, "", 1);
if (rc < 0)
return false;
gvdev->notifies++;
return true;
}
static bool no_notify_host(struct virtqueue *vq)
{
return true;
}
#define NUM_XFERS (10000000)
/* We aim for two "distant" cpus. */
static void find_cpus(unsigned int *first, unsigned int *last)
{
unsigned int i;
*first = -1U;
*last = 0;
for (i = 0; i < 4096; i++) {
cpu_set_t set;
CPU_ZERO(&set);
CPU_SET(i, &set);
if (sched_setaffinity(getpid(), sizeof(set), &set) == 0) {
if (i < *first)
*first = i;
if (i > *last)
*last = i;
}
}
}
/* Opencoded version for fast mode */
static inline int vringh_get_head(struct vringh *vrh, u16 *head)
{
u16 avail_idx, i;
int err;
err = get_user(avail_idx, &vrh->vring.avail->idx);
if (err)
return err;
if (vrh->last_avail_idx == avail_idx)
return 0;
/* Only get avail ring entries after they have been exposed by guest. */
virtio_rmb(vrh->weak_barriers);
i = vrh->last_avail_idx & (vrh->vring.num - 1);
err = get_user(*head, &vrh->vring.avail->ring[i]);
if (err)
return err;
vrh->last_avail_idx++;
return 1;
}
static int parallel_test(unsigned long features,
bool (*getrange)(struct vringh *vrh,
u64 addr, struct vringh_range *r),
bool fast_vringh)
{
void *host_map, *guest_map;
int fd, mapsize, to_guest[2], to_host[2];
unsigned long xfers = 0, notifies = 0, receives = 0;
unsigned int first_cpu, last_cpu;
cpu_set_t cpu_set;
char buf[128];
/* Create real file to mmap. */
fd = open("/tmp/vringh_test-file", O_RDWR|O_CREAT|O_TRUNC, 0600);
if (fd < 0)
err(1, "Opening /tmp/vringh_test-file");
/* Extra room at the end for some data, and indirects */
mapsize = vring_size(RINGSIZE, ALIGN)
+ RINGSIZE * 2 * sizeof(int)
+ RINGSIZE * 6 * sizeof(struct vring_desc);
mapsize = (mapsize + getpagesize() - 1) & ~(getpagesize() - 1);
ftruncate(fd, mapsize);
/* Parent and child use separate addresses, to check our mapping logic! */
host_map = mmap(NULL, mapsize, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
guest_map = mmap(NULL, mapsize, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
pipe(to_guest);
pipe(to_host);
CPU_ZERO(&cpu_set);
find_cpus(&first_cpu, &last_cpu);
printf("Using CPUS %u and %u\n", first_cpu, last_cpu);
fflush(stdout);
if (fork() != 0) {
struct vringh vrh;
int status, err, rlen = 0;
char rbuf[5];
/* We are the host: never access guest addresses! */
munmap(guest_map, mapsize);
__user_addr_min = host_map;
__user_addr_max = __user_addr_min + mapsize;
user_addr_offset = host_map - guest_map;
assert(user_addr_offset);
close(to_guest[0]);
close(to_host[1]);
vring_init(&vrh.vring, RINGSIZE, host_map, ALIGN);
vringh_init_user(&vrh, features, RINGSIZE, true,
vrh.vring.desc, vrh.vring.avail, vrh.vring.used);
CPU_SET(first_cpu, &cpu_set);
if (sched_setaffinity(getpid(), sizeof(cpu_set), &cpu_set))
errx(1, "Could not set affinity to cpu %u", first_cpu);
while (xfers < NUM_XFERS) {
