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[PATCH v4 3/6] libvduse: Add VDUSE (vDPA Device in Userspace) library
|
From: |
Xie Yongji |
|
Subject: |
[PATCH v4 3/6] libvduse: Add VDUSE (vDPA Device in Userspace) library |
|
Date: |
Wed, 6 Apr 2022 15:59:18 +0800 |
VDUSE [1] is a linux framework that makes it possible to implement
software-emulated vDPA devices in userspace. This adds a library
as a subproject to help implementing VDUSE backends in QEMU.
[1] https://www.kernel.org/doc/html/latest/userspace-api/vduse.html
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
MAINTAINERS | 5 +
meson.build | 15 +
meson_options.txt | 2 +
scripts/meson-buildoptions.sh | 3 +
subprojects/libvduse/include/atomic.h | 1 +
subprojects/libvduse/libvduse.c | 1161 +++++++++++++++++++
subprojects/libvduse/libvduse.h | 235 ++++
subprojects/libvduse/linux-headers/linux | 1 +
subprojects/libvduse/meson.build | 10 +
subprojects/libvduse/standard-headers/linux | 1 +
10 files changed, 1434 insertions(+)
create mode 120000 subprojects/libvduse/include/atomic.h
create mode 100644 subprojects/libvduse/libvduse.c
create mode 100644 subprojects/libvduse/libvduse.h
create mode 120000 subprojects/libvduse/linux-headers/linux
create mode 100644 subprojects/libvduse/meson.build
create mode 120000 subprojects/libvduse/standard-headers/linux
diff --git a/MAINTAINERS b/MAINTAINERS
index 9aed5f3e04..53a14bf7a8 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3547,6 +3547,11 @@ L: qemu-block@nongnu.org
S: Supported
F: block/export/fuse.c
+VDUSE library
+M: Xie Yongji <xieyongji@bytedance.com>
+S: Maintained
+F: subprojects/libvduse/
+
Replication
M: Wen Congyang <wencongyang2@huawei.com>
M: Xie Changlong <xiechanglong.d@gmail.com>
diff --git a/meson.build b/meson.build
index bae62efc9c..5c71904461 100644
--- a/meson.build
+++ b/meson.build
@@ -1351,6 +1351,21 @@ if get_option('fuse_lseek').allowed()
endif
endif
+have_libvduse = (targetos == 'linux')
+if get_option('libvduse').enabled()
+ if targetos != 'linux'
+ error('libvduse requires linux')
+ endif
+elif get_option('libvduse').disabled()
+ have_libvduse = false
+endif
+
+libvduse = not_found
+if have_libvduse
+ libvduse_proj = subproject('libvduse')
+ libvduse = libvduse_proj.get_variable('libvduse_dep')
+endif
+
# libbpf
libbpf = dependency('libbpf', required: get_option('bpf'), method:
'pkg-config')
if libbpf.found() and not cc.links('''
diff --git a/meson_options.txt b/meson_options.txt
index 52b11cead4..e25af3277d 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -219,6 +219,8 @@ option('virtfs', type: 'feature', value: 'auto',
description: 'virtio-9p support')
option('virtiofsd', type: 'feature', value: 'auto',
description: 'build virtiofs daemon (virtiofsd)')
+option('libvduse', type: 'feature', value: 'auto',
+ description: 'build VDUSE Library')
option('capstone', type: 'combo', value: 'auto',
choices: ['disabled', 'enabled', 'auto', 'system', 'internal'],
diff --git a/scripts/meson-buildoptions.sh b/scripts/meson-buildoptions.sh
index 1e26f4571e..ccab9ca9da 100644
--- a/scripts/meson-buildoptions.sh
+++ b/scripts/meson-buildoptions.sh
@@ -77,6 +77,7 @@ meson_options_help() {
printf "%s\n" ' libssh ssh block device support'
printf "%s\n" ' libudev Use libudev to enumerate host devices'
printf "%s\n" ' libusb libusb support for USB passthrough'
+ printf "%s\n" ' libvduse build VDUSE Library'
printf "%s\n" ' linux-aio Linux AIO support'
printf "%s\n" ' linux-io-uring Linux io_uring support'
printf "%s\n" ' live-block-migration'
@@ -244,6 +245,8 @@ _meson_option_parse() {
--disable-libudev) printf "%s" -Dlibudev=disabled ;;
--enable-libusb) printf "%s" -Dlibusb=enabled ;;
--disable-libusb) printf "%s" -Dlibusb=disabled ;;
+ --enable-libvduse) printf "%s" -Dlibvduse=enabled ;;
+ --disable-libvduse) printf "%s" -Dlibvduse=disabled ;;
--enable-linux-aio) printf "%s" -Dlinux_aio=enabled ;;
--disable-linux-aio) printf "%s" -Dlinux_aio=disabled ;;
--enable-linux-io-uring) printf "%s" -Dlinux_io_uring=enabled ;;
diff --git a/subprojects/libvduse/include/atomic.h
b/subprojects/libvduse/include/atomic.h
new file mode 120000
index 0000000000..8c2be64f7b
--- /dev/null
+++ b/subprojects/libvduse/include/atomic.h
@@ -0,0 +1 @@
+../../../include/qemu/atomic.h
\ No newline at end of file
diff --git a/subprojects/libvduse/libvduse.c b/subprojects/libvduse/libvduse.c
new file mode 100644
index 0000000000..ecee9c0568
--- /dev/null
+++ b/subprojects/libvduse/libvduse.c
@@ -0,0 +1,1161 @@
+/*
+ * VDUSE (vDPA Device in Userspace) library
+ *
+ * Copyright (C) 2022 Bytedance Inc. and/or its affiliates. All rights
reserved.
+ * Portions of codes and concepts borrowed from libvhost-user.c, so:
+ * Copyright IBM, Corp. 2007
+ * Copyright (c) 2016 Red Hat, Inc.
