Hi Fengcheng, Responses inline. I have resubmitted the patch-set as v13. Please review.
Internal Use - Confidential > -----Original Message----- > From: fengchengwen <[email protected]> > Sent: Tuesday, May 12, 2026 9:17 PM > To: Bathija, Pravin <[email protected]>; [email protected]; > [email protected]; [email protected] > Cc: [email protected] > Subject: Re: [PATCH v12 4/5] vhost_user: Function defs for add/rem mem > regions > > > [EXTERNAL EMAIL] > > The 3/5 commit is helper function, I doubt it could compile, why not merge > with this commit. > > I suggest placing the refactored code on 3/5, but it should be self-contained > and > not include functions that will not be used in 3/5 (e.g. remove_guest_pages). Good point. Suggested change has been incorporated into the new patch-set v13. > > On 5/6/2026 11:37 AM, [email protected] wrote: > > From: Pravin M Bathija <[email protected]> > > > > 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). 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. Our changes optimize the set memory table call to use > > common support functions. A new vhost_user_initialize_memory() > > function is introduced to factor out the common memory initialization > > logic from the function vhost_user_set_mem_table(), which is now > > called from both the SET_MEM_TABLE message handler and the > ADD_MEM_REG handler (for the first region). > > 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. In addition support function to invalidate > > vring is also defined which is used in add/remove memory region functions. > > > > Signed-off-by: Pravin M Bathija <[email protected]> > > --- > > lib/vhost/vhost_user.c | 311 > > ++++++++++++++++++++++++++++++++++++----- > > 1 file changed, 278 insertions(+), 33 deletions(-) > > > > diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c index > > 9f1abb1842..c6b404da75 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, true, 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) \ @@ -1431,6 +1434,52 @@ > vhost_user_mmap_region(struct virtio_net *dev, > > return 0; > > } > > > > +static int > > +vhost_user_initialize_memory(struct virtio_net **pdev) { > > + struct virtio_net *dev = *pdev; > > + int numa_node = SOCKET_ID_ANY; > > + > > + if (dev->mem != NULL) { > > + VHOST_CONFIG_LOG(dev->ifname, ERR, > > + "memory already initialized, free it first"); > > + return -1; > > + } > > + > > + /* > > + * 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"); > > + return -1; > > + } > > + } > > + > > + dev->mem = rte_zmalloc_socket("vhost-mem-table", sizeof(struct > rte_vhost_memory) + > > + sizeof(struct rte_vhost_mem_region) * > VHOST_MEMORY_MAX_NREGIONS, 0, numa_node); > > + if (dev->mem == NULL) { > > + VHOST_CONFIG_LOG(dev->ifname, ERR, "failed to allocate > memory for dev->mem"); > > + rte_free(dev->guest_pages); > > + dev->guest_pages = NULL; > > + return -1; > > + } > > + > > + return 0; > > +} > > + > > static int > > vhost_user_set_mem_table(struct virtio_net **pdev, > > struct vhu_msg_context *ctx, > > @@ -1439,7 +1488,6 @@ 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; > > @@ -1484,39 +1532,13 @@ 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]; > > @@ -1580,11 +1602,9 @@ 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; > > - > > -free_guest_pages: > > rte_free(dev->guest_pages); > > dev->guest_pages = NULL; > > close_msg_fds: > > @@ -1592,6 +1612,231 @@ vhost_user_set_mem_table(struct virtio_net > **pdev, > > return RTE_VHOST_MSG_RESULT_ERR; > > } > > > > + > > +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 void > > +_dev_invalidate_vrings(struct virtio_net **pdev) { > > + struct virtio_net *dev = *pdev; > > + uint32_t i; > > + > > + 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) { > > + vq_assert_lock(dev, vq); > > + > > + /* > > + * 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; > > +} > > + > > +/* > > + * Macro wrapper that performs the compile-time lock assertion with > > +the > > + * correct message ID at the call site, then calls the implementation. > > + */ > > +#define dev_invalidate_vrings(pdev, id) do { \ > > + static_assert(id ## _LOCK_ALL_QPS, \ > > + #id " handler is not declared as locking all queue pairs"); \ > > + _dev_invalidate_vrings(pdev); \ > > +} while (0) > > + > > +static int > > +vhost_user_add_mem_reg(struct virtio_net **pdev, > > + struct vhu_msg_context *ctx, > > + int main_fd __rte_unused) > > +{ > > + uint32_t i; > > + struct virtio_net *dev = *pdev; > > + struct VhostUserMemoryRegion *region = > > +&ctx->msg.payload.memory_single.region; > > + > > + /* convert first region add to normal memory table set */ > > + if (dev->mem == NULL) { > > + if (vhost_user_initialize_memory(pdev) < 0) > > + goto close_msg_fds; > > + } > > + > > + /* make sure new region will fit */ > > + if (dev->mem->nregions >= VHOST_MEMORY_MAX_NREGIONS) { > > + VHOST_CONFIG_LOG(dev->ifname, ERR, "too many memory > regions already (%u)", > > + dev- > >mem->nregions); > > + 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 */ > > + for (i = 0; i < dev->mem->nregions; i++) { > > + struct rte_vhost_mem_region *current_region = &dev->mem- > >regions[i]; > > + uint64_t current_region_guest_start = current_region- > >guest_user_addr; > > + uint64_t current_region_guest_end = > current_region_guest_start > > + + current_region->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; > > > > > + > > + if (!