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qemu/hw/virtio/vhost-user.c

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/*
* 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 "sysemu/kvm.h"
#include "qemu/error-report.h"
#include "qemu/sockets.h"
#include "exec/ram_addr.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;
uint64_t mmap_offset;
} 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 {
#define VHOST_USER_VRING_IDX_MASK (0xff)
#define VHOST_USER_VRING_NOFD_MASK (0x1<<8)
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 bool ioeventfd_enabled(void)
{
return kvm_enabled() && kvm_eventfds_enabled();
}
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.", 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.", 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.", 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.", 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;
struct vhost_vring_file *file = 0;
int need_reply = 0;
int fds[VHOST_MEMORY_MAX_NREGIONS];
int i, fd;
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:
break;
case VHOST_RESET_OWNER:
memcpy(&msg.state, arg, sizeof(struct vhost_vring_state));
msg.state.index += dev->vq_index;
msg.size = sizeof(m.state);
break;
case VHOST_SET_MEM_TABLE:
for (i = 0; i < dev->mem->nregions; ++i) {
struct vhost_memory_region *reg = dev->mem->regions + i;
ram_addr_t ram_addr;
assert((uintptr_t)reg->userspace_addr == reg->userspace_addr);
qemu_ram_addr_from_host((void *)(uintptr_t)reg->userspace_addr, &ram_addr);
fd = qemu_get_ram_fd(ram_addr);
if (fd > 0) {
msg.memory.regions[fd_num].userspace_addr = reg->userspace_addr;
msg.memory.regions[fd_num].memory_size = reg->memory_size;
msg.memory.regions[fd_num].guest_phys_addr = reg->guest_phys_addr;
msg.memory.regions[fd_num].mmap_offset = reg->userspace_addr -
(uintptr_t) qemu_get_ram_block_host_ptr(ram_addr);
assert(fd_num < VHOST_MEMORY_MAX_NREGIONS);
fds[fd_num++] = fd;
}
}
msg.memory.nregions = fd_num;
if (!fd_num) {
error_report("Failed initializing vhost-user memory map, "
"consider using -object memory-backend-file share=on");
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.state.index += dev->vq_index;
msg.size = sizeof(m.state);
break;
case VHOST_GET_VRING_BASE:
memcpy(&msg.state, arg, sizeof(struct vhost_vring_state));
msg.state.index += dev->vq_index;
msg.size = sizeof(m.state);
need_reply = 1;
break;
case VHOST_SET_VRING_ADDR:
memcpy(&msg.addr, arg, sizeof(struct vhost_vring_addr));
msg.addr.index += dev->vq_index;
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 + dev->vq_index) & VHOST_USER_VRING_IDX_MASK;
msg.size = sizeof(m.u64);
if (ioeventfd_enabled() && file->fd > 0) {
fds[fd_num++] = file->fd;
} else {
msg.u64 |= VHOST_USER_VRING_NOFD_MASK;
}
break;
default:
error_report("vhost-user trying to send unhandled ioctl");
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", 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.");
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.");
return -1;
}
msg.state.index -= dev->vq_index;
memcpy(arg, &msg.state, sizeof(struct vhost_vring_state));
break;
default:
error_report("Received unexpected msg type.");
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
};
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