On Tue, 7 Apr 2026 08:06:31 +0000 <[email protected]> wrote: > From: Pravin M Bathija <[email protected]> > > This is version v9 of the patchset and it incorporates the > recommendations made by Stephen Hemminger. > > Changes made to patch 3/5 > - Restored max_guest_pages initial value to hardcoded 8 instead of > VHOST_MEMORY_MAX_NREGIONS, matching upstream semantics. > > Changes made to patch 4/5 > - Added close(reg->fd) and reg->fd = -1 before goto close_msg_fds in the > mmap failure path to fix fd leak after fd was moved from ctx->fds[0]. > - Converted dev_invalidate_vrings from a plain function to a macro + > implementation function pair, accepting message ID as a parameter so > the static_assert reports the correct handler at each call site. > - Updated dev_invalidate_vrings call in add_mem_reg to pass > VHOST_USER_ADD_MEM_REG as message ID. > - Updated dev_invalidate_vrings call in rem_mem_reg to pass > VHOST_USER_ADD_MEM_REG as message ID. > > This implementation has been extensively tested by doing Read/Write I/O > from multiple instances of fio + libblkio (front-end) talking to > spdk/dpdk (back-end) based drives. Tested with qemu front-end talking to > dpdk testpmd (back-end) performing add/removal of memory regions. Also > tested post-copy live migration after doing add_memory_region. > > Version Log: > Version v9 (Current version): Incorporate code review suggestions from > Stephen Hemminger as described above. > Version v8: Incorporate code review suggestions from Stephen Hemminger. > rewrite async_dma_map_region function to iterate guest pages by host > address range matching > change function dev_invalidate_vrings to accept a double pointer to > propagate pointer updates > new function remove_guest_pages was added > add_mem_reg error path was narrowed to only clean up the single failed > region instead of destroting all existing regions > Version v7: Incorporate code review suggestions from Maxime Coquelin. > Add debug messages to vhost_postcopy_register function. > Version v6: Added the enablement of this feature as a final patch in > this patch-set and other code optimizations as suggested by Maxime > Coquelin. > Version v5: removed the patch that increased the number of memory regions > from 8 to 128. This will be submitted as a separate feature at a later > point after incorporating additional optimizations. Also includes code > optimizations as suggested by Feng Cheng Wen. > Version v4: code optimizations as suggested by Feng Cheng Wen. > Version v3: code optimizations as suggested by Maxime Coquelin > and Thomas Monjalon. > Version v2: code optimizations as suggested by Maxime Coquelin. > Version v1: Initial patch set. > > Pravin M Bathija (5): > vhost: add user to mailmap and define to vhost hdr > vhost_user: header defines for add/rem mem region > vhost_user: support function defines for back-end > vhost_user: Function defs for add/rem mem regions > vhost_user: enable configure memory slots > > .mailmap | 1 + > lib/vhost/rte_vhost.h | 4 + > lib/vhost/vhost_user.c | 403 ++++++++++++++++++++++++++++++++++++----- > lib/vhost/vhost_user.h | 10 + > 4 files changed, 375 insertions(+), 43 deletions(-) >
AI review is mostly clean now. Patch series looks good overall. One issue in 4/5: In rem_mem_reg, dev_invalidate_vrings (which calls translate_ring_addresses) runs while the region being removed is still mapped. Any vring address that resolves into that region will get a pointer that becomes invalid after the subsequent free_mem_region/munmap. Consider freeing the region first so translate only sees surviving regions. Also minor: the v9 cover letter changelog says rem_mem_reg passes VHOST_USER_ADD_MEM_REG but the code correctly uses VHOST_USER_REM_MEM_REG — just a typo in the changelog.
