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qemu/contrib/vhost-user-blk/vhost-user-blk.c

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/*
* vhost-user-blk sample application
*
* Copyright (c) 2017 Intel Corporation. All rights reserved.
*
* Author:
* Changpeng Liu <changpeng.liu@intel.com>
*
* This work is based on the "vhost-user-scsi" sample and "virtio-blk" driver
* implementation by:
* Felipe Franciosi <felipe@nutanix.com>
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2 only.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include "standard-headers/linux/virtio_blk.h"
#include "contrib/libvhost-user/libvhost-user-glib.h"
#include "contrib/libvhost-user/libvhost-user.h"
#if defined(__linux__)
#include <linux/fs.h>
#include <sys/ioctl.h>
#endif
enum {
VHOST_USER_BLK_MAX_QUEUES = 8,
};
struct virtio_blk_inhdr {
unsigned char status;
};
/* vhost user block device */
typedef struct VubDev {
VugDev parent;
int blk_fd;
struct virtio_blk_config blkcfg;
bool enable_ro;
char *blk_name;
GMainLoop *loop;
} VubDev;
typedef struct VubReq {
VuVirtqElement *elem;
int64_t sector_num;
size_t size;
struct virtio_blk_inhdr *in;
struct virtio_blk_outhdr *out;
VubDev *vdev_blk;
struct VuVirtq *vq;
} VubReq;
/* refer util/iov.c */
static size_t vub_iov_size(const struct iovec *iov,
const unsigned int iov_cnt)
{
size_t len;
unsigned int i;
len = 0;
for (i = 0; i < iov_cnt; i++) {
len += iov[i].iov_len;
}
return len;
}
static size_t vub_iov_to_buf(const struct iovec *iov,
const unsigned int iov_cnt, void *buf)
{
size_t len;
unsigned int i;
len = 0;
for (i = 0; i < iov_cnt; i++) {
memcpy(buf + len, iov[i].iov_base, iov[i].iov_len);
len += iov[i].iov_len;
}
return len;
}
static void vub_panic_cb(VuDev *vu_dev, const char *buf)
{
VugDev *gdev;
VubDev *vdev_blk;
assert(vu_dev);
gdev = container_of(vu_dev, VugDev, parent);
vdev_blk = container_of(gdev, VubDev, parent);
if (buf) {
g_warning("vu_panic: %s", buf);
}
g_main_loop_quit(vdev_blk->loop);
}
static void vub_req_complete(VubReq *req)
{
VugDev *gdev = &req->vdev_blk->parent;
VuDev *vu_dev = &gdev->parent;
/* IO size with 1 extra status byte */
vu_queue_push(vu_dev, req->vq, req->elem,
req->size + 1);
vu_queue_notify(vu_dev, req->vq);
if (req->elem) {
free(req->elem);
}
g_free(req);
}
static int vub_open(const char *file_name, bool wce)
{
int fd;
int flags = O_RDWR;
if (!wce) {
flags |= O_DIRECT;
}
fd = open(file_name, flags);
if (fd < 0) {
fprintf(stderr, "Cannot open file %s, %s\n", file_name,
strerror(errno));
return -1;
}
return fd;
}
static ssize_t
vub_readv(VubReq *req, struct iovec *iov, uint32_t iovcnt)
{
VubDev *vdev_blk = req->vdev_blk;
ssize_t rc;
if (!iovcnt) {
fprintf(stderr, "Invalid Read IOV count\n");
return -1;
}
req->size = vub_iov_size(iov, iovcnt);
