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QEMU-Nyx-fork/contrib/libvhost-user/libvhost-user.c
Dr. David Alan Gilbert 4275cd99c6 libvhost-user: Claim support for postcopy 
Tell QEMU we understand the protocol features needed for postcopy.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2018-03-20 16:40:37 +02:00

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/*
* Vhost User library
*
* Copyright IBM, Corp. 2007
* Copyright (c) 2016 Red Hat, Inc.
*
* Authors:
* 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.
*/
/* this code avoids GLib dependency */
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <stdarg.h>
#include <errno.h>
#include <string.h>
#include <assert.h>
#include <inttypes.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/eventfd.h>
#include <sys/mman.h>
#include "qemu/compiler.h"
#if defined(__linux__)
#include <sys/syscall.h>
#include <fcntl.h>
#include <sys/ioctl.h>
#include <linux/vhost.h>
#ifdef __NR_userfaultfd
#include <linux/userfaultfd.h>
#endif
#endif
#include "qemu/atomic.h"
#include "libvhost-user.h"
/* usually provided by GLib */
#ifndef MIN
#define MIN(x, y) ({ \
typeof(x) _min1 = (x); \
typeof(y) _min2 = (y); \
(void) (&_min1 == &_min2); \
_min1 < _min2 ? _min1 : _min2; })
#endif
#define VHOST_USER_HDR_SIZE offsetof(VhostUserMsg, payload.u64)
/* The version of the protocol we support */
#define VHOST_USER_VERSION 1
#define LIBVHOST_USER_DEBUG 0
#define DPRINT(...) \
do { \
if (LIBVHOST_USER_DEBUG) { \
fprintf(stderr, __VA_ARGS__); \
} \
} while (0)
static const char *
vu_request_to_string(unsigned int req)
{
#define REQ(req) [req] = #req
static const char *vu_request_str[] = {
REQ(VHOST_USER_NONE),
REQ(VHOST_USER_GET_FEATURES),
REQ(VHOST_USER_SET_FEATURES),
REQ(VHOST_USER_SET_OWNER),
REQ(VHOST_USER_RESET_OWNER),
REQ(VHOST_USER_SET_MEM_TABLE),
REQ(VHOST_USER_SET_LOG_BASE),
REQ(VHOST_USER_SET_LOG_FD),
REQ(VHOST_USER_SET_VRING_NUM),
REQ(VHOST_USER_SET_VRING_ADDR),
REQ(VHOST_USER_SET_VRING_BASE),
REQ(VHOST_USER_GET_VRING_BASE),
REQ(VHOST_USER_SET_VRING_KICK),
REQ(VHOST_USER_SET_VRING_CALL),
REQ(VHOST_USER_SET_VRING_ERR),
REQ(VHOST_USER_GET_PROTOCOL_FEATURES),
REQ(VHOST_USER_SET_PROTOCOL_FEATURES),
REQ(VHOST_USER_GET_QUEUE_NUM),
REQ(VHOST_USER_SET_VRING_ENABLE),
REQ(VHOST_USER_SEND_RARP),
REQ(VHOST_USER_NET_SET_MTU),
REQ(VHOST_USER_SET_SLAVE_REQ_FD),
REQ(VHOST_USER_IOTLB_MSG),
REQ(VHOST_USER_SET_VRING_ENDIAN),
REQ(VHOST_USER_GET_CONFIG),
REQ(VHOST_USER_SET_CONFIG),
REQ(VHOST_USER_POSTCOPY_ADVISE),
REQ(VHOST_USER_POSTCOPY_LISTEN),
REQ(VHOST_USER_POSTCOPY_END),
REQ(VHOST_USER_MAX),
};
#undef REQ
if (req < VHOST_USER_MAX) {
return vu_request_str[req];
} else {
return "unknown";
}
}
static void
vu_panic(VuDev *dev, const char *msg, ...)
{
char *buf = NULL;
va_list ap;
va_start(ap, msg);
if (vasprintf(&buf, msg, ap) < 0) {
buf = NULL;
}
va_end(ap);
dev->broken = true;
dev->panic(dev, buf);
free(buf);
/* FIXME: find a way to call virtio_error? */
}
/* Translate guest physical address to our virtual address. */
void *
vu_gpa_to_va(VuDev *dev, uint64_t *plen, uint64_t guest_addr)
{
int i;
if (*plen == 0) {
return NULL;
}
/* Find matching memory region. */
for (i = 0; i < dev->nregions; i++) {
VuDevRegion *r = &dev->regions[i];
if ((guest_addr >= r->gpa) && (guest_addr < (r->gpa + r->size))) {
if ((guest_addr + *plen) > (r->gpa + r->size)) {
*plen = r->gpa + r->size - guest_addr;
}
return (void *)(uintptr_t)
guest_addr - r->gpa + r->mmap_addr + r->mmap_offset;
}
}
return NULL;
}
/* Translate qemu virtual address to our virtual address. */
static void *
qva_to_va(VuDev *dev, uint64_t qemu_addr)
{
int i;
/* Find matching memory region. */
for (i = 0; i < dev->nregions; i++) {
VuDevRegion *r = &dev->regions[i];
if ((qemu_addr >= r->qva) && (qemu_addr < (r->qva + r->size))) {
return (void *)(uintptr_t)
qemu_addr - r->qva + r->mmap_addr + r->mmap_offset;
}
}
return NULL;
}
static void
vmsg_close_fds(VhostUserMsg *vmsg)
{
int i;
for (i = 0; i < vmsg->fd_num; i++) {
close(vmsg->fds[i]);
}
}
/* A test to see if we have userfault available */
static bool
have_userfault(void)
{
#if defined(__linux__) && defined(__NR_userfaultfd) &&\
defined(UFFD_FEATURE_MISSING_SHMEM) &&\
defined(UFFD_FEATURE_MISSING_HUGETLBFS)
/* Now test the kernel we're running on really has the features */
int ufd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
struct uffdio_api api_struct;
if (ufd < 0) {
return false;
}
api_struct.api = UFFD_API;
api_struct.features = UFFD_FEATURE_MISSING_SHMEM |
UFFD_FEATURE_MISSING_HUGETLBFS;
if (ioctl(ufd, UFFDIO_API, &api_struct)) {
close(ufd);
return false;
}
close(ufd);
return true;
#else
return false;
#endif
}
static bool
vu_message_read(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
{
char control[CMSG_SPACE(VHOST_MEMORY_MAX_NREGIONS * sizeof(int))] = { };
struct iovec iov = {
.iov_base = (char *)vmsg,
.iov_len = VHOST_USER_HDR_SIZE,
};
struct msghdr msg = {
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_control = control,
.msg_controllen = sizeof(control),
};
size_t fd_size;
struct cmsghdr *cmsg;
int rc;
do {
rc = recvmsg(conn_fd, &msg, 0);
} while (rc < 0 && (errno == EINTR || errno == EAGAIN));
if (rc < 0) {
vu_panic(dev, "Error while recvmsg: %s", strerror(errno));
return false;
}
vmsg->fd_num = 0;
for (cmsg = CMSG_FIRSTHDR(&msg);
cmsg != NULL;
cmsg = CMSG_NXTHDR(&msg, cmsg))
{
if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
fd_size = cmsg->cmsg_len - CMSG_LEN(0);
vmsg->fd_num = fd_size / sizeof(int);
memcpy(vmsg->fds, CMSG_DATA(cmsg), fd_size);
break;
}
