The initialization takes a chardev backed by a unix domain socket.
It should implement qemu_fe_set_msgfds in order to be able to pass
file descriptors to the remote process.
Each ioctl request of vhost-kernel has a vhost-user message equivalent,
which is sent over the control socket.
The general approach is to copy the data from the supplied argument
pointer to a designated field in the message. If a file descriptor is
to be passed it will be placed in the fds array for inclusion in
the sendmsg control header.
VHOST_SET_MEM_TABLE ignores the supplied vhost_memory structure and scans
the global ram_list for ram blocks with a valid fd field set. This would
be set when the -mem-path option with shared=on property is used.
Signed-off-by: Antonios Motakis <a.mota...@virtualopensystems.com>
Signed-off-by: Nikolay Nikolaev <n.nikol...@virtualopensystems.com>
---
hw/virtio/Makefile.objs | 2 +-
hw/virtio/vhost-backend.c | 5 +
hw/virtio/vhost-user.c | 331 ++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 337 insertions(+), 1 deletion(-)
create mode 100644 hw/virtio/vhost-user.c
diff --git a/hw/virtio/Makefile.objs b/hw/virtio/Makefile.objs
index 51e5bdb..ec9e855 100644
--- a/hw/virtio/Makefile.objs
+++ b/hw/virtio/Makefile.objs
@@ -5,4 +5,4 @@ common-obj-y += virtio-mmio.o
common-obj-$(CONFIG_VIRTIO_BLK_DATA_PLANE) += dataplane/
obj-y += virtio.o virtio-balloon.o
-obj-$(CONFIG_LINUX) += vhost.o vhost-backend.o
+obj-$(CONFIG_LINUX) += vhost.o vhost-backend.o vhost-user.o
diff --git a/hw/virtio/vhost-backend.c b/hw/virtio/vhost-backend.c
index 509e103..35316c4 100644
--- a/hw/virtio/vhost-backend.c
+++ b/hw/virtio/vhost-backend.c
@@ -14,6 +14,8 @@
#include <sys/ioctl.h>
+extern const VhostOps user_ops;
+
static int vhost_kernel_call(struct vhost_dev *dev, unsigned long int request,
void *arg)
{
@@ -57,6 +59,9 @@ int vhost_set_backend_type(struct vhost_dev *dev,
VhostBackendType backend_type)
case VHOST_BACKEND_TYPE_KERNEL:
dev->vhost_ops = &kernel_ops;
break;
+ case VHOST_BACKEND_TYPE_USER:
+ dev->vhost_ops = &user_ops;
+ break;
default:
error_report("Unknown vhost backend type\n");
r = -1;
diff --git a/hw/virtio/vhost-user.c b/hw/virtio/vhost-user.c
new file mode 100644
index 0000000..1483647
--- /dev/null
+++ b/hw/virtio/vhost-user.c
@@ -0,0 +1,331 @@
+/*
+ * vhost-user
+ *
+ * Copyright (c) 2013 Virtual Open Systems Sarl.
+ *
+ * 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 "hw/virtio/vhost.h"
+#include "hw/virtio/vhost-backend.h"
+#include "sysemu/char.h"
+#include "qemu/error-report.h"
+#include "qemu/sockets.h"
+
+#include <fcntl.h>
+#include <unistd.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <linux/vhost.h>
+
+#define VHOST_MEMORY_MAX_NREGIONS 8
+
+typedef enum VhostUserRequest {
+ VHOST_USER_NONE = 0,
+ VHOST_USER_GET_FEATURES = 1,
+ VHOST_USER_SET_FEATURES = 2,
+ VHOST_USER_SET_OWNER = 3,
+ VHOST_USER_RESET_OWNER = 4,
+ VHOST_USER_SET_MEM_TABLE = 5,
+ VHOST_USER_SET_LOG_BASE = 6,
+ VHOST_USER_SET_LOG_FD = 7,
+ VHOST_USER_SET_VRING_NUM = 8,
+ VHOST_USER_SET_VRING_ADDR = 9,
+ VHOST_USER_SET_VRING_BASE = 10,
+ VHOST_USER_GET_VRING_BASE = 11,
+ VHOST_USER_SET_VRING_KICK = 12,
+ VHOST_USER_SET_VRING_CALL = 13,
+ VHOST_USER_SET_VRING_ERR = 14,
+ VHOST_USER_MAX
+} VhostUserRequest;
+
+typedef struct VhostUserMemoryRegion {
+ uint64_t guest_phys_addr;
+ uint64_t memory_size;
+ uint64_t userspace_addr;
+} VhostUserMemoryRegion;
