Dear Maxime, Responses inline.
Internal Use - Confidential > -----Original Message----- > From: Maxime Coquelin <[email protected]> > Sent: Tuesday, January 6, 2026 8:29 AM > To: Bathija, Pravin <[email protected]>; [email protected] > Cc: [email protected] > Subject: Re: [PATCH v5 3/4] vhost_user: support function defines for back-end > > > [EXTERNAL EMAIL] > > > > On 11/13/25 1:44 PM, Pravin M Bathija wrote: > > Here we define support functions which are called from the various > > vhost-user back-end message functions like set memory table, get > > memory slots, add memory region, remove memory region. These are > > essentially common functions to initialize memory, unmap a set of > > memory regions, perform register copy, align memory addresses and dma > > map/unmap a single memory region. > > > > Signed-off-by: Pravin M Bathija <[email protected]> > > --- > > lib/vhost/vhost_user.c | 150 > ++++++++++++++++++++++++++++++++++++++--- > > 1 file changed, 140 insertions(+), 10 deletions(-) > > > > diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c index > > 4bfb13fb98..7dc21fe42a 100644 > > --- a/lib/vhost/vhost_user.c > > +++ b/lib/vhost/vhost_user.c > > @@ -171,6 +171,80 @@ get_blk_size(int fd) > > return ret == -1 ? (uint64_t)-1 : (uint64_t)stat.st_blksize; > > } > > > > +static void > > +async_dma_map_region(struct virtio_net *dev, struct > > +rte_vhost_mem_region *reg, bool do_map) { > > + uint32_t i; > > + int ret = 0; > > + int found = 0; > > + struct guest_page *page; > > + > > + uint64_t reg_size = reg->size; > > + uint64_t host_user_addr = reg->host_user_addr; > > + > > + for (i = 0; i < dev->nr_guest_pages; i++) { > > + page = &dev->guest_pages[i]; > > + if (host_user_addr == page->host_user_addr) { > > + found = 1; > > + break; > > + } > > + } > > + > > + if (!found) { > > + VHOST_CONFIG_LOG(dev->ifname, ERR, "DMA engine map: > region not found"); > > + return; > > + } > > + > > + if (do_map) { > > + while (reg_size) { > > + page = &dev->guest_pages[i]; > > + ret = > rte_vfio_container_dma_map(RTE_VFIO_DEFAULT_CONTAINER_FD, > > + page->host_user_addr, > > + page->host_iova, > > + page->size); > > + if (ret) { > > + if (rte_errno == ENODEV) > > + return; > > + > > + /* DMA mapping errors won't stop > VHOST_USER_SET_MEM_TABLE. */ > > + VHOST_CONFIG_LOG(dev->ifname, ERR, > "DMA engine map failed"); > > + } > > + > > + reg_size -= page->size; > > + ++i; > > + if (i >= dev->nr_guest_pages) { > > + /* shouldn't get here */ > > + VHOST_CONFIG_LOG(dev->ifname, ERR, > "DMA engine map: No more pages"); > > + return; > > + } > > + } > > + } else { > > + while (reg_size) { > > + page = &dev->guest_pages[i]; > > + ret = > rte_vfio_container_dma_unmap(RTE_VFIO_DEFAULT_CONTAINER_FD, > > + page->host_user_addr, > > + page->host_iova, > > + page->size); > > + if (ret) { > > + if (rte_errno == EINVAL) > > + return; > > + > > + /* DMA mapping errors won't stop > VHOST_USER_SET_MEM_TABLE. */ > > + VHOST_CONFIG_LOG(dev->ifname, ERR, > "DMA engine unmap failed"); > > + } > > + > > + reg_size -= page->size; > > + ++i; > > + if (i >= dev->nr_guest_pages) { > > + /* shouldn't get here */ > > + VHOST_CONFIG_LOG(dev->ifname, ERR, > "DMA engine unmap: No more pages"); > > + return; > > + } > > + } > > + } > > + > > +} > > + > > static void > > async_dma_map(struct virtio_net *dev, bool do_map) > > { > > @@ -225,7 +299,17 @@ 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; > > @@ -236,12 +320,10 @@ 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); > > } > > } > > > > @@ -255,7 +337,7 @@ 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; > > } > > @@ -704,7 +786,7 @@ 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, @@ -808,8 +890,10 > @@ > > 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); > > @@ -1248,8 +1332,12 @@ vhost_user_postcopy_register(struct virtio_net > *dev, int main_fd, > > */ > > memory = &ctx->msg.payload.memory; > > for (i = 0; i < memory->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++; > > How is it supposed to work? > reg_msg_index is re-initialized to 0 at each iteration. You are absolutely right, it is an oversight. reg_msg_index should be initialized before the for loop starts. I will make the necessary changes and retest. > > > } > > > > /* Send the addresses back to qemu */ @@ -1278,6 +1366,8 @@ > > 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++) { > > reg = &dev->mem->regions[i]; > > + if (reg->host_user_addr == 0) > > + continue; > > if (vhost_user_postcopy_region_register(dev, reg) < 0) > > return -1; > > } > > @@ -1382,6 +1472,46 @@ 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 = VHOST_MEMORY_MAX_NREGIONS; > > + 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,