}
if (vmsg->size > sizeof(vmsg->payload)) {
vu_panic(dev,
"Error: too big message request: %d, size: vmsg->size: %u, "
"while sizeof(vmsg->payload) = %zu\n",
vmsg->request, vmsg->size, sizeof(vmsg->payload));
goto fail;
}
if (vmsg->size) {
do {
rc = read(conn_fd, &vmsg->payload, vmsg->size);
} while (rc < 0 && (errno == EINTR || errno == EAGAIN));
if (rc <= 0) {
vu_panic(dev, "Error while reading: %s", strerror(errno));
goto fail;
}
assert(rc == vmsg->size);
}
return true;
fail:
vmsg_close_fds(vmsg);
return false;
}
static bool
vu_message_write(VuDev *dev, int conn_fd, VhostUserMsg *vmsg)
{
int rc;
uint8_t *p = (uint8_t *)vmsg;
char control[CMSG_SPACE(VHOST_MEMORY_MAX_NREGIONS * sizeof(int))] = { };
struct iovec iov = {
.iov_base = (char *)vmsg,
.iov_len = VHOST_USER_HDR_SIZE,
};
struct msghdr msg = {
.msg_iov = &iov,
.msg_iovlen = 1,
.msg_control = control,
};
struct cmsghdr *cmsg;
memset(control, 0, sizeof(control));
assert(vmsg->fd_num <= VHOST_MEMORY_MAX_NREGIONS);
if (vmsg->fd_num > 0) {
size_t fdsize = vmsg->fd_num * sizeof(int);
msg.msg_controllen = CMSG_SPACE(fdsize);
cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_len = CMSG_LEN(fdsize);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
memcpy(CMSG_DATA(cmsg), vmsg->fds, fdsize);
} else {
msg.msg_controllen = 0;
}
/* Set the version in the flags when sending the reply */
vmsg->flags &= ~VHOST_USER_VERSION_MASK;
vmsg->flags |= VHOST_USER_VERSION;
vmsg->flags |= VHOST_USER_REPLY_MASK;
do {
rc = sendmsg(conn_fd, &msg, 0);
} while (rc < 0 && (errno == EINTR || errno == EAGAIN));
do {
if (vmsg->data) {
rc = write(conn_fd, vmsg->data, vmsg->size);
} else {
rc = write(conn_fd, p + VHOST_USER_HDR_SIZE, vmsg->size);
}
} while (rc < 0 && (errno == EINTR || errno == EAGAIN));
if (rc <= 0) {
vu_panic(dev, "Error while writing: %s", strerror(errno));
return false;
}
return true;
}
/* Kick the log_call_fd if required. */
static void
vu_log_kick(VuDev *dev)
{
if (dev->log_call_fd != -1) {
DPRINT("Kicking the QEMU's log...\n");
if (eventfd_write(dev->log_call_fd, 1) < 0) {
vu_panic(dev, "Error writing eventfd: %s", strerror(errno));
}
}
}
static void
vu_log_page(uint8_t *log_table, uint64_t page)
{
DPRINT("Logged dirty guest page: %"PRId64"\n", page);
atomic_or(&log_table[page / 8], 1 << (page % 8));
}
static void
vu_log_write(VuDev *dev, uint64_t address, uint64_t length)
{
uint64_t page;
if (!(dev->features & (1ULL << VHOST_F_LOG_ALL)) ||
!dev->log_table || !length) {
return;
}
assert(dev->log_size > ((address + length - 1) / VHOST_LOG_PAGE / 8));
page = address / VHOST_LOG_PAGE;
while (page * VHOST_LOG_PAGE < address + length) {
vu_log_page(dev->log_table, page);
page += VHOST_LOG_PAGE;
}
vu_log_kick(dev);
}
static void
vu_kick_cb(VuDev *dev, int condition, void *data)
{
int index = (intptr_t)data;
VuVirtq *vq = &dev->vq[index];
int sock = vq->kick_fd;
eventfd_t kick_data;
ssize_t rc;
rc = eventfd_read(sock, &kick_data);
if (rc == -1) {
vu_panic(dev, "kick eventfd_read(): %s", strerror(errno));
dev->remove_watch(dev, dev->vq[index].kick_fd);
} else {
DPRINT("Got kick_data: %016"PRIx64" handler:%p idx:%d\n",
kick_data, vq->handler, index);
if (vq->handler) {
vq->handler(dev, index);
}
}
}
static bool
vu_get_features_exec(VuDev *dev, VhostUserMsg *vmsg)
{
vmsg->payload.u64 =
1ULL << VHOST_F_LOG_ALL |
1ULL << VHOST_USER_F_PROTOCOL_FEATURES;
if (dev->iface->get_features) {
vmsg->payload.u64 |= dev->iface->get_features(dev);
}
vmsg->size = sizeof(vmsg->payload.u64);
vmsg->fd_num = 0;
DPRINT("Sending back to guest u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
return true;
}
static void
vu_set_enable_all_rings(VuDev *dev, bool enabled)
{
int i;
for (i = 0; i < VHOST_MAX_NR_VIRTQUEUE; i++) {
dev->vq[i].enable = enabled;
}
}
static bool
vu_set_features_exec(VuDev *dev, VhostUserMsg *vmsg)
{
DPRINT("u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
dev->features = vmsg->payload.u64;
if (!(dev->features & VHOST_USER_F_PROTOCOL_FEATURES)) {
vu_set_enable_all_rings(dev, true);
}
if (dev->iface->set_features) {
dev->iface->set_features(dev, dev->features);
}
return false;
}
static bool
vu_set_owner_exec(VuDev *dev, VhostUserMsg *vmsg)
{
return false;
}
static void
vu_close_log(VuDev *dev)
{
if (dev->log_table) {
if (munmap(dev->log_table, dev->log_size) != 0) {
perror("close log munmap() error");
}
dev->log_table = NULL;
}
if (dev->log_call_fd != -1) {
close(dev->log_call_fd);
dev->log_call_fd = -1;
}
}
static bool
vu_reset_device_exec(VuDev *dev, VhostUserMsg *vmsg)
{
vu_set_enable_all_rings(dev, false);
return false;
}
static bool
vu_set_mem_table_exec_postcopy(VuDev *dev, VhostUserMsg *vmsg)
{
int i;
VhostUserMemory *memory = &vmsg->payload.memory;
dev->nregions = memory->nregions;
DPRINT("Nregions: %d\n", memory->nregions);
for (i = 0; i < dev->nregions; i++) {
void *mmap_addr;
VhostUserMemoryRegion *msg_region = &memory->regions[i];
VuDevRegion *dev_region = &dev->regions[i];
DPRINT("Region %d\n", i);
DPRINT(" guest_phys_addr: 0x%016"PRIx64"\n",
msg_region->guest_phys_addr);
DPRINT(" memory_size: 0x%016"PRIx64"\n",
msg_region->memory_size);
DPRINT(" userspace_addr 0x%016"PRIx64"\n",
msg_region->userspace_addr);
DPRINT(" mmap_offset 0x%016"PRIx64"\n",
msg_region->mmap_offset);
dev_region->gpa = msg_region->guest_phys_addr;
dev_region->size = msg_region->memory_size;
dev_region->qva = msg_region->userspace_addr;
dev_region->mmap_offset = msg_region->mmap_offset;
/* We don't use offset argument of mmap() since the
* mapped address has to be page aligned, and we use huge
* pages.