+
+typedef struct VhostUserMemory {
+ uint32_t nregions;
+ uint32_t padding;
+ VhostUserMemoryRegion regions[VHOST_MEMORY_MAX_NREGIONS];
+} VhostUserMemory;
+
+typedef struct VhostUserMsg {
+ VhostUserRequest request;
+
+#define VHOST_USER_VERSION_MASK (0x3)
+#define VHOST_USER_REPLY_MASK (0x1<<2)
+ uint32_t flags;
+ uint32_t size; /* the following payload size */
+ union {
+ uint64_t u64;
+ struct vhost_vring_state state;
+ struct vhost_vring_addr addr;
+ VhostUserMemory memory;
+ };
+} QEMU_PACKED VhostUserMsg;
+
+static VhostUserMsg m __attribute__ ((unused));
+#define VHOST_USER_HDR_SIZE (sizeof(m.request) \
+ + sizeof(m.flags) \
+ + sizeof(m.size))
+
+#define VHOST_USER_PAYLOAD_SIZE (sizeof(m) - VHOST_USER_HDR_SIZE)
+
+/* The version of the protocol we support */
+#define VHOST_USER_VERSION (0x1)
+
+static unsigned long int ioctl_to_vhost_user_request[VHOST_USER_MAX] = {
+ -1, /* VHOST_USER_NONE */
+ VHOST_GET_FEATURES, /* VHOST_USER_GET_FEATURES */
+ VHOST_SET_FEATURES, /* VHOST_USER_SET_FEATURES */
+ VHOST_SET_OWNER, /* VHOST_USER_SET_OWNER */
+ VHOST_RESET_OWNER, /* VHOST_USER_RESET_OWNER */
+ VHOST_SET_MEM_TABLE, /* VHOST_USER_SET_MEM_TABLE */
+ VHOST_SET_LOG_BASE, /* VHOST_USER_SET_LOG_BASE */
+ VHOST_SET_LOG_FD, /* VHOST_USER_SET_LOG_FD */
+ VHOST_SET_VRING_NUM, /* VHOST_USER_SET_VRING_NUM */
+ VHOST_SET_VRING_ADDR, /* VHOST_USER_SET_VRING_ADDR */
+ VHOST_SET_VRING_BASE, /* VHOST_USER_SET_VRING_BASE */
+ VHOST_GET_VRING_BASE, /* VHOST_USER_GET_VRING_BASE */
+ VHOST_SET_VRING_KICK, /* VHOST_USER_SET_VRING_KICK */
+ VHOST_SET_VRING_CALL, /* VHOST_USER_SET_VRING_CALL */
+ VHOST_SET_VRING_ERR /* VHOST_USER_SET_VRING_ERR */
+};
+
+static VhostUserRequest vhost_user_request_translate(unsigned long int request)
+{
+ VhostUserRequest idx;
+
+ for (idx = 0; idx < VHOST_USER_MAX; idx++) {
+ if (ioctl_to_vhost_user_request[idx] == request) {
+ break;
+ }
+ }
+
+ return (idx == VHOST_USER_MAX) ? VHOST_USER_NONE : idx;
+}
+
+static int vhost_user_read(struct vhost_dev *dev, VhostUserMsg *msg)
+{
+ CharDriverState *chr = dev->opaque;
+ uint8_t *p = (uint8_t *) msg;
+ int r, size = VHOST_USER_HDR_SIZE;
+
+ r = qemu_chr_fe_read_all(chr, p, size);
+ if (r != size) {
+ error_report("Failed to read msg header. Read %d instead of %d.\n", r,
+ size);
+ goto fail;
+ }
+
+ /* validate received flags */
+ if (msg->flags != (VHOST_USER_REPLY_MASK | VHOST_USER_VERSION)) {
+ error_report("Failed to read msg header."
+ " Flags 0x%x instead of 0x%x.\n", msg->flags,
+ VHOST_USER_REPLY_MASK | VHOST_USER_VERSION);
+ goto fail;
+ }
+
+ /* validate message size is sane */
+ if (msg->size > VHOST_USER_PAYLOAD_SIZE) {
+ error_report("Failed to read msg header."
+ " Size %d exceeds the maximum %zu.\n", msg->size,
+ VHOST_USER_PAYLOAD_SIZE);
+ goto fail;
+ }
+
+ if (msg->size) {
+ p += VHOST_USER_HDR_SIZE;
+ size = msg->size;
+ r = qemu_chr_fe_read_all(chr, p, size);
+ if (r != size) {
+ error_report("Failed to read msg payload."
+ " Read %d instead of %d.\n", r, msg->size);
+ goto fail;
+ }
+ }
+
+ return 0;
+
+fail:
+ return -1;
+}
+
+static int vhost_user_write(struct vhost_dev *dev, VhostUserMsg *msg,
+ int *fds, int fd_num)
+{
+ CharDriverState *chr = dev->opaque;
+ int size = VHOST_USER_HDR_SIZE + msg->size;
+
+ if (fd_num) {
+ qemu_chr_fe_set_msgfds(chr, fds, fd_num);
+ }
+
+ return qemu_chr_fe_write_all(chr, (const uint8_t *) msg, size) == size ?