+ *
+ * Author:
+ * Xie Yongji <xieyongji@bytedance.com>
+ * Anthony Liguori <aliguori@us.ibm.com>
+ * Marc-André Lureau <mlureau@redhat.com>
+ * Victor Kaplansky <victork@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later. See the COPYING file in the top-level directory.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <errno.h>
+#include <string.h>
+#include <assert.h>
+#include <endian.h>
+#include <unistd.h>
+#include <limits.h>
+#include <fcntl.h>
+
+#include <sys/ioctl.h>
+#include <sys/eventfd.h>
+#include <sys/mman.h>
+
+#include "include/atomic.h"
+#include "linux-headers/linux/virtio_ring.h"
+#include "linux-headers/linux/virtio_config.h"
+#include "linux-headers/linux/vduse.h"
+#include "libvduse.h"
+
+#define VDUSE_VQ_ALIGN 4096
+#define MAX_IOVA_REGIONS 256
+
+/* Round number down to multiple */
+#define ALIGN_DOWN(n, m) ((n) / (m) * (m))
+
+/* Round number up to multiple */
+#define ALIGN_UP(n, m) ALIGN_DOWN((n) + (m) - 1, (m))
+
+#ifndef unlikely
+#define unlikely(x) __builtin_expect(!!(x), 0)
+#endif
+
+typedef struct VduseRing {
+ unsigned int num;
+ uint64_t desc_addr;
+ uint64_t avail_addr;
+ uint64_t used_addr;
+ struct vring_desc *desc;
+ struct vring_avail *avail;
+ struct vring_used *used;
+} VduseRing;
+
+struct VduseVirtq {
+ VduseRing vring;
+ uint16_t last_avail_idx;
+ uint16_t shadow_avail_idx;
+ uint16_t used_idx;
+ uint16_t signalled_used;
+ bool signalled_used_valid;
+ int index;
+ int inuse;
+ bool ready;
+ int fd;
+ VduseDev *dev;
+};
+
+typedef struct VduseIovaRegion {
+ uint64_t iova;
+ uint64_t size;
+ uint64_t mmap_offset;
+ uint64_t mmap_addr;
+} VduseIovaRegion;
+
+struct VduseDev {
+ VduseVirtq *vqs;
+ VduseIovaRegion regions[MAX_IOVA_REGIONS];
+ int num_regions;
+ char *name;
+ uint32_t device_id;
+ uint32_t vendor_id;
+ uint16_t num_queues;
+ uint16_t queue_size;
+ uint64_t features;
+ const VduseOps *ops;
+ int fd;
+ int ctrl_fd;
+ void *priv;
+};
+
+static inline bool has_feature(uint64_t features, unsigned int fbit)
+{
+ assert(fbit < 64);
+ return !!(features & (1ULL << fbit));
+}
+
+static inline bool vduse_dev_has_feature(VduseDev *dev, unsigned int fbit)
+{
+ return has_feature(dev->features, fbit);
+}
+
+uint64_t vduse_get_virtio_features(void)
+{
+ return (1ULL << VIRTIO_F_IOMMU_PLATFORM) |
+ (1ULL << VIRTIO_F_VERSION_1) |
+ (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
+ (1ULL << VIRTIO_RING_F_EVENT_IDX) |
+ (1ULL << VIRTIO_RING_F_INDIRECT_DESC);
+}
+
+VduseDev *vduse_queue_get_dev(VduseVirtq *vq)
+{
+ return vq->dev;
+}
+
+int vduse_queue_get_fd(VduseVirtq *vq)
+{
+ return vq->fd;
+}
+
+void *vduse_dev_get_priv(VduseDev *dev)
+{
+ return dev->priv;
+}
+
+VduseVirtq *vduse_dev_get_queue(VduseDev *dev, int index)
+{
+ return &dev->vqs[index];
+}
+
+int vduse_dev_get_fd(VduseDev *dev)
+{
+ return dev->fd;
+}
+
+static int vduse_inject_irq(VduseDev *dev, int index)
+{
+ return ioctl(dev->fd, VDUSE_VQ_INJECT_IRQ, &index);
+}
+
+static void vduse_iova_remove_region(VduseDev *dev, uint64_t start,
+ uint64_t last)
+{
+ int i;
+
+ if (last == start) {
+ return;
+ }
+
+ for (i = 0; i < MAX_IOVA_REGIONS; i++) {
+ if (!dev->regions[i].mmap_addr) {
+ continue;
+ }
+
+ if (start <= dev->regions[i].iova &&
+ last >= (dev->regions[i].iova + dev->regions[i].size - 1)) {
+ munmap((void *)dev->regions[i].mmap_addr,
+ dev->regions[i].mmap_offset + dev->regions[i].size);
+ dev->regions[i].mmap_addr = 0;
+ dev->num_regions--;
+ }
+ }
+}
+
+static int vduse_iova_add_region(VduseDev *dev, int fd,
+ uint64_t offset, uint64_t start,
+ uint64_t last, int prot)
+{
+ int i;
+ uint64_t size = last - start + 1;
+ void *mmap_addr = mmap(0, size + offset, prot, MAP_SHARED, fd, 0);
+
+ if (mmap_addr == MAP_FAILED) {
+ close(fd);
+ return -EINVAL;
+ }
+
+ for (i = 0; i < MAX_IOVA_REGIONS; i++) {
+ if (!dev->regions[i].mmap_addr) {
+ dev->regions[i].mmap_addr = (uint64_t)(uintptr_t)mmap_addr;
+ dev->regions[i].mmap_offset = offset;
+ dev->regions[i].iova = start;
+ dev->regions[i].size = size;
+ dev->num_regions++;
+ break;
+ }
+ }
+ assert(i < MAX_IOVA_REGIONS);
+ close(fd);
+
+ return 0;
+}
+
+static int perm_to_prot(uint8_t perm)
+{
+ int prot = 0;
+
+ switch (perm) {
+ case VDUSE_ACCESS_WO:
+ prot |= PROT_WRITE;
+ break;
+ case VDUSE_ACCESS_RO:
+ prot |= PROT_READ;
+ break;
+ case VDUSE_ACCESS_RW:
+ prot |= PROT_READ | PROT_WRITE;
+ break;
+ default:
+ break;
+ }
+
+ return prot;
+}
+
+static inline void *iova_to_va(VduseDev *dev, uint64_t *plen, uint64_t iova)
+{
+ int i, ret;
+ struct vduse_iotlb_entry entry;
+
+ for (i = 0; i < MAX_IOVA_REGIONS; i++) {
+ VduseIovaRegion *r = &dev->regions[i];
+
+ if (!r->mmap_addr) {
+ continue;
+ }
+
+ if ((iova >= r->iova) && (iova < (r->iova + r->size))) {
+ if ((iova + *plen) > (r->iova + r->size)) {
+ *plen = r->iova + r->size - iova;
+ }
+ return (void *)(uintptr_t)(iova - r->iova +
+ r->mmap_addr + r->mmap_offset);
+ }
+ }
+
+ entry.start = iova;
+ entry.last = iova + 1;
+ ret = ioctl(dev->fd, VDUSE_IOTLB_GET_FD, &entry);
+ if (ret < 0) {
+ return NULL;
+ }
+
+ if (!vduse_iova_add_region(dev, ret, entry.offset, entry.start,
+ entry.last, perm_to_prot(entry.perm))) {
+ return iova_to_va(dev, plen, iova);
+ }
+
+ return NULL;
+}
+
+static inline uint16_t vring_avail_flags(VduseVirtq *vq)
+{
+ return le16toh(vq->vring.avail->flags);
+}
+
+static inline uint16_t vring_avail_idx(VduseVirtq *vq)
+{
+ vq->shadow_avail_idx = le16toh(vq->vring.avail->idx);
+
+ return vq->shadow_avail_idx;
+}
+
+static inline uint16_t vring_avail_ring(VduseVirtq *vq, int i)
+{
+ return le16toh(vq->vring.avail->ring[i]);
+}
+
+static inline uint16_t vring_get_used_event(VduseVirtq *vq)
+{
+ return vring_avail_ring(vq, vq->vring.num);
+}
+
+static bool vduse_queue_get_head(VduseVirtq *vq, unsigned int idx,
+ unsigned int *head)
+{
+ /*
+ * Grab the next descriptor number they're advertising, and increment
+ * the index we've seen.
