Dear Maxime, I have made the changes as you suggested and also have some queries inline as per your comments.
Internal Use - Confidential > -----Original Message----- > From: Maxime Coquelin <[email protected]> > Sent: Friday, August 29, 2025 5:00 AM > To: Bathija, Pravin <[email protected]>; [email protected] > Cc: [email protected] > Subject: Re: [PATCH 3/3] vhost_user: support for memory regions > > > [EXTERNAL EMAIL] > > The title is not consistent with other commits in this library. > > On 8/12/25 4:33 AM, Pravin M Bathija wrote: > > - modify data structures and add functions to support > > add and remove memory regions/slots > > - define VHOST_MEMORY_MAX_NREGIONS & modify function > > vhost_user_set_mem_table accordingly > > - dynamically add new memory slots via vhost_user_add_mem_reg > > - remove unused memory slots via vhost_user_rem_mem_reg > > - define data structure VhostUserSingleMemReg for single > > memory region > > - modify data structures VhostUserRequest & VhostUserMsg > > > > Please write full sentences, explaining the purpose of this change and not > just > listing the changes themselves. Done the best I can in the new patch-set I just submitted. > > > Signed-off-by: Pravin M Bathija <[email protected]> > > --- > > lib/vhost/vhost_user.c | 325 +++++++++++++++++++++++++++++++++++--- > --- > > lib/vhost/vhost_user.h | 10 ++ > > 2 files changed, 291 insertions(+), 44 deletions(-) > > > > diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c index > > b73dec6a22..6367f54b97 100644 > > --- a/lib/vhost/vhost_user.c > > +++ b/lib/vhost/vhost_user.c > > @@ -74,6 +74,9 @@ > 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) \ > > Shouldn't it be: > VHOST_MESSAGE_HANDLER(VHOST_USER_REM_MEM_REG, > vhost_user_rem_mem_reg, false, true) > > And if not, aren't you not leaking FDs in vhost_user_rem_mem_reg? > Good catch. I have made the suggested change in the new patch-set. > > 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) \ @@ -228,7 +231,17 @@ > async_dma_map(struct virtio_net *dev, bool do_map) > > } > > > > static void > > -free_mem_region(struct virtio_net *dev) > > +free_mem_region(struct rte_vhost_mem_region *reg) { > > + if (reg != NULL && reg->host_user_addr) { > > + munmap(reg->mmap_addr, reg->mmap_size); > > + close(reg->fd); > > + memset(reg, 0, sizeof(struct rte_vhost_mem_region)); > > + } > > +} > > + > > +static void > > +free_all_mem_regions(struct virtio_net *dev) > > { > > uint32_t i; > > struct rte_vhost_mem_region *reg; > > @@ -239,12 +252,10 @@ free_mem_region(struct virtio_net *dev) > > if (dev->async_copy && rte_vfio_is_enabled("vfio")) > > async_dma_map(dev, false); > > > > - for (i = 0; i < dev->mem->nregions; i++) { > > + for (i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) { > > reg = &dev->mem->regions[i]; > > - if (reg->host_user_addr) { > > - munmap(reg->mmap_addr, reg->mmap_size); > > - close(reg->fd); > > - } > > + if (reg->mmap_addr) > > + free_mem_region(reg); > > Please split this patch in multiple ones. > Do the refactorings in dedicated patches. I have split the original patch into multiple patches. > > > } > > } > > > > @@ -258,7 +269,7 @@ vhost_backend_cleanup(struct virtio_net *dev) > > vdpa_dev->ops->dev_cleanup(dev->vid); > > > > if (dev->mem) { > > - free_mem_region(dev); > > + free_all_mem_regions(dev); > > rte_free(dev->mem); > > dev->mem = NULL; > > } > > @@ -707,7 +718,7 @@ numa_realloc(struct virtio_net **pdev, struct > vhost_virtqueue **pvq) > > vhost_devices[dev->vid] = dev; > > > > mem_size = sizeof(struct rte_vhost_memory) + > > - sizeof(struct rte_vhost_mem_region) * dev->mem->nregions; > > + sizeof(struct rte_vhost_mem_region) * > VHOST_MEMORY_MAX_NREGIONS; > > mem = rte_realloc_socket(dev->mem, mem_size, 0, node); > > if (!mem) { > > VHOST_CONFIG_LOG(dev->ifname, ERR, @@ -811,8 +822,10 > @@ > > hua_to_alignment(struct rte_vhost_memory *mem, void *ptr) > > uint32_t i; > > uintptr_t hua = (uintptr_t)ptr; > > > > - for (i = 0; i < mem->nregions; i++) { > > + for (i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) { > > r = &mem->regions[i]; > > + if (r->host_user_addr == 0) > > + continue; > > if (hua >= r->host_user_addr && > > hua < r->host_user_addr + r->size) { > > return get_blk_size(r->fd); > > @@ -1250,9 +1263,13 @@ vhost_user_postcopy_register(struct virtio_net > *dev, int main_fd, > > * retrieve the region offset when handling userfaults. > > */ > > memory = &ctx->msg.payload.memory; > > - for (i = 0; i < memory->nregions; i++) { > > + for (i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) { > > + int reg_msg_index = 0; > > reg = &dev->mem->regions[i]; > > - memory->regions[i].userspace_addr = reg->host_user_addr; > > + if (reg->host_user_addr == 0) > > + continue; > > + memory->regions[reg_msg_index].userspace_addr = reg- > >host_user_addr; > > + reg_msg_index++; > > } > > > > /* Send the addresses back to qemu */ @@ -1279,8 +1296,10 @@ > > vhost_user_postcopy_register(struct virtio_net *dev, int main_fd, > > } > > > > /* Now userfault register and we can use the memory */ > > - for (i = 0; i < memory->nregions; i++) { > > + for (i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) { > > reg = &dev->mem->regions[i]; > > + if (reg->host_user_addr == 0) > > + continue; > > if (vhost_user_postcopy_region_register(dev, reg) < 0) > > return -1; > > } > > @@ -1385,6 +1404,46 @@ 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 