On 11/4/2025 12:21 PM, Pravin M Bathija wrote: > These changes cover the function definition for add/remove memory > region calls which are invoked on receiving vhost user message from > vhost user front-end (e.g. Qemu). The vhost-user front end sw sends > an add memory region message which includes the guest physical address > range(GPA), memory size, front-end's virtual address and offset within > tha file-descriptor mapping. The back-end(dpdk) uses this information > to create a mapping within it's own address space using mmap on the > fd + offset. This added memory region serves as sshared memory to pass > data back and forth between vhost-user front and back ends. Similarly in > the case of remove memory region, the said memory region is unmapped from > the back-end(dpdk). In our case, in addition to testing with qemu front-end, > the testing has also been performed with libblkio front-end and spdk/dpdk > back-end. We did I/O using libblkio based device driver, to spdk based drives. > There are also changes for set mem table and new definition for get memory > slots. > The message vhost set memory table essentially is how the vhost-user front-end > (qemu or libblkio) tells vhost-user back-end (dpdk) about all of it's guest > memory regions. This allows the back-end to translate guest physical > addresses > to back-end virtual addresses and perform direct I/O to guest memory. Our > changes > optimize the set memory table call to use common support functions. Message > get > memory slots is how the vhost-user front-end queries the vhost-user back-end > about > the number of memory slots available to be registered by the back-end.
Too much useless information in the commit log, this features is a de facto standard, and it supported from early qemu version (6.2 as I know), so I think we could simplfy the commit log. > > Signed-off-by: Pravin M Bathija <[email protected]> > --- > lib/vhost/vhost_user.c | 253 +++++++++++++++++++++++++++++++++++------ > 1 file changed, 221 insertions(+), 32 deletions(-) > > diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c > index 4bfb13fb98..168432e7d1 100644 > --- a/lib/vhost/vhost_user.c > +++ b/lib/vhost/vhost_user.c > @@ -71,6 +71,9 @@ VHOST_MESSAGE_HANDLER(VHOST_USER_SET_FEATURES, > vhost_user_set_features, false, t > VHOST_MESSAGE_HANDLER(VHOST_USER_SET_OWNER, vhost_user_set_owner, false, > true) \ > VHOST_MESSAGE_HANDLER(VHOST_USER_RESET_OWNER, vhost_user_reset_owner, false, > false) \ > VHOST_MESSAGE_HANDLER(VHOST_USER_SET_MEM_TABLE, vhost_user_set_mem_table, > true, true) \ > +VHOST_MESSAGE_HANDLER(VHOST_USER_GET_MAX_MEM_SLOTS, > vhost_user_get_max_mem_slots, false, false) \ > +VHOST_MESSAGE_HANDLER(VHOST_USER_ADD_MEM_REG, vhost_user_add_mem_reg, true, > true) \ > +VHOST_MESSAGE_HANDLER(VHOST_USER_REM_MEM_REG, vhost_user_rem_mem_reg, false, > true) \ > VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_BASE, vhost_user_set_log_base, > true, true) \ > VHOST_MESSAGE_HANDLER(VHOST_USER_SET_LOG_FD, vhost_user_set_log_fd, true, > true) \ > VHOST_MESSAGE_HANDLER(VHOST_USER_SET_VRING_NUM, vhost_user_set_vring_num, > false, true) \ > @@ -1390,7 +1393,6 @@ vhost_user_set_mem_table(struct virtio_net **pdev, > struct virtio_net *dev = *pdev; > struct VhostUserMemory *memory = &ctx->msg.payload.memory; > struct rte_vhost_mem_region *reg; > - int numa_node = SOCKET_ID_ANY; > uint64_t mmap_offset; > uint32_t i; > bool async_notify = false; > @@ -1435,39 +1437,13 @@ vhost_user_set_mem_table(struct virtio_net **pdev, > if (dev->features & (1ULL << VIRTIO_F_IOMMU_PLATFORM)) > vhost_user_iotlb_flush_all(dev); > > - free_mem_region(dev); > + free_all_mem_regions(dev); > rte_free(dev->mem); > dev->mem = NULL; > } > > - /* > - * If VQ 0 has already been allocated, try to allocate on the same > - * NUMA node. It can be reallocated later in numa_realloc(). > - */ > - if (dev->nr_vring > 0) > - numa_node = dev->virtqueue[0]->numa_node; > - > - dev->nr_guest_pages = 0; > - if (dev->guest_pages == NULL) { > - dev->max_guest_pages = 8; > - dev->guest_pages = rte_zmalloc_socket(NULL, > - dev->max_guest_pages * > - sizeof(struct guest_page), > - RTE_CACHE_LINE_SIZE, > - numa_node); > - if (dev->guest_pages == NULL) { > - VHOST_CONFIG_LOG(dev->ifname, ERR, > - "failed to allocate memory for > dev->guest_pages"); > - goto