rc = preadv(vdev_blk->blk_fd, iov, iovcnt, req->sector_num * 512);
if (rc < 0) {
fprintf(stderr, "%s, Sector %"PRIu64", Size %lu failed with %s\n",
vdev_blk->blk_name, req->sector_num, req->size,
strerror(errno));
return -1;
}
return rc;
}
static ssize_t
vub_writev(VubReq *req, struct iovec *iov, uint32_t iovcnt)
{
VubDev *vdev_blk = req->vdev_blk;
ssize_t rc;
if (!iovcnt) {
fprintf(stderr, "Invalid Write IOV count\n");
return -1;
}
req->size = vub_iov_size(iov, iovcnt);
rc = pwritev(vdev_blk->blk_fd, iov, iovcnt, req->sector_num * 512);
if (rc < 0) {
fprintf(stderr, "%s, Sector %"PRIu64", Size %lu failed with %s\n",
vdev_blk->blk_name, req->sector_num, req->size,
strerror(errno));
return -1;
}
return rc;
}
static int
vub_discard_write_zeroes(VubReq *req, struct iovec *iov, uint32_t iovcnt,
uint32_t type)
{
struct virtio_blk_discard_write_zeroes *desc;
ssize_t size;
void *buf;
size = vub_iov_size(iov, iovcnt);
if (size != sizeof(*desc)) {
fprintf(stderr, "Invalid size %ld, expect %ld\n", size, sizeof(*desc));
return -1;
}
buf = g_new0(char, size);
vub_iov_to_buf(iov, iovcnt, buf);
#if defined(__linux__) && defined(BLKDISCARD) && defined(BLKZEROOUT)
VubDev *vdev_blk = req->vdev_blk;
desc = (struct virtio_blk_discard_write_zeroes *)buf;
uint64_t range[2] = { le64toh(desc->sector) << 9,
le32toh(desc->num_sectors) << 9 };
if (type == VIRTIO_BLK_T_DISCARD) {
if (ioctl(vdev_blk->blk_fd, BLKDISCARD, range) == 0) {
g_free(buf);
return 0;
}
} else if (type == VIRTIO_BLK_T_WRITE_ZEROES) {
if (ioctl(vdev_blk->blk_fd, BLKZEROOUT, range) == 0) {
g_free(buf);
return 0;
}
}
#endif
g_free(buf);
return -1;
}
static void
vub_flush(VubReq *req)
{
VubDev *vdev_blk = req->vdev_blk;
fdatasync(vdev_blk->blk_fd);
}
static int vub_virtio_process_req(VubDev *vdev_blk,
VuVirtq *vq)
{
VugDev *gdev = &vdev_blk->parent;
VuDev *vu_dev = &gdev->parent;
VuVirtqElement *elem;
uint32_t type;
unsigned in_num;
unsigned out_num;
VubReq *req;
elem = vu_queue_pop(vu_dev, vq, sizeof(VuVirtqElement) + sizeof(VubReq));
if (!elem) {
return -1;
}
/* refer to hw/block/virtio_blk.c */
if (elem->out_num < 1 || elem->in_num < 1) {
fprintf(stderr, "virtio-blk request missing headers\n");
free(elem);
return -1;
}
req = g_new0(VubReq, 1);
req->vdev_blk = vdev_blk;
req->vq = vq;
req->elem = elem;
in_num = elem->in_num;
out_num = elem->out_num;
/* don't support VIRTIO_F_ANY_LAYOUT and virtio 1.0 only */
if (elem->out_sg[0].iov_len < sizeof(struct virtio_blk_outhdr)) {
fprintf(stderr, "Invalid outhdr size\n");
goto err;
}
req->out = (struct virtio_blk_outhdr *)elem->out_sg[0].iov_base;
out_num--;
if (elem->in_sg[in_num - 1].iov_len < sizeof(struct virtio_blk_inhdr)) {
fprintf(stderr, "Invalid inhdr size\n");
goto err;
}
req->in = (struct virtio_blk_inhdr *)elem->in_sg[in_num - 1].iov_base;
in_num--;
type = le32toh(req->out->type);