* In postcopy we're using PROT_NONE here to catch anyone
* accessing it before we userfault
*/
mmap_addr = mmap(0, dev_region->size + dev_region->mmap_offset,
PROT_NONE, MAP_SHARED,
vmsg->fds[i], 0);
if (mmap_addr == MAP_FAILED) {
vu_panic(dev, "region mmap error: %s", strerror(errno));
} else {
dev_region->mmap_addr = (uint64_t)(uintptr_t)mmap_addr;
DPRINT(" mmap_addr: 0x%016"PRIx64"\n",
dev_region->mmap_addr);
}
/* Return the address to QEMU so that it can translate the ufd
* fault addresses back.
*/
msg_region->userspace_addr = (uintptr_t)(mmap_addr +
dev_region->mmap_offset);
close(vmsg->fds[i]);
}
/* Send the message back to qemu with the addresses filled in */
vmsg->fd_num = 0;
if (!vu_message_write(dev, dev->sock, vmsg)) {
vu_panic(dev, "failed to respond to set-mem-table for postcopy");
return false;
}
/* Wait for QEMU to confirm that it's registered the handler for the
* faults.
*/
if (!vu_message_read(dev, dev->sock, vmsg) ||
vmsg->size != sizeof(vmsg->payload.u64) ||
vmsg->payload.u64 != 0) {
vu_panic(dev, "failed to receive valid ack for postcopy set-mem-table");
return false;
}
/* OK, now we can go and register the memory and generate faults */
for (i = 0; i < dev->nregions; i++) {
VuDevRegion *dev_region = &dev->regions[i];
int ret;
#ifdef UFFDIO_REGISTER
/* We should already have an open ufd. Mark each memory
* range as ufd.
* Discard any mapping we have here; note I can't use MADV_REMOVE
* or fallocate to make the hole since I don't want to lose
* data that's already arrived in the shared process.
* TODO: How to do hugepage
*/
ret = madvise((void *)dev_region->mmap_addr,
dev_region->size + dev_region->mmap_offset,
MADV_DONTNEED);
if (ret) {
fprintf(stderr,
"%s: Failed to madvise(DONTNEED) region %d: %s\n",
__func__, i, strerror(errno));
}
/* Turn off transparent hugepages so we dont get lose wakeups
* in neighbouring pages.
* TODO: Turn this backon later.
*/
ret = madvise((void *)dev_region->mmap_addr,
dev_region->size + dev_region->mmap_offset,
MADV_NOHUGEPAGE);
if (ret) {
/* Note: This can happen legally on kernels that are configured
* without madvise'able hugepages
*/
fprintf(stderr,
"%s: Failed to madvise(NOHUGEPAGE) region %d: %s\n",
__func__, i, strerror(errno));
}
struct uffdio_register reg_struct;
reg_struct.range.start = (uintptr_t)dev_region->mmap_addr;
reg_struct.range.len = dev_region->size + dev_region->mmap_offset;
reg_struct.mode = UFFDIO_REGISTER_MODE_MISSING;
if (ioctl(dev->postcopy_ufd, UFFDIO_REGISTER, &reg_struct)) {
vu_panic(dev, "%s: Failed to userfault region %d "
"@%p + size:%zx offset: %zx: (ufd=%d)%s\n",
__func__, i,
dev_region->mmap_addr,
dev_region->size, dev_region->mmap_offset,
dev->postcopy_ufd, strerror(errno));
return false;
}
if (!(reg_struct.ioctls & ((__u64)1 << _UFFDIO_COPY))) {
vu_panic(dev, "%s Region (%d) doesn't support COPY",
__func__, i);
return false;
}
DPRINT("%s: region %d: Registered userfault for %llx + %llx\n",
__func__, i, reg_struct.range.start, reg_struct.range.len);
/* Now it's registered we can let the client at it */
if (mprotect((void *)dev_region->mmap_addr,
dev_region->size + dev_region->mmap_offset,
PROT_READ | PROT_WRITE)) {
vu_panic(dev, "failed to mprotect region %d for postcopy (%s)",
i, strerror(errno));
return false;
}
/* TODO: Stash 'zero' support flags somewhere */
#endif
}
return false;
}
static bool
vu_set_mem_table_exec(VuDev *dev, VhostUserMsg *vmsg)
{
int i;
VhostUserMemory *memory = &vmsg->payload.memory;
for (i = 0; i < dev->nregions; i++) {
VuDevRegion *r = &dev->regions[i];
void *m = (void *) (uintptr_t) r->mmap_addr;
if (m) {
munmap(m, r->size + r->mmap_offset);
}
}
dev->nregions = memory->nregions;
if (dev->postcopy_listening) {
return vu_set_mem_table_exec_postcopy(dev, vmsg);
}
DPRINT("Nregions: %d\n", memory->nregions);
for (i = 0; i < dev->nregions; i++) {
void *mmap_addr;
VhostUserMemoryRegion *msg_region = &memory->regions[i];
VuDevRegion *dev_region = &dev->regions[i];
DPRINT("Region %d\n", i);
DPRINT(" guest_phys_addr: 0x%016"PRIx64"\n",
msg_region->guest_phys_addr);
DPRINT(" memory_size: 0x%016"PRIx64"\n",
msg_region->memory_size);
DPRINT(" userspace_addr 0x%016"PRIx64"\n",
msg_region->userspace_addr);
DPRINT(" mmap_offset 0x%016"PRIx64"\n",
msg_region->mmap_offset);
dev_region->gpa = msg_region->guest_phys_addr;
dev_region->size = msg_region->memory_size;
dev_region->qva = msg_region->userspace_addr;
dev_region->mmap_offset = msg_region->mmap_offset;
/* We don't use offset argument of mmap() since the
* mapped address has to be page aligned, and we use huge
* pages. */
mmap_addr = mmap(0, dev_region->size + dev_region->mmap_offset,
PROT_READ | PROT_WRITE, MAP_SHARED,
vmsg->fds[i], 0);
if (mmap_addr == MAP_FAILED) {
vu_panic(dev, "region mmap error: %s", strerror(errno));
} else {
dev_region->mmap_addr = (uint64_t)(uintptr_t)mmap_addr;
DPRINT(" mmap_addr: 0x%016"PRIx64"\n",
dev_region->mmap_addr);
}
close(vmsg->fds[i]);
}
return false;
}
static bool
vu_set_log_base_exec(VuDev *dev, VhostUserMsg *vmsg)
{
int fd;
uint64_t log_mmap_size, log_mmap_offset;
void *rc;
if (vmsg->fd_num != 1 ||