close_msg_fds; > - } > - } > - > - dev->mem = rte_zmalloc_socket("vhost-mem-table", sizeof(struct > rte_vhost_memory) + > - sizeof(struct rte_vhost_mem_region) * memory->nregions, 0, > numa_node); > - if (dev->mem == NULL) { > - VHOST_CONFIG_LOG(dev->ifname, ERR, "failed to allocate memory > for dev->mem"); > - goto free_guest_pages; > - } > + if (vhost_user_initialize_memory(pdev) < 0) > + goto close_msg_fds; > > for (i = 0; i < memory->nregions; i++) { > reg = &dev->mem->regions[i]; > @@ -1531,11 +1507,182 @@ vhost_user_set_mem_table(struct virtio_net **pdev, > return RTE_VHOST_MSG_RESULT_OK; > > free_mem_table: > - free_mem_region(dev); > + free_all_mem_regions(dev); > rte_free(dev->mem); > dev->mem = NULL; > + rte_free(dev->guest_pages); > + dev->guest_pages = NULL; > +close_msg_fds: > + close_msg_fds(ctx); > + return RTE_VHOST_MSG_RESULT_ERR; > +} > + > > -free_guest_pages: > +static int > +vhost_user_get_max_mem_slots(struct virtio_net **pdev __rte_unused, > + struct vhu_msg_context *ctx, > + int main_fd __rte_unused) > +{ > + uint32_t max_mem_slots = VHOST_MEMORY_MAX_NREGIONS; > + > + ctx->msg.payload.u64 = (uint64_t)max_mem_slots; > + ctx->msg.size = sizeof(ctx->msg.payload.u64); > + ctx->fd_num = 0; > + > + return RTE_VHOST_MSG_RESULT_REPLY; > +} > + > +static int > +vhost_user_add_mem_reg(struct virtio_net **pdev, > + struct vhu_msg_context *ctx, > + int main_fd __rte_unused) > +{ > + struct virtio_net *dev = *pdev; > + struct VhostUserMemoryRegion *region = > &ctx->msg.payload.memory_single.region; Please put long line in front. > + uint32_t i; > + > + /* make sure new region will fit */ > + if (dev->mem != NULL && dev->mem->nregions >= > VHOST_MEMORY_MAX_NREGIONS) { > + VHOST_CONFIG_LOG(dev->ifname, ERR, > + "too many memory regions already (%u)", > + dev->mem->nregions); Currently support 100 char per line. So maybe we could put the log oneline. the same for below log. > + goto close_msg_fds; > + } > + > + /* make sure supplied memory fd present */ > + if (ctx->fd_num != 1) { > + VHOST_CONFIG_LOG(dev->ifname, ERR, > + "fd count makes no sense (%u)", > + ctx->fd_num); > + goto close_msg_fds; > + } > + > + /* Make sure no overlap in guest virtual address space */ > + if (dev->mem != NULL && dev->mem->nregions > 0) { > + for (uint32_t i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) { > + struct rte_vhost_mem_region *current_region = > &dev->mem->regions[i]; > + > + if (current_region->mmap_size == 0) > + continue; > + > + uint64_t current_region_guest_start = > current_region->guest_user_addr; > + uint64_t current_region_guest_end = > current_region_guest_start > + + > current_region->mmap_size - 1; > + uint64_t proposed_region_guest_start = > region->userspace_addr; > + uint64_t proposed_region_guest_end = > proposed_region_guest_start > + + > region->memory_size - 1; > + bool overlap = false; > + > + bool curent_region_guest_start_overlap = > + current_region_guest_start >= > proposed_region_guest_start > + && current_region_guest_start <= > proposed_region_guest_end; the && should put tail of line according DPDK coding style. > + bool curent_region_guest_end_overlap = > + current_region_guest_end >= > proposed_region_guest_start > + && current_region_guest_end <= > proposed_region_guest_end; > + bool proposed_region_guest_start_overlap = > + proposed_region_guest_start >= > current_region_guest_start > + && proposed_region_guest_start <= > current_region_guest_end; > + bool proposed_region_guest_end_overlap = > + proposed_region_guest_end >= > current_region_guest_start > + && proposed_region_guest_end <= > current_region_guest_end; > + > + overlap = curent_region_guest_start_overlap > + || curent_region_guest_end_overlap > + || proposed_region_guest_start_overlap > + || proposed_region_guest_end_overlap; > + > + if (overlap) { > + VHOST_CONFIG_LOG(dev->ifname, ERR, > + "requested memory region overlaps with > another region"); > + VHOST_CONFIG_LOG(dev->ifname, ERR, > + "\tRequested region address:0x%" PRIx64, > + region->userspace_addr); > + VHOST_CONFIG_LOG(dev->ifname, ERR, > + "\tRequested region size:0x%" PRIx64, > + region->memory_size); > + VHOST_CONFIG_LOG(dev->ifname, ERR, > + "\tOverlapping region address:0x%" > PRIx64, > + current_region->guest_user_addr); > + VHOST_CONFIG_LOG(dev->ifname, ERR, > + "\tOverlapping region