+ */
+ *head = vring_avail_ring(vq, idx % vq->vring.num);
+
+ /* If their number is silly, that's a fatal mistake. */
+ if (*head >= vq->vring.num) {
+ fprintf(stderr, "Guest says index %u is available\n", *head);
+ return false;
+ }
+
+ return true;
+}
+
+static int
+vduse_queue_read_indirect_desc(VduseDev *dev, struct vring_desc *desc,
+ uint64_t addr, size_t len)
+{
+ struct vring_desc *ori_desc;
+ uint64_t read_len;
+
+ if (len > (VIRTQUEUE_MAX_SIZE * sizeof(struct vring_desc))) {
+ return -1;
+ }
+
+ if (len == 0) {
+ return -1;
+ }
+
+ while (len) {
+ read_len = len;
+ ori_desc = iova_to_va(dev, &read_len, addr);
+ if (!ori_desc) {
+ return -1;
+ }
+
+ memcpy(desc, ori_desc, read_len);
+ len -= read_len;
+ addr += read_len;
+ desc += read_len;
+ }
+
+ return 0;
+}
+
+enum {
+ VIRTQUEUE_READ_DESC_ERROR = -1,
+ VIRTQUEUE_READ_DESC_DONE = 0, /* end of chain */
+ VIRTQUEUE_READ_DESC_MORE = 1, /* more buffers in chain */
+};
+
+static int vduse_queue_read_next_desc(struct vring_desc *desc, int i,
+ unsigned int max, unsigned int *next)
+{
+ /* If this descriptor says it doesn't chain, we're done. */
+ if (!(le16toh(desc[i].flags) & VRING_DESC_F_NEXT)) {
+ return VIRTQUEUE_READ_DESC_DONE;
+ }
+
+ /* Check they're not leading us off end of descriptors. */
+ *next = desc[i].next;
+ /* Make sure compiler knows to grab that: we don't want it changing! */
+ smp_wmb();
+
+ if (*next >= max) {
+ fprintf(stderr, "Desc next is %u\n", *next);
+ return VIRTQUEUE_READ_DESC_ERROR;
+ }
+
+ return VIRTQUEUE_READ_DESC_MORE;
+}
+
+/*
+ * Fetch avail_idx from VQ memory only when we really need to know if
+ * guest has added some buffers.
+ */
+static bool vduse_queue_empty(VduseVirtq *vq)
+{
+ if (unlikely(!vq->vring.avail)) {
+ return true;
+ }
+
+ if (vq->shadow_avail_idx != vq->last_avail_idx) {
+ return false;
+ }
+
+ return vring_avail_idx(vq) == vq->last_avail_idx;
+}
+
+static bool vduse_queue_should_notify(VduseVirtq *vq)
+{
+ VduseDev *dev = vq->dev;
+ uint16_t old, new;
+ bool v;
+
+ /* We need to expose used array entries before checking used event. */
+ smp_mb();
+
+ /* Always notify when queue is empty (when feature acknowledge) */
+ if (vduse_dev_has_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY) &&
+ !vq->inuse && vduse_queue_empty(vq)) {
+ return true;
+ }
+
+ if (!vduse_dev_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) {
+ return !(vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT);
+ }
+
+ v = vq->signalled_used_valid;
+ vq->signalled_used_valid = true;
+ old = vq->signalled_used;
+ new = vq->signalled_used = vq->used_idx;
+ return !v || vring_need_event(vring_get_used_event(vq), new, old);
+}
+
+void vduse_queue_notify(VduseVirtq *vq)
+{
+ VduseDev *dev = vq->dev;
+
+ if (unlikely(!vq->vring.avail)) {
+ return;
+ }
+
+ if (!vduse_queue_should_notify(vq)) {
+ return;
+ }
+
+ if (vduse_inject_irq(dev, vq->index) < 0) {
+ fprintf(stderr, "Error inject irq for vq %d: %s\n",
+ vq->index, strerror(errno));
+ }
+}
+
+static inline void vring_used_flags_set_bit(VduseVirtq *vq, int mask)
+{
+ uint16_t *flags;
+
+ flags = (uint16_t *)((char*)vq->vring.used +
+ offsetof(struct vring_used, flags));
+ *flags = htole16(le16toh(*flags) | mask);
+}
+
+static inline void vring_used_flags_unset_bit(VduseVirtq *vq, int mask)
+{
+ uint16_t *flags;
+
+ flags = (uint16_t *)((char*)vq->vring.used +
+ offsetof(struct vring_used, flags));
+ *flags = htole16(le16toh(*flags) & ~mask);
+}
+
+static inline void vring_set_avail_event(VduseVirtq *vq, uint16_t val)
+{
+ *((uint16_t *)&vq->vring.used->ring[vq->vring.num]) = htole16(val);
+}
+
+static bool vduse_queue_map_single_desc(VduseVirtq *vq, unsigned int *p_num_sg,
+ struct iovec *iov, unsigned int max_num_sg,
+ bool is_write, uint64_t pa, size_t sz)
+{
+ unsigned num_sg = *p_num_sg;
+ VduseDev *dev = vq->dev;
+
+ assert(num_sg <= max_num_sg);
+
+ if (!sz) {
+ fprintf(stderr, "virtio: zero sized buffers are not allowed\n");
+ return false;
+ }
+
+ while (sz) {
+ uint64_t len = sz;
+
+ if (num_sg == max_num_sg) {
+ fprintf(stderr,
+ "virtio: too many descriptors in indirect table\n");
+ return false;
+ }
+
+ iov[num_sg].iov_base = iova_to_va(dev, &len, pa);
+ if (iov[num_sg].iov_base == NULL) {
+ fprintf(stderr, "virtio: invalid address for buffers\n");
+ return false;
+ }
+ iov[num_sg++].iov_len = len;
+ sz -= len;
+ pa += len;
+ }
+
+ *p_num_sg = num_sg;
+ return true;
+}
+
+static void *vduse_queue_alloc_element(size_t sz, unsigned out_num,