vmsg->size != sizeof(vmsg->payload.log)) {
vu_panic(dev, "Invalid log_base message");
return true;
}
fd = vmsg->fds[0];
log_mmap_offset = vmsg->payload.log.mmap_offset;
log_mmap_size = vmsg->payload.log.mmap_size;
DPRINT("Log mmap_offset: %"PRId64"\n", log_mmap_offset);
DPRINT("Log mmap_size: %"PRId64"\n", log_mmap_size);
rc = mmap(0, log_mmap_size, PROT_READ | PROT_WRITE, MAP_SHARED, fd,
log_mmap_offset);
close(fd);
if (rc == MAP_FAILED) {
perror("log mmap error");
}
if (dev->log_table) {
munmap(dev->log_table, dev->log_size);
}
dev->log_table = rc;
dev->log_size = log_mmap_size;
vmsg->size = sizeof(vmsg->payload.u64);
vmsg->fd_num = 0;
return true;
}
static bool
vu_set_log_fd_exec(VuDev *dev, VhostUserMsg *vmsg)
{
if (vmsg->fd_num != 1) {
vu_panic(dev, "Invalid log_fd message");
return false;
}
if (dev->log_call_fd != -1) {
close(dev->log_call_fd);
}
dev->log_call_fd = vmsg->fds[0];
DPRINT("Got log_call_fd: %d\n", vmsg->fds[0]);
return false;
}
static bool
vu_set_vring_num_exec(VuDev *dev, VhostUserMsg *vmsg)
{
unsigned int index = vmsg->payload.state.index;
unsigned int num = vmsg->payload.state.num;
DPRINT("State.index: %d\n", index);
DPRINT("State.num: %d\n", num);
dev->vq[index].vring.num = num;
return false;
}
static bool
vu_set_vring_addr_exec(VuDev *dev, VhostUserMsg *vmsg)
{
struct vhost_vring_addr *vra = &vmsg->payload.addr;
unsigned int index = vra->index;
VuVirtq *vq = &dev->vq[index];
DPRINT("vhost_vring_addr:\n");
DPRINT(" index: %d\n", vra->index);
DPRINT(" flags: %d\n", vra->flags);
DPRINT(" desc_user_addr: 0x%016llx\n", vra->desc_user_addr);
DPRINT(" used_user_addr: 0x%016llx\n", vra->used_user_addr);
DPRINT(" avail_user_addr: 0x%016llx\n", vra->avail_user_addr);
DPRINT(" log_guest_addr: 0x%016llx\n", vra->log_guest_addr);
vq->vring.flags = vra->flags;
vq->vring.desc = qva_to_va(dev, vra->desc_user_addr);
vq->vring.used = qva_to_va(dev, vra->used_user_addr);
vq->vring.avail = qva_to_va(dev, vra->avail_user_addr);
vq->vring.log_guest_addr = vra->log_guest_addr;
DPRINT("Setting virtq addresses:\n");
DPRINT(" vring_desc at %p\n", vq->vring.desc);
DPRINT(" vring_used at %p\n", vq->vring.used);
DPRINT(" vring_avail at %p\n", vq->vring.avail);
if (!(vq->vring.desc && vq->vring.used && vq->vring.avail)) {
vu_panic(dev, "Invalid vring_addr message");
return false;
}
vq->used_idx = vq->vring.used->idx;
if (vq->last_avail_idx != vq->used_idx) {
bool resume = dev->iface->queue_is_processed_in_order &&
dev->iface->queue_is_processed_in_order(dev, index);
DPRINT("Last avail index != used index: %u != %u%s\n",
vq->last_avail_idx, vq->used_idx,
resume ? ", resuming" : "");
if (resume) {
vq->shadow_avail_idx = vq->last_avail_idx = vq->used_idx;
}
}
return false;
}
static bool
vu_set_vring_base_exec(VuDev *dev, VhostUserMsg *vmsg)
{
unsigned int index = vmsg->payload.state.index;
unsigned int num = vmsg->payload.state.num;
DPRINT("State.index: %d\n", index);
DPRINT("State.num: %d\n", num);
dev->vq[index].shadow_avail_idx = dev->vq[index].last_avail_idx = num;
return false;
}
static bool
vu_get_vring_base_exec(VuDev *dev, VhostUserMsg *vmsg)
{
unsigned int index = vmsg->payload.state.index;
DPRINT("State.index: %d\n", index);
vmsg->payload.state.num = dev->vq[index].last_avail_idx;
vmsg->size = sizeof(vmsg->payload.state);
dev->vq[index].started = false;
if (dev->iface->queue_set_started) {
dev->iface->queue_set_started(dev, index, false);
}
if (dev->vq[index].call_fd != -1) {
close(dev->vq[index].call_fd);
dev->vq[index].call_fd = -1;
}
if (dev->vq[index].kick_fd != -1) {
dev->remove_watch(dev, dev->vq[index].kick_fd);
close(dev->vq[index].kick_fd);
dev->vq[index].kick_fd = -1;
}
return true;
}
static bool
vu_check_queue_msg_file(VuDev *dev, VhostUserMsg *vmsg)
{
int index = vmsg->payload.u64 & VHOST_USER_VRING_IDX_MASK;
if (index >= VHOST_MAX_NR_VIRTQUEUE) {
vmsg_close_fds(vmsg);
vu_panic(dev, "Invalid queue index: %u", index);
return false;
}
if (vmsg->payload.u64 & VHOST_USER_VRING_NOFD_MASK ||
vmsg->fd_num != 1) {
vmsg_close_fds(vmsg);
vu_panic(dev, "Invalid fds in request: %d", vmsg->request);
return false;
}
return true;
}
static bool
vu_set_vring_kick_exec(VuDev *dev, VhostUserMsg *vmsg)
{
int index = vmsg->payload.u64 & VHOST_USER_VRING_IDX_MASK;
DPRINT("u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
if (!vu_check_queue_msg_file(dev, vmsg)) {
return false;
}
if (dev->vq[index].kick_fd != -1) {
dev->remove_watch(dev, dev->vq[index].kick_fd);
close(dev->vq[index].kick_fd);
dev->vq[index].kick_fd = -1;
}
if (!(vmsg->payload.u64 & VHOST_USER_VRING_NOFD_MASK)) {
dev->vq[index].kick_fd = vmsg->fds[0];
DPRINT("Got kick_fd: %d for vq: %d\n", vmsg->fds[0], index);
}
dev->vq[index].started = true;
if (dev->iface->queue_set_started) {
dev->iface->queue_set_started(dev, index, true);
}
if (dev->vq[index].kick_fd != -1 && dev->vq[index].handler) {
dev->set_watch(dev, dev->vq[index].kick_fd, VU_WATCH_IN,
vu_kick_cb, (void *)(long)index);
DPRINT("Waiting for kicks on fd: %d for vq: %d\n",
dev->vq[index].kick_fd, index);
}
return false;
}
void vu_set_queue_handler(VuDev *dev, VuVirtq *vq,
vu_queue_handler_cb handler)