struct iovec host_riov[2], host_wiov[2];
struct vringh_iov riov, wiov;
u16 head, written;
if (fast_vringh) {
for (;;) {
err = vringh_get_head(&vrh, &head);
if (err != 0)
break;
err = vringh_need_notify_user(&vrh);
if (err < 0)
errx(1, "vringh_need_notify_user: %i",
err);
if (err) {
write(to_guest[1], "", 1);
notifies++;
}
}
if (err != 1)
errx(1, "vringh_get_head");
written = 0;
goto complete;
} else {
vringh_iov_init(&riov,
host_riov,
ARRAY_SIZE(host_riov));
vringh_iov_init(&wiov,
host_wiov,
ARRAY_SIZE(host_wiov));
err = vringh_getdesc_user(&vrh, &riov, &wiov,
getrange, &head);
}
if (err == 0) {
err = vringh_need_notify_user(&vrh);
if (err < 0)
errx(1, "vringh_need_notify_user: %i",
err);
if (err) {
write(to_guest[1], "", 1);
notifies++;
}
if (!vringh_notify_enable_user(&vrh))
continue;
/* Swallow all notifies at once. */
if (read(to_host[0], buf, sizeof(buf)) < 1)
break;
vringh_notify_disable_user(&vrh);
receives++;
continue;
}
if (err != 1)
errx(1, "vringh_getdesc_user: %i", err);
/* We simply copy bytes. */
if (riov.used) {
rlen = vringh_iov_pull_user(&riov, rbuf,
sizeof(rbuf));
if (rlen != 4)
errx(1, "vringh_iov_pull_user: %i",
rlen);
assert(riov.i == riov.used);
written = 0;
} else {
err = vringh_iov_push_user(&wiov, rbuf, rlen);
if (err != rlen)
errx(1, "vringh_iov_push_user: %i",
err);
assert(wiov.i == wiov.used);
written = err;
}
complete:
xfers++;
err = vringh_complete_user(&vrh, head, written);
if (err != 0)
errx(1, "vringh_complete_user: %i", err);
}
err = vringh_need_notify_user(&vrh);
if (err < 0)
errx(1, "vringh_need_notify_user: %i", err);
if (err) {
write(to_guest[1], "", 1);
notifies++;
}
wait(&status);
if (!WIFEXITED(status))
errx(1, "Child died with signal %i?", WTERMSIG(status));
if (WEXITSTATUS(status) != 0)
errx(1, "Child exited %i?", WEXITSTATUS(status));
printf("Host: notified %lu, pinged %lu\n", notifies, receives);
return 0;
} else {
struct guest_virtio_device gvdev;
struct virtqueue *vq;
unsigned int *data;
struct vring_desc *indirects;
unsigned int finished = 0;
/* We pass sg[]s pointing into here, but we need RINGSIZE+1 */
data = guest_map + vring_size(RINGSIZE, ALIGN);
indirects = (void *)data + (RINGSIZE + 1) * 2 * sizeof(int);
/* We are the guest. */
munmap(host_map, mapsize);
close(to_guest[1]);
close(to_host[0]);
gvdev.vdev.features[0] = features;
gvdev.to_host_fd = to_host[1];
gvdev.notifies = 0;
CPU_SET(first_cpu, &cpu_set);
if (sched_setaffinity(getpid(), sizeof(cpu_set), &cpu_set))
err(1, "Could not set affinity to cpu %u", first_cpu);
vq = vring_new_virtqueue(0, RINGSIZE, ALIGN, &gvdev.vdev, true,
guest_map, fast_vringh ? no_notify_host
: parallel_notify_host,
never_callback_guest, "guest vq");
/* Don't kfree indirects. */
__kfree_ignore_start = indirects;
__kfree_ignore_end = indirects + RINGSIZE * 6;
while (xfers < NUM_XFERS) {