+ unsigned in_num)
+{
+ VduseVirtqElement *elem;
+ size_t in_sg_ofs = ALIGN_UP(sz, __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(VduseVirtqElement));
+ elem = malloc(out_sg_end);
+ if (!elem) {
+ return NULL;
+ }
+ elem->out_num = out_num;
+ elem->in_num = in_num;
+ elem->in_sg = (void *)elem + in_sg_ofs;
+ elem->out_sg = (void *)elem + out_sg_ofs;
+ return elem;
+}
+
+static void *vduse_queue_map_desc(VduseVirtq *vq, unsigned int idx, size_t sz)
+{
+ struct vring_desc *desc = vq->vring.desc;
+ VduseDev *dev = vq->dev;
+ uint64_t desc_addr, read_len;
+ unsigned int desc_len;
+ unsigned int max = vq->vring.num;
+ unsigned int i = idx;
+ VduseVirtqElement *elem;
+ struct iovec iov[VIRTQUEUE_MAX_SIZE];
+ struct vring_desc desc_buf[VIRTQUEUE_MAX_SIZE];
+ unsigned int out_num = 0, in_num = 0;
+ int rc;
+
+ if (le16toh(desc[i].flags) & VRING_DESC_F_INDIRECT) {
+ if (le32toh(desc[i].len) % sizeof(struct vring_desc)) {
+ fprintf(stderr, "Invalid size for indirect buffer table\n");
+ return NULL;
+ }
+
+ /* loop over the indirect descriptor table */
+ desc_addr = le64toh(desc[i].addr);
+ desc_len = le32toh(desc[i].len);
+ max = desc_len / sizeof(struct vring_desc);
+ read_len = desc_len;
+ desc = iova_to_va(dev, &read_len, desc_addr);
+ if (unlikely(desc && read_len != desc_len)) {
+ /* Failed to use zero copy */
+ desc = NULL;
+ if (!vduse_queue_read_indirect_desc(dev, desc_buf,
+ desc_addr,
+ desc_len)) {
+ desc = desc_buf;
+ }
+ }
+ if (!desc) {
+ fprintf(stderr, "Invalid indirect buffer table\n");
+ return NULL;
+ }
+ i = 0;
+ }
+
+ /* Collect all the descriptors */
+ do {
+ if (le16toh(desc[i].flags) & VRING_DESC_F_WRITE) {
+ if (!vduse_queue_map_single_desc(vq, &in_num, iov + out_num,
+ VIRTQUEUE_MAX_SIZE - out_num,
+ true, le64toh(desc[i].addr),
+ le32toh(desc[i].len))) {
+ return NULL;
+ }
+ } else {
+ if (in_num) {
+ fprintf(stderr, "Incorrect order for descriptors\n");
+ return NULL;
+ }
+ if (!vduse_queue_map_single_desc(vq, &out_num, iov,
+ VIRTQUEUE_MAX_SIZE, false,
+ le64toh(desc[i].addr),
+ le32toh(desc[i].len))) {
+ return NULL;
+ }
+ }
+
+ /* If we've got too many, that implies a descriptor loop. */
+ if ((in_num + out_num) > max) {
+ fprintf(stderr, "Looped descriptor\n");
+ return NULL;
+ }
+ rc = vduse_queue_read_next_desc(desc, i, max, &i);
+ } while (rc == VIRTQUEUE_READ_DESC_MORE);
+
+ if (rc == VIRTQUEUE_READ_DESC_ERROR) {
+ fprintf(stderr, "read descriptor error\n");
+ return NULL;
+ }
+
+ /* Now copy what we have collected and mapped */
+ elem = vduse_queue_alloc_element(sz, out_num, in_num);
+ if (!elem) {
+ fprintf(stderr, "read descriptor error\n");
+ return NULL;
+ }
+ elem->index = idx;
+ for (i = 0; i < out_num; i++) {
+ elem->out_sg[i] = iov[i];
+ }
+ for (i = 0; i < in_num; i++) {
+ elem->in_sg[i] = iov[out_num + i];
+ }
+
+ return elem;
+}
+
+void *vduse_queue_pop(VduseVirtq *vq, size_t sz)
+{
+ unsigned int head;
+ VduseVirtqElement *elem;
+ VduseDev *dev = vq->dev;
+
+ if (unlikely(!vq->vring.avail)) {
+ return NULL;
+ }
+
+ if (vduse_queue_empty(vq)) {
+ return NULL;
+ }
+ /* Needed after virtio_queue_empty() */
+ smp_rmb();
+
+ if (vq->inuse >= vq->vring.num) {
+ fprintf(stderr, "Virtqueue size exceeded: %d\n", vq->inuse);
+ return NULL;
+ }
+
+ if (!vduse_queue_get_head(vq, vq->last_avail_idx++, &head)) {
+ return NULL;
+ }
+
+ if (vduse_dev_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) {
+ vring_set_avail_event(vq, vq->last_avail_idx);
+ }
+
+ elem = vduse_queue_map_desc(vq, head, sz);
+
+ if (!elem) {
+ return NULL;
+ }
+
+ vq->inuse++;
+
+ return elem;
+}
+
+static inline void vring_used_write(VduseVirtq *vq,
+ struct vring_used_elem *uelem, int i)
+{
+ struct vring_used *used = vq->vring.used;
+
+ used->ring[i] = *uelem;
+}
+
+static void vduse_queue_fill(VduseVirtq *vq, const VduseVirtqElement *elem,
+ unsigned int len, unsigned int idx)
+{
+ struct vring_used_elem uelem;
+
+ if (unlikely(!vq->vring.used)) {
+ return;
+ }
+
+ idx = (idx + vq->used_idx) % vq->vring.num;
+
+ uelem.id = htole32(elem->index);
+ uelem.len = htole32(len);
+ vring_used_write(vq, &uelem, idx);
+}
+
+static inline void vring_used_idx_set(VduseVirtq *vq, uint16_t val)
+{
+ vq->vring.used->idx = htole16(val);
+ vq->used_idx = val;
+}
+
+static void vduse_queue_flush(VduseVirtq *vq, unsigned int count)
+{
+ uint16_t old, new;
+
+ if (unlikely(!vq->vring.used)) {
+ return;
+ }
+
+ /* Make sure buffer is written before we update index. */
+ smp_wmb();
+
+ old = vq->used_idx;