{
int qidx = vq - dev->vq;
vq->handler = handler;
if (vq->kick_fd >= 0) {
if (handler) {
dev->set_watch(dev, vq->kick_fd, VU_WATCH_IN,
vu_kick_cb, (void *)(long)qidx);
} else {
dev->remove_watch(dev, vq->kick_fd);
}
}
}
static bool
vu_set_vring_call_exec(VuDev *dev, VhostUserMsg *vmsg)
{
int index = vmsg->payload.u64 & VHOST_USER_VRING_IDX_MASK;
DPRINT("u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
if (!vu_check_queue_msg_file(dev, vmsg)) {
return false;
}
if (dev->vq[index].call_fd != -1) {
close(dev->vq[index].call_fd);
dev->vq[index].call_fd = -1;
}
if (!(vmsg->payload.u64 & VHOST_USER_VRING_NOFD_MASK)) {
dev->vq[index].call_fd = vmsg->fds[0];
}
DPRINT("Got call_fd: %d for vq: %d\n", vmsg->fds[0], index);
return false;
}
static bool
vu_set_vring_err_exec(VuDev *dev, VhostUserMsg *vmsg)
{
int index = vmsg->payload.u64 & VHOST_USER_VRING_IDX_MASK;
DPRINT("u64: 0x%016"PRIx64"\n", vmsg->payload.u64);
if (!vu_check_queue_msg_file(dev, vmsg)) {
return false;
}
if (dev->vq[index].err_fd != -1) {
close(dev->vq[index].err_fd);
dev->vq[index].err_fd = -1;
}
if (!(vmsg->payload.u64 & VHOST_USER_VRING_NOFD_MASK)) {
dev->vq[index].err_fd = vmsg->fds[0];
}
return false;
}
static bool
vu_get_protocol_features_exec(VuDev *dev, VhostUserMsg *vmsg)
{
uint64_t features = 1ULL << VHOST_USER_PROTOCOL_F_LOG_SHMFD |
1ULL << VHOST_USER_PROTOCOL_F_SLAVE_REQ;
if (have_userfault()) {
features |= 1ULL << VHOST_USER_PROTOCOL_F_PAGEFAULT;
}
if (dev->iface->get_protocol_features) {
features |= dev->iface->get_protocol_features(dev);
}
vmsg->payload.u64 = features;
vmsg->size = sizeof(vmsg->payload.u64);
vmsg->fd_num = 0;
return true;
}
static bool
vu_set_protocol_features_exec(VuDev *dev, VhostUserMsg *vmsg)
{
uint64_t features = vmsg->payload.u64;
DPRINT("u64: 0x%016"PRIx64"\n", features);
dev->protocol_features = vmsg->payload.u64;
if (dev->iface->set_protocol_features) {
dev->iface->set_protocol_features(dev, features);
}
return false;
}
static bool
vu_get_queue_num_exec(VuDev *dev, VhostUserMsg *vmsg)
{
DPRINT("Function %s() not implemented yet.\n", __func__);
return false;
}
static bool
vu_set_vring_enable_exec(VuDev *dev, VhostUserMsg *vmsg)
{
unsigned int index = vmsg->payload.state.index;
unsigned int enable = vmsg->payload.state.num;
DPRINT("State.index: %d\n", index);
DPRINT("State.enable: %d\n", enable);
if (index >= VHOST_MAX_NR_VIRTQUEUE) {
vu_panic(dev, "Invalid vring_enable index: %u", index);
return false;
}
dev->vq[index].enable = enable;
return false;
}
static bool
vu_set_slave_req_fd(VuDev *dev, VhostUserMsg *vmsg)
{
if (vmsg->fd_num != 1) {
vu_panic(dev, "Invalid slave_req_fd message (%d fd's)", vmsg->fd_num);
return false;
}
if (dev->slave_fd != -1) {
close(dev->slave_fd);
}
dev->slave_fd = vmsg->fds[0];
DPRINT("Got slave_fd: %d\n", vmsg->fds[0]);
return false;
}
static bool
vu_get_config(VuDev *dev, VhostUserMsg *vmsg)
{
int ret = -1;
if (dev->iface->get_config) {
ret = dev->iface->get_config(dev, vmsg->payload.config.region,
vmsg->payload.config.size);
}
if (ret) {
/* resize to zero to indicate an error to master */
vmsg->size = 0;
}
return true;
}
static bool
vu_set_config(VuDev *dev, VhostUserMsg *vmsg)
{
int ret = -1;
if (dev->iface->set_config) {
ret = dev->iface->set_config(dev, vmsg->payload.config.region,
vmsg->payload.config.offset,
vmsg->payload.config.size,
vmsg->payload.config.flags);
if (ret) {
vu_panic(dev, "Set virtio configuration space failed");
}
}
return false;
}
static bool
vu_set_postcopy_advise(VuDev *dev, VhostUserMsg *vmsg)
{
dev->postcopy_ufd = -1;
#ifdef UFFDIO_API
struct uffdio_api api_struct;
dev->postcopy_ufd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
vmsg->size = 0;
#endif
if (dev->postcopy_ufd == -1) {
vu_panic(dev, "Userfaultfd not available: %s", strerror(errno));
goto out;
}
#ifdef UFFDIO_API
api_struct.api = UFFD_API;
api_struct.features = 0;
if (ioctl(dev->postcopy_ufd, UFFDIO_API, &api_struct)) {
vu_panic(dev, "Failed UFFDIO_API: %s", strerror(errno));
close(dev->postcopy_ufd);
dev->postcopy_ufd = -1;
goto out;
}
/* TODO: Stash feature flags somewhere */
#endif
out:
/* Return a ufd to the QEMU */
vmsg->fd_num = 1;
vmsg->fds[0] = dev->postcopy_ufd;
return true; /* = send a reply */
}
static bool
vu_set_postcopy_listen(VuDev *dev, VhostUserMsg *vmsg)
{
vmsg->payload.u64 = -1;
vmsg->size = sizeof(vmsg->payload.u64);
if (dev->nregions) {
vu_panic(dev, "Regions already registered at postcopy-listen");
return true;
}
dev->postcopy_listening = true;
vmsg->flags = VHOST_USER_VERSION | VHOST_USER_REPLY_MASK;
vmsg->payload.u64 = 0; /* Success */
return true;
}
static bool
vu_set_postcopy_end(VuDev *dev, VhostUserMsg *vmsg)
{
DPRINT("%s: Entry\n", __func__);
dev->postcopy_listening = false;
if (dev->postcopy_ufd > 0) {
close(dev->postcopy_ufd);
dev->postcopy_ufd = -1;
DPRINT("%s: Done close\n", __func__);
}
vmsg->fd_num = 0;
vmsg->payload.u64 = 0;
vmsg->size = sizeof(vmsg->payload.u64);
vmsg->flags = VHOST_USER_VERSION | VHOST_USER_REPLY_MASK;
DPRINT("%s: exit\n", __func__);
return true;
}
static bool
vu_process_message(VuDev *dev, VhostUserMsg *vmsg)