struct scatterlist sg[4];
unsigned int num_sg, len;
int *dbuf, err;
bool output = !(xfers % 2);
/* Consume bufs. */
while ((dbuf = virtqueue_get_buf(vq, &len)) != NULL) {
if (len == 4)
assert(*dbuf == finished - 1);
else if (!fast_vringh)
assert(*dbuf == finished);
finished++;
}
/* Produce a buffer. */
dbuf = data + (xfers % (RINGSIZE + 1));
if (output)
*dbuf = xfers;
else
*dbuf = -1;
switch ((xfers / sizeof(*dbuf)) % 4) {
case 0:
/* Nasty three-element sg list. */
sg_init_table(sg, num_sg = 3);
sg_set_buf(&sg[0], (void *)dbuf, 1);
sg_set_buf(&sg[1], (void *)dbuf + 1, 2);
sg_set_buf(&sg[2], (void *)dbuf + 3, 1);
break;
case 1:
sg_init_table(sg, num_sg = 2);
sg_set_buf(&sg[0], (void *)dbuf, 1);
sg_set_buf(&sg[1], (void *)dbuf + 1, 3);
break;
case 2:
sg_init_table(sg, num_sg = 1);
sg_set_buf(&sg[0], (void *)dbuf, 4);
break;
case 3:
sg_init_table(sg, num_sg = 4);
sg_set_buf(&sg[0], (void *)dbuf, 1);
sg_set_buf(&sg[1], (void *)dbuf + 1, 1);
sg_set_buf(&sg[2], (void *)dbuf + 2, 1);
sg_set_buf(&sg[3], (void *)dbuf + 3, 1);
break;
}
/* May allocate an indirect, so force it to allocate
* user addr */
__kmalloc_fake = indirects + (xfers % RINGSIZE) * 4;
if (output)
err = virtqueue_add_outbuf(vq, sg, num_sg, dbuf,
GFP_KERNEL);
else
err = virtqueue_add_inbuf(vq, sg, num_sg,
dbuf, GFP_KERNEL);
if (err == -ENOSPC) {
if (!virtqueue_enable_cb_delayed(vq))
continue;
/* Swallow all notifies at once. */
if (read(to_guest[0], buf, sizeof(buf)) < 1)
break;
receives++;
virtqueue_disable_cb(vq);
continue;
}
if (err)
errx(1, "virtqueue_add_in/outbuf: %i", err);
xfers++;
virtqueue_kick(vq);
}
/* Any extra? */
while (finished != xfers) {
int *dbuf;
unsigned int len;
/* Consume bufs. */
dbuf = virtqueue_get_buf(vq, &len);
if (dbuf) {
if (len == 4)
assert(*dbuf == finished - 1);
else
assert(len == 0);
finished++;
continue;
}
if (!virtqueue_enable_cb_delayed(vq))
continue;
if (read(to_guest[0], buf, sizeof(buf)) < 1)
break;
receives++;
virtqueue_disable_cb(vq);
}
printf("Guest: notified %lu, pinged %lu\n",
gvdev.notifies, receives);
vring_del_virtqueue(vq);
return 0;
}
}
int main(int argc, char *argv[])
{
struct virtio_device vdev;
struct virtqueue *vq;
struct vringh vrh;
struct scatterlist guest_sg[RINGSIZE], *sgs[2];
struct iovec host_riov[2], host_wiov[2];
struct vringh_iov riov, wiov;
struct vring_used_elem used[RINGSIZE];
char buf[28];
u16 head;
int err;
unsigned i;
void *ret;
bool (*getrange)(struct vringh *vrh, u64 addr, struct vringh_range *r);
bool fast_vringh = false, parallel = false;
getrange = getrange_iov;
vdev.features[0] = 0;
while (argv[1]) {
if (strcmp(argv[1], "--indirect") == 0)
vdev.features[0] |= (1 << VIRTIO_RING_F_INDIRECT_DESC);
else if (strcmp(argv[1], "--eventidx") == 0)
vdev.features[0] |= (1 << VIRTIO_RING_F_EVENT_IDX);
else if (strcmp(argv[1], "--slow-range") == 0)
