This series adds support for more memslots (509) to libvhost-user, to
make it fully compatible with virtio-mem that uses up to 256 memslots
accross all memory devices in "dynamic-memslot" mode (more details
in patch #3).
One simple fix upfront.
With that in place, this series optimizes and extens memory region
handling in libvhost-user:
* Heavily deduplicate and clean up the memory region handling code
* Speeds up GPA->VA translation with many memslots using binary search
* Optimize mmap_offset handling to use it as fd_offset for mmap()
* Avoid ring remapping when adding a single memory region
* Avoid dumping all guest memory, possibly allocating memory in sparse
memory mappings when the process crashes
I'm being very careful to not break some weird corner case that modern
QEMU might no longer trigger, but older one could have triggered or some
other frontend might trigger.
The only thing where I am not careful is to forbid memory regions that
overlap in GPA space: it doesn't make any sense.
With this series, virtio-mem (with dynamic-memslots=on) +
qemu-storage-daemon works flawlessly and as expected in my tests.
Cc: Michael S. Tsirkin <m...@redhat.com>
Cc: Jason Wang <jasow...@redhat.com>
Cc: Stefan Hajnoczi <stefa...@redhat.com>
Cc: Stefano Garzarella <sgarz...@redhat.com>
Cc: Germano Veit Michel <germ...@redhat.com>
Cc: Raphael Norwitz <raphael.norw...@nutanix.com>
David Hildenbrand (15):
libvhost-user: Fix msg_region->userspace_addr computation
libvhost-user: Dynamically allocate memory for memory slots
libvhost-user: Bump up VHOST_USER_MAX_RAM_SLOTS to 509
libvhost-user: Factor out removing all mem regions
libvhost-user: Merge vu_set_mem_table_exec_postcopy() into
vu_set_mem_table_exec()
libvhost-user: Factor out adding a memory region
libvhost-user: No need to check for NULL when unmapping
libvhost-user: Don't zero out memory for memory regions
libvhost-user: Don't search for duplicates when removing memory
regions
libvhost-user: Factor out search for memory region by GPA and simplify
libvhost-user: Speedup gpa_to_mem_region() and vu_gpa_to_va()
libvhost-user: Use most of mmap_offset as fd_offset
libvhost-user: Factor out vq usability check
libvhost-user: Dynamically remap rings after (temporarily?) removing
memory regions
libvhost-user: Mark mmap'ed region memory as MADV_DONTDUMP
subprojects/libvhost-user/libvhost-user.c | 593 ++++++++++++----------
subprojects/libvhost-user/libvhost-user.h | 10 +-
2 files changed, 332 insertions(+), 271 deletions(-)
--
2.43.0