+ new = old + count;
+ vring_used_idx_set(vq, new);
+ vq->inuse -= count;
+ if (unlikely((int16_t)(new - vq->signalled_used) < (uint16_t)(new - old)))
{
+ vq->signalled_used_valid = false;
+ }
+}
+
+void vduse_queue_push(VduseVirtq *vq, const VduseVirtqElement *elem,
+ unsigned int len)
+{
+ vduse_queue_fill(vq, elem, len, 0);
+ vduse_queue_flush(vq, 1);
+}
+
+static int vduse_queue_update_vring(VduseVirtq *vq, uint64_t desc_addr,
+ uint64_t avail_addr, uint64_t used_addr)
+{
+ struct VduseDev *dev = vq->dev;
+ uint64_t len;
+
+ len = sizeof(struct vring_desc);
+ vq->vring.desc = iova_to_va(dev, &len, desc_addr);
+ assert(len == sizeof(struct vring_desc));
+
+ len = sizeof(struct vring_avail);
+ vq->vring.avail = iova_to_va(dev, &len, avail_addr);
+ assert(len == sizeof(struct vring_avail));
+
+ len = sizeof(struct vring_used);
+ vq->vring.used = iova_to_va(dev, &len, used_addr);
+ assert(len == sizeof(struct vring_used));
+
+ if (!vq->vring.desc || !vq->vring.avail || !vq->vring.used) {
+ fprintf(stderr, "Failed to get vq[%d] iova mapping\n", vq->index);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static void vduse_queue_enable(VduseVirtq *vq)
+{
+ struct VduseDev *dev = vq->dev;
+ struct vduse_vq_info vq_info;
+ struct vduse_vq_eventfd vq_eventfd;
+ int fd;
+
+ vq_info.index = vq->index;
+ if (ioctl(dev->fd, VDUSE_VQ_GET_INFO, &vq_info)) {
+ fprintf(stderr, "Failed to get vq[%d] info: %s\n",
+ vq->index, strerror(errno));
+ return;
+ }
+
+ if (!vq_info.ready) {
+ return;
+ }
+
+ vq->vring.num = vq_info.num;
+ vq->vring.desc_addr = vq_info.desc_addr;
+ vq->vring.avail_addr = vq_info.driver_addr;
+ vq->vring.used_addr = vq_info.device_addr;
+
+ if (vduse_queue_update_vring(vq, vq_info.desc_addr,
+ vq_info.driver_addr, vq_info.device_addr)) {
+ fprintf(stderr, "Failed to update vring for vq[%d]\n", vq->index);
+ return;
+ }
+
+ fd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
+ if (fd < 0) {
+ fprintf(stderr, "Failed to init eventfd for vq[%d]\n", vq->index);
+ return;
+ }
+
+ vq_eventfd.index = vq->index;
+ vq_eventfd.fd = fd;
+ if (ioctl(dev->fd, VDUSE_VQ_SETUP_KICKFD, &vq_eventfd)) {
+ fprintf(stderr, "Failed to setup kick fd for vq[%d]\n", vq->index);
+ close(fd);
+ return;
+ }
+
+ vq->fd = fd;
+ vq->shadow_avail_idx = vq->last_avail_idx = vq_info.split.avail_index;
+ vq->inuse = 0;
+ vq->used_idx = 0;
+ vq->signalled_used_valid = false;
+ vq->ready = true;
+
+ dev->ops->enable_queue(dev, vq);
+}
+
+static void vduse_queue_disable(VduseVirtq *vq)
+{
+ struct VduseDev *dev = vq->dev;
+ struct vduse_vq_eventfd eventfd;
+
+ if (!vq->ready) {
+ return;
+ }
+
+ dev->ops->disable_queue(dev, vq);
+
+ eventfd.index = vq->index;
+ eventfd.fd = VDUSE_EVENTFD_DEASSIGN;
+ ioctl(dev->fd, VDUSE_VQ_SETUP_KICKFD, &eventfd);
+ close(vq->fd);
+
+ assert(vq->inuse == 0);
+
+ vq->vring.num = 0;
+ vq->vring.desc_addr = 0;
+ vq->vring.avail_addr = 0;
+ vq->vring.used_addr = 0;
+ vq->vring.desc = 0;
+ vq->vring.avail = 0;
+ vq->vring.used = 0;
+ vq->ready = false;
+ vq->fd = -1;
+}
+
+static void vduse_dev_start_dataplane(VduseDev *dev)
+{
+ int i;
+
+ if (ioctl(dev->fd, VDUSE_DEV_GET_FEATURES, &dev->features)) {
+ fprintf(stderr, "Failed to get features: %s\n", strerror(errno));
+ return;
+ }
+ assert(vduse_dev_has_feature(dev, VIRTIO_F_VERSION_1));
+
+ for (i = 0; i < dev->num_queues; i++) {
+ vduse_queue_enable(&dev->vqs[i]);
+ }
+}
+
+static void vduse_dev_stop_dataplane(VduseDev *dev)
+{
+ int i;
+
+ for (i = 0; i < dev->num_queues; i++) {
+ vduse_queue_disable(&dev->vqs[i]);
+ }
+ dev->features = 0;
+ vduse_iova_remove_region(dev, 0, ULONG_MAX);
+}
+
+int vduse_dev_handler(VduseDev *dev)
+{
+ struct vduse_dev_request req;
+ struct vduse_dev_response resp = { 0 };
+ VduseVirtq *vq;
+ int i, ret;
+
+ ret = read(dev->fd, &req, sizeof(req));
+ if (ret != sizeof(req)) {
+ fprintf(stderr, "Read request error [%d]: %s\n",
+ ret, strerror(errno));
+ return -errno;
+ }
+ resp.request_id = req.request_id;
+
+ switch (req.type) {
+ case VDUSE_GET_VQ_STATE:
+ vq = &dev->vqs[req.vq_state.index];
+ resp.vq_state.split.avail_index = vq->last_avail_idx;
+ resp.result = VDUSE_REQ_RESULT_OK;
+ break;
+ case VDUSE_SET_STATUS:
+ if (req.s.status & VIRTIO_CONFIG_S_DRIVER_OK) {
+ vduse_dev_start_dataplane(dev);
+ } else if (req.s.status == 0) {
+ vduse_dev_stop_dataplane(dev);
+ }
+ resp.result = VDUSE_REQ_RESULT_OK;
+ break;
+ case VDUSE_UPDATE_IOTLB:
+ /* The iova will be updated by iova_to_va() later, so just remove it */