{
int do_reply = 0;
/* Print out generic part of the request. */
DPRINT("================ Vhost user message ================\n");
DPRINT("Request: %s (%d)\n", vu_request_to_string(vmsg->request),
vmsg->request);
DPRINT("Flags: 0x%x\n", vmsg->flags);
DPRINT("Size: %d\n", vmsg->size);
if (vmsg->fd_num) {
int i;
DPRINT("Fds:");
for (i = 0; i < vmsg->fd_num; i++) {
DPRINT(" %d", vmsg->fds[i]);
}
DPRINT("\n");
}
if (dev->iface->process_msg &&
dev->iface->process_msg(dev, vmsg, &do_reply)) {
return do_reply;
}
switch (vmsg->request) {
case VHOST_USER_GET_FEATURES:
return vu_get_features_exec(dev, vmsg);
case VHOST_USER_SET_FEATURES:
return vu_set_features_exec(dev, vmsg);
case VHOST_USER_GET_PROTOCOL_FEATURES:
return vu_get_protocol_features_exec(dev, vmsg);
case VHOST_USER_SET_PROTOCOL_FEATURES:
return vu_set_protocol_features_exec(dev, vmsg);
case VHOST_USER_SET_OWNER:
return vu_set_owner_exec(dev, vmsg);
case VHOST_USER_RESET_OWNER:
return vu_reset_device_exec(dev, vmsg);
case VHOST_USER_SET_MEM_TABLE:
return vu_set_mem_table_exec(dev, vmsg);
case VHOST_USER_SET_LOG_BASE:
return vu_set_log_base_exec(dev, vmsg);
case VHOST_USER_SET_LOG_FD:
return vu_set_log_fd_exec(dev, vmsg);
case VHOST_USER_SET_VRING_NUM:
return vu_set_vring_num_exec(dev, vmsg);
case VHOST_USER_SET_VRING_ADDR:
return vu_set_vring_addr_exec(dev, vmsg);
case VHOST_USER_SET_VRING_BASE:
return vu_set_vring_base_exec(dev, vmsg);
case VHOST_USER_GET_VRING_BASE:
return vu_get_vring_base_exec(dev, vmsg);
case VHOST_USER_SET_VRING_KICK:
return vu_set_vring_kick_exec(dev, vmsg);
case VHOST_USER_SET_VRING_CALL:
return vu_set_vring_call_exec(dev, vmsg);
case VHOST_USER_SET_VRING_ERR:
return vu_set_vring_err_exec(dev, vmsg);
case VHOST_USER_GET_QUEUE_NUM:
return vu_get_queue_num_exec(dev, vmsg);
case VHOST_USER_SET_VRING_ENABLE:
return vu_set_vring_enable_exec(dev, vmsg);
case VHOST_USER_SET_SLAVE_REQ_FD:
return vu_set_slave_req_fd(dev, vmsg);
case VHOST_USER_GET_CONFIG:
return vu_get_config(dev, vmsg);
case VHOST_USER_SET_CONFIG:
return vu_set_config(dev, vmsg);
case VHOST_USER_NONE:
break;
case VHOST_USER_POSTCOPY_ADVISE:
return vu_set_postcopy_advise(dev, vmsg);
case VHOST_USER_POSTCOPY_LISTEN:
return vu_set_postcopy_listen(dev, vmsg);
case VHOST_USER_POSTCOPY_END:
return vu_set_postcopy_end(dev, vmsg);
default:
vmsg_close_fds(vmsg);
vu_panic(dev, "Unhandled request: %d", vmsg->request);
}
return false;
}
bool
vu_dispatch(VuDev *dev)
{
VhostUserMsg vmsg = { 0, };
int reply_requested;
bool success = false;
if (!vu_message_read(dev, dev->sock, &vmsg)) {
goto end;
}
reply_requested = vu_process_message(dev, &vmsg);
if (!reply_requested) {
success = true;
goto end;
}
if (!vu_message_write(dev, dev->sock, &vmsg)) {
goto end;
}
success = true;
end:
free(vmsg.data);
return success;
}
void
vu_deinit(VuDev *dev)
{
int i;
for (i = 0; i < dev->nregions; i++) {
VuDevRegion *r = &dev->regions[i];
void *m = (void *) (uintptr_t) r->mmap_addr;
if (m != MAP_FAILED) {
munmap(m, r->size + r->mmap_offset);
}
}
dev->nregions = 0;
for (i = 0; i < VHOST_MAX_NR_VIRTQUEUE; i++) {
VuVirtq *vq = &dev->vq[i];
if (vq->call_fd != -1) {
close(vq->call_fd);
vq->call_fd = -1;
}
if (vq->kick_fd != -1) {
close(vq->kick_fd);
vq->kick_fd = -1;
}
if (vq->err_fd != -1) {
close(vq->err_fd);
vq->err_fd = -1;
}
}
vu_close_log(dev);
if (dev->slave_fd != -1) {
close(dev->slave_fd);
dev->slave_fd = -1;
}
if (dev->sock != -1) {
close(dev->sock);
}
}
void
vu_init(VuDev *dev,
int socket,
vu_panic_cb panic,
vu_set_watch_cb set_watch,
vu_remove_watch_cb remove_watch,
const VuDevIface *iface)
{
int i;
assert(socket >= 0);
assert(set_watch);
assert(remove_watch);
assert(iface);
assert(panic);
memset(dev, 0, sizeof(*dev));
dev->sock = socket;
dev->panic = panic;
dev->set_watch = set_watch;
dev->remove_watch = remove_watch;
dev->iface = iface;
dev->log_call_fd = -1;
dev->slave_fd = -1;
for (i = 0; i < VHOST_MAX_NR_VIRTQUEUE; i++) {
dev->vq[i] = (VuVirtq) {
.call_fd = -1, .kick_fd = -1, .err_fd = -1,
.notification = true,
};
}
}
VuVirtq *
vu_get_queue(VuDev *dev, int qidx)
{
assert(qidx < VHOST_MAX_NR_VIRTQUEUE);
return &dev->vq[qidx];
}
bool
vu_queue_enabled(VuDev *dev, VuVirtq *vq)
{
return vq->enable;
}
bool
vu_queue_started(const VuDev *dev, const VuVirtq *vq)
{
return vq->started;
}
static inline uint16_t
vring_avail_flags(VuVirtq *vq)
{
return vq->vring.avail->flags;
}
static inline uint16_t
vring_avail_idx(VuVirtq *vq)
{
vq->shadow_avail_idx = vq->vring.avail->idx;
return vq->shadow_avail_idx;
}
static inline uint16_t
vring_avail_ring(VuVirtq *vq, int i)
{
return vq->vring.avail->ring[i];
}
static inline uint16_t
vring_get_used_event(VuVirtq *vq)
{
return vring_avail_ring(vq, vq->vring.num);
}
static int
virtqueue_num_heads(VuDev *dev, VuVirtq *vq, unsigned int idx)
{
uint16_t num_heads = vring_avail_idx(vq) - idx;
/* Check it isn't doing very strange things with descriptor numbers. */
if (num_heads > vq->vring.num) {
vu_panic(dev, "Guest moved used index from %u to %u",
idx, vq->shadow_avail_idx);
return -1;
}
if (num_heads) {
/* On success, callers read a descriptor at vq->last_avail_idx.