((proposed_region_guest_end < > current_region_guest_start) || > > + (proposed_region_guest_start > > current_region_guest_end))) { > > + 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->size); > > + goto close_msg_fds; > > + } > > + } > > + > > + /* New region goes at the end of the contiguous array */ > > + struct rte_vhost_mem_region *reg = > > +&dev->mem->regions[dev->mem->nregions]; > > + > > + 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]; > > + ctx->fds[0] = -1; > > + > > + if (vhost_user_mmap_region(dev, reg, region->mmap_offset) < 0) { > > + VHOST_CONFIG_LOG(dev->ifname, ERR, "failed to mmap > region"); > > + if (reg->mmap_addr) { > > + /* mmap succeeded but a later step (e.g. > add_guest_pages) > > + * failed; undo the mapping and any guest-page > entries. > > + */ > > + remove_guest_pages(dev, reg); > > + free_mem_region(reg); > > + } else { > > + close(reg->fd); > > + reg->fd = -1; > > + } > > + goto close_msg_fds; > > + } > > + > > + dev->mem->nregions++; > > + > > + if (dev->async_copy && rte_vfio_is_enabled("vfio")) { > > + if (async_dma_map_region(dev, reg, true) < 0) > > + goto free_new_region; > > It will invoke in goto label > > > + } > > + > > + if (dev->postcopy_listening) { > > + /* > > + * Cannot use vhost_user_postcopy_register() here because it > > + * reads ctx->msg.payload.memory (SET_MEM_TABLE layout), > but > > + * ADD_MEM_REG uses the memory_single payload. Register > the > > + * single new region directly instead. > > + */ > > + if (vhost_user_postcopy_region_register(dev, reg) < 0) > > + goto free_new_region; > > + } > > + > > + dev_invalidate_vrings(pdev, VHOST_USER_ADD_MEM_REG); > > + dev = *pdev; > > no need to do this, there are: struct virtio_net *dev = *pdev; in beginning > > > + dump_guest_pages(dev); > > + > > + return RTE_VHOST_MSG_RESULT_OK; > > + > > +free_new_region: > > + if (dev->async_copy && rte_vfio_is_enabled("vfio")) > > + async_dma_map_region(dev, reg, false); > > + remove_guest_pages(dev, reg); > > + free_mem_region(reg); > > + dev->mem->nregions--; > > +close_msg_fds: > > + close_msg_fds(ctx); > > + return RTE_VHOST_MSG_RESULT_ERR; > > +} > > + > > +static int > > +vhost_user_rem_mem_reg(struct virtio_net **pdev, > > + struct vhu_msg_context *ctx, > > + int main_fd __rte_unused) > > +{ > > + uint32_t i; > > + struct virtio_net *dev = *pdev; > > + struct VhostUserMemoryRegion *region = > > +&ctx->msg.payload.memory_single.region; > > + > > + if (dev->mem == NULL || dev->mem->nregions == 0) { > > + VHOST_CONFIG_LOG(dev->ifname, ERR, "no memory regions > to remove"); > > + close_msg_fds(ctx); > > no fd when remove, so please don't invoke close_msg_fds > > > + return RTE_VHOST_MSG_RESULT_ERR; > > + } > > + > > + for (i = 0; i < dev->mem->nregions; i++) { > > + struct rte_vhost_mem_region *current_region = > > +&dev->mem->regions[i]; > > + > > + /* > > + * According to the vhost-user specification: > > + * The memory region to be removed is identified by its GPA, > > + * 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) { > > + if (dev->async_copy && rte_vfio_is_enabled("vfio")) > > + async_dma_map_region(dev, current_region, > false); > > I'm afaid it not enough, we should drain DMA's pending request. But I think > the > original impl also has this problem. > > > + remove_guest_pages(dev, current_region); > > + free_mem_region(current_region); > > + > > + /* Compact the regions array to keep it contiguous */ > > + if (i < dev->mem->nregions - 1) { > > + memmove(&dev->mem->regions[i], > > + &dev->mem->regions[i + 1], > > + (dev->mem->nregions - 1 - i) * > > + sizeof(struct rte_vhost_mem_region)); > > + memset(&dev->mem->regions[dev->mem- > >nregions - 1], > > + 0, sizeof(struct > rte_vhost_mem_region)); > > + } > > + > > + dev->mem->nregions--; > > + dev_invalidate_vrings(pdev, > VHOST_USER_REM_MEM_REG); > > + dev = *pdev; > > no need to do this, there are: struct virtio_net *dev = *pdev; in beginning > > > + close_msg_fds(ctx); > > + return RTE_VHOST_MSG_RESULT_OK; > > + } > > + } > > + > > + VHOST_CONFIG_LOG(dev->ifname, ERR, "failed to find region"); > > + close_msg_fds(ctx); > > + return RTE_VHOST_MSG_RESULT_ERR; > > +} > > + > > static bool > > vq_is_ready(struct virtio_net *dev, struct vhost_virtqueue *vq) {