+ vduse_iova_remove_region(dev, req.iova.start, req.iova.last);
+ for (i = 0; i < dev->num_queues; i++) {
+ VduseVirtq *vq = &dev->vqs[i];
+ if (vq->ready) {
+ if (vduse_queue_update_vring(vq, vq->vring.desc_addr,
+ vq->vring.avail_addr,
+ vq->vring.used_addr)) {
+ fprintf(stderr, "Failed to update vring for vq[%d]\n",
+ vq->index);
+ }
+ }
+ }
+ resp.result = VDUSE_REQ_RESULT_OK;
+ break;
+ default:
+ resp.result = VDUSE_REQ_RESULT_FAILED;
+ break;
+ }
+
+ ret = write(dev->fd, &resp, sizeof(resp));
+ if (ret != sizeof(resp)) {
+ fprintf(stderr, "Write request %d error [%d]: %s\n",
+ req.type, ret, strerror(errno));
+ return -errno;
+ }
+ return 0;
+}
+
+int vduse_dev_update_config(VduseDev *dev, uint32_t size,
+ uint32_t offset, char *buffer)
+{
+ int ret;
+ struct vduse_config_data *data;
+
+ data = malloc(offsetof(struct vduse_config_data, buffer) + size);
+ if (!data) {
+ return -ENOMEM;
+ }
+
+ data->offset = offset;
+ data->length = size;
+ memcpy(data->buffer, buffer, size);
+
+ ret = ioctl(dev->fd, VDUSE_DEV_SET_CONFIG, data);
+ free(data);
+
+ if (ret) {
+ return -errno;
+ }
+
+ if (ioctl(dev->fd, VDUSE_DEV_INJECT_CONFIG_IRQ)) {
+ return -errno;
+ }
+
+ return 0;
+}
+
+int vduse_dev_setup_queue(VduseDev *dev, int index, int max_size)
+{
+ VduseVirtq *vq = &dev->vqs[index];
+ struct vduse_vq_config vq_config = { 0 };
+
+ if (max_size > VIRTQUEUE_MAX_SIZE) {
+ return -EINVAL;
+ }
+
+ vq_config.index = vq->index;
+ vq_config.max_size = max_size;
+
+ if (ioctl(dev->fd, VDUSE_VQ_SETUP, &vq_config)) {
+ return -errno;
+ }
+
+ return 0;
+}
+
+static int vduse_dev_init_vqs(VduseDev *dev, uint16_t num_queues)
+{
+ VduseVirtq *vqs;
+ int i;
+
+ vqs = calloc(sizeof(VduseVirtq), num_queues);
+ if (!vqs) {
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < num_queues; i++) {
+ vqs[i].index = i;
+ vqs[i].dev = dev;
+ vqs[i].fd = -1;
+ }
+ dev->vqs = vqs;
+
+ return 0;
+}
+
+static int vduse_dev_init(VduseDev *dev, const char *name,
+ uint16_t num_queues, const VduseOps *ops,
+ void *priv)
+{
+ char *dev_path, *dev_name;
+ int ret, fd;
+
+ dev_path = malloc(strlen(name) + strlen("/dev/vduse/") + 1);
+ if (!dev_path) {
+ return -ENOMEM;
+ }
+ sprintf(dev_path, "/dev/vduse/%s", name);
+
+ fd = open(dev_path, O_RDWR);
+ free(dev_path);
+ if (fd < 0) {
+ fprintf(stderr, "Failed to open vduse dev %s: %s\n",
+ name, strerror(errno));
+ return -errno;
+ }
+
+ dev_name = strdup(name);
+ if (!dev_name) {
+ close(fd);
+ return -ENOMEM;
+ }
+
+ ret = vduse_dev_init_vqs(dev, num_queues);
+ if (ret) {
+ free(dev_name);
+ close(fd);
+ return ret;
+ }
+
+ dev->name = dev_name;
+ dev->num_queues = num_queues;
+ dev->fd = fd;
+ dev->ops = ops;
+ dev->priv = priv;
+
+ return 0;
+}
+
+static inline bool vduse_name_is_valid(const char *name)
+{
+ return strlen(name) >= VDUSE_NAME_MAX || strstr(name, "..");
+}
+
+VduseDev *vduse_dev_create_by_fd(int fd, uint16_t num_queues,
+ const VduseOps *ops, void *priv)
+{
+ VduseDev *dev;
+ int ret;
+
+ if (!ops || !ops->enable_queue || !ops->disable_queue) {
+ fprintf(stderr, "Invalid parameter for vduse\n");
+ return NULL;
+ }
+
+ dev = calloc(sizeof(VduseDev), 1);
+ if (!dev) {
+ fprintf(stderr, "Failed to allocate vduse device\n");
+ return NULL;
+ }
+
+ ret = vduse_dev_init_vqs(dev, num_queues);
+ if (ret) {
+ fprintf(stderr, "Failed to init vqs\n");
+ free(dev);
+ return NULL;
+ }
+
+ dev->num_queues = num_queues;
+ dev->fd = fd;
+ dev->ops = ops;
+ dev->priv = priv;
+
+ return dev;
+}
+
+VduseDev *vduse_dev_create_by_name(const char *name, uint16_t num_queues,
+ const VduseOps *ops, void *priv)
+{
+ VduseDev *dev;
+ int ret;
+
+ if (!name || vduse_name_is_valid(name) || !ops ||
+ !ops->enable_queue || !ops->disable_queue) {
+ fprintf(stderr, "Invalid parameter for vduse\n");
+ return NULL;
+ }
+
+ dev = calloc(sizeof(VduseDev), 1);
+ if (!dev) {
+ fprintf(stderr, "Failed to allocate vduse device\n");
+ return NULL;
+ }
+
+ ret = vduse_dev_init(dev, name, num_queues, ops, priv);
+ if (ret < 0) {
+ fprintf(stderr, "Failed to init vduse device %s: %s\n",
+ name, strerror(ret));
+ free(dev);
+ return NULL;
+ }
+
+ return dev;
+}
+
+VduseDev *vduse_dev_create(const char *name, uint32_t device_id,
+ uint32_t vendor_id, uint64_t features,
+ uint16_t num_queues, uint32_t config_size,
+ char *config, const VduseOps *ops, void *priv)
+{
+ VduseDev *dev;
+ int ret, ctrl_fd;
+ uint64_t version;
+ struct vduse_dev_config *dev_config;
+ size_t size = offsetof(struct vduse_dev_config, config);