* Make sure descriptor read does not bypass avail index read. */
smp_rmb();
}
return num_heads;
}
static bool
virtqueue_get_head(VuDev *dev, VuVirtq *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) {
vu_panic(dev, "Guest says index %u is available", head);
return false;
}
return true;
}
static int
virtqueue_read_indirect_desc(VuDev *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 = vu_gpa_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
virtqueue_read_next_desc(VuDev *dev, struct vring_desc *desc,
int i, unsigned int max, unsigned int *next)
{
/* If this descriptor says it doesn't chain, we're done. */
if (!(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) {
vu_panic(dev, "Desc next is %u", next);
return VIRTQUEUE_READ_DESC_ERROR;
}
return VIRTQUEUE_READ_DESC_MORE;
}
void
vu_queue_get_avail_bytes(VuDev *dev, VuVirtq *vq, unsigned int *in_bytes,
unsigned int *out_bytes,
unsigned max_in_bytes, unsigned max_out_bytes)
{
unsigned int idx;
unsigned int total_bufs, in_total, out_total;
int rc;
idx = vq->last_avail_idx;
total_bufs = in_total = out_total = 0;
if (unlikely(dev->broken) ||
unlikely(!vq->vring.avail)) {
goto done;
}
while ((rc = virtqueue_num_heads(dev, vq, idx)) > 0) {
unsigned int max, desc_len, num_bufs, indirect = 0;
uint64_t desc_addr, read_len;
struct vring_desc *desc;
struct vring_desc desc_buf[VIRTQUEUE_MAX_SIZE];
unsigned int i;
max = vq->vring.num;
num_bufs = total_bufs;
if (!virtqueue_get_head(dev, vq, idx++, &i)) {
goto err;
}
desc = vq->vring.desc;
if (desc[i].flags & VRING_DESC_F_INDIRECT) {
if (desc[i].len % sizeof(struct vring_desc)) {
vu_panic(dev, "Invalid size for indirect buffer table");
goto err;
}
/* If we've got too many, that implies a descriptor loop. */
if (num_bufs >= max) {
vu_panic(dev, "Looped descriptor");
goto err;
}
/* loop over the indirect descriptor table */
indirect = 1;
desc_addr = desc[i].addr;
desc_len = desc[i].len;
max = desc_len / sizeof(struct vring_desc);
read_len = desc_len;
desc = vu_gpa_to_va(dev, &read_len, desc_addr);
if (unlikely(desc && read_len != desc_len)) {
/* Failed to use zero copy */
desc = NULL;
if (!virtqueue_read_indirect_desc(dev, desc_buf,
desc_addr,
desc_len)) {
desc = desc_buf;
}
}
if (!desc) {
vu_panic(dev, "Invalid indirect buffer table");
goto err;
}
num_bufs = i = 0;
}
do {
/* If we've got too many, that implies a descriptor loop. */
if (++num_bufs > max) {
vu_panic(dev, "Looped descriptor");
goto err;
}
if (desc[i].flags & VRING_DESC_F_WRITE) {
in_total += desc[i].len;
} else {
out_total += desc[i].len;
}
if (in_total >= max_in_bytes && out_total >= max_out_bytes) {
goto done;
}
rc = virtqueue_read_next_desc(dev, desc, i, max, &i);
} while (rc == VIRTQUEUE_READ_DESC_MORE);
if (rc == VIRTQUEUE_READ_DESC_ERROR) {
goto err;
}
if (!indirect) {
total_bufs = num_bufs;
} else {
total_bufs++;
}
}
if (rc < 0) {
goto err;
}
done:
if (in_bytes) {
*in_bytes = in_total;
}
if (out_bytes) {
*out_bytes = out_total;
}
return;
err:
in_total = out_total = 0;
goto done;
}
bool
vu_queue_avail_bytes(VuDev *dev, VuVirtq *vq, unsigned int in_bytes,
unsigned int out_bytes)
{
unsigned int in_total, out_total;
vu_queue_get_avail_bytes(dev, vq, &in_total, &out_total,
in_bytes, out_bytes);
return in_bytes <= in_total && out_bytes <= out_total;
}
/* Fetch avail_idx from VQ memory only when we really need to know if
* guest has added some buffers. */
bool
vu_queue_empty(VuDev *dev, VuVirtq *vq)
{
if (unlikely(dev->broken) ||
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 inline
bool has_feature(uint64_t features, unsigned int fbit)
{
assert(fbit < 64);
return !!(features & (1ULL << fbit));
}
static inline
bool vu_has_feature(VuDev *dev,
unsigned int fbit)
{
return has_feature(dev->features, fbit);
}
static bool
vring_notify(VuDev *dev, VuVirtq *vq)
{
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 (vu_has_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY) &&
!vq->inuse && vu_queue_empty(dev, vq)) {
return true;
}
if (!vu_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
vu_queue_notify(VuDev *dev, VuVirtq *vq)
{
if (unlikely(dev->broken) ||
unlikely(!vq->vring.avail)) {
return;
}
if (!vring_notify(dev, vq)) {
DPRINT("skipped notify...\n");
return;
}
if (eventfd_write(vq->call_fd, 1) < 0) {
vu_panic(dev, "Error writing eventfd: %s", strerror(errno));
}
}
static inline void
vring_used_flags_set_bit(VuVirtq *vq, int mask)
{
uint16_t *flags;
flags = (uint16_t *)((char*)vq->vring.used +
offsetof(struct vring_used, flags));
*flags |= mask;
}
static inline void
vring_used_flags_unset_bit(VuVirtq *vq, int mask)
{
uint16_t *flags;
flags = (uint16_t *)((char*)vq->vring.used +
offsetof(struct vring_used, flags));
*flags &= ~mask;
}
static inline void
vring_set_avail_event(VuVirtq *vq, uint16_t val)
{
if (!vq->notification) {
return;
}
*((uint16_t *) &vq->vring.used->ring[vq->vring.num]) = val;
}
void
vu_queue_set_notification(VuDev *dev, VuVirtq *vq, int enable)
{
vq->notification = enable;
if (vu_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) {
vring_set_avail_event(vq, vring_avail_idx(vq));
} else if (enable) {
vring_used_flags_unset_bit(vq, VRING_USED_F_NO_NOTIFY);
} else {
vring_used_flags_set_bit(vq, VRING_USED_F_NO_NOTIFY);
}
if (enable) {
/* Expose avail event/used flags before caller checks the avail idx. */
smp_mb();
}
}
static void
virtqueue_map_desc(VuDev *dev,
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;
assert(num_sg <= max_num_sg);
if (!sz) {
vu_panic(dev, "virtio: zero sized buffers are not allowed");
return;
}
while (sz) {
uint64_t len = sz;
if (num_sg == max_num_sg) {
vu_panic(dev, "virtio: too many descriptors in indirect table");
return;
}
iov[num_sg].iov_base = vu_gpa_to_va(dev, &len, pa);
if (iov[num_sg].iov_base == NULL) {
vu_panic(dev, "virtio: invalid address for buffers");