getrange = getrange_slow;
else if (strcmp(argv[1], "--fast-vringh") == 0)
fast_vringh = true;
else if (strcmp(argv[1], "--parallel") == 0)
parallel = true;
else
errx(1, "Unknown arg %s", argv[1]);
argv++;
}
if (parallel)
return parallel_test(vdev.features[0], getrange, fast_vringh);
if (posix_memalign(&__user_addr_min, PAGE_SIZE, USER_MEM) != 0)
abort();
__user_addr_max = __user_addr_min + USER_MEM;
memset(__user_addr_min, 0, vring_size(RINGSIZE, ALIGN));
/* Set up guest side. */
vq = vring_new_virtqueue(0, RINGSIZE, ALIGN, &vdev, true,
__user_addr_min,
never_notify_host, never_callback_guest,
"guest vq");
/* Set up host side. */
vring_init(&vrh.vring, RINGSIZE, __user_addr_min, ALIGN);
vringh_init_user(&vrh, vdev.features[0], RINGSIZE, true,
vrh.vring.desc, vrh.vring.avail, vrh.vring.used);
/* No descriptor to get yet... */
err = vringh_getdesc_user(&vrh, &riov, &wiov, getrange, &head);
if (err != 0)
errx(1, "vringh_getdesc_user: %i", err);
/* Guest puts in a descriptor. */
memcpy(__user_addr_max - 1, "a", 1);
sg_init_table(guest_sg, 1);
sg_set_buf(&guest_sg[0], __user_addr_max - 1, 1);
sg_init_table(guest_sg+1, 1);
sg_set_buf(&guest_sg[1], __user_addr_max - 3, 2);
sgs[0] = &guest_sg[0];
sgs[1] = &guest_sg[1];
/* May allocate an indirect, so force it to allocate user addr */
__kmalloc_fake = __user_addr_min + vring_size(RINGSIZE, ALIGN);
err = virtqueue_add_sgs(vq, sgs, 1, 1, &err, GFP_KERNEL);
if (err)
errx(1, "virtqueue_add_sgs: %i", err);
__kmalloc_fake = NULL;
/* Host retreives it. */
vringh_iov_init(&riov, host_riov, ARRAY_SIZE(host_riov));
vringh_iov_init(&wiov, host_wiov, ARRAY_SIZE(host_wiov));
err = vringh_getdesc_user(&vrh, &riov, &wiov, getrange, &head);
if (err != 1)
errx(1, "vringh_getdesc_user: %i", err);
assert(riov.used == 1);
assert(riov.iov[0].iov_base == __user_addr_max - 1);
assert(riov.iov[0].iov_len == 1);
if (getrange != getrange_slow) {
assert(wiov.used == 1);
assert(wiov.iov[0].iov_base == __user_addr_max - 3);
assert(wiov.iov[0].iov_len == 2);
} else {
assert(wiov.used == 2);
assert(wiov.iov[0].iov_base == __user_addr_max - 3);
assert(wiov.iov[0].iov_len == 1);
assert(wiov.iov[1].iov_base == __user_addr_max - 2);
assert(wiov.iov[1].iov_len == 1);
}
err = vringh_iov_pull_user(&riov, buf, 5);
if (err != 1)
errx(1, "vringh_iov_pull_user: %i", err);
assert(buf[0] == 'a');
assert(riov.i == 1);
assert(vringh_iov_pull_user(&riov, buf, 5) == 0);
memcpy(buf, "bcdef", 5);
err = vringh_iov_push_user(&wiov, buf, 5);
if (err != 2)
errx(1, "vringh_iov_push_user: %i", err);
assert(memcmp(__user_addr_max - 3, "bc", 2) == 0);
assert(wiov.i == wiov.used);
assert(vringh_iov_push_user(&wiov, buf, 5) == 0);
/* Host is done. */
err = vringh_complete_user(&vrh, head, err);
if (err != 0)
errx(1, "vringh_complete_user: %i", err);
/* Guest should see used token now. */
__kfree_ignore_start = __user_addr_min + vring_size(RINGSIZE, ALIGN);
__kfree_ignore_end = __kfree_ignore_start + 1;
ret = virtqueue_get_buf(vq, &i);
if (ret != &err)
errx(1, "virtqueue_get_buf: %p", ret);
assert(i == 2);
/* Guest puts in a huge descriptor. */
sg_init_table(guest_sg, RINGSIZE);
for (i = 0; i < RINGSIZE; i++) {
sg_set_buf(&guest_sg[i],
__user_addr_max - USER_MEM/4, USER_MEM/4);
}
/* Fill contents with recognisable garbage. */
for (i = 0; i < USER_MEM/4; i++)
((char *)__user_addr_max - USER_MEM/4)[i] = i;
/* This will allocate an indirect, so force it to allocate user addr */
__kmalloc_fake = __user_addr_min + vring_size(RINGSIZE, ALIGN);
err = virtqueue_add_outbuf(vq, guest_sg, RINGSIZE, &err, GFP_KERNEL);
if (err)
errx(1, "virtqueue_add_outbuf (large): %i", err);
__kmalloc_fake = NULL;
/* Host picks it up (allocates new iov). */
vringh_iov_init(&riov, host_riov, ARRAY_SIZE(host_riov));
vringh_iov_init(&wiov, host_wiov, ARRAY_SIZE(host_wiov));
err = vringh_getdesc_user(&vrh, &riov, &wiov, getrange, &head);
if (err != 1)
errx(1, "vringh_getdesc_user: %i", err);
assert(riov.max_num & VRINGH_IOV_ALLOCATED);
assert(riov.iov != host_riov);
if (getrange != getrange_slow)
assert(riov.used == RINGSIZE);
else
assert(riov.used == RINGSIZE * USER_MEM/4);
assert(!(wiov.max_num & VRINGH_IOV_ALLOCATED));
assert(wiov.used == 0);
/* Pull data back out (in odd chunks), should be as expected. */
for (i = 0; i < RINGSIZE * USER_MEM/4; i += 3) {
err = vringh_iov_pull_user(&riov, buf, 3);
if (err != 3 && i + err != RINGSIZE * USER_MEM/4)
errx(1, "vringh_iov_pull_user large: %i", err);
assert(buf[0] == (char)i);
assert(err < 2 || buf[1] == (char)(i + 1));
assert(err < 3 || buf[2] == (char)(i + 2));
}
assert(riov.i == riov.used);
vringh_iov_cleanup(&riov);
vringh_iov_cleanup(&wiov);
/* Complete using multi interface, just because we can. */
used[0].id = head;
used[0].len = 0;
err = vringh_complete_multi_user(&vrh, used, 1);
if (err)
errx(1, "vringh_complete_multi_user(1): %i", err);
/* Free up those descriptors. */
ret = virtqueue_get_buf(vq, &i);
if (ret != &err)
errx(1, "virtqueue_get_buf: %p", ret);
/* Add lots of descriptors. */
sg_init_table(guest_sg, 1);
sg_set_buf(&guest_sg[0], __user_addr_max - 1, 1);
for (i = 0; i < RINGSIZE; i++) {
err = virtqueue_add_outbuf(vq, guest_sg, 1, &err, GFP_KERNEL);
if (err)
errx(1, "virtqueue_add_outbuf (multiple): %i", err);
}
/* Now get many, and consume them all at once. */
vringh_iov_init(&riov, host_riov, ARRAY_SIZE(host_riov));
vringh_iov_init(&wiov, host_wiov, ARRAY_SIZE(host_wiov));
for (i = 0; i < RINGSIZE; i++) {
err = vringh_getdesc_user(&vrh, &riov, &wiov, getrange, &head);
if (err != 1)
errx(1, "vringh_getdesc_user: %i", err);
used[i].id = head;
used[i].len = 0;
}
/* Make sure it wraps around ring, to test! */
