Sending second version of this patchset as @stefanha requested. The main difference from the previous version is added vhost multithreading support.
Also I must note currently there are several problems which I intend to reconsider/fix later: - vmsd is present but migration is not supported - BlockConf is used but block layer is actually bypassed - posix BlockDriver internal state guessing --- Although QEMU virtio-blk is quite fast, there is still some room for improvements. Disk latency can be reduced if we handle virito-blk requests in host kernel so we avoid a lot of syscalls and context switches. The biggest disadvantage of this vhost-blk flavor is raw format. Luckily Kirill Thai proposed device mapper driver for QCOW2 format to attach files as block devices: https://www.spinics.net/lists/kernel/msg4292965.html Also by using kernel modules we can bypass iothread limitation and finaly scale block requests with cpus for high-performance devices. This is planned to be implemented in next version. Linux kernel module part: v2: https://lore.kernel.org/kvm/20221013151839.689700-1-andrey.zhadche...@virtuozzo.com/ test setups and results: fio --direct=1 --rw=randread --bs=4k --ioengine=libaio --iodepth=128 QEMU options: cache=none, iothread, aio=threads filesystem: xfs SSD: | randread, IOPS | randwrite, IOPS | Host | 95.8k | 85.3k | QEMU virtio | 61.5k | 79.9k | QEMU vhost-blk | 95.6k | 84.3k | RAMDISK (vq == vcpu == numjobs): | randread, IOPS | randwrite, IOPS | virtio, 1vcpu | 133k | 133k | virtio, 2vcpu | 305k | 306k | virtio, 4vcpu | 310k | 298k | virtio, 8vcpu | 271k | 252k | vhost-blk, 1vcpu | 110k | 113k | vhost-blk, 2vcpu | 247k | 252k | vhost-blk, 4vcpu | 558k | 556k | vhost-blk, 8vcpu | 576k | 575k | *single kernel thread vhost-blk, 8vcpu | 803k | 779k | *two kernel threads Andrey Zhadchenko (1): block: add vhost-blk backend hw/block/Kconfig | 5 + hw/block/meson.build | 4 + hw/block/vhost-blk.c | 403 ++++++++++++++++++++++++++++++++++ hw/virtio/meson.build | 3 + hw/virtio/vhost-blk-pci.c | 102 +++++++++ include/hw/virtio/vhost-blk.h | 52 +++++ meson.build | 6 + meson_options.txt | 2 + scripts/meson-buildoptions.sh | 3 + 9 files changed, 580 insertions(+) create mode 100644 hw/block/vhost-blk.c create mode 100644 hw/virtio/vhost-blk-pci.c create mode 100644 include/hw/virtio/vhost-blk.h -- 2.31.1