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, > > @@ -1393,7 +1452,6 @@ 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; > > @@ -1438,39 +1496,13 @@ 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; > > This part should be refactored into a dedicated preliminary patch. The original patch has been divided into multiple patches. > > > > > for (i = 0; i < memory->nregions; i++) { > > reg = &dev->mem->regions[i]; > > @@ -1534,11 +1566,182 @@ 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; > > +} > > + > > + > > +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; > > This VHOST_MEMORY_MAX_NREGIONS value was hardcoded when only > VHOST_USER_SET_MEM_TABLE was introduced. > > With this new features, my understanding is that we can get rid off this > limit, > right? > > The good news is increasing it should not break the DPDK ABI. > > Would it make sense to increase it? I have increased the VHOST_MEMORY_MAX_NREGIONS to 128 and tested with qemu, talking to vhost testpmd and adding/removing 128 memory regions. > > + > > + ctx->msg.payload.u64 = (uint64_t)max_mem_slots; > > + ctx->msg.size = sizeof(ctx->msg.payload.u64); > > + ctx->fd_num = 0; > > > > -free_guest_pages: > > + 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; > > + 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); > > + 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; > > + } > > There is a lack of support for vDPA devices. > My understanding here is that the vDPA device does not get the new table > entry. > > In set_mem_table, we call its close callback, but that might be a bit too much > for simple memory hotplug. we might need another mechanism. Could you please suggest the other mechanism ? > > > + > > + /* 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; > > Shouldn't it use size instead of mmap_size to check for overlaps? > > > + 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 current_region_guest_start_overlap = > > + current_region_guest_start >= > proposed_region_guest_start > > + && current_region_guest_start <= > proposed_region_guest_end; > > + bool current_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 = current_region_guest_start_overlap > > + || current_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; > > + } > > + > > + } > > + } > > + > > + /* convert first region add to normal memory table set */ > > + if (dev->mem == NULL) { > > + if (vhost_user_initialize_memory(pdev) < 0) > > + goto close_msg_fds; > > + } > > + > > + /* find a new region and set it like memory table set does */ > > + struct rte_vhost_mem_region *reg = NULL; > > + uint64_t mmap_offset; > > + > > + 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; > > + > > + 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); > > + > > + 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_SET_MEM_TABLE); > > 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: > > @@ -1546,6 +1749,40 @@ 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; > > + > > It lacks support for vDPA devices. > In set_mem_table, we call the vDPA close cb to ensure it is not actively > accessing memoring being unmapped. > > We need something similar here, otherwise the vDPA device is not aware of the > memory being unplugged. I have incorporated this change in the latest patch-set. > > > + 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->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); > > + dev->mem->nregions--; > > + return RTE_VHOST_MSG_RESULT_OK; > > + } > > There is a lack of IOTLB entries invalidation here, as IOTLB entries in the > cache > could point to memory being unmapped in this function. > > Same comment for vring invalidation, as the vring adresses are not re- > translated at each burst. I will incorporate in the next version. > > > + } > > + } > > + > > + 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) > > { > > diff --git a/lib/vhost/vhost_user.h b/lib/vhost/vhost_user.h index > > ef486545ba..5a0e747b58 100644 > > --- a/lib/vhost/vhost_user.h > > +++ b/lib/vhost/vhost_user.h > > @@ -32,6 +32,7 @@ > > (1ULL << > VHOST_USER_PROTOCOL_F_BACKEND_SEND_FD) | \ > > (1ULL << > VHOST_USER_PROTOCOL_F_HOST_NOTIFIER) | \ > > (1ULL << > VHOST_USER_PROTOCOL_F_PAGEFAULT) | \ > > + (1ULL << > VHOST_USER_PROTOCOL_F_CONFIGURE_MEM_SLOTS) | \ > > (1ULL << > VHOST_USER_PROTOCOL_F_STATUS)) > > > > typedef enum VhostUserRequest { > > @@ -67,6 +68,9 @@ typedef enum VhostUserRequest { > > VHOST_USER_POSTCOPY_END = 30, > > VHOST_USER_GET_INFLIGHT_FD = 31, > > VHOST_USER_SET_INFLIGHT_FD = 32, > > + VHOST_USER_GET_MAX_MEM_SLOTS = 36, > > + VHOST_USER_ADD_MEM_REG = 37, > > + VHOST_USER_REM_MEM_REG = 38, > > VHOST_USER_SET_STATUS = 39, > > VHOST_USER_GET_STATUS = 40, > > } VhostUserRequest; > > @@ -91,6 +95,11 @@ typedef struct VhostUserMemory { > > VhostUserMemoryRegion > regions[VHOST_MEMORY_MAX_NREGIONS]; > > } VhostUserMemory; > > > > +typedef struct VhostUserSingleMemReg { > > + uint64_t padding; > > + VhostUserMemoryRegion region; > > +} VhostUserSingleMemReg; > > + > > typedef struct VhostUserLog { > > uint64_t mmap_size; > > uint64_t mmap_offset; > > @@ -186,6 +195,7 @@ typedef struct __rte_packed_begin VhostUserMsg { > > struct vhost_vring_state state; > > struct vhost_vring_addr addr; > > VhostUserMemory memory; > > + VhostUserSingleMemReg memory_single; > > VhostUserLog log; > > struct vhost_iotlb_msg iotlb; > > VhostUserCryptoSessionParam crypto_session;