+ 0 : -1;
+}
+
+static int vhost_user_call(struct vhost_dev *dev, unsigned long int request,
+ void *arg)
+{
+ VhostUserMsg msg;
+ VhostUserRequest msg_request;
+ RAMBlock *block = 0;
+ struct vhost_vring_file *file = 0;
+ int need_reply = 0;
+ int fds[VHOST_MEMORY_MAX_NREGIONS];
+ size_t fd_num = 0;
+
+ assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
+
+ msg_request = vhost_user_request_translate(request);
+ msg.request = msg_request;
+ msg.flags = VHOST_USER_VERSION;
+ msg.size = 0;
+
+ switch (request) {
+ case VHOST_GET_FEATURES:
+ need_reply = 1;
+ break;
+
+ case VHOST_SET_FEATURES:
+ case VHOST_SET_LOG_BASE:
+ msg.u64 = *((__u64 *) arg);
+ msg.size = sizeof(m.u64);
+ break;
+
+ case VHOST_SET_OWNER:
+ case VHOST_RESET_OWNER:
+ break;
+
+ case VHOST_SET_MEM_TABLE:
+ QTAILQ_FOREACH(block, &ram_list.blocks, next)
+ {
+ if (block->fd > 0) {
+ msg.memory.regions[fd_num].userspace_addr = (__u64)
block->host;
+ msg.memory.regions[fd_num].memory_size = block->length;
+ msg.memory.regions[fd_num].guest_phys_addr = block->offset;
+ fds[fd_num++] = block->fd;
+ }
+ }
+
+ msg.memory.nregions = fd_num;
+
+ if (!fd_num) {
+ error_report("Failed initializing vhost-user memory map\n"
+ "consider using -mem-path option\n");
+ return -1;
+ }
+
+ msg.size = sizeof(m.memory.nregions);
+ msg.size += sizeof(m.memory.padding);
+ msg.size += fd_num * sizeof(VhostUserMemoryRegion);
+
+ break;
+
+ case VHOST_SET_LOG_FD:
+ fds[fd_num++] = *((int *) arg);
+ break;
+
+ case VHOST_SET_VRING_NUM:
+ case VHOST_SET_VRING_BASE:
+ memcpy(&msg.state, arg, sizeof(struct vhost_vring_state));
+ msg.size = sizeof(m.state);
+ break;
+
+ case VHOST_GET_VRING_BASE:
+ memcpy(&msg.state, arg, sizeof(struct vhost_vring_state));
+ msg.size = sizeof(m.state);
+ need_reply = 1;
+ break;
+
+ case VHOST_SET_VRING_ADDR:
+ memcpy(&msg.addr, arg, sizeof(struct vhost_vring_addr));
+ msg.size = sizeof(m.addr);
+ break;
+
+ case VHOST_SET_VRING_KICK:
+ case VHOST_SET_VRING_CALL:
+ case VHOST_SET_VRING_ERR:
+ file = arg;
+ msg.u64 = file->index;
+ msg.size = sizeof(m.u64);
+ if (file->fd > 0) {
+ fds[fd_num++] = file->fd;
+ }
+ break;
+ default:
+ error_report("vhost-user trying to send unhandled ioctl\n");
+ return -1;
+ break;
+ }
+
+ if (vhost_user_write(dev, &msg, fds, fd_num) < 0) {
+ return 0;
+ }
+
+ if (need_reply) {
+ if (vhost_user_read(dev, &msg) < 0) {
+ return 0;
+ }
+
+ if (msg_request != msg.request) {
+ error_report("Received unexpected msg type."
+ " Expected %d received %d\n", msg_request, msg.request);
+ return -1;
+ }
+
+ switch (msg_request) {
+ case VHOST_USER_GET_FEATURES:
+ if (msg.size != sizeof(m.u64)) {
+ error_report("Received bad msg size.\n");
+ return -1;
+ }
+ *((__u64 *) arg) = msg.u64;
+ break;
+ case VHOST_USER_GET_VRING_BASE:
+ if (msg.size != sizeof(m.state)) {
+ error_report("Received bad msg size.\n");
+ return -1;
+ }
+ memcpy(arg, &msg.state, sizeof(struct vhost_vring_state));
+ break;
+ default:
+ error_report("Received unexpected msg type.\n");
+ return -1;
+ break;
+ }
+ }
+
+ return 0;
+}
+
+static int vhost_user_init(struct vhost_dev *dev, void *opaque)
+{
+ assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
+
+ dev->opaque = opaque;
+
+ return 0;
+}
+
+static int vhost_user_cleanup(struct vhost_dev *dev)
+{
+ assert(dev->vhost_ops->backend_type == VHOST_BACKEND_TYPE_USER);
+
+ dev->opaque = 0;
+
+ return 0;
+}
+
+const VhostOps user_ops = {
+ .backend_type = VHOST_BACKEND_TYPE_USER,
+ .vhost_call = vhost_user_call,
+ .vhost_backend_init = vhost_user_init,
+ .vhost_backend_cleanup = vhost_user_cleanup
+ };
--
1.8.3.2