switch (type & ~VIRTIO_BLK_T_BARRIER) {
case VIRTIO_BLK_T_IN:
case VIRTIO_BLK_T_OUT: {
ssize_t ret = 0;
bool is_write = type & VIRTIO_BLK_T_OUT;
req->sector_num = le64toh(req->out->sector);
if (is_write) {
ret = vub_writev(req, &elem->out_sg[1], out_num);
} else {
ret = vub_readv(req, &elem->in_sg[0], in_num);
}
if (ret >= 0) {
req->in->status = VIRTIO_BLK_S_OK;
} else {
req->in->status = VIRTIO_BLK_S_IOERR;
}
vub_req_complete(req);
break;
}
case VIRTIO_BLK_T_FLUSH:
vub_flush(req);
req->in->status = VIRTIO_BLK_S_OK;
vub_req_complete(req);
break;
case VIRTIO_BLK_T_GET_ID: {
size_t size = MIN(vub_iov_size(&elem->in_sg[0], in_num),
VIRTIO_BLK_ID_BYTES);
snprintf(elem->in_sg[0].iov_base, size, "%s", "vhost_user_blk");
req->in->status = VIRTIO_BLK_S_OK;
req->size = elem->in_sg[0].iov_len;
vub_req_complete(req);
break;
}
case VIRTIO_BLK_T_DISCARD:
case VIRTIO_BLK_T_WRITE_ZEROES: {
int rc;
rc = vub_discard_write_zeroes(req, &elem->out_sg[1], out_num, type);
if (rc == 0) {
req->in->status = VIRTIO_BLK_S_OK;
} else {
req->in->status = VIRTIO_BLK_S_IOERR;
}
vub_req_complete(req);
break;
}
default:
req->in->status = VIRTIO_BLK_S_UNSUPP;
vub_req_complete(req);
break;
}
return 0;
err:
free(elem);
g_free(req);
return -1;
}
static void vub_process_vq(VuDev *vu_dev, int idx)
{
VugDev *gdev;
VubDev *vdev_blk;
VuVirtq *vq;
int ret;
gdev = container_of(vu_dev, VugDev, parent);
vdev_blk = container_of(gdev, VubDev, parent);
assert(vdev_blk);
vq = vu_get_queue(vu_dev, idx);
assert(vq);
while (1) {
ret = vub_virtio_process_req(vdev_blk, vq);
if (ret) {
break;
}
}
}
static void vub_queue_set_started(VuDev *vu_dev, int idx, bool started)
{
VuVirtq *vq;
assert(vu_dev);
vq = vu_get_queue(vu_dev, idx);
vu_set_queue_handler(vu_dev, vq, started ? vub_process_vq : NULL);
}
static uint64_t
vub_get_features(VuDev *dev)
{
uint64_t features;
VugDev *gdev;
VubDev *vdev_blk;
gdev = container_of(dev, VugDev, parent);
vdev_blk = container_of(gdev, VubDev, parent);
features = 1ull << VIRTIO_BLK_F_SIZE_MAX |
1ull << VIRTIO_BLK_F_SEG_MAX |
1ull << VIRTIO_BLK_F_TOPOLOGY |
1ull << VIRTIO_BLK_F_BLK_SIZE |
1ull << VIRTIO_BLK_F_FLUSH |
#if defined(__linux__) && defined(BLKDISCARD) && defined(BLKZEROOUT)
1ull << VIRTIO_BLK_F_DISCARD |
1ull << VIRTIO_BLK_F_WRITE_ZEROES |
#endif
1ull << VIRTIO_BLK_F_CONFIG_WCE |
1ull << VIRTIO_F_VERSION_1 |
1ull << VHOST_USER_F_PROTOCOL_FEATURES;
if (vdev_blk->enable_ro) {
features |= 1ull << VIRTIO_BLK_F_RO;
}
return features;
}
static uint64_t
vub_get_protocol_features(VuDev *dev)
{
return 1ull << VHOST_USER_PROTOCOL_F_CONFIG |
1ull << VHOST_USER_PROTOCOL_F_INFLIGHT_SHMFD;
}
static int
vub_get_config(VuDev *vu_dev, uint8_t *config, uint32_t len)
{
VugDev *gdev;
VubDev *vdev_blk;
gdev = container_of(vu_dev, VugDev, parent);
vdev_blk = container_of(gdev, VubDev, parent);
memcpy(config, &vdev_blk->blkcfg, len);
return 0;
}
static int
vub_set_config(VuDev *vu_dev, const uint8_t *data,
uint32_t offset, uint32_t size, uint32_t flags)
{
VugDev *gdev;
VubDev *vdev_blk;
uint8_t wce;
int fd;
/* don't support live migration */
if (flags != VHOST_SET_CONFIG_TYPE_MASTER) {
return -1;
}
gdev = container_of(vu_dev, VugDev, parent);
vdev_blk = container_of(gdev, VubDev, parent);
if (offset != offsetof(struct virtio_blk_config, wce) ||
size != 1) {
return -1;
}
wce = *data;
if (wce == vdev_blk->blkcfg.wce) {
/* Do nothing as same with old configuration */
return 0;
}
vdev_blk->blkcfg.wce = wce;
fprintf(stdout, "Write Cache Policy Changed\n");
if (vdev_blk->blk_fd >= 0) {
close(vdev_blk->blk_fd);
vdev_blk->blk_fd = -1;
}
fd = vub_open(vdev_blk->blk_name, wce);
if (fd < 0) {
fprintf(stderr, "Error to open block device %s\n", vdev_blk->blk_name);
vdev_blk->blk_fd = -1;
return -1;
}
vdev_blk->blk_fd = fd;
return 0;
}
static const VuDevIface vub_iface = {
.get_features = vub_get_features,
.queue_set_started = vub_queue_set_started,
.get_protocol_features = vub_get_protocol_features,
.get_config = vub_get_config,
.set_config = vub_set_config,
};
static int unix_sock_new(char *unix_fn)
{
int sock;
struct sockaddr_un un;
size_t len;
assert(unix_fn);
sock = socket(AF_UNIX, SOCK_STREAM, 0);
if (sock <= 0) {
perror("socket");
return -1;
}
un.sun_family = AF_UNIX;
(void)snprintf(un.sun_path, sizeof(un.sun_path), "%s", unix_fn);
len = sizeof(un.sun_family) + strlen(un.sun_path);
(void)unlink(unix_fn);
if (bind(sock, (struct sockaddr *)&un, len) < 0) {
perror("bind");
goto fail;
}
if (listen(sock, 1) < 0) {
perror("listen");
goto fail;
}
return sock;
fail:
(void)close(sock);
return -1;
}
static void vub_free(struct VubDev *vdev_blk)
{
if (!vdev_blk) {
return;
}
g_main_loop_unref(vdev_blk->loop);
if (vdev_blk->blk_fd >= 0) {
close(vdev_blk->blk_fd);
}
g_free(vdev_blk);
}
static uint32_t
vub_get_blocksize(int fd)
{
uint32_t blocksize = 512;
#if defined(__linux__) && defined(BLKSSZGET)
if (ioctl(fd, BLKSSZGET, &blocksize) == 0) {
return blocksize;
}
#endif
return blocksize;
}
static void
vub_initialize_config(int fd, struct virtio_blk_config *config)
{
off64_t capacity;
capacity = lseek64(fd, 0, SEEK_END);
config->capacity = capacity >> 9;
config->blk_size = vub_get_blocksize(fd);
config->size_max = 65536;
config->seg_max = 128 - 2;
config->min_io_size = 1;
config->opt_io_size = 1;
config->num_queues = 1;
#if defined(__linux__) && defined(BLKDISCARD) && defined(BLKZEROOUT)
config->max_discard_sectors = 32768;
config->max_discard_seg = 1;
config->discard_sector_alignment = config->blk_size >> 9;
config->max_write_zeroes_sectors = 32768;
config->max_write_zeroes_seg = 1;
#endif
}
static VubDev *
vub_new(char *blk_file)
{
VubDev *vdev_blk;