+
+ if (!name || vduse_name_is_valid(name) ||
+ !has_feature(features, VIRTIO_F_VERSION_1) || !config ||
+ !config_size || !ops || !ops->enable_queue || !ops->disable_queue) {
+ fprintf(stderr, "Invalid parameter for vduse\n");
+ return NULL;
+ }
+
+ dev = calloc(sizeof(VduseDev), 1);
+ if (!dev) {
+ fprintf(stderr, "Failed to allocate vduse device\n");
+ return NULL;
+ }
+
+ ctrl_fd = open("/dev/vduse/control", O_RDWR);
+ if (ctrl_fd < 0) {
+ fprintf(stderr, "Failed to open /dev/vduse/control: %s\n",
+ strerror(errno));
+ goto err_ctrl;
+ }
+
+ version = VDUSE_API_VERSION;
+ if (ioctl(ctrl_fd, VDUSE_SET_API_VERSION, &version)) {
+ fprintf(stderr, "Failed to set api version %lu: %s\n",
+ version, strerror(errno));
+ goto err_dev;
+ }
+
+ dev_config = calloc(size + config_size, 1);
+ if (!dev_config) {
+ fprintf(stderr, "Failed to allocate config space\n");
+ goto err_dev;
+ }
+
+ strcpy(dev_config->name, name);
+ dev_config->device_id = device_id;
+ dev_config->vendor_id = vendor_id;
+ dev_config->features = features;
+ dev_config->vq_num = num_queues;
+ dev_config->vq_align = VDUSE_VQ_ALIGN;
+ dev_config->config_size = config_size;
+ memcpy(dev_config->config, config, config_size);
+
+ ret = ioctl(ctrl_fd, VDUSE_CREATE_DEV, dev_config);
+ free(dev_config);
+ if (ret < 0) {
+ fprintf(stderr, "Failed to create vduse device %s: %s\n",
+ name, strerror(errno));
+ goto err_dev;
+ }
+ dev->ctrl_fd = ctrl_fd;
+
+ ret = vduse_dev_init(dev, name, num_queues, ops, priv);
+ if (ret < 0) {
+ fprintf(stderr, "Failed to init vduse device %s: %s\n",
+ name, strerror(ret));
+ goto err;
+ }
+
+ return dev;
+err:
+ ioctl(ctrl_fd, VDUSE_DESTROY_DEV, name);
+err_dev:
+ close(ctrl_fd);
+err_ctrl:
+ free(dev);
+
+ return NULL;
+}
+
+int vduse_dev_destroy(VduseDev *dev)
+{
+ int ret = 0;
+
+ free(dev->vqs);
+ if (dev->fd > 0) {
+ close(dev->fd);
+ dev->fd = -1;
+ }
+ if (dev->ctrl_fd > 0) {
+ if (ioctl(dev->ctrl_fd, VDUSE_DESTROY_DEV, dev->name)) {
+ ret = -errno;
+ }
+ close(dev->ctrl_fd);
+ dev->ctrl_fd = -1;
+ }
+ free(dev->name);
+ free(dev);
+
+ return ret;
+}
diff --git a/subprojects/libvduse/libvduse.h b/subprojects/libvduse/libvduse.h
new file mode 100644
index 0000000000..6c2fe98213
--- /dev/null
+++ b/subprojects/libvduse/libvduse.h
@@ -0,0 +1,235 @@
+/*
+ * VDUSE (vDPA Device in Userspace) library
+ *
+ * Copyright (C) 2022 Bytedance Inc. and/or its affiliates. All rights
reserved.
+ *
+ * Author:
+ * Xie Yongji <xieyongji@bytedance.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later. See the COPYING file in the top-level directory.
+ */
+
+#ifndef LIBVDUSE_H
+#define LIBVDUSE_H
+
+#include <stdint.h>
+#include <sys/uio.h>
+
+#define VIRTQUEUE_MAX_SIZE 1024
+
+/* VDUSE device structure */
+typedef struct VduseDev VduseDev;
+
+/* Virtqueue structure */
+typedef struct VduseVirtq VduseVirtq;
+
+/* Some operation of VDUSE backend */
+typedef struct VduseOps {
+ /* Called when virtqueue can be processed */
+ void (*enable_queue)(VduseDev *dev, VduseVirtq *vq);
+ /* Called when virtqueue processing should be stopped */
+ void (*disable_queue)(VduseDev *dev, VduseVirtq *vq);
+} VduseOps;
+
+/* Describing elements of the I/O buffer */
+typedef struct VduseVirtqElement {
+ /* Descriptor table index */
+ unsigned int index;
+ /* Number of physically-contiguous device-readable descriptors */
+ unsigned int out_num;
+ /* Number of physically-contiguous device-writable descriptors */
+ unsigned int in_num;
+ /* Array to store physically-contiguous device-writable descriptors */
+ struct iovec *in_sg;
+ /* Array to store physically-contiguous device-readable descriptors */
+ struct iovec *out_sg;
+} VduseVirtqElement;
+
+
+/**
+ * vduse_get_virtio_features:
+ *
+ * Get supported virtio features
+ *
+ * Returns: supported feature bits
+ */
+uint64_t vduse_get_virtio_features(void);
+
+/**
+ * vduse_queue_get_dev:
+ * @vq: specified virtqueue
+ *
+ * Get corresponding VDUSE device from the virtqueue.
+ *
+ * Returns: a pointer to VDUSE device on success, NULL on failure.
+ */
+VduseDev *vduse_queue_get_dev(VduseVirtq *vq);
+
+/**
+ * vduse_queue_get_fd:
+ * @vq: specified virtqueue
+ *
+ * Get the kick fd for the virtqueue.
+ *
+ * Returns: file descriptor on success, -1 on failure.
+ */
+int vduse_queue_get_fd(VduseVirtq *vq);
+
+/**
+ * vduse_queue_pop:
+ * @vq: specified virtqueue
+ * @sz: the size of struct to return (must be >= VduseVirtqElement)
+ *
+ * Pop an element from virtqueue available ring.
