On Tue, 7 Apr 2026 22:42:04 +0000 <[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. 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]> > ---
The rest of the series review cleanly but AI flagged one issue. The initial description was a mess. Asked it to be clearer. ## Review: PATCH v10 4/5 — vhost_user: Function defs for add/rem mem regions **Warning: incomplete cleanup in `vhost_user_add_mem_reg()` mmap-failure path.** What is wrong: when `vhost_user_mmap_region()` returns -1, the handler only closes `reg->fd`. But `vhost_user_mmap_region()` can fail *after* setting `reg->mmap_addr`/`mmap_size`/`host_user_addr` and after `add_guest_pages()` has appended entries (the `add_one_guest_page()` realloc path). Impact: leaked mmap and stale `dev->guest_pages` entries. Since `nregions` is not incremented, the next ADD_MEM_REG reuses the same slot and overwrites `mmap_addr`, so `free_all_mem_regions()` can no longer reach the original mapping. Fix: when `reg->mmap_addr` is set, take the `free_new_region` path (`remove_guest_pages()` + `free_mem_region(reg)`) instead of just `close(reg->fd)`. Keep the explicit `close()` for the case where `mmap()` itself failed before `mmap_addr` was assigned.