assert(vrh.vring.used->idx % RINGSIZE != 0);
err = vringh_complete_multi_user(&vrh, used, RINGSIZE);
if (err)
errx(1, "vringh_complete_multi_user: %i", err);
/* Free those buffers. */
for (i = 0; i < RINGSIZE; i++) {
unsigned len;
assert(virtqueue_get_buf(vq, &len) != NULL);
}
/* Test weird (but legal!) indirect. */
if (vdev.features[0] & (1 << VIRTIO_RING_F_INDIRECT_DESC)) {
char *data = __user_addr_max - USER_MEM/4;
struct vring_desc *d = __user_addr_max - USER_MEM/2;
struct vring vring;
/* Force creation of direct, which we modify. */
vdev.features[0] &= ~(1 << VIRTIO_RING_F_INDIRECT_DESC);
vq = vring_new_virtqueue(0, RINGSIZE, ALIGN, &vdev, true,
__user_addr_min,
never_notify_host,
never_callback_guest,
"guest vq");
sg_init_table(guest_sg, 4);
sg_set_buf(&guest_sg[0], d, sizeof(*d)*2);
sg_set_buf(&guest_sg[1], d + 2, sizeof(*d)*1);
sg_set_buf(&guest_sg[2], data + 6, 4);
sg_set_buf(&guest_sg[3], d + 3, sizeof(*d)*3);
err = virtqueue_add_outbuf(vq, guest_sg, 4, &err, GFP_KERNEL);
if (err)
errx(1, "virtqueue_add_outbuf (indirect): %i", err);
vring_init(&vring, RINGSIZE, __user_addr_min, ALIGN);
/* They're used in order, but double-check... */
assert(vring.desc[0].addr == (unsigned long)d);
assert(vring.desc[1].addr == (unsigned long)(d+2));
assert(vring.desc[2].addr == (unsigned long)data + 6);
assert(vring.desc[3].addr == (unsigned long)(d+3));
vring.desc[0].flags |= VRING_DESC_F_INDIRECT;
vring.desc[1].flags |= VRING_DESC_F_INDIRECT;
vring.desc[3].flags |= VRING_DESC_F_INDIRECT;
/* First indirect */
d[0].addr = (unsigned long)data;
d[0].len = 1;
d[0].flags = VRING_DESC_F_NEXT;
d[0].next = 1;
d[1].addr = (unsigned long)data + 1;
d[1].len = 2;
d[1].flags = 0;
/* Second indirect */
d[2].addr = (unsigned long)data + 3;
d[2].len = 3;
d[2].flags = 0;
/* Third indirect */
d[3].addr = (unsigned long)data + 10;
d[3].len = 5;
d[3].flags = VRING_DESC_F_NEXT;
d[3].next = 1;
d[4].addr = (unsigned long)data + 15;
d[4].len = 6;
d[4].flags = VRING_DESC_F_NEXT;
d[4].next = 2;
d[5].addr = (unsigned long)data + 21;
d[5].len = 7;
d[5].flags = 0;
/* Host picks it up (allocates new iov). */
vringh_iov_init(&riov, host_riov, ARRAY_SIZE(host_riov));
vringh_iov_init(&wiov, host_wiov, ARRAY_SIZE(host_wiov));
err = vringh_getdesc_user(&vrh, &riov, &wiov, getrange, &head);
if (err != 1)
errx(1, "vringh_getdesc_user: %i", err);
if (head != 0)
errx(1, "vringh_getdesc_user: head %i not 0", head);
assert(riov.max_num & VRINGH_IOV_ALLOCATED);
if (getrange != getrange_slow)
assert(riov.used == 7);
else
assert(riov.used == 28);
err = vringh_iov_pull_user(&riov, buf, 29);
assert(err == 28);
/* Data should be linear. */
for (i = 0; i < err; i++)
assert(buf[i] == i);
vringh_iov_cleanup(&riov);
}
/* Don't leak memory... */
vring_del_virtqueue(vq);
free(__user_addr_min);
return 0;
}