Internal Use - Confidential
> -----Original Message-----
> From: fengchengwen <[email protected]>
> Sent: Thursday, May 14, 2026 5:33 PM
> To: Bathija, Pravin <[email protected]>; [email protected];
> [email protected]; [email protected]
> Cc: [email protected]
> Subject: Re: [PATCH v13 3/5] vhost_user: support function defines for back-end
>
>
> [EXTERNAL EMAIL]
>
> please use vhost as the commit title prefix (please use git blame to refer),
> the
> same as other commit in this patchset.
>
> How about: vhost: refactor memory helper functions
>
> On 5/15/2026 6:46 AM, [email protected] wrote:
> > From: Pravin M Bathija <[email protected]>
> >
> > 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 unmap a set of memory regions, perform
> > register copy, align memory addresses and dma map/unmap a single
> > memory region.
>
> Two much detail, how about:
>
> Extract reusable helper routines for vhost-user backend memory operations:
> split DMA map/unmap into per-region logic, decouple and rework memory
> region free routines, and iterate over VHOST_MEMORY_MAX_NREGIONS
> uniformly across related functions to simplify code reuse.
>
> As above fixed:
> Acked-by: Chengwen Feng <[email protected]>
>
Made the changes as suggested in patch-set v14.
> >
> > Signed-off-by: Pravin M Bathija <[email protected]>
> > ---
> > lib/vhost/vhost_user.c | 89
> > ++++++++++++++++++++++++++++--------------
> > 1 file changed, 60 insertions(+), 29 deletions(-)
> >
> > diff --git a/lib/vhost/vhost_user.c b/lib/vhost/vhost_user.c index
> > 4bfb13fb98..0ee3fe7a5e 100644
> > --- a/lib/vhost/vhost_user.c
> > +++ b/lib/vhost/vhost_user.c
> > @@ -171,20 +171,27 @@ get_blk_size(int fd)
> > return ret == -1 ? (uint64_t)-1 : (uint64_t)stat.st_blksize; }
> >
> > -static void
> > -async_dma_map(struct virtio_net *dev, bool do_map)
> > +static int
> > +async_dma_map_region(struct virtio_net *dev, struct
> > +rte_vhost_mem_region *reg, bool do_map)
> > {
> > - int ret = 0;
> > uint32_t i;
> > - struct guest_page *page;
> > + int ret;
> > + uint64_t reg_start = reg->host_user_addr;
> > + uint64_t reg_end = reg_start + reg->size;
> > +
> > + for (i = 0; i < dev->nr_guest_pages; i++) {
> > + struct guest_page *page = &dev->guest_pages[i];
> > +
> > + /* Only process pages belonging to this region */
> > + if (page->host_user_addr < reg_start ||
> > + page->host_user_addr >= reg_end)
> > + continue;
> >
> > - if (do_map) {
> > - for (i = 0; i < dev->nr_guest_pages; i++) {
> > - page = &dev->guest_pages[i];
> > + if (do_map) {
> > ret =
> rte_vfio_container_dma_map(RTE_VFIO_DEFAULT_CONTAINER_FD,
> > - page-
> >host_user_addr,
> > - page->host_iova,
> > - page->size);
> > + page->host_user_addr,
> > + page->host_iova,
> > + page->size);
> > if (ret) {
> > /*
> > * DMA device may bind with kernel driver, in
> this case, @@
> > -199,33 +206,57 @@ async_dma_map(struct virtio_net *dev, bool do_map)
> > * normal case in async path. This is a
> workaround.
> > */
> > if (rte_errno == ENODEV)
> > - return;
> > + return 0;
> >
> > /* DMA mapping errors won't stop
> VHOST_USER_SET_MEM_TABLE. */
> > VHOST_CONFIG_LOG(dev->ifname, ERR, "DMA
> engine map failed");
> > + return -1;
> > }
> > - }
> > -
> > - } else {
> > - for (i = 0; i < dev->nr_guest_pages; i++) {
> > - page = &dev->guest_pages[i];
> > + } else {
> > ret =
> rte_vfio_container_dma_unmap(RTE_VFIO_DEFAULT_CONTAINER_FD,
> > - page-
> >host_user_addr,
> > - page->host_iova,
> > - page->size);
> > + page->host_user_addr,
> > + page->host_iova,
> > + page->size);
> > if (ret) {
> > /* like DMA map, ignore the kernel driver case
> when unmap. */
> > if (rte_errno == EINVAL)
> > - return;
> > + return 0;
> >
> > VHOST_CONFIG_LOG(dev->ifname, ERR, "DMA
> engine unmap failed");
> > + return -1;
> > }
> > }
> > }
> > +
> > + return 0;
> > +}
> > +
> > +static void
> > +async_dma_map(struct virtio_net *dev, bool do_map) {
> > + uint32_t i;
> > + struct rte_vhost_mem_region *reg;
> > +
> > + for (i = 0; i < VHOST_MEMORY_MAX_NREGIONS; i++) {
> > + reg = &dev->mem->regions[i];
> > + if (reg->host_user_addr == 0)
> > + continue;
> > + async_dma_map_region(dev, reg, do_map);
> > + }
> > }
> >
> > static void
> > -free_mem_region(struct virtio_net *dev)
> > +free_mem_region(struct rte_vhost_mem_region *reg) {
> > + if (reg != NULL && reg->mmap_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 +267,10 @@ 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 +284,7 @@ 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 +733,7 @@ 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 +837,10 @@ 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);