+ *
+ * Returns: a pointer to a structure containing VduseVirtqElement on success,
+ * NULL on failure.
+ */
+void *vduse_queue_pop(VduseVirtq *vq, size_t sz);
+
+/**
+ * vduse_queue_push:
+ * @vq: specified virtqueue
+ * @elem: pointer to VduseVirtqElement returned by vduse_queue_pop()
+ * @len: length in bytes to write
+ *
+ * Push an element to virtqueue used ring.
+ */
+void vduse_queue_push(VduseVirtq *vq, const VduseVirtqElement *elem,
+ unsigned int len);
+/**
+ * vduse_queue_notify:
+ * @vq: specified virtqueue
+ *
+ * Request to notify the queue.
+ */
+void vduse_queue_notify(VduseVirtq *vq);
+
+/**
+ * vduse_dev_get_priv:
+ * @dev: VDUSE device
+ *
+ * Get the private pointer passed to vduse_dev_create().
+ *
+ * Returns: private pointer on success, NULL on failure.
+ */
+void *vduse_dev_get_priv(VduseDev *dev);
+
+/**
+ * vduse_dev_get_queue:
+ * @dev: VDUSE device
+ * @index: virtqueue index
+ *
+ * Get the specified virtqueue.
+ *
+ * Returns: a pointer to the virtqueue on success, NULL on failure.
+ */
+VduseVirtq *vduse_dev_get_queue(VduseDev *dev, int index);
+
+/**
+ * vduse_dev_get_fd:
+ * @dev: VDUSE device
+ *
+ * Get the control message fd for the VDUSE device.
+ *
+ * Returns: file descriptor on success, -1 on failure.
+ */
+int vduse_dev_get_fd(VduseDev *dev);
+
+/**
+ * vduse_dev_handler:
+ * @dev: VDUSE device
+ *
+ * Used to process the control message.
+ *
+ * Returns: file descriptor on success, -errno on failure.
+ */
+int vduse_dev_handler(VduseDev *dev);
+
+/**
+ * vduse_dev_update_config:
+ * @dev: VDUSE device
+ * @size: the size to write to configuration space
+ * @offset: the offset from the beginning of configuration space
+ * @buffer: the buffer used to write from
+ *
+ * Update device configuration space and inject a config interrupt.
+ *
+ * Returns: 0 on success, -errno on failure.
+ */
+int vduse_dev_update_config(VduseDev *dev, uint32_t size,
+ uint32_t offset, char *buffer);
+
+/**
+ * vduse_dev_setup_queue:
+ * @dev: VDUSE device
+ * @index: virtqueue index
+ * @max_size: the max size of virtqueue
+ *
+ * Setup the specified virtqueue.
+ *
+ * Returns: 0 on success, -errno on failure.
+ */
+int vduse_dev_setup_queue(VduseDev *dev, int index, int max_size);
+
+/**
+ * vduse_dev_create_by_fd:
+ * @fd: passed file descriptor
+ * @num_queues: the number of virtqueues
+ * @ops: the operation of VDUSE backend
+ * @priv: private pointer
+ *
+ * Create VDUSE device from a passed file descriptor.
+ *
+ * Returns: pointer to VDUSE device on success, NULL on failure.
+ */
+VduseDev *vduse_dev_create_by_fd(int fd, uint16_t num_queues,
+ const VduseOps *ops, void *priv);
+
+/**
+ * vduse_dev_create_by_name:
+ * @name: VDUSE device name
+ * @num_queues: the number of virtqueues
+ * @ops: the operation of VDUSE backend
+ * @priv: private pointer
+ *
+ * Create VDUSE device on /dev/vduse/$NAME.
+ *
+ * Returns: pointer to VDUSE device on success, NULL on failure.
+ */
+VduseDev *vduse_dev_create_by_name(const char *name, uint16_t num_queues,
+ const VduseOps *ops, void *priv);
+
+/**
+ * vduse_dev_create:
+ * @name: VDUSE device name
+ * @device_id: virtio device id
+ * @vendor_id: virtio vendor id
+ * @features: virtio features
+ * @num_queues: the number of virtqueues
+ * @config_size: the size of the configuration space
+ * @config: the buffer of the configuration space
+ * @ops: the operation of VDUSE backend
+ * @priv: private pointer
+ *
+ * Create VDUSE device.
+ *
+ * Returns: pointer to VDUSE device on success, NULL on failure.
+ */
+VduseDev *vduse_dev_create(const char *name, uint32_t device_id,
+ uint32_t vendor_id, uint64_t features,
+ uint16_t num_queues, uint32_t config_size,
+ char *config, const VduseOps *ops, void *priv);
+
+/**
+ * vduse_dev_destroy:
+ * @dev: VDUSE device
+ *
+ * Destroy the VDUSE device.
+ *
+ * Returns: 0 on success, -errno on failure.
+ */
+int vduse_dev_destroy(VduseDev *dev);
+
+#endif
diff --git a/subprojects/libvduse/linux-headers/linux
b/subprojects/libvduse/linux-headers/linux
new file mode 120000
index 0000000000..04f3304f79
--- /dev/null
+++ b/subprojects/libvduse/linux-headers/linux
@@ -0,0 +1 @@
+../../../linux-headers/linux/
\ No newline at end of file
diff --git a/subprojects/libvduse/meson.build b/subprojects/libvduse/meson.build
new file mode 100644
index 0000000000..ba08f5ee1a
--- /dev/null
+++ b/subprojects/libvduse/meson.build
@@ -0,0 +1,10 @@
+project('libvduse', 'c',
+ license: 'GPL-2.0-or-later',
+ default_options: ['c_std=gnu99'])
+
+libvduse = static_library('vduse',
+ files('libvduse.c'),
+ c_args: '-D_GNU_SOURCE')
+
+libvduse_dep = declare_dependency(link_with: libvduse,
+ include_directories:
include_directories('.'))
diff --git a/subprojects/libvduse/standard-headers/linux
b/subprojects/libvduse/standard-headers/linux
new file mode 120000
index 0000000000..c416f068ac
--- /dev/null
+++ b/subprojects/libvduse/standard-headers/linux
@@ -0,0 +1 @@
+../../../include/standard-headers/linux/
\ No newline at end of file
--
2.20.1
[PATCH v4 5/6] vduse-blk: Add vduse-blk resize support, Xie Yongji, 2022/04/06
[PATCH v4 6/6] libvduse: Add support for reconnecting, Xie Yongji, 2022/04/06