return;
}
iov[num_sg].iov_len = len;
num_sg++;
sz -= len;
pa += len;
}
*p_num_sg = num_sg;
}
/* 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))
static void *
virtqueue_alloc_element(size_t sz,
unsigned out_num, unsigned in_num)
{
VuVirtqElement *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(VuVirtqElement));
elem = malloc(out_sg_end);
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;
}
void *
vu_queue_pop(VuDev *dev, VuVirtq *vq, size_t sz)
{
unsigned int i, head, max, desc_len;
uint64_t desc_addr, read_len;
VuVirtqElement *elem;
unsigned out_num, in_num;
struct iovec iov[VIRTQUEUE_MAX_SIZE];
struct vring_desc desc_buf[VIRTQUEUE_MAX_SIZE];
struct vring_desc *desc;
int rc;
if (unlikely(dev->broken) ||
unlikely(!vq->vring.avail)) {
return NULL;
}
if (vu_queue_empty(dev, vq)) {
return NULL;
}
/* Needed after virtio_queue_empty(), see comment in
* virtqueue_num_heads(). */
smp_rmb();
/* When we start there are none of either input nor output. */
out_num = in_num = 0;
max = vq->vring.num;
if (vq->inuse >= vq->vring.num) {
vu_panic(dev, "Virtqueue size exceeded");
return NULL;
}
if (!virtqueue_get_head(dev, vq, vq->last_avail_idx++, &head)) {
return NULL;
}
if (vu_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) {
vring_set_avail_event(vq, vq->last_avail_idx);
}
i = head;
desc = vq->vring.desc;
if (desc[i].flags & VRING_DESC_F_INDIRECT) {
if (desc[i].len % sizeof(struct vring_desc)) {
vu_panic(dev, "Invalid size for indirect buffer table");
}
/* loop over the indirect descriptor table */
desc_addr = desc[i].addr;
desc_len = desc[i].len;
max = desc_len / sizeof(struct vring_desc);
read_len = desc_len;
desc = vu_gpa_to_va(dev, &read_len, desc_addr);
if (unlikely(desc && read_len != desc_len)) {
/* Failed to use zero copy */
desc = NULL;
if (!virtqueue_read_indirect_desc(dev, desc_buf,
desc_addr,
desc_len)) {
desc = desc_buf;
}
}
if (!desc) {
vu_panic(dev, "Invalid indirect buffer table");
return NULL;
}
i = 0;
}
/* Collect all the descriptors */
do {
if (desc[i].flags & VRING_DESC_F_WRITE) {
virtqueue_map_desc(dev, &in_num, iov + out_num,
VIRTQUEUE_MAX_SIZE - out_num, true,
desc[i].addr, desc[i].len);
} else {
if (in_num) {
vu_panic(dev, "Incorrect order for descriptors");
return NULL;
}
virtqueue_map_desc(dev, &out_num, iov,
VIRTQUEUE_MAX_SIZE, false,
desc[i].addr, desc[i].len);
}
/* If we've got too many, that implies a descriptor loop. */
if ((in_num + out_num) > max) {
vu_panic(dev, "Looped descriptor");
}
rc = virtqueue_read_next_desc(dev, desc, i, max, &i);
} while (rc == VIRTQUEUE_READ_DESC_MORE);
if (rc == VIRTQUEUE_READ_DESC_ERROR) {
return NULL;
}
/* Now copy what we have collected and mapped */
elem = virtqueue_alloc_element(sz, out_num, in_num);
elem->index = head;
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];
}
vq->inuse++;
return elem;
}
bool
vu_queue_rewind(VuDev *dev, VuVirtq *vq, unsigned int num)
{
if (num > vq->inuse) {
return false;
}
vq->last_avail_idx -= num;
vq->inuse -= num;
return true;
}
static inline
void vring_used_write(VuDev *dev, VuVirtq *vq,
struct vring_used_elem *uelem, int i)
{
struct vring_used *used = vq->vring.used;
used->ring[i] = *uelem;
vu_log_write(dev, vq->vring.log_guest_addr +
offsetof(struct vring_used, ring[i]),
sizeof(used->ring[i]));
}
static void
vu_log_queue_fill(VuDev *dev, VuVirtq *vq,
const VuVirtqElement *elem,
unsigned int len)
{
struct vring_desc *desc = vq->vring.desc;
unsigned int i, max, min, desc_len;
uint64_t desc_addr, read_len;
struct vring_desc desc_buf[VIRTQUEUE_MAX_SIZE];
unsigned num_bufs = 0;
max = vq->vring.num;
i = elem->index;
if (desc[i].flags & VRING_DESC_F_INDIRECT) {
if (desc[i].len % sizeof(struct vring_desc)) {
vu_panic(dev, "Invalid size for indirect buffer table");
}
/* loop over the indirect descriptor table */
desc_addr = desc[i].addr;
desc_len = desc[i].len;
max = desc_len / sizeof(struct vring_desc);
read_len = desc_len;
desc = vu_gpa_to_va(dev, &read_len, desc_addr);
if (unlikely(desc && read_len != desc_len)) {
/* Failed to use zero copy */
desc = NULL;
if (!virtqueue_read_indirect_desc(dev, desc_buf,
desc_addr,
desc_len)) {
desc = desc_buf;
}
}
if (!desc) {
vu_panic(dev, "Invalid indirect buffer table");
return;
}
i = 0;
}
do {
if (++num_bufs > max) {
vu_panic(dev, "Looped descriptor");
return;
}
if (desc[i].flags & VRING_DESC_F_WRITE) {
min = MIN(desc[i].len, len);
vu_log_write(dev, desc[i].addr, min);
len -= min;
}
} while (len > 0 &&
(virtqueue_read_next_desc(dev, desc, i, max, &i)
== VIRTQUEUE_READ_DESC_MORE));
}
void
vu_queue_fill(VuDev *dev, VuVirtq *vq,
const VuVirtqElement *elem,
unsigned int len, unsigned int idx)
{
struct vring_used_elem uelem;
if (unlikely(dev->broken) ||
unlikely(!vq->vring.avail)) {
return;
}
vu_log_queue_fill(dev, vq, elem, len);
idx = (idx + vq->used_idx) % vq->vring.num;
uelem.id = elem->index;
uelem.len = len;
vring_used_write(dev, vq, &uelem, idx);
}
static inline
void vring_used_idx_set(VuDev *dev, VuVirtq *vq, uint16_t val)
{
vq->vring.used->idx = val;
vu_log_write(dev,
vq->vring.log_guest_addr + offsetof(struct vring_used, idx),
sizeof(vq->vring.used->idx));
vq->used_idx = val;
}
void
vu_queue_flush(VuDev *dev, VuVirtq *vq, unsigned int count)
{
uint16_t old, new;
if (unlikely(dev->broken) ||
unlikely(!vq->vring.avail)) {
return;
}
/* Make sure buffer is written before we update index. */
smp_wmb();
old = vq->used_idx;
new = old + count;
vring_used_idx_set(dev, vq, new);
vq->inuse -= count;
if (unlikely((int16_t)(new - vq->signalled_used) < (uint16_t)(new - old))) {
vq->signalled_used_valid = false;
}
}
void
vu_queue_push(VuDev *dev, VuVirtq *vq,
const VuVirtqElement *elem, unsigned int len)
{
vu_queue_fill(dev, vq, elem, len, 0);
vu_queue_flush(dev, vq, 1);
}
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