vdev_blk = g_new0(VubDev, 1);
vdev_blk->loop = g_main_loop_new(NULL, FALSE);
vdev_blk->blk_fd = vub_open(blk_file, 0);
if (vdev_blk->blk_fd < 0) {
fprintf(stderr, "Error to open block device %s\n", blk_file);
vub_free(vdev_blk);
return NULL;
}
vdev_blk->enable_ro = false;
vdev_blk->blkcfg.wce = 0;
vdev_blk->blk_name = blk_file;
/* fill virtio_blk_config with block parameters */
vub_initialize_config(vdev_blk->blk_fd, &vdev_blk->blkcfg);
return vdev_blk;
}
static int opt_fdnum = -1;
static char *opt_socket_path;
static char *opt_blk_file;
static gboolean opt_print_caps;
static gboolean opt_read_only;
static GOptionEntry entries[] = {
{ "print-capabilities", 'c', 0, G_OPTION_ARG_NONE, &opt_print_caps,
"Print capabilities", NULL },
{ "fd", 'f', 0, G_OPTION_ARG_INT, &opt_fdnum,
"Use inherited fd socket", "FDNUM" },
{ "socket-path", 's', 0, G_OPTION_ARG_FILENAME, &opt_socket_path,
"Use UNIX socket path", "PATH" },
{"blk-file", 'b', 0, G_OPTION_ARG_FILENAME, &opt_blk_file,
"block device or file path", "PATH"},
{ "read-only", 'r', 0, G_OPTION_ARG_NONE, &opt_read_only,
"Enable read-only", NULL }
};
int main(int argc, char **argv)
{
int lsock = -1, csock = -1;
VubDev *vdev_blk = NULL;
GError *error = NULL;
GOptionContext *context;
context = g_option_context_new(NULL);
g_option_context_add_main_entries(context, entries, NULL);
if (!g_option_context_parse(context, &argc, &argv, &error)) {
g_printerr("Option parsing failed: %s\n", error->message);
exit(EXIT_FAILURE);
}
if (opt_print_caps) {
g_print("{\n");
g_print(" \"type\": \"block\",\n");
g_print(" \"features\": [\n");
g_print(" \"read-only\",\n");
g_print(" \"blk-file\"\n");
g_print(" ]\n");
g_print("}\n");
exit(EXIT_SUCCESS);
}
if (!opt_blk_file) {
g_print("%s\n", g_option_context_get_help(context, true, NULL));
exit(EXIT_FAILURE);
}
if (opt_socket_path) {
lsock = unix_sock_new(opt_socket_path);
if (lsock < 0) {
exit(EXIT_FAILURE);
}
} else if (opt_fdnum < 0) {
g_print("%s\n", g_option_context_get_help(context, true, NULL));
exit(EXIT_FAILURE);
} else {
lsock = opt_fdnum;
}
csock = accept(lsock, NULL, NULL);
if (csock < 0) {
g_printerr("Accept error %s\n", strerror(errno));
exit(EXIT_FAILURE);
}
vdev_blk = vub_new(opt_blk_file);
if (!vdev_blk) {
exit(EXIT_FAILURE);
}
if (opt_read_only) {
vdev_blk->enable_ro = true;
}
if (!vug_init(&vdev_blk->parent, VHOST_USER_BLK_MAX_QUEUES, csock,
vub_panic_cb, &vub_iface)) {
g_printerr("Failed to initialize libvhost-user-glib\n");
exit(EXIT_FAILURE);
}
g_main_loop_run(vdev_blk->loop);
g_main_loop_unref(vdev_blk->loop);
g_option_context_free(context);
vug_deinit(&vdev_blk->parent);
vub_free(vdev_blk);
if (csock >= 0) {
close(csock);
}
if (lsock >= 0) {
close(lsock);
}
g_free(opt_socket_path);
g_free(opt_blk_file);
return 0;
}
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