size:0x%" PRIx64, > + current_region->mmap_size); > + goto close_msg_fds; how about add sub function to wrap the check? > + } > + > + } > + } > + > + /* convert first region add to normal memory table set */ > + if (dev->mem == NULL) { > + if (vhost_user_initialize_memory(pdev) < 0) > + goto close_msg_fds; > + } I think we could put this judgement at the beginning of function, so that we could drop so many judgement for 'if (dev->mem == NULL)' > + > + /* find a new region and set it like memory table set does */ > + struct rte_vhost_mem_region *reg = NULL; > + uint64_t mmap_offset; Suggest place them at the beginning of function. > + > + for (uint32_t i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) { > + if (dev->mem->regions[i].guest_user_addr == 0) { > + reg = &dev->mem->regions[i]; > + break; > + } > + } > + if (reg == NULL) { > + VHOST_CONFIG_LOG(dev->ifname, ERR, "no free memory region"); > + goto close_msg_fds; > + } > + > + reg->guest_phys_addr = region->guest_phys_addr; > + reg->guest_user_addr = region->userspace_addr; > + reg->size = region->memory_size; > + reg->fd = ctx->fds[0]; > + > + mmap_offset = region->mmap_offset; no need to define mmap_offset which only used once. > + > + if (vhost_user_mmap_region(dev, reg, mmap_offset) < 0) { > + VHOST_CONFIG_LOG(dev->ifname, ERR, "failed to mmap region"); > + goto close_msg_fds; > + } > + > + dev->mem->nregions++; > + > + if (dev->async_copy && rte_vfio_is_enabled("vfio")) > + async_dma_map(dev, true); it will map all region, we should map only this region. > + > + if (vhost_user_postcopy_register(dev, main_fd, ctx) < 0) > + goto free_mem_table; > + > + for (i = 0; i < dev->nr_vring; i++) { > + struct vhost_virtqueue *vq = dev->virtqueue[i]; > + > + if (!vq) > + continue; > + > + if (vq->desc || vq->avail || vq->used) { > + /* vhost_user_lock_all_queue_pairs locked all qps */ > + VHOST_USER_ASSERT_LOCK(dev, vq, VHOST_USER_ADD_MEM_REG); > + > + /* > + * If the memory table got updated, the ring addresses > + * need to be translated again as virtual addresses have > + * changed. > + */ > + vring_invalidate(dev, vq); > + > + translate_ring_addresses(&dev, &vq); > + *pdev = dev; > + } > + } > + > + dump_guest_pages(dev); > + > + return RTE_VHOST_MSG_RESULT_OK; > + > +free_mem_table: > + free_all_mem_regions(dev); > + rte_free(dev->mem); > + dev->mem = NULL; > rte_free(dev->guest_pages); > dev->guest_pages = NULL; > close_msg_fds: > @@ -1543,6 +1690,48 @@ vhost_user_set_mem_table(struct virtio_net **pdev, > return RTE_VHOST_MSG_RESULT_ERR; > } > > +static int > +vhost_user_rem_mem_reg(struct virtio_net **pdev __rte_unused, > + struct vhu_msg_context *ctx __rte_unused, > + int main_fd __rte_unused) > +{ > + struct virtio_net *dev = *pdev; > + struct VhostUserMemoryRegion *region = > &ctx->msg.payload.memory_single.region; > + > + if ((dev->mem) && (dev->flags & VIRTIO_DEV_VDPA_CONFIGURED)) { > + struct rte_vdpa_device *vdpa_dev = dev->vdpa_dev; > + > + if (vdpa_dev && vdpa_dev->ops->dev_close) > + vdpa_dev->ops->dev_close(dev->vid); > + dev->flags &= ~VIRTIO_DEV_VDPA_CONFIGURED; The DPDK's vdpa devices will not report the new feature, so this will be dead code I think. > + } > + > + if (dev->mem != NULL && dev->mem->nregions > 0) { > + for (uint32_t i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) { suggest i defined in beginning of func. > + struct rte_vhost_mem_region *current_region = > &dev->mem->regions[i]; > + > + if (current_region->guest_user_addr == 0) > + continue; > + > + /* > + * According to the vhost-user specification: > + * The memory region to be removed is identified by its > guest address, > + * user address and size. The mmap offset is ignored. > + */ > + if (region->userspace_addr == > current_region->guest_user_addr > + && region->guest_phys_addr == > current_region->guest_phys_addr > + && region->memory_size == current_region->size) > { > + free_mem_region(current_region); I checked the 4/5 commit, and we should do async_dma unmap this region here. Beside, should we invalidate vring here? > + dev->mem->nregions--; > + return RTE_VHOST_MSG_RESULT_OK; > + } > + } > + } > + > + VHOST_CONFIG_LOG(dev->ifname, ERR, "failed to find region"); > + return RTE_VHOST_MSG_RESULT_ERR; > +} > + > static bool > vq_is_ready(struct virtio_net *dev, struct vhost_virtqueue *vq) > {
