/* * Vhost User library * * Copyright IBM, Corp. 2007 * Copyright (c) 2016 Red Hat, Inc. * * Authors: * Anthony Liguori * Marc-AndrĂ© Lureau * Victor Kaplansky * * 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 #include #include #include #include #include #include #include #include #include #include #include #include "qemu/compiler.h" #if defined(__linux__) #include #include #include #include #ifdef __NR_userfaultfd #include #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)); if (vmsg->size) { 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, ®_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); }