Commit bdd6a90a authored by Fam Zheng's avatar Fam Zheng

block: Add VFIO based NVMe driver

This is a new protocol driver that exclusively opens a host NVMe
controller through VFIO. It achieves better latency than linux-aio by
completely bypassing host kernel vfs/block layer.

    $rw-$bs-$iodepth  linux-aio     nvme://
    randread-4k-1     10.5k         21.6k
    randread-512k-1   745           1591
    randwrite-4k-1    30.7k         37.0k
    randwrite-512k-1  1945          1980

    (unit: IOPS)

The driver also integrates with the polling mechanism of iothread.

This patch is co-authored by Paolo and me.
Signed-off-by: 's avatarPaolo Bonzini <>
Signed-off-by: 's avatarFam Zheng <>
Message-Id: <>
Reviewed-by: 's avatarStefan Hajnoczi <>
Signed-off-by: 's avatarFam Zheng <>
parent 418026ca
......@@ -1888,6 +1888,12 @@ L:
S: Supported
F: block/null.c
NVMe Block Driver
M: Fam Zheng <>
S: Supported
F: block/nvme*
M: Gonglei <>
S: Maintained
......@@ -11,6 +11,7 @@ block-obj-$(CONFIG_POSIX) += file-posix.o
block-obj-$(CONFIG_LINUX_AIO) += linux-aio.o
block-obj-y += null.o mirror.o commit.o io.o
block-obj-y += throttle-groups.o
block-obj-$(CONFIG_LINUX) += nvme.o
block-obj-y += nbd.o nbd-client.o sheepdog.o
block-obj-$(CONFIG_LIBISCSI) += iscsi.o
This diff is collapsed.
......@@ -124,3 +124,24 @@ vxhs_open_iio_open(const char *host) "Failed to connect to storage agent on host
vxhs_parse_uri_hostinfo(char *host, int port) "Host: IP %s, Port %d"
vxhs_close(char *vdisk_guid) "Closing vdisk %s"
vxhs_get_creds(const char *cacert, const char *client_key, const char *client_cert) "cacert %s, client_key %s, client_cert %s"
# block/nvme.c
nvme_kick(void *s, int queue) "s %p queue %d"
nvme_dma_flush_queue_wait(void *s) "s %p"
nvme_error(int cmd_specific, int sq_head, int sqid, int cid, int status) "cmd_specific %d sq_head %d sqid %d cid %d status 0x%x"
nvme_process_completion(void *s, int index, int inflight) "s %p queue %d inflight %d"
nvme_process_completion_queue_busy(void *s, int index) "s %p queue %d"
nvme_complete_command(void *s, int index, int cid) "s %p queue %d cid %d"
nvme_submit_command(void *s, int index, int cid) "s %p queue %d cid %d"
nvme_submit_command_raw(int c0, int c1, int c2, int c3, int c4, int c5, int c6, int c7) "%02x %02x %02x %02x %02x %02x %02x %02x"
nvme_handle_event(void *s) "s %p"
nvme_poll_cb(void *s) "s %p"
nvme_prw_aligned(void *s, int is_write, uint64_t offset, uint64_t bytes, int flags, int niov) "s %p is_write %d offset %"PRId64" bytes %"PRId64" flags %d niov %d"
nvme_qiov_unaligned(const void *qiov, int n, void *base, size_t size, int align) "qiov %p n %d base %p size 0x%zx align 0x%x"
nvme_prw_buffered(void *s, uint64_t offset, uint64_t bytes, int niov, int is_write) "s %p offset %"PRId64" bytes %"PRId64" niov %d is_write %d"
nvme_rw_done(void *s, int is_write, uint64_t offset, uint64_t bytes, int ret) "s %p is_write %d offset %"PRId64" bytes %"PRId64" ret %d"
nvme_dma_map_flush(void *s) "s %p"
nvme_free_req_queue_wait(void *q) "q %p"
nvme_cmd_map_qiov(void *s, void *cmd, void *req, void *qiov, int entries) "s %p cmd %p req %p qiov %p entries %d"
nvme_cmd_map_qiov_pages(void *s, int i, uint64_t page) "s %p page[%d] 0x%"PRIx64
nvme_cmd_map_qiov_iov(void *s, int i, void *page, int pages) "s %p iov[%d] %p pages %d"
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment