* [PATCH v2 0/6] Support exporting BDSs via VDUSE
@ 2022-02-15 10:59 Xie Yongji
2022-02-15 10:59 ` [PATCH v2 1/6] block: Support passing NULL ops to blk_set_dev_ops() Xie Yongji
` (6 more replies)
0 siblings, 7 replies; 27+ messages in thread
From: Xie Yongji @ 2022-02-15 10:59 UTC (permalink / raw)
To: mst, jasowang, stefanha, sgarzare, kwolf, mreitz, mlureau
Cc: qemu-devel, qemu-block
Hi all,
Last few months ago, VDUSE (vDPA Device in Userspace) [1] has
been merged into Linux kernel as a framework that make it
possible to emulate a vDPA device in userspace. This series
aimed at implementing a VDUSE block backend based on the
qemu-storage-daemon infrastructure.
To support that, we firstly introduce a VDUSE library as a
subproject (like what libvhost-user does) to help implementing
VDUSE backends in QEMU. Then a VDUSE block export is implemented
based on this library. At last, we add resize and reconnect support
to the VDUSE block export and VDUSE library.
Since we don't support vdpa-blk in QEMU currently, the VM case is
tested with my previous patchset [2].
[1] https://www.kernel.org/doc/html/latest/userspace-api/vduse.html
[2] https://www.mail-archive.com/qemu-devel@nongnu.org/msg797569.html
Please review, thanks!
V1 to V2:
- Move vduse header to linux-headers [Stefan]
- Add two new API to support creating device from /dev/vduse/$NAME or
file descriptor [Stefan]
- Check VIRTIO_F_VERSION_1 during intialization [Stefan]
- Replace malloc() + memset to calloc() [Stefan]
- Increase default queue size to 256 for vduse-blk [Stefan]
- Zero-initialize virtio-blk config space [Stefan]
- Add a patch to support reset blk->dev_ops
- Validate vq->log->inflight fields [Stefan]
- Add vduse_set_reconnect_log_file() API to support specifing the
reconnect log file
- Fix some bugs [Stefan]
Xie Yongji (6):
block: Support passing NULL ops to blk_set_dev_ops()
linux-headers: Add vduse.h
libvduse: Add VDUSE (vDPA Device in Userspace) library
vduse-blk: implements vduse-blk export
vduse-blk: Add vduse-blk resize support
libvduse: Add support for reconnecting
block/block-backend.c | 2 +-
block/export/export.c | 6 +
block/export/meson.build | 5 +
block/export/vduse-blk.c | 462 +++++++
block/export/vduse-blk.h | 20 +
linux-headers/linux/vduse.h | 306 +++++
meson.build | 28 +
meson_options.txt | 4 +
qapi/block-export.json | 24 +-
scripts/meson-buildoptions.sh | 7 +
scripts/update-linux-headers.sh | 2 +-
subprojects/libvduse/include/atomic.h | 1 +
subprojects/libvduse/libvduse.c | 1374 +++++++++++++++++++
subprojects/libvduse/libvduse.h | 237 ++++
subprojects/libvduse/linux-headers/linux | 1 +
subprojects/libvduse/meson.build | 10 +
subprojects/libvduse/standard-headers/linux | 1 +
17 files changed, 2486 insertions(+), 4 deletions(-)
create mode 100644 block/export/vduse-blk.c
create mode 100644 block/export/vduse-blk.h
create mode 100644 linux-headers/linux/vduse.h
create mode 120000 subprojects/libvduse/include/atomic.h
create mode 100644 subprojects/libvduse/libvduse.c
create mode 100644 subprojects/libvduse/libvduse.h
create mode 120000 subprojects/libvduse/linux-headers/linux
create mode 100644 subprojects/libvduse/meson.build
create mode 120000 subprojects/libvduse/standard-headers/linux
--
2.20.1
^ permalink raw reply [flat|nested] 27+ messages in thread
* [PATCH v2 1/6] block: Support passing NULL ops to blk_set_dev_ops()
2022-02-15 10:59 [PATCH v2 0/6] Support exporting BDSs via VDUSE Xie Yongji
@ 2022-02-15 10:59 ` Xie Yongji
2022-03-14 17:23 ` Stefan Hajnoczi
2022-02-15 10:59 ` [PATCH v2 2/6] linux-headers: Add vduse.h Xie Yongji
` (5 subsequent siblings)
6 siblings, 1 reply; 27+ messages in thread
From: Xie Yongji @ 2022-02-15 10:59 UTC (permalink / raw)
To: mst, jasowang, stefanha, sgarzare, kwolf, mreitz, mlureau
Cc: qemu-devel, qemu-block
This supports passing NULL ops to blk_set_dev_ops()
so that we can remove stale ops in some cases.
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
block/block-backend.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/block/block-backend.c b/block/block-backend.c
index 4ff6b4d785..08dd0a3093 100644
--- a/block/block-backend.c
+++ b/block/block-backend.c
@@ -1015,7 +1015,7 @@ void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops,
blk->dev_opaque = opaque;
/* Are we currently quiesced? Should we enforce this right now? */
- if (blk->quiesce_counter && ops->drained_begin) {
+ if (blk->quiesce_counter && ops && ops->drained_begin) {
ops->drained_begin(opaque);
}
}
--
2.20.1
^ permalink raw reply related [flat|nested] 27+ messages in thread
* [PATCH v2 2/6] linux-headers: Add vduse.h
2022-02-15 10:59 [PATCH v2 0/6] Support exporting BDSs via VDUSE Xie Yongji
2022-02-15 10:59 ` [PATCH v2 1/6] block: Support passing NULL ops to blk_set_dev_ops() Xie Yongji
@ 2022-02-15 10:59 ` Xie Yongji
2022-02-15 10:59 ` [PATCH v2 3/6] libvduse: Add VDUSE (vDPA Device in Userspace) library Xie Yongji
` (4 subsequent siblings)
6 siblings, 0 replies; 27+ messages in thread
From: Xie Yongji @ 2022-02-15 10:59 UTC (permalink / raw)
To: mst, jasowang, stefanha, sgarzare, kwolf, mreitz, mlureau
Cc: qemu-devel, qemu-block
This adds vduse header to linux headers so that the
relevant VDUSE API can be used in subsequent patches.
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
| 306 ++++++++++++++++++++++++++++++++
| 2 +-
2 files changed, 307 insertions(+), 1 deletion(-)
create mode 100644 linux-headers/linux/vduse.h
--git a/linux-headers/linux/vduse.h b/linux-headers/linux/vduse.h
new file mode 100644
index 0000000000..d47b004ce6
--- /dev/null
+++ b/linux-headers/linux/vduse.h
@@ -0,0 +1,306 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _VDUSE_H_
+#define _VDUSE_H_
+
+#include <linux/types.h>
+
+#define VDUSE_BASE 0x81
+
+/* The ioctls for control device (/dev/vduse/control) */
+
+#define VDUSE_API_VERSION 0
+
+/*
+ * Get the version of VDUSE API that kernel supported (VDUSE_API_VERSION).
+ * This is used for future extension.
+ */
+#define VDUSE_GET_API_VERSION _IOR(VDUSE_BASE, 0x00, __u64)
+
+/* Set the version of VDUSE API that userspace supported. */
+#define VDUSE_SET_API_VERSION _IOW(VDUSE_BASE, 0x01, __u64)
+
+/**
+ * struct vduse_dev_config - basic configuration of a VDUSE device
+ * @name: VDUSE device name, needs to be NUL terminated
+ * @vendor_id: virtio vendor id
+ * @device_id: virtio device id
+ * @features: virtio features
+ * @vq_num: the number of virtqueues
+ * @vq_align: the allocation alignment of virtqueue's metadata
+ * @reserved: for future use, needs to be initialized to zero
+ * @config_size: the size of the configuration space
+ * @config: the buffer of the configuration space
+ *
+ * Structure used by VDUSE_CREATE_DEV ioctl to create VDUSE device.
+ */
+struct vduse_dev_config {
+#define VDUSE_NAME_MAX 256
+ char name[VDUSE_NAME_MAX];
+ __u32 vendor_id;
+ __u32 device_id;
+ __u64 features;
+ __u32 vq_num;
+ __u32 vq_align;
+ __u32 reserved[13];
+ __u32 config_size;
+ __u8 config[];
+};
+
+/* Create a VDUSE device which is represented by a char device (/dev/vduse/$NAME) */
+#define VDUSE_CREATE_DEV _IOW(VDUSE_BASE, 0x02, struct vduse_dev_config)
+
+/*
+ * Destroy a VDUSE device. Make sure there are no more references
+ * to the char device (/dev/vduse/$NAME).
+ */
+#define VDUSE_DESTROY_DEV _IOW(VDUSE_BASE, 0x03, char[VDUSE_NAME_MAX])
+
+/* The ioctls for VDUSE device (/dev/vduse/$NAME) */
+
+/**
+ * struct vduse_iotlb_entry - entry of IOTLB to describe one IOVA region [start, last]
+ * @offset: the mmap offset on returned file descriptor
+ * @start: start of the IOVA region
+ * @last: last of the IOVA region
+ * @perm: access permission of the IOVA region
+ *
+ * Structure used by VDUSE_IOTLB_GET_FD ioctl to find an overlapped IOVA region.
+ */
+struct vduse_iotlb_entry {
+ __u64 offset;
+ __u64 start;
+ __u64 last;
+#define VDUSE_ACCESS_RO 0x1
+#define VDUSE_ACCESS_WO 0x2
+#define VDUSE_ACCESS_RW 0x3
+ __u8 perm;
+};
+
+/*
+ * Find the first IOVA region that overlaps with the range [start, last]
+ * and return the corresponding file descriptor. Return -EINVAL means the
+ * IOVA region doesn't exist. Caller should set start and last fields.
+ */
+#define VDUSE_IOTLB_GET_FD _IOWR(VDUSE_BASE, 0x10, struct vduse_iotlb_entry)
+
+/*
+ * Get the negotiated virtio features. It's a subset of the features in
+ * struct vduse_dev_config which can be accepted by virtio driver. It's
+ * only valid after FEATURES_OK status bit is set.
+ */
+#define VDUSE_DEV_GET_FEATURES _IOR(VDUSE_BASE, 0x11, __u64)
+
+/**
+ * struct vduse_config_data - data used to update configuration space
+ * @offset: the offset from the beginning of configuration space
+ * @length: the length to write to configuration space
+ * @buffer: the buffer used to write from
+ *
+ * Structure used by VDUSE_DEV_SET_CONFIG ioctl to update device
+ * configuration space.
+ */
+struct vduse_config_data {
+ __u32 offset;
+ __u32 length;
+ __u8 buffer[];
+};
+
+/* Set device configuration space */
+#define VDUSE_DEV_SET_CONFIG _IOW(VDUSE_BASE, 0x12, struct vduse_config_data)
+
+/*
+ * Inject a config interrupt. It's usually used to notify virtio driver
+ * that device configuration space has changed.
+ */
+#define VDUSE_DEV_INJECT_CONFIG_IRQ _IO(VDUSE_BASE, 0x13)
+
+/**
+ * struct vduse_vq_config - basic configuration of a virtqueue
+ * @index: virtqueue index
+ * @max_size: the max size of virtqueue
+ * @reserved: for future use, needs to be initialized to zero
+ *
+ * Structure used by VDUSE_VQ_SETUP ioctl to setup a virtqueue.
+ */
+struct vduse_vq_config {
+ __u32 index;
+ __u16 max_size;
+ __u16 reserved[13];
+};
+
+/*
+ * Setup the specified virtqueue. Make sure all virtqueues have been
+ * configured before the device is attached to vDPA bus.
+ */
+#define VDUSE_VQ_SETUP _IOW(VDUSE_BASE, 0x14, struct vduse_vq_config)
+
+/**
+ * struct vduse_vq_state_split - split virtqueue state
+ * @avail_index: available index
+ */
+struct vduse_vq_state_split {
+ __u16 avail_index;
+};
+
+/**
+ * struct vduse_vq_state_packed - packed virtqueue state
+ * @last_avail_counter: last driver ring wrap counter observed by device
+ * @last_avail_idx: device available index
+ * @last_used_counter: device ring wrap counter
+ * @last_used_idx: used index
+ */
+struct vduse_vq_state_packed {
+ __u16 last_avail_counter;
+ __u16 last_avail_idx;
+ __u16 last_used_counter;
+ __u16 last_used_idx;
+};
+
+/**
+ * struct vduse_vq_info - information of a virtqueue
+ * @index: virtqueue index
+ * @num: the size of virtqueue
+ * @desc_addr: address of desc area
+ * @driver_addr: address of driver area
+ * @device_addr: address of device area
+ * @split: split virtqueue state
+ * @packed: packed virtqueue state
+ * @ready: ready status of virtqueue
+ *
+ * Structure used by VDUSE_VQ_GET_INFO ioctl to get virtqueue's information.
+ */
+struct vduse_vq_info {
+ __u32 index;
+ __u32 num;
+ __u64 desc_addr;
+ __u64 driver_addr;
+ __u64 device_addr;
+ union {
+ struct vduse_vq_state_split split;
+ struct vduse_vq_state_packed packed;
+ };
+ __u8 ready;
+};
+
+/* Get the specified virtqueue's information. Caller should set index field. */
+#define VDUSE_VQ_GET_INFO _IOWR(VDUSE_BASE, 0x15, struct vduse_vq_info)
+
+/**
+ * struct vduse_vq_eventfd - eventfd configuration for a virtqueue
+ * @index: virtqueue index
+ * @fd: eventfd, -1 means de-assigning the eventfd
+ *
+ * Structure used by VDUSE_VQ_SETUP_KICKFD ioctl to setup kick eventfd.
+ */
+struct vduse_vq_eventfd {
+ __u32 index;
+#define VDUSE_EVENTFD_DEASSIGN -1
+ int fd;
+};
+
+/*
+ * Setup kick eventfd for specified virtqueue. The kick eventfd is used
+ * by VDUSE kernel module to notify userspace to consume the avail vring.
+ */
+#define VDUSE_VQ_SETUP_KICKFD _IOW(VDUSE_BASE, 0x16, struct vduse_vq_eventfd)
+
+/*
+ * Inject an interrupt for specific virtqueue. It's used to notify virtio driver
+ * to consume the used vring.
+ */
+#define VDUSE_VQ_INJECT_IRQ _IOW(VDUSE_BASE, 0x17, __u32)
+
+/* The control messages definition for read(2)/write(2) on /dev/vduse/$NAME */
+
+/**
+ * enum vduse_req_type - request type
+ * @VDUSE_GET_VQ_STATE: get the state for specified virtqueue from userspace
+ * @VDUSE_SET_STATUS: set the device status
+ * @VDUSE_UPDATE_IOTLB: Notify userspace to update the memory mapping for
+ * specified IOVA range via VDUSE_IOTLB_GET_FD ioctl
+ */
+enum vduse_req_type {
+ VDUSE_GET_VQ_STATE,
+ VDUSE_SET_STATUS,
+ VDUSE_UPDATE_IOTLB,
+};
+
+/**
+ * struct vduse_vq_state - virtqueue state
+ * @index: virtqueue index
+ * @split: split virtqueue state
+ * @packed: packed virtqueue state
+ */
+struct vduse_vq_state {
+ __u32 index;
+ union {
+ struct vduse_vq_state_split split;
+ struct vduse_vq_state_packed packed;
+ };
+};
+
+/**
+ * struct vduse_dev_status - device status
+ * @status: device status
+ */
+struct vduse_dev_status {
+ __u8 status;
+};
+
+/**
+ * struct vduse_iova_range - IOVA range [start, last]
+ * @start: start of the IOVA range
+ * @last: last of the IOVA range
+ */
+struct vduse_iova_range {
+ __u64 start;
+ __u64 last;
+};
+
+/**
+ * struct vduse_dev_request - control request
+ * @type: request type
+ * @request_id: request id
+ * @reserved: for future use
+ * @vq_state: virtqueue state, only index field is available
+ * @s: device status
+ * @iova: IOVA range for updating
+ * @padding: padding
+ *
+ * Structure used by read(2) on /dev/vduse/$NAME.
+ */
+struct vduse_dev_request {
+ __u32 type;
+ __u32 request_id;
+ __u32 reserved[4];
+ union {
+ struct vduse_vq_state vq_state;
+ struct vduse_dev_status s;
+ struct vduse_iova_range iova;
+ __u32 padding[32];
+ };
+};
+
+/**
+ * struct vduse_dev_response - response to control request
+ * @request_id: corresponding request id
+ * @result: the result of request
+ * @reserved: for future use, needs to be initialized to zero
+ * @vq_state: virtqueue state
+ * @padding: padding
+ *
+ * Structure used by write(2) on /dev/vduse/$NAME.
+ */
+struct vduse_dev_response {
+ __u32 request_id;
+#define VDUSE_REQ_RESULT_OK 0x00
+#define VDUSE_REQ_RESULT_FAILED 0x01
+ __u32 result;
+ __u32 reserved[4];
+ union {
+ struct vduse_vq_state vq_state;
+ __u32 padding[32];
+ };
+};
+
+#endif /* _VDUSE_H_ */
--git a/scripts/update-linux-headers.sh b/scripts/update-linux-headers.sh
index fe850763c5..fd5f83ecd4 100755
--- a/scripts/update-linux-headers.sh
+++ b/scripts/update-linux-headers.sh
@@ -161,7 +161,7 @@ done
rm -rf "$output/linux-headers/linux"
mkdir -p "$output/linux-headers/linux"
for header in kvm.h vfio.h vfio_ccw.h vfio_zdev.h vhost.h \
- psci.h psp-sev.h userfaultfd.h mman.h; do
+ psci.h psp-sev.h userfaultfd.h mman.h vduse.h; do
cp "$tmpdir/include/linux/$header" "$output/linux-headers/linux"
done
--
2.20.1
^ permalink raw reply related [flat|nested] 27+ messages in thread
* [PATCH v2 3/6] libvduse: Add VDUSE (vDPA Device in Userspace) library
2022-02-15 10:59 [PATCH v2 0/6] Support exporting BDSs via VDUSE Xie Yongji
2022-02-15 10:59 ` [PATCH v2 1/6] block: Support passing NULL ops to blk_set_dev_ops() Xie Yongji
2022-02-15 10:59 ` [PATCH v2 2/6] linux-headers: Add vduse.h Xie Yongji
@ 2022-02-15 10:59 ` Xie Yongji
2022-03-15 9:48 ` Stefan Hajnoczi
2022-02-15 10:59 ` [PATCH v2 4/6] vduse-blk: implements vduse-blk export Xie Yongji
` (3 subsequent siblings)
6 siblings, 1 reply; 27+ messages in thread
From: Xie Yongji @ 2022-02-15 10:59 UTC (permalink / raw)
To: mst, jasowang, stefanha, sgarzare, kwolf, mreitz, mlureau
Cc: qemu-devel, qemu-block
VDUSE [1] is a linux framework that makes it possible to implement
software-emulated vDPA devices in userspace. This adds a library
as a subproject to help implementing VDUSE backends in QEMU.
[1] https://www.kernel.org/doc/html/latest/userspace-api/vduse.html
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
meson.build | 15 +
meson_options.txt | 2 +
scripts/meson-buildoptions.sh | 3 +
subprojects/libvduse/include/atomic.h | 1 +
subprojects/libvduse/libvduse.c | 1152 +++++++++++++++++++
subprojects/libvduse/libvduse.h | 225 ++++
| 1 +
subprojects/libvduse/meson.build | 10 +
subprojects/libvduse/standard-headers/linux | 1 +
9 files changed, 1410 insertions(+)
create mode 120000 subprojects/libvduse/include/atomic.h
create mode 100644 subprojects/libvduse/libvduse.c
create mode 100644 subprojects/libvduse/libvduse.h
create mode 120000 subprojects/libvduse/linux-headers/linux
create mode 100644 subprojects/libvduse/meson.build
create mode 120000 subprojects/libvduse/standard-headers/linux
diff --git a/meson.build b/meson.build
index ae5f7eec6e..27e6e07110 100644
--- a/meson.build
+++ b/meson.build
@@ -1304,6 +1304,21 @@ if not get_option('fuse_lseek').disabled()
endif
endif
+have_libvduse = (targetos == 'linux')
+if get_option('libvduse').enabled()
+ if targetos != 'linux'
+ error('libvduse requires linux')
+ endif
+elif get_option('libvduse').disabled()
+ have_libvduse = false
+endif
+
+libvduse = not_found
+if have_libvduse
+ libvduse_proj = subproject('libvduse')
+ libvduse = libvduse_proj.get_variable('libvduse_dep')
+endif
+
# libbpf
libbpf = dependency('libbpf', required: get_option('bpf'), method: 'pkg-config')
if libbpf.found() and not cc.links('''
diff --git a/meson_options.txt b/meson_options.txt
index 95d527f773..7099ab7b8b 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -193,6 +193,8 @@ option('virtfs', type: 'feature', value: 'auto',
description: 'virtio-9p support')
option('virtiofsd', type: 'feature', value: 'auto',
description: 'build virtiofs daemon (virtiofsd)')
+option('libvduse', type: 'feature', value: 'auto',
+ description: 'build VDUSE Library')
option('capstone', type: 'combo', value: 'auto',
choices: ['disabled', 'enabled', 'auto', 'system', 'internal'],
diff --git a/scripts/meson-buildoptions.sh b/scripts/meson-buildoptions.sh
index 48a454cece..8f031ea92e 100644
--- a/scripts/meson-buildoptions.sh
+++ b/scripts/meson-buildoptions.sh
@@ -58,6 +58,7 @@ meson_options_help() {
printf "%s\n" ' libssh ssh block device support'
printf "%s\n" ' libudev Use libudev to enumerate host devices'
printf "%s\n" ' libusb libusb support for USB passthrough'
+ printf "%s\n" ' libvduse build VDUSE Library'
printf "%s\n" ' linux-aio Linux AIO support'
printf "%s\n" ' linux-io-uring Linux io_uring support'
printf "%s\n" ' lzfse lzfse support for DMG images'
@@ -187,6 +188,8 @@ _meson_option_parse() {
--disable-libudev) printf "%s" -Dlibudev=disabled ;;
--enable-libusb) printf "%s" -Dlibusb=enabled ;;
--disable-libusb) printf "%s" -Dlibusb=disabled ;;
+ --enable-libvduse) printf "%s" -Dlibvduse=enabled ;;
+ --disable-libvduse) printf "%s" -Dlibvduse=disabled ;;
--enable-linux-aio) printf "%s" -Dlinux_aio=enabled ;;
--disable-linux-aio) printf "%s" -Dlinux_aio=disabled ;;
--enable-linux-io-uring) printf "%s" -Dlinux_io_uring=enabled ;;
diff --git a/subprojects/libvduse/include/atomic.h b/subprojects/libvduse/include/atomic.h
new file mode 120000
index 0000000000..8c2be64f7b
--- /dev/null
+++ b/subprojects/libvduse/include/atomic.h
@@ -0,0 +1 @@
+../../../include/qemu/atomic.h
\ No newline at end of file
diff --git a/subprojects/libvduse/libvduse.c b/subprojects/libvduse/libvduse.c
new file mode 100644
index 0000000000..9c6a8bcf6e
--- /dev/null
+++ b/subprojects/libvduse/libvduse.c
@@ -0,0 +1,1152 @@
+/*
+ * VDUSE (vDPA Device in Userspace) library
+ *
+ * Copyright (C) 2022 Bytedance Inc. and/or its affiliates. All rights reserved.
+ * Portions of codes and concepts borrowed from libvhost-user.c, so:
+ * Copyright IBM, Corp. 2007
+ * Copyright (c) 2016 Red Hat, Inc.
+ *
+ * Author:
+ * Xie Yongji <xieyongji@bytedance.com>
+ * Anthony Liguori <aliguori@us.ibm.com>
+ * Marc-André Lureau <mlureau@redhat.com>
+ * Victor Kaplansky <victork@redhat.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later. See the COPYING file in the top-level directory.
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <errno.h>
+#include <string.h>
+#include <assert.h>
+#include <endian.h>
+#include <unistd.h>
+#include <limits.h>
+#include <fcntl.h>
+
+#include <sys/ioctl.h>
+#include <sys/eventfd.h>
+#include <sys/mman.h>
+
+#include "include/atomic.h"
+#include "linux-headers/linux/virtio_ring.h"
+#include "linux-headers/linux/virtio_config.h"
+#include "linux-headers/linux/vduse.h"
+#include "libvduse.h"
+
+#define VDUSE_VQ_ALIGN 4096
+#define MAX_IOVA_REGIONS 256
+
+/* Round number down to multiple */
+#define ALIGN_DOWN(n, m) ((n) / (m) * (m))
+
+/* Round number up to multiple */
+#define ALIGN_UP(n, m) ALIGN_DOWN((n) + (m) - 1, (m))
+
+#ifndef unlikely
+#define unlikely(x) __builtin_expect(!!(x), 0)
+#endif
+
+typedef struct VduseRing {
+ unsigned int num;
+ uint64_t desc_addr;
+ uint64_t avail_addr;
+ uint64_t used_addr;
+ struct vring_desc *desc;
+ struct vring_avail *avail;
+ struct vring_used *used;
+} VduseRing;
+
+struct VduseVirtq {
+ VduseRing vring;
+ uint16_t last_avail_idx;
+ uint16_t shadow_avail_idx;
+ uint16_t used_idx;
+ uint16_t signalled_used;
+ bool signalled_used_valid;
+ int index;
+ int inuse;
+ bool ready;
+ int fd;
+ VduseDev *dev;
+};
+
+typedef struct VduseIovaRegion {
+ uint64_t iova;
+ uint64_t size;
+ uint64_t mmap_offset;
+ uint64_t mmap_addr;
+} VduseIovaRegion;
+
+struct VduseDev {
+ VduseVirtq *vqs;
+ VduseIovaRegion regions[MAX_IOVA_REGIONS];
+ int num_regions;
+ char *name;
+ uint32_t device_id;
+ uint32_t vendor_id;
+ uint16_t num_queues;
+ uint16_t queue_size;
+ uint64_t features;
+ const VduseOps *ops;
+ int fd;
+ int ctrl_fd;
+ void *priv;
+};
+
+static inline bool has_feature(uint64_t features, unsigned int fbit)
+{
+ assert(fbit < 64);
+ return !!(features & (1ULL << fbit));
+}
+
+static inline bool vduse_dev_has_feature(VduseDev *dev, unsigned int fbit)
+{
+ return has_feature(dev->features, fbit);
+}
+
+VduseDev *vduse_queue_get_dev(VduseVirtq *vq)
+{
+ return vq->dev;
+}
+
+int vduse_queue_get_fd(VduseVirtq *vq)
+{
+ return vq->fd;
+}
+
+void *vduse_dev_get_priv(VduseDev *dev)
+{
+ return dev->priv;
+}
+
+VduseVirtq *vduse_dev_get_queue(VduseDev *dev, int index)
+{
+ return &dev->vqs[index];
+}
+
+int vduse_dev_get_fd(VduseDev *dev)
+{
+ return dev->fd;
+}
+
+static int vduse_inject_irq(VduseDev *dev, int index)
+{
+ return ioctl(dev->fd, VDUSE_VQ_INJECT_IRQ, &index);
+}
+
+static void vduse_iova_remove_region(VduseDev *dev, uint64_t start,
+ uint64_t last)
+{
+ int i;
+
+ if (last == start) {
+ return;
+ }
+
+ for (i = 0; i < MAX_IOVA_REGIONS; i++) {
+ if (!dev->regions[i].mmap_addr) {
+ continue;
+ }
+
+ if (start <= dev->regions[i].iova &&
+ last >= (dev->regions[i].iova + dev->regions[i].size - 1)) {
+ munmap((void *)dev->regions[i].mmap_addr,
+ dev->regions[i].mmap_offset + dev->regions[i].size);
+ dev->regions[i].mmap_addr = 0;
+ dev->num_regions--;
+ }
+ }
+}
+
+static int vduse_iova_add_region(VduseDev *dev, int fd,
+ uint64_t offset, uint64_t start,
+ uint64_t last, int prot)
+{
+ int i;
+ uint64_t size = last - start + 1;
+ void *mmap_addr = mmap(0, size + offset, prot, MAP_SHARED, fd, 0);
+
+ if (mmap_addr == MAP_FAILED) {
+ close(fd);
+ return -EINVAL;
+ }
+
+ for (i = 0; i < MAX_IOVA_REGIONS; i++) {
+ if (!dev->regions[i].mmap_addr) {
+ dev->regions[i].mmap_addr = (uint64_t)(uintptr_t)mmap_addr;
+ dev->regions[i].mmap_offset = offset;
+ dev->regions[i].iova = start;
+ dev->regions[i].size = size;
+ dev->num_regions++;
+ break;
+ }
+ }
+ assert(i < MAX_IOVA_REGIONS);
+ close(fd);
+
+ return 0;
+}
+
+static int perm_to_prot(uint8_t perm)
+{
+ int prot = 0;
+
+ switch (perm) {
+ case VDUSE_ACCESS_WO:
+ prot |= PROT_WRITE;
+ break;
+ case VDUSE_ACCESS_RO:
+ prot |= PROT_READ;
+ break;
+ case VDUSE_ACCESS_RW:
+ prot |= PROT_READ | PROT_WRITE;
+ break;
+ default:
+ break;
+ }
+
+ return prot;
+}
+
+static inline void *iova_to_va(VduseDev *dev, uint64_t *plen, uint64_t iova)
+{
+ int i, ret;
+ struct vduse_iotlb_entry entry;
+
+ for (i = 0; i < MAX_IOVA_REGIONS; i++) {
+ VduseIovaRegion *r = &dev->regions[i];
+
+ if (!r->mmap_addr) {
+ continue;
+ }
+
+ if ((iova >= r->iova) && (iova < (r->iova + r->size))) {
+ if ((iova + *plen) > (r->iova + r->size)) {
+ *plen = r->iova + r->size - iova;
+ }
+ return (void *)(uintptr_t)(iova - r->iova +
+ r->mmap_addr + r->mmap_offset);
+ }
+ }
+
+ entry.start = iova;
+ entry.last = iova + 1;
+ ret = ioctl(dev->fd, VDUSE_IOTLB_GET_FD, &entry);
+ if (ret < 0) {
+ return NULL;
+ }
+
+ if (!vduse_iova_add_region(dev, ret, entry.offset, entry.start,
+ entry.last, perm_to_prot(entry.perm))) {
+ return iova_to_va(dev, plen, iova);
+ }
+
+ return NULL;
+}
+
+static inline uint16_t vring_avail_flags(VduseVirtq *vq)
+{
+ return le16toh(vq->vring.avail->flags);
+}
+
+static inline uint16_t vring_avail_idx(VduseVirtq *vq)
+{
+ vq->shadow_avail_idx = le16toh(vq->vring.avail->idx);
+
+ return vq->shadow_avail_idx;
+}
+
+static inline uint16_t vring_avail_ring(VduseVirtq *vq, int i)
+{
+ return le16toh(vq->vring.avail->ring[i]);
+}
+
+static inline uint16_t vring_get_used_event(VduseVirtq *vq)
+{
+ return vring_avail_ring(vq, vq->vring.num);
+}
+
+static bool vduse_queue_get_head(VduseVirtq *vq, unsigned int idx,
+ unsigned int *head)
+{
+ /*
+ * Grab the next descriptor number they're advertising, and increment
+ * the index we've seen.
+ */
+ *head = vring_avail_ring(vq, idx % vq->vring.num);
+
+ /* If their number is silly, that's a fatal mistake. */
+ if (*head >= vq->vring.num) {
+ fprintf(stderr, "Guest says index %u is available\n", *head);
+ return false;
+ }
+
+ return true;
+}
+
+static int
+vduse_queue_read_indirect_desc(VduseDev *dev, struct vring_desc *desc,
+ uint64_t addr, size_t len)
+{
+ struct vring_desc *ori_desc;
+ uint64_t read_len;
+
+ if (len > (VIRTQUEUE_MAX_SIZE * sizeof(struct vring_desc))) {
+ return -1;
+ }
+
+ if (len == 0) {
+ return -1;
+ }
+
+ while (len) {
+ read_len = len;
+ ori_desc = iova_to_va(dev, &read_len, addr);
+ if (!ori_desc) {
+ return -1;
+ }
+
+ memcpy(desc, ori_desc, read_len);
+ len -= read_len;
+ addr += read_len;
+ desc += read_len;
+ }
+
+ return 0;
+}
+
+enum {
+ VIRTQUEUE_READ_DESC_ERROR = -1,
+ VIRTQUEUE_READ_DESC_DONE = 0, /* end of chain */
+ VIRTQUEUE_READ_DESC_MORE = 1, /* more buffers in chain */
+};
+
+static int vduse_queue_read_next_desc(struct vring_desc *desc, int i,
+ unsigned int max, unsigned int *next)
+{
+ /* If this descriptor says it doesn't chain, we're done. */
+ if (!(le16toh(desc[i].flags) & VRING_DESC_F_NEXT)) {
+ return VIRTQUEUE_READ_DESC_DONE;
+ }
+
+ /* Check they're not leading us off end of descriptors. */
+ *next = desc[i].next;
+ /* Make sure compiler knows to grab that: we don't want it changing! */
+ smp_wmb();
+
+ if (*next >= max) {
+ fprintf(stderr, "Desc next is %u\n", *next);
+ return VIRTQUEUE_READ_DESC_ERROR;
+ }
+
+ return VIRTQUEUE_READ_DESC_MORE;
+}
+
+/*
+ * Fetch avail_idx from VQ memory only when we really need to know if
+ * guest has added some buffers.
+ */
+static bool vduse_queue_empty(VduseVirtq *vq)
+{
+ if (unlikely(!vq->vring.avail)) {
+ return true;
+ }
+
+ if (vq->shadow_avail_idx != vq->last_avail_idx) {
+ return false;
+ }
+
+ return vring_avail_idx(vq) == vq->last_avail_idx;
+}
+
+static bool vduse_queue_should_notify(VduseVirtq *vq)
+{
+ VduseDev *dev = vq->dev;
+ uint16_t old, new;
+ bool v;
+
+ /* We need to expose used array entries before checking used event. */
+ smp_mb();
+
+ /* Always notify when queue is empty (when feature acknowledge) */
+ if (vduse_dev_has_feature(dev, VIRTIO_F_NOTIFY_ON_EMPTY) &&
+ !vq->inuse && vduse_queue_empty(vq)) {
+ return true;
+ }
+
+ if (!vduse_dev_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) {
+ return !(vring_avail_flags(vq) & VRING_AVAIL_F_NO_INTERRUPT);
+ }
+
+ v = vq->signalled_used_valid;
+ vq->signalled_used_valid = true;
+ old = vq->signalled_used;
+ new = vq->signalled_used = vq->used_idx;
+ return !v || vring_need_event(vring_get_used_event(vq), new, old);
+}
+
+void vduse_queue_notify(VduseVirtq *vq)
+{
+ VduseDev *dev = vq->dev;
+
+ if (unlikely(!vq->vring.avail)) {
+ return;
+ }
+
+ if (!vduse_queue_should_notify(vq)) {
+ return;
+ }
+
+ if (vduse_inject_irq(dev, vq->index) < 0) {
+ fprintf(stderr, "Error inject irq for vq %d: %s\n",
+ vq->index, strerror(errno));
+ }
+}
+
+static inline void vring_used_flags_set_bit(VduseVirtq *vq, int mask)
+{
+ uint16_t *flags;
+
+ flags = (uint16_t *)((char*)vq->vring.used +
+ offsetof(struct vring_used, flags));
+ *flags = htole16(le16toh(*flags) | mask);
+}
+
+static inline void vring_used_flags_unset_bit(VduseVirtq *vq, int mask)
+{
+ uint16_t *flags;
+
+ flags = (uint16_t *)((char*)vq->vring.used +
+ offsetof(struct vring_used, flags));
+ *flags = htole16(le16toh(*flags) & ~mask);
+}
+
+static inline void vring_set_avail_event(VduseVirtq *vq, uint16_t val)
+{
+ *((uint16_t *)&vq->vring.used->ring[vq->vring.num]) = htole16(val);
+}
+
+static bool vduse_queue_map_single_desc(VduseVirtq *vq, unsigned int *p_num_sg,
+ struct iovec *iov, unsigned int max_num_sg,
+ bool is_write, uint64_t pa, size_t sz)
+{
+ unsigned num_sg = *p_num_sg;
+ VduseDev *dev = vq->dev;
+
+ assert(num_sg <= max_num_sg);
+
+ if (!sz) {
+ fprintf(stderr, "virtio: zero sized buffers are not allowed\n");
+ return false;
+ }
+
+ while (sz) {
+ uint64_t len = sz;
+
+ if (num_sg == max_num_sg) {
+ fprintf(stderr,
+ "virtio: too many descriptors in indirect table\n");
+ return false;
+ }
+
+ iov[num_sg].iov_base = iova_to_va(dev, &len, pa);
+ if (iov[num_sg].iov_base == NULL) {
+ fprintf(stderr, "virtio: invalid address for buffers\n");
+ return false;
+ }
+ iov[num_sg++].iov_len = len;
+ sz -= len;
+ pa += len;
+ }
+
+ *p_num_sg = num_sg;
+ return true;
+}
+
+static void *vduse_queue_alloc_element(size_t sz, unsigned out_num,
+ unsigned in_num)
+{
+ VduseVirtqElement *elem;
+ size_t in_sg_ofs = ALIGN_UP(sz, __alignof__(elem->in_sg[0]));
+ size_t out_sg_ofs = in_sg_ofs + in_num * sizeof(elem->in_sg[0]);
+ size_t out_sg_end = out_sg_ofs + out_num * sizeof(elem->out_sg[0]);
+
+ assert(sz >= sizeof(VduseVirtqElement));
+ elem = malloc(out_sg_end);
+ if (!elem) {
+ return NULL;
+ }
+ elem->out_num = out_num;
+ elem->in_num = in_num;
+ elem->in_sg = (void *)elem + in_sg_ofs;
+ elem->out_sg = (void *)elem + out_sg_ofs;
+ return elem;
+}
+
+static void *vduse_queue_map_desc(VduseVirtq *vq, unsigned int idx, size_t sz)
+{
+ struct vring_desc *desc = vq->vring.desc;
+ VduseDev *dev = vq->dev;
+ uint64_t desc_addr, read_len;
+ unsigned int desc_len;
+ unsigned int max = vq->vring.num;
+ unsigned int i = idx;
+ VduseVirtqElement *elem;
+ struct iovec iov[VIRTQUEUE_MAX_SIZE];
+ struct vring_desc desc_buf[VIRTQUEUE_MAX_SIZE];
+ unsigned int out_num = 0, in_num = 0;
+ int rc;
+
+ if (le16toh(desc[i].flags) & VRING_DESC_F_INDIRECT) {
+ if (le32toh(desc[i].len) % sizeof(struct vring_desc)) {
+ fprintf(stderr, "Invalid size for indirect buffer table\n");
+ return NULL;
+ }
+
+ /* loop over the indirect descriptor table */
+ desc_addr = le64toh(desc[i].addr);
+ desc_len = le32toh(desc[i].len);
+ max = desc_len / sizeof(struct vring_desc);
+ read_len = desc_len;
+ desc = iova_to_va(dev, &read_len, desc_addr);
+ if (unlikely(desc && read_len != desc_len)) {
+ /* Failed to use zero copy */
+ desc = NULL;
+ if (!vduse_queue_read_indirect_desc(dev, desc_buf,
+ desc_addr,
+ desc_len)) {
+ desc = desc_buf;
+ }
+ }
+ if (!desc) {
+ fprintf(stderr, "Invalid indirect buffer table\n");
+ return NULL;
+ }
+ i = 0;
+ }
+
+ /* Collect all the descriptors */
+ do {
+ if (le16toh(desc[i].flags) & VRING_DESC_F_WRITE) {
+ if (!vduse_queue_map_single_desc(vq, &in_num, iov + out_num,
+ VIRTQUEUE_MAX_SIZE - out_num,
+ true, le64toh(desc[i].addr),
+ le32toh(desc[i].len))) {
+ return NULL;
+ }
+ } else {
+ if (in_num) {
+ fprintf(stderr, "Incorrect order for descriptors\n");
+ return NULL;
+ }
+ if (!vduse_queue_map_single_desc(vq, &out_num, iov,
+ VIRTQUEUE_MAX_SIZE, false,
+ le64toh(desc[i].addr),
+ le32toh(desc[i].len))) {
+ return NULL;
+ }
+ }
+
+ /* If we've got too many, that implies a descriptor loop. */
+ if ((in_num + out_num) > max) {
+ fprintf(stderr, "Looped descriptor\n");
+ return NULL;
+ }
+ rc = vduse_queue_read_next_desc(desc, i, max, &i);
+ } while (rc == VIRTQUEUE_READ_DESC_MORE);
+
+ if (rc == VIRTQUEUE_READ_DESC_ERROR) {
+ fprintf(stderr, "read descriptor error\n");
+ return NULL;
+ }
+
+ /* Now copy what we have collected and mapped */
+ elem = vduse_queue_alloc_element(sz, out_num, in_num);
+ if (!elem) {
+ fprintf(stderr, "read descriptor error\n");
+ return NULL;
+ }
+ elem->index = idx;
+ for (i = 0; i < out_num; i++) {
+ elem->out_sg[i] = iov[i];
+ }
+ for (i = 0; i < in_num; i++) {
+ elem->in_sg[i] = iov[out_num + i];
+ }
+
+ return elem;
+}
+
+void *vduse_queue_pop(VduseVirtq *vq, size_t sz)
+{
+ unsigned int head;
+ VduseVirtqElement *elem;
+ VduseDev *dev = vq->dev;
+
+ if (unlikely(!vq->vring.avail)) {
+ return NULL;
+ }
+
+ if (vduse_queue_empty(vq)) {
+ return NULL;
+ }
+ /* Needed after virtio_queue_empty() */
+ smp_rmb();
+
+ if (vq->inuse >= vq->vring.num) {
+ fprintf(stderr, "Virtqueue size exceeded: %d\n", vq->inuse);
+ return NULL;
+ }
+
+ if (!vduse_queue_get_head(vq, vq->last_avail_idx++, &head)) {
+ return NULL;
+ }
+
+ if (vduse_dev_has_feature(dev, VIRTIO_RING_F_EVENT_IDX)) {
+ vring_set_avail_event(vq, vq->last_avail_idx);
+ }
+
+ elem = vduse_queue_map_desc(vq, head, sz);
+
+ if (!elem) {
+ return NULL;
+ }
+
+ vq->inuse++;
+
+ return elem;
+}
+
+static inline void vring_used_write(VduseVirtq *vq,
+ struct vring_used_elem *uelem, int i)
+{
+ struct vring_used *used = vq->vring.used;
+
+ used->ring[i] = *uelem;
+}
+
+static void vduse_queue_fill(VduseVirtq *vq, const VduseVirtqElement *elem,
+ unsigned int len, unsigned int idx)
+{
+ struct vring_used_elem uelem;
+
+ if (unlikely(!vq->vring.used)) {
+ return;
+ }
+
+ idx = (idx + vq->used_idx) % vq->vring.num;
+
+ uelem.id = htole32(elem->index);
+ uelem.len = htole32(len);
+ vring_used_write(vq, &uelem, idx);
+}
+
+static inline void vring_used_idx_set(VduseVirtq *vq, uint16_t val)
+{
+ vq->vring.used->idx = htole16(val);
+ vq->used_idx = val;
+}
+
+static void vduse_queue_flush(VduseVirtq *vq, unsigned int count)
+{
+ uint16_t old, new;
+
+ if (unlikely(!vq->vring.used)) {
+ return;
+ }
+
+ /* Make sure buffer is written before we update index. */
+ smp_wmb();
+
+ old = vq->used_idx;
+ new = old + count;
+ vring_used_idx_set(vq, new);
+ vq->inuse -= count;
+ if (unlikely((int16_t)(new - vq->signalled_used) < (uint16_t)(new - old))) {
+ vq->signalled_used_valid = false;
+ }
+}
+
+void vduse_queue_push(VduseVirtq *vq, const VduseVirtqElement *elem,
+ unsigned int len)
+{
+ vduse_queue_fill(vq, elem, len, 0);
+ vduse_queue_flush(vq, 1);
+}
+
+static int vduse_queue_update_vring(VduseVirtq *vq, uint64_t desc_addr,
+ uint64_t avail_addr, uint64_t used_addr)
+{
+ struct VduseDev *dev = vq->dev;
+ uint64_t len;
+
+ len = sizeof(struct vring_desc);
+ vq->vring.desc = iova_to_va(dev, &len, desc_addr);
+ assert(len == sizeof(struct vring_desc));
+
+ len = sizeof(struct vring_avail);
+ vq->vring.avail = iova_to_va(dev, &len, avail_addr);
+ assert(len == sizeof(struct vring_avail));
+
+ len = sizeof(struct vring_used);
+ vq->vring.used = iova_to_va(dev, &len, used_addr);
+ assert(len == sizeof(struct vring_used));
+
+ if (!vq->vring.desc || !vq->vring.avail || !vq->vring.used) {
+ fprintf(stderr, "Failed to get vq[%d] iova mapping\n", vq->index);
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static void vduse_queue_enable(VduseVirtq *vq)
+{
+ struct VduseDev *dev = vq->dev;
+ struct vduse_vq_info vq_info;
+ struct vduse_vq_eventfd vq_eventfd;
+ int fd;
+
+ vq_info.index = vq->index;
+ if (ioctl(dev->fd, VDUSE_VQ_GET_INFO, &vq_info)) {
+ fprintf(stderr, "Failed to get vq[%d] info: %s\n",
+ vq->index, strerror(errno));
+ return;
+ }
+
+ if (!vq_info.ready) {
+ return;
+ }
+
+ vq->vring.num = vq_info.num;
+ vq->vring.desc_addr = vq_info.desc_addr;
+ vq->vring.avail_addr = vq_info.driver_addr;
+ vq->vring.used_addr = vq_info.device_addr;
+
+ if (vduse_queue_update_vring(vq, vq_info.desc_addr,
+ vq_info.driver_addr, vq_info.device_addr)) {
+ fprintf(stderr, "Failed to update vring for vq[%d]\n", vq->index);
+ return;
+ }
+
+ fd = eventfd(0, EFD_NONBLOCK | EFD_CLOEXEC);
+ if (fd < 0) {
+ fprintf(stderr, "Failed to init eventfd for vq[%d]\n", vq->index);
+ return;
+ }
+
+ vq_eventfd.index = vq->index;
+ vq_eventfd.fd = fd;
+ if (ioctl(dev->fd, VDUSE_VQ_SETUP_KICKFD, &vq_eventfd)) {
+ fprintf(stderr, "Failed to setup kick fd for vq[%d]\n", vq->index);
+ close(fd);
+ return;
+ }
+
+ vq->fd = fd;
+ vq->shadow_avail_idx = vq->last_avail_idx = vq_info.split.avail_index;
+ vq->inuse = 0;
+ vq->used_idx = 0;
+ vq->signalled_used_valid = false;
+ vq->ready = true;
+
+ dev->ops->enable_queue(dev, vq);
+}
+
+static void vduse_queue_disable(VduseVirtq *vq)
+{
+ struct VduseDev *dev = vq->dev;
+ struct vduse_vq_eventfd eventfd;
+
+ if (!vq->ready) {
+ return;
+ }
+
+ dev->ops->disable_queue(dev, vq);
+
+ eventfd.index = vq->index;
+ eventfd.fd = VDUSE_EVENTFD_DEASSIGN;
+ ioctl(dev->fd, VDUSE_VQ_SETUP_KICKFD, &eventfd);
+ close(vq->fd);
+
+ assert(vq->inuse == 0);
+
+ vq->vring.num = 0;
+ vq->vring.desc_addr = 0;
+ vq->vring.avail_addr = 0;
+ vq->vring.used_addr = 0;
+ vq->vring.desc = 0;
+ vq->vring.avail = 0;
+ vq->vring.used = 0;
+ vq->ready = false;
+ vq->fd = -1;
+}
+
+static void vduse_dev_start_dataplane(VduseDev *dev)
+{
+ int i;
+
+ if (ioctl(dev->fd, VDUSE_DEV_GET_FEATURES, &dev->features)) {
+ fprintf(stderr, "Failed to get features: %s\n", strerror(errno));
+ return;
+ }
+ assert(vduse_dev_has_feature(dev, VIRTIO_F_VERSION_1));
+
+ for (i = 0; i < dev->num_queues; i++) {
+ vduse_queue_enable(&dev->vqs[i]);
+ }
+}
+
+static void vduse_dev_stop_dataplane(VduseDev *dev)
+{
+ int i;
+
+ for (i = 0; i < dev->num_queues; i++) {
+ vduse_queue_disable(&dev->vqs[i]);
+ }
+ dev->features = 0;
+ vduse_iova_remove_region(dev, 0, ULONG_MAX);
+}
+
+int vduse_dev_handler(VduseDev *dev)
+{
+ struct vduse_dev_request req;
+ struct vduse_dev_response resp = { 0 };
+ VduseVirtq *vq;
+ int i, ret;
+
+ ret = read(dev->fd, &req, sizeof(req));
+ if (ret != sizeof(req)) {
+ fprintf(stderr, "Read request error [%d]: %s\n",
+ ret, strerror(errno));
+ return -errno;
+ }
+ resp.request_id = req.request_id;
+
+ switch (req.type) {
+ case VDUSE_GET_VQ_STATE:
+ vq = &dev->vqs[req.vq_state.index];
+ resp.vq_state.split.avail_index = vq->last_avail_idx;
+ resp.result = VDUSE_REQ_RESULT_OK;
+ break;
+ case VDUSE_SET_STATUS:
+ if (req.s.status & VIRTIO_CONFIG_S_DRIVER_OK) {
+ vduse_dev_start_dataplane(dev);
+ } else if (req.s.status == 0) {
+ vduse_dev_stop_dataplane(dev);
+ }
+ resp.result = VDUSE_REQ_RESULT_OK;
+ break;
+ case VDUSE_UPDATE_IOTLB:
+ /* The iova will be updated by iova_to_va() later, so just remove it */
+ vduse_iova_remove_region(dev, req.iova.start, req.iova.last);
+ for (i = 0; i < dev->num_queues; i++) {
+ VduseVirtq *vq = &dev->vqs[i];
+ if (vq->ready) {
+ if (vduse_queue_update_vring(vq, vq->vring.desc_addr,
+ vq->vring.avail_addr,
+ vq->vring.used_addr)) {
+ fprintf(stderr, "Failed to update vring for vq[%d]\n",
+ vq->index);
+ }
+ }
+ }
+ resp.result = VDUSE_REQ_RESULT_OK;
+ break;
+ default:
+ resp.result = VDUSE_REQ_RESULT_FAILED;
+ break;
+ }
+
+ ret = write(dev->fd, &resp, sizeof(resp));
+ if (ret != sizeof(resp)) {
+ fprintf(stderr, "Write request %d error [%d]: %s\n",
+ req.type, ret, strerror(errno));
+ return -errno;
+ }
+ return 0;
+}
+
+int vduse_dev_update_config(VduseDev *dev, uint32_t size,
+ uint32_t offset, char *buffer)
+{
+ int ret;
+ struct vduse_config_data *data;
+
+ data = malloc(offsetof(struct vduse_config_data, buffer) + size);
+ if (!data) {
+ return -ENOMEM;
+ }
+
+ data->offset = offset;
+ data->length = size;
+ memcpy(data->buffer, buffer, size);
+
+ ret = ioctl(dev->fd, VDUSE_DEV_SET_CONFIG, data);
+ free(data);
+
+ if (ret) {
+ return -errno;
+ }
+
+ if (ioctl(dev->fd, VDUSE_DEV_INJECT_CONFIG_IRQ)) {
+ return -errno;
+ }
+
+ return 0;
+}
+
+int vduse_dev_setup_queue(VduseDev *dev, int index, int max_size)
+{
+ VduseVirtq *vq = &dev->vqs[index];
+ struct vduse_vq_config vq_config = { 0 };
+
+ if (max_size > VIRTQUEUE_MAX_SIZE) {
+ return -EINVAL;
+ }
+
+ vq_config.index = vq->index;
+ vq_config.max_size = max_size;
+
+ if (ioctl(dev->fd, VDUSE_VQ_SETUP, &vq_config)) {
+ return -errno;
+ }
+
+ return 0;
+}
+
+static int vduse_dev_init_vqs(VduseDev *dev, uint16_t num_queues)
+{
+ VduseVirtq *vqs;
+ int i;
+
+ vqs = calloc(sizeof(VduseVirtq), num_queues);
+ if (!vqs) {
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < num_queues; i++) {
+ vqs[i].index = i;
+ vqs[i].dev = dev;
+ vqs[i].fd = -1;
+ }
+ dev->vqs = vqs;
+
+ return 0;
+}
+
+static int vduse_dev_init(VduseDev *dev, const char *name,
+ uint16_t num_queues, const VduseOps *ops,
+ void *priv)
+{
+ char *dev_path, *dev_name;
+ int ret, fd;
+
+ dev_path = malloc(strlen(name) + strlen("/dev/vduse/") + 1);
+ if (!dev_path) {
+ return -ENOMEM;
+ }
+ sprintf(dev_path, "/dev/vduse/%s", name);
+
+ fd = open(dev_path, O_RDWR);
+ free(dev_path);
+ if (fd < 0) {
+ fprintf(stderr, "Failed to open vduse dev %s: %s\n",
+ name, strerror(errno));
+ return -errno;
+ }
+
+ dev_name = strdup(name);
+ if (!dev_name) {
+ close(fd);
+ return -ENOMEM;
+ }
+
+ ret = vduse_dev_init_vqs(dev, num_queues);
+ if (ret) {
+ free(dev_name);
+ close(fd);
+ return ret;
+ }
+
+ dev->name = dev_name;
+ dev->num_queues = num_queues;
+ dev->fd = fd;
+ dev->ops = ops;
+ dev->priv = priv;
+
+ return 0;
+}
+
+static inline bool vduse_name_is_valid(const char *name)
+{
+ return strlen(name) >= VDUSE_NAME_MAX || strstr(name, "..");
+}
+
+VduseDev *vduse_dev_create_by_fd(int fd, uint16_t num_queues,
+ const VduseOps *ops, void *priv)
+{
+ VduseDev *dev;
+ int ret;
+
+ if (!ops || !ops->enable_queue || !ops->disable_queue) {
+ fprintf(stderr, "Invalid parameter for vduse\n");
+ return NULL;
+ }
+
+ dev = calloc(sizeof(VduseDev), 1);
+ if (!dev) {
+ fprintf(stderr, "Failed to allocate vduse device\n");
+ return NULL;
+ }
+
+ ret = vduse_dev_init_vqs(dev, num_queues);
+ if (ret) {
+ fprintf(stderr, "Failed to init vqs\n");
+ free(dev);
+ return NULL;
+ }
+
+ dev->num_queues = num_queues;
+ dev->fd = fd;
+ dev->ops = ops;
+ dev->priv = priv;
+
+ return dev;
+}
+
+VduseDev *vduse_dev_create_by_name(const char *name, uint16_t num_queues,
+ const VduseOps *ops, void *priv)
+{
+ VduseDev *dev;
+ int ret;
+
+ if (!name || vduse_name_is_valid(name) || !ops ||
+ !ops->enable_queue || !ops->disable_queue) {
+ fprintf(stderr, "Invalid parameter for vduse\n");
+ return NULL;
+ }
+
+ dev = calloc(sizeof(VduseDev), 1);
+ if (!dev) {
+ fprintf(stderr, "Failed to allocate vduse device\n");
+ return NULL;
+ }
+
+ ret = vduse_dev_init(dev, name, num_queues, ops, priv);
+ if (ret < 0) {
+ fprintf(stderr, "Failed to init vduse device %s: %s\n",
+ name, strerror(ret));
+ free(dev);
+ return NULL;
+ }
+
+ return dev;
+}
+
+VduseDev *vduse_dev_create(const char *name, uint32_t device_id,
+ uint32_t vendor_id, uint64_t features,
+ uint16_t num_queues, uint32_t config_size,
+ char *config, const VduseOps *ops, void *priv)
+{
+ VduseDev *dev;
+ int ret, ctrl_fd;
+ uint64_t version;
+ struct vduse_dev_config *dev_config;
+ size_t size = offsetof(struct vduse_dev_config, config);
+
+ if (!name || vduse_name_is_valid(name) ||
+ !has_feature(features, VIRTIO_F_VERSION_1) || !config ||
+ !config_size || !ops || !ops->enable_queue || !ops->disable_queue) {
+ fprintf(stderr, "Invalid parameter for vduse\n");
+ return NULL;
+ }
+
+ dev = calloc(sizeof(VduseDev), 1);
+ if (!dev) {
+ fprintf(stderr, "Failed to allocate vduse device\n");
+ return NULL;
+ }
+
+ ctrl_fd = open("/dev/vduse/control", O_RDWR);
+ if (ctrl_fd < 0) {
+ fprintf(stderr, "Failed to open /dev/vduse/control: %s\n",
+ strerror(errno));
+ goto err_ctrl;
+ }
+
+ version = VDUSE_API_VERSION;
+ if (ioctl(ctrl_fd, VDUSE_SET_API_VERSION, &version)) {
+ fprintf(stderr, "Failed to set api version %lu: %s\n",
+ version, strerror(errno));
+ goto err_dev;
+ }
+
+ dev_config = calloc(size + config_size, 1);
+ if (!dev_config) {
+ fprintf(stderr, "Failed to allocate config space\n");
+ goto err_dev;
+ }
+
+ strcpy(dev_config->name, name);
+ dev_config->device_id = device_id;
+ dev_config->vendor_id = vendor_id;
+ dev_config->features = features;
+ dev_config->vq_num = num_queues;
+ dev_config->vq_align = VDUSE_VQ_ALIGN;
+ dev_config->config_size = config_size;
+ memcpy(dev_config->config, config, config_size);
+
+ ret = ioctl(ctrl_fd, VDUSE_CREATE_DEV, dev_config);
+ free(dev_config);
+ if (ret < 0) {
+ fprintf(stderr, "Failed to create vduse device %s: %s\n",
+ name, strerror(errno));
+ goto err_dev;
+ }
+ dev->ctrl_fd = ctrl_fd;
+
+ ret = vduse_dev_init(dev, name, num_queues, ops, priv);
+ if (ret < 0) {
+ fprintf(stderr, "Failed to init vduse device %s: %s\n",
+ name, strerror(ret));
+ goto err;
+ }
+
+ return dev;
+err:
+ ioctl(ctrl_fd, VDUSE_DESTROY_DEV, name);
+err_dev:
+ close(ctrl_fd);
+err_ctrl:
+ free(dev);
+
+ return NULL;
+}
+
+int vduse_dev_destroy(VduseDev *dev)
+{
+ int ret = 0;
+
+ free(dev->vqs);
+ if (dev->fd > 0) {
+ close(dev->fd);
+ dev->fd = -1;
+ }
+ if (dev->ctrl_fd > 0) {
+ if (ioctl(dev->ctrl_fd, VDUSE_DESTROY_DEV, dev->name)) {
+ ret = -errno;
+ }
+ close(dev->ctrl_fd);
+ dev->ctrl_fd = -1;
+ }
+ free(dev->name);
+ free(dev);
+
+ return ret;
+}
diff --git a/subprojects/libvduse/libvduse.h b/subprojects/libvduse/libvduse.h
new file mode 100644
index 0000000000..d972e5e070
--- /dev/null
+++ b/subprojects/libvduse/libvduse.h
@@ -0,0 +1,225 @@
+/*
+ * VDUSE (vDPA Device in Userspace) library
+ *
+ * Copyright (C) 2022 Bytedance Inc. and/or its affiliates. All rights reserved.
+ *
+ * Author:
+ * Xie Yongji <xieyongji@bytedance.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later. See the COPYING file in the top-level directory.
+ */
+
+#ifndef LIBVDUSE_H
+#define LIBVDUSE_H
+
+#include <stdint.h>
+#include <sys/uio.h>
+
+#define VIRTQUEUE_MAX_SIZE 1024
+
+/* VDUSE device structure */
+typedef struct VduseDev VduseDev;
+
+/* Virtqueue structure */
+typedef struct VduseVirtq VduseVirtq;
+
+/* Some operation of VDUSE backend */
+typedef struct VduseOps {
+ /* Called when virtqueue can be processed */
+ void (*enable_queue)(VduseDev *dev, VduseVirtq *vq);
+ /* Called when virtqueue processing should be stopped */
+ void (*disable_queue)(VduseDev *dev, VduseVirtq *vq);
+} VduseOps;
+
+/* Describing elements of the I/O buffer */
+typedef struct VduseVirtqElement {
+ /* Descriptor table index */
+ unsigned int index;
+ /* Number of physically-contiguous device-readable descriptors */
+ unsigned int out_num;
+ /* Number of physically-contiguous device-writable descriptors */
+ unsigned int in_num;
+ /* Array to store physically-contiguous device-writable descriptors */
+ struct iovec *in_sg;
+ /* Array to store physically-contiguous device-readable descriptors */
+ struct iovec *out_sg;
+} VduseVirtqElement;
+
+/**
+ * vduse_queue_get_dev:
+ * @vq: specified virtqueue
+ *
+ * Get corresponding VDUSE device from the virtqueue.
+ *
+ * Returns: a pointer to VDUSE device on success, NULL on failure.
+ */
+VduseDev *vduse_queue_get_dev(VduseVirtq *vq);
+
+/**
+ * vduse_queue_get_fd:
+ * @vq: specified virtqueue
+ *
+ * Get the kick fd for the virtqueue.
+ *
+ * Returns: file descriptor on success, -1 on failure.
+ */
+int vduse_queue_get_fd(VduseVirtq *vq);
+
+/**
+ * vduse_queue_pop:
+ * @vq: specified virtqueue
+ * @sz: the size of struct to return (must be >= VduseVirtqElement)
+ *
+ * Pop an element from virtqueue available ring.
+ *
+ * Returns: a pointer to a structure containing VduseVirtqElement on success,
+ * NULL on failure.
+ */
+void *vduse_queue_pop(VduseVirtq *vq, size_t sz);
+
+/**
+ * vduse_queue_push:
+ * @vq: specified virtqueue
+ * @elem: pointer to VduseVirtqElement returned by vduse_queue_pop()
+ * @len: length in bytes to write
+ *
+ * Push an element to virtqueue used ring.
+ */
+void vduse_queue_push(VduseVirtq *vq, const VduseVirtqElement *elem,
+ unsigned int len);
+/**
+ * vduse_queue_notify:
+ * @vq: specified virtqueue
+ *
+ * Request to notify the queue.
+ */
+void vduse_queue_notify(VduseVirtq *vq);
+
+/**
+ * vduse_dev_get_priv:
+ * @dev: VDUSE device
+ *
+ * Get the private pointer passed to vduse_dev_create().
+ *
+ * Returns: private pointer on success, NULL on failure.
+ */
+void *vduse_dev_get_priv(VduseDev *dev);
+
+/**
+ * vduse_dev_get_queue:
+ * @dev: VDUSE device
+ * @index: virtqueue index
+ *
+ * Get the specified virtqueue.
+ *
+ * Returns: a pointer to the virtqueue on success, NULL on failure.
+ */
+VduseVirtq *vduse_dev_get_queue(VduseDev *dev, int index);
+
+/**
+ * vduse_dev_get_fd:
+ * @dev: VDUSE device
+ *
+ * Get the control message fd for the VDUSE device.
+ *
+ * Returns: file descriptor on success, -1 on failure.
+ */
+int vduse_dev_get_fd(VduseDev *dev);
+
+/**
+ * vduse_dev_handler:
+ * @dev: VDUSE device
+ *
+ * Used to process the control message.
+ *
+ * Returns: file descriptor on success, -errno on failure.
+ */
+int vduse_dev_handler(VduseDev *dev);
+
+/**
+ * vduse_dev_update_config:
+ * @dev: VDUSE device
+ * @size: the size to write to configuration space
+ * @offset: the offset from the beginning of configuration space
+ * @buffer: the buffer used to write from
+ *
+ * Update device configuration space and inject a config interrupt.
+ *
+ * Returns: 0 on success, -errno on failure.
+ */
+int vduse_dev_update_config(VduseDev *dev, uint32_t size,
+ uint32_t offset, char *buffer);
+
+/**
+ * vduse_dev_setup_queue:
+ * @dev: VDUSE device
+ * @index: virtqueue index
+ * @max_size: the max size of virtqueue
+ *
+ * Setup the specified virtqueue.
+ *
+ * Returns: 0 on success, -errno on failure.
+ */
+int vduse_dev_setup_queue(VduseDev *dev, int index, int max_size);
+
+/**
+ * vduse_dev_create_by_fd:
+ * @fd: passed file descriptor
+ * @num_queues: the number of virtqueues
+ * @ops: the operation of VDUSE backend
+ * @priv: private pointer
+ *
+ * Create VDUSE device from a passed file descriptor.
+ *
+ * Returns: pointer to VDUSE device on success, NULL on failure.
+ */
+VduseDev *vduse_dev_create_by_fd(int fd, uint16_t num_queues,
+ const VduseOps *ops, void *priv);
+
+/**
+ * vduse_dev_create_by_name:
+ * @name: VDUSE device name
+ * @num_queues: the number of virtqueues
+ * @ops: the operation of VDUSE backend
+ * @priv: private pointer
+ *
+ * Create VDUSE device on /dev/vduse/$NAME.
+ *
+ * Returns: pointer to VDUSE device on success, NULL on failure.
+ */
+VduseDev *vduse_dev_create_by_name(const char *name, uint16_t num_queues,
+ const VduseOps *ops, void *priv);
+
+/**
+ * vduse_dev_create:
+ * @name: VDUSE device name
+ * @device_id: virtio device id
+ * @vendor_id: virtio vendor id
+ * @features: virtio features
+ * @num_queues: the number of virtqueues
+ * @config_size: the size of the configuration space
+ * @config: the buffer of the configuration space
+ * @ops: the operation of VDUSE backend
+ * @priv: private pointer
+ *
+ * Create VDUSE device.
+ *
+ * Returns: pointer to VDUSE device on success, NULL on failure.
+ */
+VduseDev *vduse_dev_create(const char *name, uint32_t device_id,
+ uint32_t vendor_id, uint64_t features,
+ uint16_t num_queues, uint32_t config_size,
+ char *config, const VduseOps *ops, void *priv);
+
+/**
+ * vduse_dev_destroy:
+ * @dev: VDUSE device
+ *
+ * Destroy the VDUSE device.
+ *
+ * Returns: 0 on success, -errno on failure.
+ */
+int vduse_dev_destroy(VduseDev *dev);
+
+#endif
--git a/subprojects/libvduse/linux-headers/linux b/subprojects/libvduse/linux-headers/linux
new file mode 120000
index 0000000000..04f3304f79
--- /dev/null
+++ b/subprojects/libvduse/linux-headers/linux
@@ -0,0 +1 @@
+../../../linux-headers/linux/
\ No newline at end of file
diff --git a/subprojects/libvduse/meson.build b/subprojects/libvduse/meson.build
new file mode 100644
index 0000000000..ba08f5ee1a
--- /dev/null
+++ b/subprojects/libvduse/meson.build
@@ -0,0 +1,10 @@
+project('libvduse', 'c',
+ license: 'GPL-2.0-or-later',
+ default_options: ['c_std=gnu99'])
+
+libvduse = static_library('vduse',
+ files('libvduse.c'),
+ c_args: '-D_GNU_SOURCE')
+
+libvduse_dep = declare_dependency(link_with: libvduse,
+ include_directories: include_directories('.'))
diff --git a/subprojects/libvduse/standard-headers/linux b/subprojects/libvduse/standard-headers/linux
new file mode 120000
index 0000000000..c416f068ac
--- /dev/null
+++ b/subprojects/libvduse/standard-headers/linux
@@ -0,0 +1 @@
+../../../include/standard-headers/linux/
\ No newline at end of file
--
2.20.1
^ permalink raw reply related [flat|nested] 27+ messages in thread
* [PATCH v2 4/6] vduse-blk: implements vduse-blk export
2022-02-15 10:59 [PATCH v2 0/6] Support exporting BDSs via VDUSE Xie Yongji
` (2 preceding siblings ...)
2022-02-15 10:59 ` [PATCH v2 3/6] libvduse: Add VDUSE (vDPA Device in Userspace) library Xie Yongji
@ 2022-02-15 10:59 ` Xie Yongji
2022-03-15 11:08 ` Stefan Hajnoczi
2022-02-15 10:59 ` [PATCH v2 5/6] vduse-blk: Add vduse-blk resize support Xie Yongji
` (2 subsequent siblings)
6 siblings, 1 reply; 27+ messages in thread
From: Xie Yongji @ 2022-02-15 10:59 UTC (permalink / raw)
To: mst, jasowang, stefanha, sgarzare, kwolf, mreitz, mlureau
Cc: qemu-devel, qemu-block
This implements a VDUSE block backends based on
the libvduse library. We can use it to export the BDSs
for both VM and container (host) usage.
The new command-line syntax is:
$ qemu-storage-daemon \
--blockdev file,node-name=drive0,filename=test.img \
--export vduse-blk,node-name=drive0,id=vduse-export0,writable=on
After the qemu-storage-daemon started, we need to use
the "vdpa" command to attach the device to vDPA bus:
$ vdpa dev add name vduse-export0 mgmtdev vduse
Also the device must be removed via the "vdpa" command
before we stop the qemu-storage-daemon.
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
block/export/export.c | 6 +
block/export/meson.build | 5 +
block/export/vduse-blk.c | 428 ++++++++++++++++++++++++++++++++++
block/export/vduse-blk.h | 20 ++
meson.build | 13 ++
meson_options.txt | 2 +
qapi/block-export.json | 24 +-
scripts/meson-buildoptions.sh | 4 +
8 files changed, 500 insertions(+), 2 deletions(-)
create mode 100644 block/export/vduse-blk.c
create mode 100644 block/export/vduse-blk.h
diff --git a/block/export/export.c b/block/export/export.c
index 6d3b9964c8..00dd505540 100644
--- a/block/export/export.c
+++ b/block/export/export.c
@@ -26,6 +26,9 @@
#ifdef CONFIG_VHOST_USER_BLK_SERVER
#include "vhost-user-blk-server.h"
#endif
+#ifdef CONFIG_VDUSE_BLK_EXPORT
+#include "vduse-blk.h"
+#endif
static const BlockExportDriver *blk_exp_drivers[] = {
&blk_exp_nbd,
@@ -35,6 +38,9 @@ static const BlockExportDriver *blk_exp_drivers[] = {
#ifdef CONFIG_FUSE
&blk_exp_fuse,
#endif
+#ifdef CONFIG_VDUSE_BLK_EXPORT
+ &blk_exp_vduse_blk,
+#endif
};
/* Only accessed from the main thread */
diff --git a/block/export/meson.build b/block/export/meson.build
index 0a08e384c7..cf311d2b1b 100644
--- a/block/export/meson.build
+++ b/block/export/meson.build
@@ -5,3 +5,8 @@ if have_vhost_user_blk_server
endif
blockdev_ss.add(when: fuse, if_true: files('fuse.c'))
+
+if have_vduse_blk_export
+ blockdev_ss.add(files('vduse-blk.c'))
+ blockdev_ss.add(libvduse)
+endif
diff --git a/block/export/vduse-blk.c b/block/export/vduse-blk.c
new file mode 100644
index 0000000000..942f985de3
--- /dev/null
+++ b/block/export/vduse-blk.c
@@ -0,0 +1,428 @@
+/*
+ * Export QEMU block device via VDUSE
+ *
+ * Copyright (C) 2022 Bytedance Inc. and/or its affiliates. All rights reserved.
+ * Portions of codes and concepts borrowed from vhost-user-blk-server.c, so:
+ * Copyright (c) 2020 Red Hat, Inc.
+ *
+ * Author:
+ * Xie Yongji <xieyongji@bytedance.com>
+ * Coiby Xu <coiby.xu@gmail.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later. See the COPYING file in the top-level directory.
+ */
+
+#include <sys/eventfd.h>
+
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "sysemu/block-backend.h"
+#include "block/export.h"
+#include "qemu/error-report.h"
+#include "util/block-helpers.h"
+#include "subprojects/libvduse/libvduse.h"
+
+#include "standard-headers/linux/virtio_ring.h"
+#include "standard-headers/linux/virtio_blk.h"
+
+#define VIRTIO_BLK_SECTOR_BITS 9
+#define VIRTIO_BLK_SECTOR_SIZE (1ULL << VIRTIO_BLK_SECTOR_BITS)
+
+#define VDUSE_DEFAULT_NUM_QUEUE 1
+#define VDUSE_DEFAULT_QUEUE_SIZE 256
+
+typedef struct VduseBlkExport {
+ BlockExport export;
+ VduseDev *dev;
+ uint16_t num_queues;
+ uint32_t blk_size;
+ bool writable;
+} VduseBlkExport;
+
+struct virtio_blk_inhdr {
+ unsigned char status;
+};
+
+typedef struct VduseBlkReq {
+ VduseVirtqElement elem;
+ int64_t sector_num;
+ size_t in_len;
+ struct virtio_blk_inhdr *in;
+ struct virtio_blk_outhdr out;
+ VduseVirtq *vq;
+} VduseBlkReq;
+
+static void vduse_blk_req_complete(VduseBlkReq *req)
+{
+ vduse_queue_push(req->vq, &req->elem, req->in_len);
+ vduse_queue_notify(req->vq);
+
+ free(req);
+}
+
+static bool vduse_blk_sect_range_ok(VduseBlkExport *vblk_exp,
+ uint64_t sector, size_t size)
+{
+ uint64_t nb_sectors;
+ uint64_t total_sectors;
+
+ if (size % VIRTIO_BLK_SECTOR_SIZE) {
+ return false;
+ }
+
+ nb_sectors = size >> VIRTIO_BLK_SECTOR_BITS;
+
+ QEMU_BUILD_BUG_ON(BDRV_SECTOR_SIZE != VIRTIO_BLK_SECTOR_SIZE);
+ if (nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
+ return false;
+ }
+ if ((sector << VIRTIO_BLK_SECTOR_BITS) % vblk_exp->blk_size) {
+ return false;
+ }
+ blk_get_geometry(vblk_exp->export.blk, &total_sectors);
+ if (sector > total_sectors || nb_sectors > total_sectors - sector) {
+ return false;
+ }
+ return true;
+}
+
+static void coroutine_fn vduse_blk_virtio_process_req(void *opaque)
+{
+ VduseBlkReq *req = opaque;
+ VduseVirtq *vq = req->vq;
+ VduseDev *dev = vduse_queue_get_dev(vq);
+ VduseBlkExport *vblk_exp = vduse_dev_get_priv(dev);
+ BlockBackend *blk = vblk_exp->export.blk;
+ VduseVirtqElement *elem = &req->elem;
+ struct iovec *in_iov = elem->in_sg;
+ struct iovec *out_iov = elem->out_sg;
+ unsigned in_num = elem->in_num;
+ unsigned out_num = elem->out_num;
+ uint32_t type;
+
+ if (elem->out_num < 1 || elem->in_num < 1) {
+ error_report("virtio-blk request missing headers");
+ goto err;
+ }
+
+ if (unlikely(iov_to_buf(out_iov, out_num, 0, &req->out,
+ sizeof(req->out)) != sizeof(req->out))) {
+ error_report("virtio-blk request outhdr too short");
+ goto err;
+ }
+
+ iov_discard_front(&out_iov, &out_num, sizeof(req->out));
+
+ if (in_iov[in_num - 1].iov_len < sizeof(struct virtio_blk_inhdr)) {
+ error_report("virtio-blk request inhdr too short");
+ goto err;
+ }
+
+ /* We always touch the last byte, so just see how big in_iov is. */
+ req->in_len = iov_size(in_iov, in_num);
+ req->in = (void *)in_iov[in_num - 1].iov_base
+ + in_iov[in_num - 1].iov_len
+ - sizeof(struct virtio_blk_inhdr);
+ iov_discard_back(in_iov, &in_num, sizeof(struct virtio_blk_inhdr));
+
+ type = le32_to_cpu(req->out.type);
+ switch (type & ~VIRTIO_BLK_T_BARRIER) {
+ case VIRTIO_BLK_T_IN:
+ case VIRTIO_BLK_T_OUT: {
+ QEMUIOVector qiov;
+ int64_t offset;
+ ssize_t ret = 0;
+ bool is_write = type & VIRTIO_BLK_T_OUT;
+ req->sector_num = le64_to_cpu(req->out.sector);
+
+ if (is_write && !vblk_exp->writable) {
+ req->in->status = VIRTIO_BLK_S_IOERR;
+ break;
+ }
+
+ if (is_write) {
+ qemu_iovec_init_external(&qiov, out_iov, out_num);
+ } else {
+ qemu_iovec_init_external(&qiov, in_iov, in_num);
+ }
+
+ if (unlikely(!vduse_blk_sect_range_ok(vblk_exp,
+ req->sector_num,
+ qiov.size))) {
+ req->in->status = VIRTIO_BLK_S_IOERR;
+ break;
+ }
+
+ offset = req->sector_num << VIRTIO_BLK_SECTOR_BITS;
+
+ if (is_write) {
+ ret = blk_co_pwritev(blk, offset, qiov.size, &qiov, 0);
+ } else {
+ ret = blk_co_preadv(blk, offset, qiov.size, &qiov, 0);
+ }
+ if (ret >= 0) {
+ req->in->status = VIRTIO_BLK_S_OK;
+ } else {
+ req->in->status = VIRTIO_BLK_S_IOERR;
+ }
+ break;
+ }
+ case VIRTIO_BLK_T_FLUSH:
+ if (blk_co_flush(blk) == 0) {
+ req->in->status = VIRTIO_BLK_S_OK;
+ } else {
+ req->in->status = VIRTIO_BLK_S_IOERR;
+ }
+ break;
+ case VIRTIO_BLK_T_GET_ID: {
+ size_t size = MIN(iov_size(&elem->in_sg[0], in_num),
+ VIRTIO_BLK_ID_BYTES);
+ snprintf(elem->in_sg[0].iov_base, size, "%s", vblk_exp->export.id);
+ req->in->status = VIRTIO_BLK_S_OK;
+ break;
+ }
+ default:
+ req->in->status = VIRTIO_BLK_S_UNSUPP;
+ break;
+ }
+
+ vduse_blk_req_complete(req);
+ return;
+
+err:
+ free(req);
+}
+
+static void vduse_blk_vq_handler(VduseDev *dev, VduseVirtq *vq)
+{
+ while (1) {
+ VduseBlkReq *req;
+
+ req = vduse_queue_pop(vq, sizeof(VduseBlkReq));
+ if (!req) {
+ break;
+ }
+ req->vq = vq;
+
+ Coroutine *co =
+ qemu_coroutine_create(vduse_blk_virtio_process_req, req);
+ qemu_coroutine_enter(co);
+ }
+}
+
+static void on_vduse_vq_kick(void *opaque)
+{
+ VduseVirtq *vq = opaque;
+ VduseDev *dev = vduse_queue_get_dev(vq);
+ int fd = vduse_queue_get_fd(vq);
+ eventfd_t kick_data;
+
+ if (eventfd_read(fd, &kick_data) == -1) {
+ error_report("failed to read data from eventfd");
+ return;
+ }
+
+ vduse_blk_vq_handler(dev, vq);
+}
+
+static void vduse_blk_enable_queue(VduseDev *dev, VduseVirtq *vq)
+{
+ VduseBlkExport *vblk_exp = vduse_dev_get_priv(dev);
+
+ aio_set_fd_handler(vblk_exp->export.ctx, vduse_queue_get_fd(vq),
+ true, on_vduse_vq_kick, NULL, NULL, NULL, vq);
+}
+
+static void vduse_blk_disable_queue(VduseDev *dev, VduseVirtq *vq)
+{
+ VduseBlkExport *vblk_exp = vduse_dev_get_priv(dev);
+
+ aio_set_fd_handler(vblk_exp->export.ctx, vduse_queue_get_fd(vq),
+ true, NULL, NULL, NULL, NULL, NULL);
+}
+
+static const VduseOps vduse_blk_ops = {
+ .enable_queue = vduse_blk_enable_queue,
+ .disable_queue = vduse_blk_disable_queue,
+};
+
+static void on_vduse_dev_kick(void *opaque)
+{
+ VduseDev *dev = opaque;
+
+ vduse_dev_handler(dev);
+}
+
+static void vduse_blk_attach_ctx(VduseBlkExport *vblk_exp, AioContext *ctx)
+{
+ int i;
+
+ aio_set_fd_handler(vblk_exp->export.ctx, vduse_dev_get_fd(vblk_exp->dev),
+ true, on_vduse_dev_kick, NULL, NULL, NULL,
+ vblk_exp->dev);
+
+ for (i = 0; i < vblk_exp->num_queues; i++) {
+ VduseVirtq *vq = vduse_dev_get_queue(vblk_exp->dev, i);
+ int fd = vduse_queue_get_fd(vq);
+
+ if (fd < 0) {
+ continue;
+ }
+ aio_set_fd_handler(vblk_exp->export.ctx, fd, true,
+ on_vduse_vq_kick, NULL, NULL, NULL, vq);
+ }
+}
+
+static void vduse_blk_detach_ctx(VduseBlkExport *vblk_exp)
+{
+ int i;
+
+ for (i = 0; i < vblk_exp->num_queues; i++) {
+ VduseVirtq *vq = vduse_dev_get_queue(vblk_exp->dev, i);
+ int fd = vduse_queue_get_fd(vq);
+
+ if (fd < 0) {
+ continue;
+ }
+ aio_set_fd_handler(vblk_exp->export.ctx, fd,
+ true, NULL, NULL, NULL, NULL, NULL);
+ }
+ aio_set_fd_handler(vblk_exp->export.ctx, vduse_dev_get_fd(vblk_exp->dev),
+ true, NULL, NULL, NULL, NULL, NULL);
+}
+
+
+static void blk_aio_attached(AioContext *ctx, void *opaque)
+{
+ VduseBlkExport *vblk_exp = opaque;
+
+ vblk_exp->export.ctx = ctx;
+ vduse_blk_attach_ctx(vblk_exp, ctx);
+}
+
+static void blk_aio_detach(void *opaque)
+{
+ VduseBlkExport *vblk_exp = opaque;
+
+ vduse_blk_detach_ctx(vblk_exp);
+ vblk_exp->export.ctx = NULL;
+}
+
+static int vduse_blk_exp_create(BlockExport *exp, BlockExportOptions *opts,
+ Error **errp)
+{
+ VduseBlkExport *vblk_exp = container_of(exp, VduseBlkExport, export);
+ BlockExportOptionsVduseBlk *vblk_opts = &opts->u.vduse_blk;
+ uint64_t logical_block_size = VIRTIO_BLK_SECTOR_SIZE;
+ uint16_t num_queues = VDUSE_DEFAULT_NUM_QUEUE;
+ uint16_t queue_size = VDUSE_DEFAULT_QUEUE_SIZE;
+ Error *local_err = NULL;
+ struct virtio_blk_config config = { 0 };
+ uint64_t features;
+ int i;
+
+ if (vblk_opts->has_num_queues) {
+ num_queues = vblk_opts->num_queues;
+ if (num_queues == 0) {
+ error_setg(errp, "num-queues must be greater than 0");
+ return -EINVAL;
+ }
+ }
+
+ if (vblk_opts->has_queue_size) {
+ queue_size = vblk_opts->queue_size;
+ if (queue_size <= 2 || !is_power_of_2(queue_size) ||
+ queue_size > VIRTQUEUE_MAX_SIZE) {
+ error_setg(errp, "queue-size is invalid");
+ return -EINVAL;
+ }
+ }
+
+ if (vblk_opts->has_logical_block_size) {
+ logical_block_size = vblk_opts->logical_block_size;
+ check_block_size(exp->id, "logical-block-size", logical_block_size,
+ &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ return -EINVAL;
+ }
+ }
+ blk_set_guest_block_size(exp->blk, logical_block_size);
+
+ vblk_exp->blk_size = logical_block_size;
+ vblk_exp->writable = opts->writable;
+ vblk_exp->num_queues = num_queues;
+
+ config.capacity =
+ cpu_to_le64(blk_getlength(exp->blk) >> VIRTIO_BLK_SECTOR_BITS);
+ config.seg_max = cpu_to_le32(queue_size - 2);
+ config.size_max = cpu_to_le32(0);
+ config.min_io_size = cpu_to_le16(1);
+ config.opt_io_size = cpu_to_le32(1);
+ config.num_queues = cpu_to_le16(num_queues);
+ config.blk_size = cpu_to_le32(logical_block_size);
+
+ features = (1ULL << VIRTIO_F_IOMMU_PLATFORM) |
+ (1ULL << VIRTIO_F_VERSION_1) |
+ (1ULL << VIRTIO_RING_F_EVENT_IDX) |
+ (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
+ (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
+ (1ULL << VIRTIO_BLK_F_SIZE_MAX) |
+ (1ULL << VIRTIO_BLK_F_SEG_MAX) |
+ (1ULL << VIRTIO_BLK_F_TOPOLOGY) |
+ (1ULL << VIRTIO_BLK_F_BLK_SIZE);
+
+ if (num_queues > 1) {
+ features |= 1ULL << VIRTIO_BLK_F_MQ;
+ }
+ if (!vblk_exp->writable) {
+ features |= 1ULL << VIRTIO_BLK_F_RO;
+ }
+
+ vblk_exp->dev = vduse_dev_create(exp->id, VIRTIO_ID_BLOCK, 0,
+ features, num_queues,
+ sizeof(struct virtio_blk_config),
+ (char *)&config, &vduse_blk_ops,
+ vblk_exp);
+ if (!vblk_exp->dev) {
+ error_setg(errp, "failed to create vduse device");
+ return -ENOMEM;
+ }
+
+ for (i = 0; i < num_queues; i++) {
+ vduse_dev_setup_queue(vblk_exp->dev, i, queue_size);
+ }
+
+ aio_set_fd_handler(exp->ctx, vduse_dev_get_fd(vblk_exp->dev), true,
+ on_vduse_dev_kick, NULL, NULL, NULL, vblk_exp->dev);
+
+ blk_add_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
+ vblk_exp);
+
+ return 0;
+}
+
+static void vduse_blk_exp_delete(BlockExport *exp)
+{
+ VduseBlkExport *vblk_exp = container_of(exp, VduseBlkExport, export);
+
+ blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
+ vblk_exp);
+ vduse_dev_destroy(vblk_exp->dev);
+}
+
+static void vduse_blk_exp_request_shutdown(BlockExport *exp)
+{
+ VduseBlkExport *vblk_exp = container_of(exp, VduseBlkExport, export);
+
+ vduse_blk_detach_ctx(vblk_exp);
+}
+
+const BlockExportDriver blk_exp_vduse_blk = {
+ .type = BLOCK_EXPORT_TYPE_VDUSE_BLK,
+ .instance_size = sizeof(VduseBlkExport),
+ .create = vduse_blk_exp_create,
+ .delete = vduse_blk_exp_delete,
+ .request_shutdown = vduse_blk_exp_request_shutdown,
+};
diff --git a/block/export/vduse-blk.h b/block/export/vduse-blk.h
new file mode 100644
index 0000000000..c4eeb1b70e
--- /dev/null
+++ b/block/export/vduse-blk.h
@@ -0,0 +1,20 @@
+/*
+ * Export QEMU block device via VDUSE
+ *
+ * Copyright (C) 2022 Bytedance Inc. and/or its affiliates. All rights reserved.
+ *
+ * Author:
+ * Xie Yongji <xieyongji@bytedance.com>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or
+ * later. See the COPYING file in the top-level directory.
+ */
+
+#ifndef VDUSE_BLK_H
+#define VDUSE_BLK_H
+
+#include "block/export.h"
+
+extern const BlockExportDriver blk_exp_vduse_blk;
+
+#endif /* VDUSE_BLK_H */
diff --git a/meson.build b/meson.build
index 27e6e07110..b6c308023e 100644
--- a/meson.build
+++ b/meson.build
@@ -1319,6 +1319,17 @@ if have_libvduse
libvduse = libvduse_proj.get_variable('libvduse_dep')
endif
+have_vduse_blk_export = (have_libvduse and targetos == 'linux')
+if get_option('vduse_blk_export').enabled()
+ if targetos != 'linux'
+ error('vduse_blk_export requires linux')
+ elif not have_libvduse
+ error('vduse_blk_export requires libvduse support')
+ endif
+elif get_option('vduse_blk_export').disabled()
+ have_vduse_blk_export = false
+endif
+
# libbpf
libbpf = dependency('libbpf', required: get_option('bpf'), method: 'pkg-config')
if libbpf.found() and not cc.links('''
@@ -1513,6 +1524,7 @@ config_host_data.set('CONFIG_SNAPPY', snappy.found())
config_host_data.set('CONFIG_USB_LIBUSB', libusb.found())
config_host_data.set('CONFIG_VDE', vde.found())
config_host_data.set('CONFIG_VHOST_USER_BLK_SERVER', have_vhost_user_blk_server)
+config_host_data.set('CONFIG_VDUSE_BLK_EXPORT', have_vduse_blk_export)
config_host_data.set('CONFIG_VNC', vnc.found())
config_host_data.set('CONFIG_VNC_JPEG', jpeg.found())
config_host_data.set('CONFIG_VNC_PNG', png.found())
@@ -3405,6 +3417,7 @@ if have_block
summary_info += {'qed support': config_host.has_key('CONFIG_QED')}
summary_info += {'parallels support': config_host.has_key('CONFIG_PARALLELS')}
summary_info += {'FUSE exports': fuse}
+ summary_info += {'VDUSE block exports': have_vduse_blk_export}
endif
summary(summary_info, bool_yn: true, section: 'Block layer support')
diff --git a/meson_options.txt b/meson_options.txt
index 7099ab7b8b..2da70a524f 100644
--- a/meson_options.txt
+++ b/meson_options.txt
@@ -195,6 +195,8 @@ option('virtiofsd', type: 'feature', value: 'auto',
description: 'build virtiofs daemon (virtiofsd)')
option('libvduse', type: 'feature', value: 'auto',
description: 'build VDUSE Library')
+option('vduse_blk_export', type: 'feature', value: 'auto',
+ description: 'VDUSE block export support')
option('capstone', type: 'combo', value: 'auto',
choices: ['disabled', 'enabled', 'auto', 'system', 'internal'],
diff --git a/qapi/block-export.json b/qapi/block-export.json
index f183522d0d..7ba0805625 100644
--- a/qapi/block-export.json
+++ b/qapi/block-export.json
@@ -170,6 +170,22 @@
'*allow-other': 'FuseExportAllowOther' },
'if': 'CONFIG_FUSE' }
+##
+# @BlockExportOptionsVduseBlk:
+#
+# A vduse-blk block export.
+#
+# @num-queues: the number of virtqueues. Defaults to 1.
+# @queue-size: the size of virtqueue. Defaults to 128.
+# @logical-block-size: Logical block size in bytes. Defaults to 512 bytes.
+#
+# Since: 7.0
+##
+{ 'struct': 'BlockExportOptionsVduseBlk',
+ 'data': { '*num-queues': 'uint16',
+ '*queue-size': 'uint16',
+ '*logical-block-size': 'size'} }
+
##
# @NbdServerAddOptions:
#
@@ -273,6 +289,7 @@
# @nbd: NBD export
# @vhost-user-blk: vhost-user-blk export (since 5.2)
# @fuse: FUSE export (since: 6.0)
+# @vduse-blk: vduse-blk export (since 7.0)
#
# Since: 4.2
##
@@ -280,7 +297,8 @@
'data': [ 'nbd',
{ 'name': 'vhost-user-blk',
'if': 'CONFIG_VHOST_USER_BLK_SERVER' },
- { 'name': 'fuse', 'if': 'CONFIG_FUSE' } ] }
+ { 'name': 'fuse', 'if': 'CONFIG_FUSE' },
+ { 'name': 'vduse-blk', 'if': 'CONFIG_VDUSE_BLK_EXPORT' } ] }
##
# @BlockExportOptions:
@@ -324,7 +342,9 @@
'vhost-user-blk': { 'type': 'BlockExportOptionsVhostUserBlk',
'if': 'CONFIG_VHOST_USER_BLK_SERVER' },
'fuse': { 'type': 'BlockExportOptionsFuse',
- 'if': 'CONFIG_FUSE' }
+ 'if': 'CONFIG_FUSE' },
+ 'vduse-blk': { 'type': 'BlockExportOptionsVduseBlk',
+ 'if': 'CONFIG_VDUSE_BLK_EXPORT' }
} }
##
diff --git a/scripts/meson-buildoptions.sh b/scripts/meson-buildoptions.sh
index 8f031ea92e..7c7aa1bcc5 100644
--- a/scripts/meson-buildoptions.sh
+++ b/scripts/meson-buildoptions.sh
@@ -85,6 +85,8 @@ meson_options_help() {
printf "%s\n" ' u2f U2F emulation support'
printf "%s\n" ' usb-redir libusbredir support'
printf "%s\n" ' vde vde network backend support'
+ printf "%s\n" ' vduse-blk-export'
+ printf "%s\n" ' VDUSE block export support'
printf "%s\n" ' vhost-user-blk-server'
printf "%s\n" ' build vhost-user-blk server'
printf "%s\n" ' virglrenderer virgl rendering support'
@@ -251,6 +253,8 @@ _meson_option_parse() {
--disable-usb-redir) printf "%s" -Dusb_redir=disabled ;;
--enable-vde) printf "%s" -Dvde=enabled ;;
--disable-vde) printf "%s" -Dvde=disabled ;;
+ --enable-vduse-blk-export) printf "%s" -Dvduse_blk_export=enabled ;;
+ --disable-vduse-blk-export) printf "%s" -Dvduse_blk_export=disabled ;;
--enable-vhost-user-blk-server) printf "%s" -Dvhost_user_blk_server=enabled ;;
--disable-vhost-user-blk-server) printf "%s" -Dvhost_user_blk_server=disabled ;;
--enable-virglrenderer) printf "%s" -Dvirglrenderer=enabled ;;
--
2.20.1
^ permalink raw reply related [flat|nested] 27+ messages in thread
* [PATCH v2 5/6] vduse-blk: Add vduse-blk resize support
2022-02-15 10:59 [PATCH v2 0/6] Support exporting BDSs via VDUSE Xie Yongji
` (3 preceding siblings ...)
2022-02-15 10:59 ` [PATCH v2 4/6] vduse-blk: implements vduse-blk export Xie Yongji
@ 2022-02-15 10:59 ` Xie Yongji
2022-03-15 13:36 ` Stefan Hajnoczi
2022-02-15 10:59 ` [PATCH v2 6/6] libvduse: Add support for reconnecting Xie Yongji
2022-03-09 15:37 ` [PATCH v2 0/6] Support exporting BDSs via VDUSE Stefan Hajnoczi
6 siblings, 1 reply; 27+ messages in thread
From: Xie Yongji @ 2022-02-15 10:59 UTC (permalink / raw)
To: mst, jasowang, stefanha, sgarzare, kwolf, mreitz, mlureau
Cc: qemu-devel, qemu-block
To support block resize, this uses vduse_dev_update_config()
to update the capacity field in configuration space and inject
config interrupt on the block resize callback.
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
block/export/vduse-blk.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)
diff --git a/block/export/vduse-blk.c b/block/export/vduse-blk.c
index 942f985de3..e456dfe2b3 100644
--- a/block/export/vduse-blk.c
+++ b/block/export/vduse-blk.c
@@ -309,6 +309,23 @@ static void blk_aio_detach(void *opaque)
vblk_exp->export.ctx = NULL;
}
+static void vduse_blk_resize(void *opaque)
+{
+ BlockExport *exp = opaque;
+ VduseBlkExport *vblk_exp = container_of(exp, VduseBlkExport, export);
+ struct virtio_blk_config config;
+
+ config.capacity =
+ cpu_to_le64(blk_getlength(exp->blk) >> VIRTIO_BLK_SECTOR_BITS);
+ vduse_dev_update_config(vblk_exp->dev, sizeof(config.capacity),
+ offsetof(struct virtio_blk_config, capacity),
+ (char *)&config.capacity);
+}
+
+static const BlockDevOps vduse_block_ops = {
+ .resize_cb = vduse_blk_resize,
+};
+
static int vduse_blk_exp_create(BlockExport *exp, BlockExportOptions *opts,
Error **errp)
{
@@ -400,6 +417,8 @@ static int vduse_blk_exp_create(BlockExport *exp, BlockExportOptions *opts,
blk_add_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
vblk_exp);
+ blk_set_dev_ops(exp->blk, &vduse_block_ops, exp);
+
return 0;
}
@@ -409,6 +428,7 @@ static void vduse_blk_exp_delete(BlockExport *exp)
blk_remove_aio_context_notifier(exp->blk, blk_aio_attached, blk_aio_detach,
vblk_exp);
+ blk_set_dev_ops(exp->blk, NULL, NULL);
vduse_dev_destroy(vblk_exp->dev);
}
--
2.20.1
^ permalink raw reply related [flat|nested] 27+ messages in thread
* [PATCH v2 6/6] libvduse: Add support for reconnecting
2022-02-15 10:59 [PATCH v2 0/6] Support exporting BDSs via VDUSE Xie Yongji
` (4 preceding siblings ...)
2022-02-15 10:59 ` [PATCH v2 5/6] vduse-blk: Add vduse-blk resize support Xie Yongji
@ 2022-02-15 10:59 ` Xie Yongji
2022-03-15 13:48 ` Stefan Hajnoczi
2022-03-09 15:37 ` [PATCH v2 0/6] Support exporting BDSs via VDUSE Stefan Hajnoczi
6 siblings, 1 reply; 27+ messages in thread
From: Xie Yongji @ 2022-02-15 10:59 UTC (permalink / raw)
To: mst, jasowang, stefanha, sgarzare, kwolf, mreitz, mlureau
Cc: qemu-devel, qemu-block
To support reconnecting after restart or crash, VDUSE backend
might need to resubmit inflight I/Os. This stores the metadata
such as the index of inflight I/O's descriptors to a shm file so
that VDUSE backend can restore them during reconnecting.
Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
---
block/export/vduse-blk.c | 14 ++
subprojects/libvduse/libvduse.c | 232 +++++++++++++++++++++++++++++++-
subprojects/libvduse/libvduse.h | 12 ++
3 files changed, 253 insertions(+), 5 deletions(-)
diff --git a/block/export/vduse-blk.c b/block/export/vduse-blk.c
index e456dfe2b3..b519a34370 100644
--- a/block/export/vduse-blk.c
+++ b/block/export/vduse-blk.c
@@ -38,6 +38,7 @@ typedef struct VduseBlkExport {
uint16_t num_queues;
uint32_t blk_size;
bool writable;
+ char *recon_file;
} VduseBlkExport;
struct virtio_blk_inhdr {
@@ -232,6 +233,8 @@ static void vduse_blk_enable_queue(VduseDev *dev, VduseVirtq *vq)
aio_set_fd_handler(vblk_exp->export.ctx, vduse_queue_get_fd(vq),
true, on_vduse_vq_kick, NULL, NULL, NULL, vq);
+ /* Make sure we don't miss any kick afer reconnecting */
+ eventfd_write(vduse_queue_get_fd(vq), 1);
}
static void vduse_blk_disable_queue(VduseDev *dev, VduseVirtq *vq)
@@ -407,6 +410,15 @@ static int vduse_blk_exp_create(BlockExport *exp, BlockExportOptions *opts,
return -ENOMEM;
}
+ vblk_exp->recon_file = g_strdup_printf("%s/vduse-blk-%s",
+ g_get_tmp_dir(), exp->id);
+ if (vduse_set_reconnect_log_file(vblk_exp->dev, vblk_exp->recon_file)) {
+ error_setg(errp, "failed to set reconnect log file");
+ vduse_dev_destroy(vblk_exp->dev);
+ g_free(vblk_exp->recon_file);
+ return -EINVAL;
+ }
+
for (i = 0; i < num_queues; i++) {
vduse_dev_setup_queue(vblk_exp->dev, i, queue_size);
}
@@ -430,6 +442,8 @@ static void vduse_blk_exp_delete(BlockExport *exp)
vblk_exp);
blk_set_dev_ops(exp->blk, NULL, NULL);
vduse_dev_destroy(vblk_exp->dev);
+ unlink(vblk_exp->recon_file);
+ g_free(vblk_exp->recon_file);
}
static void vduse_blk_exp_request_shutdown(BlockExport *exp)
diff --git a/subprojects/libvduse/libvduse.c b/subprojects/libvduse/libvduse.c
index 9c6a8bcf6e..31f7d6e119 100644
--- a/subprojects/libvduse/libvduse.c
+++ b/subprojects/libvduse/libvduse.c
@@ -41,6 +41,8 @@
#define VDUSE_VQ_ALIGN 4096
#define MAX_IOVA_REGIONS 256
+#define LOG_ALIGNMENT 64
+
/* Round number down to multiple */
#define ALIGN_DOWN(n, m) ((n) / (m) * (m))
@@ -51,6 +53,31 @@
#define unlikely(x) __builtin_expect(!!(x), 0)
#endif
+typedef struct VduseDescStateSplit {
+ uint8_t inflight;
+ uint8_t padding[5];
+ uint16_t next;
+ uint64_t counter;
+} VduseDescStateSplit;
+
+typedef struct VduseVirtqLogInflight {
+ uint64_t features;
+ uint16_t version;
+ uint16_t desc_num;
+ uint16_t last_batch_head;
+ uint16_t used_idx;
+ VduseDescStateSplit desc[];
+} VduseVirtqLogInflight;
+
+typedef struct VduseVirtqLog {
+ VduseVirtqLogInflight inflight;
+} VduseVirtqLog;
+
+typedef struct VduseVirtqInflightDesc {
+ uint16_t index;
+ uint64_t counter;
+} VduseVirtqInflightDesc;
+
typedef struct VduseRing {
unsigned int num;
uint64_t desc_addr;
@@ -73,6 +100,10 @@ struct VduseVirtq {
bool ready;
int fd;
VduseDev *dev;
+ VduseVirtqInflightDesc *resubmit_list;
+ uint16_t resubmit_num;
+ uint64_t counter;
+ VduseVirtqLog *log;
};
typedef struct VduseIovaRegion {
@@ -96,8 +127,36 @@ struct VduseDev {
int fd;
int ctrl_fd;
void *priv;
+ void *log;
};
+static inline size_t vduse_vq_log_size(uint16_t queue_size)
+{
+ return ALIGN_UP(sizeof(VduseDescStateSplit) * queue_size +
+ sizeof(VduseVirtqLogInflight), LOG_ALIGNMENT);
+}
+
+static void *vduse_log_get(const char *filename, size_t size)
+{
+ void *ptr = MAP_FAILED;
+ int fd;
+
+ fd = open(filename, O_RDWR | O_CREAT, 0600);
+ if (fd == -1) {
+ return MAP_FAILED;
+ }
+
+ if (ftruncate(fd, size) == -1) {
+ goto out;
+ }
+
+ ptr = mmap(0, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
+
+out:
+ close(fd);
+ return ptr;
+}
+
static inline bool has_feature(uint64_t features, unsigned int fbit)
{
assert(fbit < 64);
@@ -139,6 +198,102 @@ static int vduse_inject_irq(VduseDev *dev, int index)
return ioctl(dev->fd, VDUSE_VQ_INJECT_IRQ, &index);
}
+static int inflight_desc_compare(const void *a, const void *b)
+{
+ VduseVirtqInflightDesc *desc0 = (VduseVirtqInflightDesc *)a,
+ *desc1 = (VduseVirtqInflightDesc *)b;
+
+ if (desc1->counter > desc0->counter &&
+ (desc1->counter - desc0->counter) < VIRTQUEUE_MAX_SIZE * 2) {
+ return 1;
+ }
+
+ return -1;
+}
+
+static int vduse_queue_check_inflights(VduseVirtq *vq)
+{
+ int i = 0;
+ VduseDev *dev = vq->dev;
+
+ vq->used_idx = le16toh(vq->vring.used->idx);
+ vq->resubmit_num = 0;
+ vq->resubmit_list = NULL;
+ vq->counter = 0;
+
+ if (unlikely(vq->log->inflight.used_idx != vq->used_idx)) {
+ if (vq->log->inflight.last_batch_head > VIRTQUEUE_MAX_SIZE) {
+ return -1;
+ }
+
+ vq->log->inflight.desc[vq->log->inflight.last_batch_head].inflight = 0;
+
+ barrier();
+
+ vq->log->inflight.used_idx = vq->used_idx;
+ }
+
+ for (i = 0; i < vq->log->inflight.desc_num; i++) {
+ if (vq->log->inflight.desc[i].inflight == 1) {
+ vq->inuse++;
+ }
+ }
+
+ vq->shadow_avail_idx = vq->last_avail_idx = vq->inuse + vq->used_idx;
+
+ if (vq->inuse) {
+ vq->resubmit_list = calloc(vq->inuse, sizeof(VduseVirtqInflightDesc));
+ if (!vq->resubmit_list) {
+ return -1;
+ }
+
+ for (i = 0; i < vq->log->inflight.desc_num; i++) {
+ if (vq->log->inflight.desc[i].inflight) {
+ vq->resubmit_list[vq->resubmit_num].index = i;
+ vq->resubmit_list[vq->resubmit_num].counter =
+ vq->log->inflight.desc[i].counter;
+ vq->resubmit_num++;
+ }
+ }
+
+ if (vq->resubmit_num > 1) {
+ qsort(vq->resubmit_list, vq->resubmit_num,
+ sizeof(VduseVirtqInflightDesc), inflight_desc_compare);
+ }
+ vq->counter = vq->resubmit_list[0].counter + 1;
+ }
+
+ vduse_inject_irq(dev, vq->index);
+
+ return 0;
+}
+
+static int vduse_queue_inflight_get(VduseVirtq *vq, int desc_idx)
+{
+ vq->log->inflight.desc[desc_idx].counter = vq->counter++;
+ vq->log->inflight.desc[desc_idx].inflight = 1;
+
+ return 0;
+}
+
+static int vduse_queue_inflight_pre_put(VduseVirtq *vq, int desc_idx)
+{
+ vq->log->inflight.last_batch_head = desc_idx;
+
+ return 0;
+}
+
+static int vduse_queue_inflight_post_put(VduseVirtq *vq, int desc_idx)
+{
+ vq->log->inflight.desc[desc_idx].inflight = 0;
+
+ barrier();
+
+ vq->log->inflight.used_idx = vq->used_idx;
+
+ return 0;
+}
+
static void vduse_iova_remove_region(VduseDev *dev, uint64_t start,
uint64_t last)
{
@@ -587,11 +742,24 @@ void *vduse_queue_pop(VduseVirtq *vq, size_t sz)
unsigned int head;
VduseVirtqElement *elem;
VduseDev *dev = vq->dev;
+ int i;
if (unlikely(!vq->vring.avail)) {
return NULL;
}
+ if (unlikely(vq->resubmit_list && vq->resubmit_num > 0)) {
+ i = (--vq->resubmit_num);
+ elem = vduse_queue_map_desc(vq, vq->resubmit_list[i].index, sz);
+
+ if (!vq->resubmit_num) {
+ free(vq->resubmit_list);
+ vq->resubmit_list = NULL;
+ }
+
+ return elem;
+ }
+
if (vduse_queue_empty(vq)) {
return NULL;
}
@@ -619,6 +787,8 @@ void *vduse_queue_pop(VduseVirtq *vq, size_t sz)
vq->inuse++;
+ vduse_queue_inflight_get(vq, head);
+
return elem;
}
@@ -676,7 +846,9 @@ void vduse_queue_push(VduseVirtq *vq, const VduseVirtqElement *elem,
unsigned int len)
{
vduse_queue_fill(vq, elem, len, 0);
+ vduse_queue_inflight_pre_put(vq, elem->index);
vduse_queue_flush(vq, 1);
+ vduse_queue_inflight_post_put(vq, elem->index);
}
static int vduse_queue_update_vring(VduseVirtq *vq, uint64_t desc_addr,
@@ -749,12 +921,15 @@ static void vduse_queue_enable(VduseVirtq *vq)
}
vq->fd = fd;
- vq->shadow_avail_idx = vq->last_avail_idx = vq_info.split.avail_index;
- vq->inuse = 0;
- vq->used_idx = 0;
vq->signalled_used_valid = false;
vq->ready = true;
+ if (vduse_queue_check_inflights(vq)) {
+ fprintf(stderr, "Failed to check inflights for vq[%d]\n", vq->index);
+ close(fd);
+ return;
+ }
+
dev->ops->enable_queue(dev, vq);
}
@@ -804,11 +979,15 @@ static void vduse_dev_start_dataplane(VduseDev *dev)
static void vduse_dev_stop_dataplane(VduseDev *dev)
{
+ size_t log_size = dev->num_queues * vduse_vq_log_size(VIRTQUEUE_MAX_SIZE);
int i;
for (i = 0; i < dev->num_queues; i++) {
vduse_queue_disable(&dev->vqs[i]);
}
+ if (dev->log) {
+ memset(dev->log, 0, log_size);
+ }
dev->features = 0;
vduse_iova_remove_region(dev, 0, ULONG_MAX);
}
@@ -917,6 +1096,30 @@ int vduse_dev_setup_queue(VduseDev *dev, int index, int max_size)
return -errno;
}
+ vduse_queue_enable(vq);
+
+ return 0;
+}
+
+int vduse_set_reconnect_log_file(VduseDev *dev, const char *filename)
+{
+
+ size_t log_size = dev->num_queues * vduse_vq_log_size(VIRTQUEUE_MAX_SIZE);
+ void *log;
+ int i;
+
+ dev->log = log = vduse_log_get(filename, log_size);
+ if (log == MAP_FAILED) {
+ fprintf(stderr, "Failed to get vduse log\n");
+ return -EINVAL;
+ }
+
+ for (i = 0; i < dev->num_queues; i++) {
+ dev->vqs[i].log = log;
+ dev->vqs[i].log->inflight.desc_num = VIRTQUEUE_MAX_SIZE;
+ log = (void *)((char *)log + vduse_vq_log_size(VIRTQUEUE_MAX_SIZE));
+ }
+
return 0;
}
@@ -961,6 +1164,12 @@ static int vduse_dev_init(VduseDev *dev, const char *name,
return -errno;
}
+ if (ioctl(fd, VDUSE_DEV_GET_FEATURES, &dev->features)) {
+ fprintf(stderr, "Failed to get features: %s\n", strerror(errno));
+ close(fd);
+ return -errno;
+ }
+
dev_name = strdup(name);
if (!dev_name) {
close(fd);
@@ -1005,6 +1214,12 @@ VduseDev *vduse_dev_create_by_fd(int fd, uint16_t num_queues,
return NULL;
}
+ if (ioctl(fd, VDUSE_DEV_GET_FEATURES, &dev->features)) {
+ fprintf(stderr, "Failed to get features: %s\n", strerror(errno));
+ free(dev);
+ return NULL;
+ }
+
ret = vduse_dev_init_vqs(dev, num_queues);
if (ret) {
fprintf(stderr, "Failed to init vqs\n");
@@ -1104,7 +1319,7 @@ VduseDev *vduse_dev_create(const char *name, uint32_t device_id,
ret = ioctl(ctrl_fd, VDUSE_CREATE_DEV, dev_config);
free(dev_config);
- if (ret < 0) {
+ if (ret && errno != EEXIST) {
fprintf(stderr, "Failed to create vduse device %s: %s\n",
name, strerror(errno));
goto err_dev;
@@ -1131,8 +1346,15 @@ err_ctrl:
int vduse_dev_destroy(VduseDev *dev)
{
- int ret = 0;
+ size_t log_size = dev->num_queues * vduse_vq_log_size(VIRTQUEUE_MAX_SIZE);
+ int i, ret = 0;
+ if (dev->log) {
+ munmap(dev->log, log_size);
+ }
+ for (i = 0; i < dev->num_queues; i++) {
+ free(dev->vqs[i].resubmit_list);
+ }
free(dev->vqs);
if (dev->fd > 0) {
close(dev->fd);
diff --git a/subprojects/libvduse/libvduse.h b/subprojects/libvduse/libvduse.h
index d972e5e070..853dc6ccad 100644
--- a/subprojects/libvduse/libvduse.h
+++ b/subprojects/libvduse/libvduse.h
@@ -163,6 +163,18 @@ int vduse_dev_update_config(VduseDev *dev, uint32_t size,
*/
int vduse_dev_setup_queue(VduseDev *dev, int index, int max_size);
+/**
+ * vduse_set_reconnect_log_file:
+ * @dev: VDUSE device
+ * @file: filename of reconnect log
+ *
+ * Specify the file to store log for reconnecting. It should
+ * be called before vduse_dev_setup_queue().
+ *
+ * Returns: 0 on success, -errno on failure.
+ */
+int vduse_set_reconnect_log_file(VduseDev *dev, const char *filename);
+
/**
* vduse_dev_create_by_fd:
* @fd: passed file descriptor
--
2.20.1
^ permalink raw reply related [flat|nested] 27+ messages in thread
* Re: [PATCH v2 0/6] Support exporting BDSs via VDUSE
2022-02-15 10:59 [PATCH v2 0/6] Support exporting BDSs via VDUSE Xie Yongji
` (5 preceding siblings ...)
2022-02-15 10:59 ` [PATCH v2 6/6] libvduse: Add support for reconnecting Xie Yongji
@ 2022-03-09 15:37 ` Stefan Hajnoczi
6 siblings, 0 replies; 27+ messages in thread
From: Stefan Hajnoczi @ 2022-03-09 15:37 UTC (permalink / raw)
To: Xie Yongji
Cc: kwolf, qemu-block, mst, jasowang, qemu-devel, mreitz, mlureau, sgarzare
[-- Attachment #1: Type: text/plain, Size: 1039 bytes --]
On Tue, Feb 15, 2022 at 06:59:37PM +0800, Xie Yongji wrote:
> Hi all,
>
> Last few months ago, VDUSE (vDPA Device in Userspace) [1] has
> been merged into Linux kernel as a framework that make it
> possible to emulate a vDPA device in userspace. This series
> aimed at implementing a VDUSE block backend based on the
> qemu-storage-daemon infrastructure.
>
> To support that, we firstly introduce a VDUSE library as a
> subproject (like what libvhost-user does) to help implementing
> VDUSE backends in QEMU. Then a VDUSE block export is implemented
> based on this library. At last, we add resize and reconnect support
> to the VDUSE block export and VDUSE library.
>
> Since we don't support vdpa-blk in QEMU currently, the VM case is
> tested with my previous patchset [2].
>
> [1] https://www.kernel.org/doc/html/latest/userspace-api/vduse.html
> [2] https://www.mail-archive.com/qemu-devel@nongnu.org/msg797569.html
>
> Please review, thanks!
Sorry for the delay. I will review this on Monday.
Stefan
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^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v2 1/6] block: Support passing NULL ops to blk_set_dev_ops()
2022-02-15 10:59 ` [PATCH v2 1/6] block: Support passing NULL ops to blk_set_dev_ops() Xie Yongji
@ 2022-03-14 17:23 ` Stefan Hajnoczi
2022-03-14 19:09 ` John Snow
0 siblings, 1 reply; 27+ messages in thread
From: Stefan Hajnoczi @ 2022-03-14 17:23 UTC (permalink / raw)
To: Xie Yongji, John Snow
Cc: kwolf, qemu-block, mst, jasowang, qemu-devel, mreitz, mlureau, sgarzare
[-- Attachment #1: Type: text/plain, Size: 997 bytes --]
On Tue, Feb 15, 2022 at 06:59:38PM +0800, Xie Yongji wrote:
> This supports passing NULL ops to blk_set_dev_ops()
> so that we can remove stale ops in some cases.
>
> Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> ---
> block/block-backend.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/block/block-backend.c b/block/block-backend.c
> index 4ff6b4d785..08dd0a3093 100644
> --- a/block/block-backend.c
> +++ b/block/block-backend.c
> @@ -1015,7 +1015,7 @@ void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops,
> blk->dev_opaque = opaque;
>
> /* Are we currently quiesced? Should we enforce this right now? */
> - if (blk->quiesce_counter && ops->drained_begin) {
> + if (blk->quiesce_counter && ops && ops->drained_begin) {
> ops->drained_begin(opaque);
> }
> }
John: You added this code in f4d9cc88ee6. Does blk_set_dev_ops() need to
call ->drained_end() when ops is set to NULL?
Stefan
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^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v2 1/6] block: Support passing NULL ops to blk_set_dev_ops()
2022-03-14 17:23 ` Stefan Hajnoczi
@ 2022-03-14 19:09 ` John Snow
2022-03-15 8:47 ` Stefan Hajnoczi
0 siblings, 1 reply; 27+ messages in thread
From: John Snow @ 2022-03-14 19:09 UTC (permalink / raw)
To: Stefan Hajnoczi
Cc: Kevin Wolf, Qemu-block, Michael Tsirkin, Jason Wang, qemu-devel,
Hanna Reitz, Xie Yongji, mlureau, sgarzare
On Mon, Mar 14, 2022 at 1:23 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
>
> On Tue, Feb 15, 2022 at 06:59:38PM +0800, Xie Yongji wrote:
> > This supports passing NULL ops to blk_set_dev_ops()
> > so that we can remove stale ops in some cases.
> >
> > Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> > ---
> > block/block-backend.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/block/block-backend.c b/block/block-backend.c
> > index 4ff6b4d785..08dd0a3093 100644
> > --- a/block/block-backend.c
> > +++ b/block/block-backend.c
> > @@ -1015,7 +1015,7 @@ void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops,
> > blk->dev_opaque = opaque;
> >
> > /* Are we currently quiesced? Should we enforce this right now? */
> > - if (blk->quiesce_counter && ops->drained_begin) {
> > + if (blk->quiesce_counter && ops && ops->drained_begin) {
> > ops->drained_begin(opaque);
> > }
> > }
>
> John: You added this code in f4d9cc88ee6. Does blk_set_dev_ops() need to
> call ->drained_end() when ops is set to NULL?
>
> Stefan
I'm not sure I trust my memory from five years ago.
From what I recall, the problem was that block jobs weren't getting
drained/paused when the backend was getting quiesced -- we wanted to
be sure that a blockjob wasn't continuing to run and submit requests
against a backend we wanted to have on ice during a sensitive
operation. This conditional stanza here is meant to check if the node
we're already attached to is *already quiesced* and we missed the
signal (so-to-speak), so we replay the drained_begin() request right
there.
i.e. there was some case where blockjobs were getting added to an
already quiesced node, and this code here post-hoc relays that drain
request to the blockjob. This gets used in
600ac6a0ef5c06418446ef2f37407bddcc51b21c to pause/unpause jobs.
Original thread is here:
https://lists.gnu.org/archive/html/qemu-devel/2017-03/msg03416.html
Now, I'm not sure why you want to set ops to NULL here. If we're in a
drained section, that sounds like it might be potentially bad because
we lose track of the operation to end the drained section. If your
intent is to destroy the thing that we'd need to call drained_end on,
I guess it doesn't matter -- provided you've cleaned up the target
object correctly. Just calling drained_end() pre-emptively seems like
it might be bad, what if it unpauses something you're in the middle of
trying to delete?
I might need slightly more context to know what you're hoping to
accomplish, but I hope this info helps contextualize this code
somewhat.
--js
^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v2 1/6] block: Support passing NULL ops to blk_set_dev_ops()
2022-03-14 19:09 ` John Snow
@ 2022-03-15 8:47 ` Stefan Hajnoczi
2022-03-15 19:30 ` John Snow
0 siblings, 1 reply; 27+ messages in thread
From: Stefan Hajnoczi @ 2022-03-15 8:47 UTC (permalink / raw)
To: John Snow
Cc: Kevin Wolf, Qemu-block, Michael Tsirkin, Jason Wang, qemu-devel,
Hanna Reitz, Xie Yongji, mlureau, sgarzare
[-- Attachment #1: Type: text/plain, Size: 3506 bytes --]
On Mon, Mar 14, 2022 at 03:09:35PM -0400, John Snow wrote:
> On Mon, Mar 14, 2022 at 1:23 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
> >
> > On Tue, Feb 15, 2022 at 06:59:38PM +0800, Xie Yongji wrote:
> > > This supports passing NULL ops to blk_set_dev_ops()
> > > so that we can remove stale ops in some cases.
> > >
> > > Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> > > ---
> > > block/block-backend.c | 2 +-
> > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/block/block-backend.c b/block/block-backend.c
> > > index 4ff6b4d785..08dd0a3093 100644
> > > --- a/block/block-backend.c
> > > +++ b/block/block-backend.c
> > > @@ -1015,7 +1015,7 @@ void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops,
> > > blk->dev_opaque = opaque;
> > >
> > > /* Are we currently quiesced? Should we enforce this right now? */
> > > - if (blk->quiesce_counter && ops->drained_begin) {
> > > + if (blk->quiesce_counter && ops && ops->drained_begin) {
> > > ops->drained_begin(opaque);
> > > }
> > > }
> >
> > John: You added this code in f4d9cc88ee6. Does blk_set_dev_ops() need to
> > call ->drained_end() when ops is set to NULL?
> >
> > Stefan
>
> I'm not sure I trust my memory from five years ago.
>
> From what I recall, the problem was that block jobs weren't getting
> drained/paused when the backend was getting quiesced -- we wanted to
> be sure that a blockjob wasn't continuing to run and submit requests
> against a backend we wanted to have on ice during a sensitive
> operation. This conditional stanza here is meant to check if the node
> we're already attached to is *already quiesced* and we missed the
> signal (so-to-speak), so we replay the drained_begin() request right
> there.
>
> i.e. there was some case where blockjobs were getting added to an
> already quiesced node, and this code here post-hoc relays that drain
> request to the blockjob. This gets used in
> 600ac6a0ef5c06418446ef2f37407bddcc51b21c to pause/unpause jobs.
> Original thread is here:
> https://lists.gnu.org/archive/html/qemu-devel/2017-03/msg03416.html
>
> Now, I'm not sure why you want to set ops to NULL here. If we're in a
> drained section, that sounds like it might be potentially bad because
> we lose track of the operation to end the drained section. If your
> intent is to destroy the thing that we'd need to call drained_end on,
> I guess it doesn't matter -- provided you've cleaned up the target
> object correctly. Just calling drained_end() pre-emptively seems like
> it might be bad, what if it unpauses something you're in the middle of
> trying to delete?
>
> I might need slightly more context to know what you're hoping to
> accomplish, but I hope this info helps contextualize this code
> somewhat.
Setting to NULL in this patch is a subset of blk_detach_dev(), which
gets called when a storage controller is hot unplugged.
In this patch series there is no DeviceState because a VDUSE export is
not a device. The VDUSE code calls blk_set_dev_ops() to
register/unregister callbacks (e.g. ->resize_cb()).
The reason I asked about ->drained_end() is for symmetry. If the
device's ->drained_begin() callback changed state or allocated resources
then they may need to be freed/reset. On the other hand, the
blk_set_dev_ops(blk, NULL, NULL) call should be made by the dev_ops
owner so they can clean up without a ->drained_end() call.
Stefan
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^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v2 3/6] libvduse: Add VDUSE (vDPA Device in Userspace) library
2022-02-15 10:59 ` [PATCH v2 3/6] libvduse: Add VDUSE (vDPA Device in Userspace) library Xie Yongji
@ 2022-03-15 9:48 ` Stefan Hajnoczi
2022-03-15 11:38 ` Yongji Xie
0 siblings, 1 reply; 27+ messages in thread
From: Stefan Hajnoczi @ 2022-03-15 9:48 UTC (permalink / raw)
To: Xie Yongji
Cc: kwolf, qemu-block, mst, jasowang, qemu-devel, mreitz, mlureau, sgarzare
[-- Attachment #1: Type: text/plain, Size: 1406 bytes --]
On Tue, Feb 15, 2022 at 06:59:40PM +0800, Xie Yongji wrote:
> VDUSE [1] is a linux framework that makes it possible to implement
> software-emulated vDPA devices in userspace. This adds a library
> as a subproject to help implementing VDUSE backends in QEMU.
>
> [1] https://www.kernel.org/doc/html/latest/userspace-api/vduse.html
>
> Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> ---
> meson.build | 15 +
> meson_options.txt | 2 +
> scripts/meson-buildoptions.sh | 3 +
> subprojects/libvduse/include/atomic.h | 1 +
> subprojects/libvduse/libvduse.c | 1152 +++++++++++++++++++
> subprojects/libvduse/libvduse.h | 225 ++++
> subprojects/libvduse/linux-headers/linux | 1 +
> subprojects/libvduse/meson.build | 10 +
> subprojects/libvduse/standard-headers/linux | 1 +
> 9 files changed, 1410 insertions(+)
> create mode 120000 subprojects/libvduse/include/atomic.h
> create mode 100644 subprojects/libvduse/libvduse.c
> create mode 100644 subprojects/libvduse/libvduse.h
> create mode 120000 subprojects/libvduse/linux-headers/linux
> create mode 100644 subprojects/libvduse/meson.build
> create mode 120000 subprojects/libvduse/standard-headers/linux
Please update the ./MAINTAINERS file when adding new source files.
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^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v2 4/6] vduse-blk: implements vduse-blk export
2022-02-15 10:59 ` [PATCH v2 4/6] vduse-blk: implements vduse-blk export Xie Yongji
@ 2022-03-15 11:08 ` Stefan Hajnoczi
2022-03-15 11:52 ` Yongji Xie
0 siblings, 1 reply; 27+ messages in thread
From: Stefan Hajnoczi @ 2022-03-15 11:08 UTC (permalink / raw)
To: Xie Yongji
Cc: kwolf, qemu-block, mst, jasowang, qemu-devel, mreitz, mlureau, sgarzare
[-- Attachment #1: Type: text/plain, Size: 2117 bytes --]
On Tue, Feb 15, 2022 at 06:59:41PM +0800, Xie Yongji wrote:
> This implements a VDUSE block backends based on
> the libvduse library. We can use it to export the BDSs
> for both VM and container (host) usage.
>
> The new command-line syntax is:
>
> $ qemu-storage-daemon \
> --blockdev file,node-name=drive0,filename=test.img \
> --export vduse-blk,node-name=drive0,id=vduse-export0,writable=on
>
> After the qemu-storage-daemon started, we need to use
> the "vdpa" command to attach the device to vDPA bus:
>
> $ vdpa dev add name vduse-export0 mgmtdev vduse
The per-QEMU export id is used as the global vdpa device name. If this
becomes a problem in the future then a new --export
vduse-blk,vdpa-dev-name= option can be added.
> + case VIRTIO_BLK_T_GET_ID: {
> + size_t size = MIN(iov_size(&elem->in_sg[0], in_num),
> + VIRTIO_BLK_ID_BYTES);
> + snprintf(elem->in_sg[0].iov_base, size, "%s", vblk_exp->export.id);
Please use iov_from_buf(). The driver is allowed to submit as many
in_sg[] elements as it wants and a compliant virtio-blk device
implementation must support that.
Here is the VIRTIO specification section that covers message framing:
https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/virtio-v1.1-cs01.html#x1-280004
> + features = (1ULL << VIRTIO_F_IOMMU_PLATFORM) |
> + (1ULL << VIRTIO_F_VERSION_1) |
> + (1ULL << VIRTIO_RING_F_EVENT_IDX) |
> + (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
> + (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
> + (1ULL << VIRTIO_BLK_F_SIZE_MAX) |
> + (1ULL << VIRTIO_BLK_F_SEG_MAX) |
> + (1ULL << VIRTIO_BLK_F_TOPOLOGY) |
> + (1ULL << VIRTIO_BLK_F_BLK_SIZE);
The VIRTIO_F_ and VIRTIO_RING_F_ feature bits report the capabilities of
libvduse. They should probably be defined in libvduse. That way no
changes to vduse-blk.c are required when libvduse changes:
features = LIBVDUSE_VIRTIO_FEATURES |
(1ULL << VIRTIO_BLK_F_SIZE_MAX) |
...;
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^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v2 3/6] libvduse: Add VDUSE (vDPA Device in Userspace) library
2022-03-15 9:48 ` Stefan Hajnoczi
@ 2022-03-15 11:38 ` Yongji Xie
2022-03-16 13:28 ` Stefan Hajnoczi
0 siblings, 1 reply; 27+ messages in thread
From: Yongji Xie @ 2022-03-15 11:38 UTC (permalink / raw)
To: Stefan Hajnoczi
Cc: Kevin Wolf, qemu-block, Michael S. Tsirkin, Jason Wang,
qemu-devel, mreitz, mlureau, Stefano Garzarella
On Tue, Mar 15, 2022 at 5:48 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
>
> On Tue, Feb 15, 2022 at 06:59:40PM +0800, Xie Yongji wrote:
> > VDUSE [1] is a linux framework that makes it possible to implement
> > software-emulated vDPA devices in userspace. This adds a library
> > as a subproject to help implementing VDUSE backends in QEMU.
> >
> > [1] https://www.kernel.org/doc/html/latest/userspace-api/vduse.html
> >
> > Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> > ---
> > meson.build | 15 +
> > meson_options.txt | 2 +
> > scripts/meson-buildoptions.sh | 3 +
> > subprojects/libvduse/include/atomic.h | 1 +
> > subprojects/libvduse/libvduse.c | 1152 +++++++++++++++++++
> > subprojects/libvduse/libvduse.h | 225 ++++
> > subprojects/libvduse/linux-headers/linux | 1 +
> > subprojects/libvduse/meson.build | 10 +
> > subprojects/libvduse/standard-headers/linux | 1 +
> > 9 files changed, 1410 insertions(+)
> > create mode 120000 subprojects/libvduse/include/atomic.h
> > create mode 100644 subprojects/libvduse/libvduse.c
> > create mode 100644 subprojects/libvduse/libvduse.h
> > create mode 120000 subprojects/libvduse/linux-headers/linux
> > create mode 100644 subprojects/libvduse/meson.build
> > create mode 120000 subprojects/libvduse/standard-headers/linux
>
> Please update the ./MAINTAINERS file when adding new source files.
OK, sure. And would you mind being one of the maintainers since I'm
not sure if I can do this job well.
Thanks,
Yongji
^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v2 4/6] vduse-blk: implements vduse-blk export
2022-03-15 11:08 ` Stefan Hajnoczi
@ 2022-03-15 11:52 ` Yongji Xie
2022-03-16 12:16 ` Stefan Hajnoczi
0 siblings, 1 reply; 27+ messages in thread
From: Yongji Xie @ 2022-03-15 11:52 UTC (permalink / raw)
To: Stefan Hajnoczi
Cc: Kevin Wolf, qemu-block, Michael S. Tsirkin, Jason Wang,
qemu-devel, mreitz, mlureau, Stefano Garzarella
On Tue, Mar 15, 2022 at 7:08 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
>
> On Tue, Feb 15, 2022 at 06:59:41PM +0800, Xie Yongji wrote:
> > This implements a VDUSE block backends based on
> > the libvduse library. We can use it to export the BDSs
> > for both VM and container (host) usage.
> >
> > The new command-line syntax is:
> >
> > $ qemu-storage-daemon \
> > --blockdev file,node-name=drive0,filename=test.img \
> > --export vduse-blk,node-name=drive0,id=vduse-export0,writable=on
> >
> > After the qemu-storage-daemon started, we need to use
> > the "vdpa" command to attach the device to vDPA bus:
> >
> > $ vdpa dev add name vduse-export0 mgmtdev vduse
>
> The per-QEMU export id is used as the global vdpa device name. If this
> becomes a problem in the future then a new --export
> vduse-blk,vdpa-dev-name= option can be added.
>
Yes.
> > + case VIRTIO_BLK_T_GET_ID: {
> > + size_t size = MIN(iov_size(&elem->in_sg[0], in_num),
> > + VIRTIO_BLK_ID_BYTES);
> > + snprintf(elem->in_sg[0].iov_base, size, "%s", vblk_exp->export.id);
>
> Please use iov_from_buf(). The driver is allowed to submit as many
> in_sg[] elements as it wants and a compliant virtio-blk device
> implementation must support that.
>
Got it.
> Here is the VIRTIO specification section that covers message framing:
> https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/virtio-v1.1-cs01.html#x1-280004
>
> > + features = (1ULL << VIRTIO_F_IOMMU_PLATFORM) |
> > + (1ULL << VIRTIO_F_VERSION_1) |
> > + (1ULL << VIRTIO_RING_F_EVENT_IDX) |
> > + (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
> > + (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
> > + (1ULL << VIRTIO_BLK_F_SIZE_MAX) |
> > + (1ULL << VIRTIO_BLK_F_SEG_MAX) |
> > + (1ULL << VIRTIO_BLK_F_TOPOLOGY) |
> > + (1ULL << VIRTIO_BLK_F_BLK_SIZE);
>
> The VIRTIO_F_ and VIRTIO_RING_F_ feature bits report the capabilities of
> libvduse. They should probably be defined in libvduse. That way no
> changes to vduse-blk.c are required when libvduse changes:
>
> features = LIBVDUSE_VIRTIO_FEATURES |
> (1ULL << VIRTIO_BLK_F_SIZE_MAX) |
> ...;
It's OK to define the VIRTIO_F_* feature bits in libvduse since daemon
might not want to disable it. But maybe not including VIRTIO_RING_F_*
feature bits since daemon might want to disable them in some cases.
Thanks,
Yongji
^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v2 5/6] vduse-blk: Add vduse-blk resize support
2022-02-15 10:59 ` [PATCH v2 5/6] vduse-blk: Add vduse-blk resize support Xie Yongji
@ 2022-03-15 13:36 ` Stefan Hajnoczi
0 siblings, 0 replies; 27+ messages in thread
From: Stefan Hajnoczi @ 2022-03-15 13:36 UTC (permalink / raw)
To: Xie Yongji
Cc: kwolf, qemu-block, mst, jasowang, qemu-devel, mreitz, mlureau, sgarzare
[-- Attachment #1: Type: text/plain, Size: 453 bytes --]
On Tue, Feb 15, 2022 at 06:59:42PM +0800, Xie Yongji wrote:
> To support block resize, this uses vduse_dev_update_config()
> to update the capacity field in configuration space and inject
> config interrupt on the block resize callback.
>
> Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> ---
> block/export/vduse-blk.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
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^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v2 6/6] libvduse: Add support for reconnecting
2022-02-15 10:59 ` [PATCH v2 6/6] libvduse: Add support for reconnecting Xie Yongji
@ 2022-03-15 13:48 ` Stefan Hajnoczi
2022-03-16 2:33 ` Yongji Xie
0 siblings, 1 reply; 27+ messages in thread
From: Stefan Hajnoczi @ 2022-03-15 13:48 UTC (permalink / raw)
To: Xie Yongji
Cc: kwolf, qemu-block, mst, jasowang, qemu-devel, mreitz, mlureau, sgarzare
[-- Attachment #1: Type: text/plain, Size: 355 bytes --]
On Tue, Feb 15, 2022 at 06:59:43PM +0800, Xie Yongji wrote:
> +static int vduse_queue_inflight_get(VduseVirtq *vq, int desc_idx)
> +{
> + vq->log->inflight.desc[desc_idx].counter = vq->counter++;
> + vq->log->inflight.desc[desc_idx].inflight = 1;
Is a barrier needed between these two lines to prevent inflight = 1 with
an undefined counter value?
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^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v2 1/6] block: Support passing NULL ops to blk_set_dev_ops()
2022-03-15 8:47 ` Stefan Hajnoczi
@ 2022-03-15 19:30 ` John Snow
2022-03-16 12:18 ` Stefan Hajnoczi
0 siblings, 1 reply; 27+ messages in thread
From: John Snow @ 2022-03-15 19:30 UTC (permalink / raw)
To: Stefan Hajnoczi
Cc: Kevin Wolf, Sergio Lopez Pascual, Qemu-block, Michael Tsirkin,
Jason Wang, qemu-devel, Hanna Reitz, Xie Yongji, mlureau,
sgarzare
On Tue, Mar 15, 2022 at 4:47 AM Stefan Hajnoczi <stefanha@redhat.com> wrote:
>
> On Mon, Mar 14, 2022 at 03:09:35PM -0400, John Snow wrote:
> > On Mon, Mar 14, 2022 at 1:23 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
> > >
> > > On Tue, Feb 15, 2022 at 06:59:38PM +0800, Xie Yongji wrote:
> > > > This supports passing NULL ops to blk_set_dev_ops()
> > > > so that we can remove stale ops in some cases.
> > > >
> > > > Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> > > > ---
> > > > block/block-backend.c | 2 +-
> > > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > > >
> > > > diff --git a/block/block-backend.c b/block/block-backend.c
> > > > index 4ff6b4d785..08dd0a3093 100644
> > > > --- a/block/block-backend.c
> > > > +++ b/block/block-backend.c
> > > > @@ -1015,7 +1015,7 @@ void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops,
> > > > blk->dev_opaque = opaque;
> > > >
> > > > /* Are we currently quiesced? Should we enforce this right now? */
> > > > - if (blk->quiesce_counter && ops->drained_begin) {
> > > > + if (blk->quiesce_counter && ops && ops->drained_begin) {
> > > > ops->drained_begin(opaque);
> > > > }
> > > > }
> > >
> > > John: You added this code in f4d9cc88ee6. Does blk_set_dev_ops() need to
> > > call ->drained_end() when ops is set to NULL?
> > >
> > > Stefan
> >
> > I'm not sure I trust my memory from five years ago.
> >
> > From what I recall, the problem was that block jobs weren't getting
> > drained/paused when the backend was getting quiesced -- we wanted to
> > be sure that a blockjob wasn't continuing to run and submit requests
> > against a backend we wanted to have on ice during a sensitive
> > operation. This conditional stanza here is meant to check if the node
> > we're already attached to is *already quiesced* and we missed the
> > signal (so-to-speak), so we replay the drained_begin() request right
> > there.
> >
> > i.e. there was some case where blockjobs were getting added to an
> > already quiesced node, and this code here post-hoc relays that drain
> > request to the blockjob. This gets used in
> > 600ac6a0ef5c06418446ef2f37407bddcc51b21c to pause/unpause jobs.
> > Original thread is here:
> > https://lists.gnu.org/archive/html/qemu-devel/2017-03/msg03416.html
> >
> > Now, I'm not sure why you want to set ops to NULL here. If we're in a
> > drained section, that sounds like it might be potentially bad because
> > we lose track of the operation to end the drained section. If your
> > intent is to destroy the thing that we'd need to call drained_end on,
> > I guess it doesn't matter -- provided you've cleaned up the target
> > object correctly. Just calling drained_end() pre-emptively seems like
> > it might be bad, what if it unpauses something you're in the middle of
> > trying to delete?
> >
> > I might need slightly more context to know what you're hoping to
> > accomplish, but I hope this info helps contextualize this code
> > somewhat.
>
> Setting to NULL in this patch is a subset of blk_detach_dev(), which
> gets called when a storage controller is hot unplugged.
>
> In this patch series there is no DeviceState because a VDUSE export is
> not a device. The VDUSE code calls blk_set_dev_ops() to
> register/unregister callbacks (e.g. ->resize_cb()).
>
> The reason I asked about ->drained_end() is for symmetry. If the
> device's ->drained_begin() callback changed state or allocated resources
> then they may need to be freed/reset. On the other hand, the
> blk_set_dev_ops(blk, NULL, NULL) call should be made by the dev_ops
> owner so they can clean up without a ->drained_end() call.
OK, got it... Hm, we don't actually use these for BlockJobs anymore.
It looks like the only user of these callbacks now is the NBD driver.
ad90febaf22d95e49fb6821bfb3ebd05b4919417 followed not long after my
initial patch and removed my intended user. I tried just removing the
fields, but the build chokes on NBD.
It looks like these usages are pretty modern, Sergio added them in
fd6afc50 (2021-06-02). So, I guess we do actually still use these
hooks. (After a period of maybe not using them for 4 years? Wow.)
I'm not clear on what we *want* to happen here, though. It doesn't
sound like NBD is the anticipated use case, so maybe just make the
removal fail if the drained section is active and callbacks are
defined? That's the safe thing to do, probably.
--js
^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v2 6/6] libvduse: Add support for reconnecting
2022-03-15 13:48 ` Stefan Hajnoczi
@ 2022-03-16 2:33 ` Yongji Xie
0 siblings, 0 replies; 27+ messages in thread
From: Yongji Xie @ 2022-03-16 2:33 UTC (permalink / raw)
To: Stefan Hajnoczi
Cc: Kevin Wolf, qemu-block, Michael S. Tsirkin, Jason Wang,
qemu-devel, mreitz, mlureau, Stefano Garzarella
On Tue, Mar 15, 2022 at 9:48 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
>
> On Tue, Feb 15, 2022 at 06:59:43PM +0800, Xie Yongji wrote:
> > +static int vduse_queue_inflight_get(VduseVirtq *vq, int desc_idx)
> > +{
> > + vq->log->inflight.desc[desc_idx].counter = vq->counter++;
> > + vq->log->inflight.desc[desc_idx].inflight = 1;
>
> Is a barrier needed between these two lines to prevent inflight = 1 with
> an undefined counter value?
Yes, I will fix it in v3.
Thanks,
Yongji
^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v2 4/6] vduse-blk: implements vduse-blk export
2022-03-15 11:52 ` Yongji Xie
@ 2022-03-16 12:16 ` Stefan Hajnoczi
2022-03-16 13:24 ` Yongji Xie
0 siblings, 1 reply; 27+ messages in thread
From: Stefan Hajnoczi @ 2022-03-16 12:16 UTC (permalink / raw)
To: Yongji Xie
Cc: Kevin Wolf, qemu-block, Michael S. Tsirkin, Jason Wang,
qemu-devel, mreitz, mlureau, Stefano Garzarella
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On Tue, Mar 15, 2022 at 07:52:03PM +0800, Yongji Xie wrote:
> On Tue, Mar 15, 2022 at 7:08 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
> >
> > On Tue, Feb 15, 2022 at 06:59:41PM +0800, Xie Yongji wrote:
> > > This implements a VDUSE block backends based on
> > > the libvduse library. We can use it to export the BDSs
> > > for both VM and container (host) usage.
> > >
> > > The new command-line syntax is:
> > >
> > > $ qemu-storage-daemon \
> > > --blockdev file,node-name=drive0,filename=test.img \
> > > --export vduse-blk,node-name=drive0,id=vduse-export0,writable=on
> > >
> > > After the qemu-storage-daemon started, we need to use
> > > the "vdpa" command to attach the device to vDPA bus:
> > >
> > > $ vdpa dev add name vduse-export0 mgmtdev vduse
> >
> > The per-QEMU export id is used as the global vdpa device name. If this
> > becomes a problem in the future then a new --export
> > vduse-blk,vdpa-dev-name= option can be added.
> >
>
> Yes.
>
> > > + case VIRTIO_BLK_T_GET_ID: {
> > > + size_t size = MIN(iov_size(&elem->in_sg[0], in_num),
> > > + VIRTIO_BLK_ID_BYTES);
> > > + snprintf(elem->in_sg[0].iov_base, size, "%s", vblk_exp->export.id);
> >
> > Please use iov_from_buf(). The driver is allowed to submit as many
> > in_sg[] elements as it wants and a compliant virtio-blk device
> > implementation must support that.
> >
>
> Got it.
>
> > Here is the VIRTIO specification section that covers message framing:
> > https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/virtio-v1.1-cs01.html#x1-280004
> >
> > > + features = (1ULL << VIRTIO_F_IOMMU_PLATFORM) |
> > > + (1ULL << VIRTIO_F_VERSION_1) |
> > > + (1ULL << VIRTIO_RING_F_EVENT_IDX) |
> > > + (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
> > > + (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
> > > + (1ULL << VIRTIO_BLK_F_SIZE_MAX) |
> > > + (1ULL << VIRTIO_BLK_F_SEG_MAX) |
> > > + (1ULL << VIRTIO_BLK_F_TOPOLOGY) |
> > > + (1ULL << VIRTIO_BLK_F_BLK_SIZE);
> >
> > The VIRTIO_F_ and VIRTIO_RING_F_ feature bits report the capabilities of
> > libvduse. They should probably be defined in libvduse. That way no
> > changes to vduse-blk.c are required when libvduse changes:
> >
> > features = LIBVDUSE_VIRTIO_FEATURES |
> > (1ULL << VIRTIO_BLK_F_SIZE_MAX) |
> > ...;
>
> It's OK to define the VIRTIO_F_* feature bits in libvduse since daemon
> might not want to disable it. But maybe not including VIRTIO_RING_F_*
> feature bits since daemon might want to disable them in some cases.
The VIRTIO_RING_F_* functionality is implemented inside libvduse and not
the device code. If the device wants to disable specific features, it
can clear those bits.
Thinking about the LIBVDUSE_VIRTIO_FEATURES idea I think it's slightly
better to make it a function so that libvduse code supports dynamic
linking. That way the device calls libvduse to query the feature bits
instead of compiling a constant from the libvduse header file into the
device executable.
So something like:
features = (vdu_get_virtio_features() & ~(...features we wish to clear...)) |
(1ULL << VIRTIO_BLK_F_SIZE_MAX) |
...;
Stefan
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^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v2 1/6] block: Support passing NULL ops to blk_set_dev_ops()
2022-03-15 19:30 ` John Snow
@ 2022-03-16 12:18 ` Stefan Hajnoczi
2022-03-17 8:57 ` Kevin Wolf
0 siblings, 1 reply; 27+ messages in thread
From: Stefan Hajnoczi @ 2022-03-16 12:18 UTC (permalink / raw)
To: John Snow
Cc: Kevin Wolf, Sergio Lopez Pascual, Qemu-block, Michael Tsirkin,
Jason Wang, qemu-devel, Hanna Reitz, Xie Yongji, mlureau, eblake,
sgarzare
[-- Attachment #1: Type: text/plain, Size: 4827 bytes --]
On Tue, Mar 15, 2022 at 03:30:22PM -0400, John Snow wrote:
> On Tue, Mar 15, 2022 at 4:47 AM Stefan Hajnoczi <stefanha@redhat.com> wrote:
> >
> > On Mon, Mar 14, 2022 at 03:09:35PM -0400, John Snow wrote:
> > > On Mon, Mar 14, 2022 at 1:23 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
> > > >
> > > > On Tue, Feb 15, 2022 at 06:59:38PM +0800, Xie Yongji wrote:
> > > > > This supports passing NULL ops to blk_set_dev_ops()
> > > > > so that we can remove stale ops in some cases.
> > > > >
> > > > > Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> > > > > ---
> > > > > block/block-backend.c | 2 +-
> > > > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > > > >
> > > > > diff --git a/block/block-backend.c b/block/block-backend.c
> > > > > index 4ff6b4d785..08dd0a3093 100644
> > > > > --- a/block/block-backend.c
> > > > > +++ b/block/block-backend.c
> > > > > @@ -1015,7 +1015,7 @@ void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops,
> > > > > blk->dev_opaque = opaque;
> > > > >
> > > > > /* Are we currently quiesced? Should we enforce this right now? */
> > > > > - if (blk->quiesce_counter && ops->drained_begin) {
> > > > > + if (blk->quiesce_counter && ops && ops->drained_begin) {
> > > > > ops->drained_begin(opaque);
> > > > > }
> > > > > }
> > > >
> > > > John: You added this code in f4d9cc88ee6. Does blk_set_dev_ops() need to
> > > > call ->drained_end() when ops is set to NULL?
> > > >
> > > > Stefan
> > >
> > > I'm not sure I trust my memory from five years ago.
> > >
> > > From what I recall, the problem was that block jobs weren't getting
> > > drained/paused when the backend was getting quiesced -- we wanted to
> > > be sure that a blockjob wasn't continuing to run and submit requests
> > > against a backend we wanted to have on ice during a sensitive
> > > operation. This conditional stanza here is meant to check if the node
> > > we're already attached to is *already quiesced* and we missed the
> > > signal (so-to-speak), so we replay the drained_begin() request right
> > > there.
> > >
> > > i.e. there was some case where blockjobs were getting added to an
> > > already quiesced node, and this code here post-hoc relays that drain
> > > request to the blockjob. This gets used in
> > > 600ac6a0ef5c06418446ef2f37407bddcc51b21c to pause/unpause jobs.
> > > Original thread is here:
> > > https://lists.gnu.org/archive/html/qemu-devel/2017-03/msg03416.html
> > >
> > > Now, I'm not sure why you want to set ops to NULL here. If we're in a
> > > drained section, that sounds like it might be potentially bad because
> > > we lose track of the operation to end the drained section. If your
> > > intent is to destroy the thing that we'd need to call drained_end on,
> > > I guess it doesn't matter -- provided you've cleaned up the target
> > > object correctly. Just calling drained_end() pre-emptively seems like
> > > it might be bad, what if it unpauses something you're in the middle of
> > > trying to delete?
> > >
> > > I might need slightly more context to know what you're hoping to
> > > accomplish, but I hope this info helps contextualize this code
> > > somewhat.
> >
> > Setting to NULL in this patch is a subset of blk_detach_dev(), which
> > gets called when a storage controller is hot unplugged.
> >
> > In this patch series there is no DeviceState because a VDUSE export is
> > not a device. The VDUSE code calls blk_set_dev_ops() to
> > register/unregister callbacks (e.g. ->resize_cb()).
> >
> > The reason I asked about ->drained_end() is for symmetry. If the
> > device's ->drained_begin() callback changed state or allocated resources
> > then they may need to be freed/reset. On the other hand, the
> > blk_set_dev_ops(blk, NULL, NULL) call should be made by the dev_ops
> > owner so they can clean up without a ->drained_end() call.
>
> OK, got it... Hm, we don't actually use these for BlockJobs anymore.
> It looks like the only user of these callbacks now is the NBD driver.
>
> ad90febaf22d95e49fb6821bfb3ebd05b4919417 followed not long after my
> initial patch and removed my intended user. I tried just removing the
> fields, but the build chokes on NBD.
> It looks like these usages are pretty modern, Sergio added them in
> fd6afc50 (2021-06-02). So, I guess we do actually still use these
> hooks. (After a period of maybe not using them for 4 years? Wow.)
>
> I'm not clear on what we *want* to happen here, though. It doesn't
> sound like NBD is the anticipated use case, so maybe just make the
> removal fail if the drained section is active and callbacks are
> defined? That's the safe thing to do, probably.
I'm not sure either. CCing Eric. Maybe the answer is to just leave it
as-is.
Stefan
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^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v2 4/6] vduse-blk: implements vduse-blk export
2022-03-16 12:16 ` Stefan Hajnoczi
@ 2022-03-16 13:24 ` Yongji Xie
0 siblings, 0 replies; 27+ messages in thread
From: Yongji Xie @ 2022-03-16 13:24 UTC (permalink / raw)
To: Stefan Hajnoczi
Cc: Kevin Wolf, qemu-block, Michael S. Tsirkin, Jason Wang,
qemu-devel, mreitz, mlureau, Stefano Garzarella
On Wed, Mar 16, 2022 at 8:16 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
>
> On Tue, Mar 15, 2022 at 07:52:03PM +0800, Yongji Xie wrote:
> > On Tue, Mar 15, 2022 at 7:08 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
> > >
> > > On Tue, Feb 15, 2022 at 06:59:41PM +0800, Xie Yongji wrote:
> > > > This implements a VDUSE block backends based on
> > > > the libvduse library. We can use it to export the BDSs
> > > > for both VM and container (host) usage.
> > > >
> > > > The new command-line syntax is:
> > > >
> > > > $ qemu-storage-daemon \
> > > > --blockdev file,node-name=drive0,filename=test.img \
> > > > --export vduse-blk,node-name=drive0,id=vduse-export0,writable=on
> > > >
> > > > After the qemu-storage-daemon started, we need to use
> > > > the "vdpa" command to attach the device to vDPA bus:
> > > >
> > > > $ vdpa dev add name vduse-export0 mgmtdev vduse
> > >
> > > The per-QEMU export id is used as the global vdpa device name. If this
> > > becomes a problem in the future then a new --export
> > > vduse-blk,vdpa-dev-name= option can be added.
> > >
> >
> > Yes.
> >
> > > > + case VIRTIO_BLK_T_GET_ID: {
> > > > + size_t size = MIN(iov_size(&elem->in_sg[0], in_num),
> > > > + VIRTIO_BLK_ID_BYTES);
> > > > + snprintf(elem->in_sg[0].iov_base, size, "%s", vblk_exp->export.id);
> > >
> > > Please use iov_from_buf(). The driver is allowed to submit as many
> > > in_sg[] elements as it wants and a compliant virtio-blk device
> > > implementation must support that.
> > >
> >
> > Got it.
> >
> > > Here is the VIRTIO specification section that covers message framing:
> > > https://docs.oasis-open.org/virtio/virtio/v1.1/cs01/virtio-v1.1-cs01.html#x1-280004
> > >
> > > > + features = (1ULL << VIRTIO_F_IOMMU_PLATFORM) |
> > > > + (1ULL << VIRTIO_F_VERSION_1) |
> > > > + (1ULL << VIRTIO_RING_F_EVENT_IDX) |
> > > > + (1ULL << VIRTIO_F_NOTIFY_ON_EMPTY) |
> > > > + (1ULL << VIRTIO_RING_F_INDIRECT_DESC) |
> > > > + (1ULL << VIRTIO_BLK_F_SIZE_MAX) |
> > > > + (1ULL << VIRTIO_BLK_F_SEG_MAX) |
> > > > + (1ULL << VIRTIO_BLK_F_TOPOLOGY) |
> > > > + (1ULL << VIRTIO_BLK_F_BLK_SIZE);
> > >
> > > The VIRTIO_F_ and VIRTIO_RING_F_ feature bits report the capabilities of
> > > libvduse. They should probably be defined in libvduse. That way no
> > > changes to vduse-blk.c are required when libvduse changes:
> > >
> > > features = LIBVDUSE_VIRTIO_FEATURES |
> > > (1ULL << VIRTIO_BLK_F_SIZE_MAX) |
> > > ...;
> >
> > It's OK to define the VIRTIO_F_* feature bits in libvduse since daemon
> > might not want to disable it. But maybe not including VIRTIO_RING_F_*
> > feature bits since daemon might want to disable them in some cases.
>
> The VIRTIO_RING_F_* functionality is implemented inside libvduse and not
> the device code. If the device wants to disable specific features, it
> can clear those bits.
>
> Thinking about the LIBVDUSE_VIRTIO_FEATURES idea I think it's slightly
> better to make it a function so that libvduse code supports dynamic
> linking. That way the device calls libvduse to query the feature bits
> instead of compiling a constant from the libvduse header file into the
> device executable.
>
> So something like:
>
> features = (vdu_get_virtio_features() & ~(...features we wish to clear...)) |
> (1ULL << VIRTIO_BLK_F_SIZE_MAX) |
> ...;
>
OK, it looks good to me.
Thanks,
Yongji
^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v2 3/6] libvduse: Add VDUSE (vDPA Device in Userspace) library
2022-03-15 11:38 ` Yongji Xie
@ 2022-03-16 13:28 ` Stefan Hajnoczi
2022-03-16 13:49 ` Yongji Xie
0 siblings, 1 reply; 27+ messages in thread
From: Stefan Hajnoczi @ 2022-03-16 13:28 UTC (permalink / raw)
To: Yongji Xie
Cc: Kevin Wolf, qemu-block, Michael S. Tsirkin, Jason Wang,
qemu-devel, mreitz, mlureau, Stefano Garzarella
[-- Attachment #1: Type: text/plain, Size: 1986 bytes --]
On Tue, Mar 15, 2022 at 07:38:12PM +0800, Yongji Xie wrote:
> On Tue, Mar 15, 2022 at 5:48 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
> >
> > On Tue, Feb 15, 2022 at 06:59:40PM +0800, Xie Yongji wrote:
> > > VDUSE [1] is a linux framework that makes it possible to implement
> > > software-emulated vDPA devices in userspace. This adds a library
> > > as a subproject to help implementing VDUSE backends in QEMU.
> > >
> > > [1] https://www.kernel.org/doc/html/latest/userspace-api/vduse.html
> > >
> > > Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> > > ---
> > > meson.build | 15 +
> > > meson_options.txt | 2 +
> > > scripts/meson-buildoptions.sh | 3 +
> > > subprojects/libvduse/include/atomic.h | 1 +
> > > subprojects/libvduse/libvduse.c | 1152 +++++++++++++++++++
> > > subprojects/libvduse/libvduse.h | 225 ++++
> > > subprojects/libvduse/linux-headers/linux | 1 +
> > > subprojects/libvduse/meson.build | 10 +
> > > subprojects/libvduse/standard-headers/linux | 1 +
> > > 9 files changed, 1410 insertions(+)
> > > create mode 120000 subprojects/libvduse/include/atomic.h
> > > create mode 100644 subprojects/libvduse/libvduse.c
> > > create mode 100644 subprojects/libvduse/libvduse.h
> > > create mode 120000 subprojects/libvduse/linux-headers/linux
> > > create mode 100644 subprojects/libvduse/meson.build
> > > create mode 120000 subprojects/libvduse/standard-headers/linux
> >
> > Please update the ./MAINTAINERS file when adding new source files.
>
> OK, sure. And would you mind being one of the maintainers since I'm
> not sure if I can do this job well.
You're welcome to become the maintainer. It means that you will be CCed
on patches affecting this code and sometimes people might send you
questions about VDUSE exports.
Is the issue lack of time?
Stefan
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^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v2 3/6] libvduse: Add VDUSE (vDPA Device in Userspace) library
2022-03-16 13:28 ` Stefan Hajnoczi
@ 2022-03-16 13:49 ` Yongji Xie
2022-03-16 15:51 ` Stefan Hajnoczi
0 siblings, 1 reply; 27+ messages in thread
From: Yongji Xie @ 2022-03-16 13:49 UTC (permalink / raw)
To: Stefan Hajnoczi
Cc: Kevin Wolf, qemu-block, Michael S. Tsirkin, Jason Wang,
qemu-devel, mreitz, mlureau, Stefano Garzarella
On Wed, Mar 16, 2022 at 9:28 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
>
> On Tue, Mar 15, 2022 at 07:38:12PM +0800, Yongji Xie wrote:
> > On Tue, Mar 15, 2022 at 5:48 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
> > >
> > > On Tue, Feb 15, 2022 at 06:59:40PM +0800, Xie Yongji wrote:
> > > > VDUSE [1] is a linux framework that makes it possible to implement
> > > > software-emulated vDPA devices in userspace. This adds a library
> > > > as a subproject to help implementing VDUSE backends in QEMU.
> > > >
> > > > [1] https://www.kernel.org/doc/html/latest/userspace-api/vduse.html
> > > >
> > > > Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> > > > ---
> > > > meson.build | 15 +
> > > > meson_options.txt | 2 +
> > > > scripts/meson-buildoptions.sh | 3 +
> > > > subprojects/libvduse/include/atomic.h | 1 +
> > > > subprojects/libvduse/libvduse.c | 1152 +++++++++++++++++++
> > > > subprojects/libvduse/libvduse.h | 225 ++++
> > > > subprojects/libvduse/linux-headers/linux | 1 +
> > > > subprojects/libvduse/meson.build | 10 +
> > > > subprojects/libvduse/standard-headers/linux | 1 +
> > > > 9 files changed, 1410 insertions(+)
> > > > create mode 120000 subprojects/libvduse/include/atomic.h
> > > > create mode 100644 subprojects/libvduse/libvduse.c
> > > > create mode 100644 subprojects/libvduse/libvduse.h
> > > > create mode 120000 subprojects/libvduse/linux-headers/linux
> > > > create mode 100644 subprojects/libvduse/meson.build
> > > > create mode 120000 subprojects/libvduse/standard-headers/linux
> > >
> > > Please update the ./MAINTAINERS file when adding new source files.
> >
> > OK, sure. And would you mind being one of the maintainers since I'm
> > not sure if I can do this job well.
>
> You're welcome to become the maintainer. It means that you will be CCed
> on patches affecting this code and sometimes people might send you
> questions about VDUSE exports.
>
I see. I will try my best.
> Is the issue lack of time?
>
I think the time is enough. But since I have no experience, I'm not
sure if I can do this well.
Thanks,
Yongji
^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v2 3/6] libvduse: Add VDUSE (vDPA Device in Userspace) library
2022-03-16 13:49 ` Yongji Xie
@ 2022-03-16 15:51 ` Stefan Hajnoczi
2022-03-17 2:15 ` Yongji Xie
0 siblings, 1 reply; 27+ messages in thread
From: Stefan Hajnoczi @ 2022-03-16 15:51 UTC (permalink / raw)
To: Yongji Xie
Cc: Kevin Wolf, qemu-block, Michael S. Tsirkin, Jason Wang,
qemu-devel, mreitz, mlureau, Stefano Garzarella
[-- Attachment #1: Type: text/plain, Size: 2705 bytes --]
On Wed, Mar 16, 2022 at 09:49:19PM +0800, Yongji Xie wrote:
> On Wed, Mar 16, 2022 at 9:28 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
> >
> > On Tue, Mar 15, 2022 at 07:38:12PM +0800, Yongji Xie wrote:
> > > On Tue, Mar 15, 2022 at 5:48 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
> > > >
> > > > On Tue, Feb 15, 2022 at 06:59:40PM +0800, Xie Yongji wrote:
> > > > > VDUSE [1] is a linux framework that makes it possible to implement
> > > > > software-emulated vDPA devices in userspace. This adds a library
> > > > > as a subproject to help implementing VDUSE backends in QEMU.
> > > > >
> > > > > [1] https://www.kernel.org/doc/html/latest/userspace-api/vduse.html
> > > > >
> > > > > Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> > > > > ---
> > > > > meson.build | 15 +
> > > > > meson_options.txt | 2 +
> > > > > scripts/meson-buildoptions.sh | 3 +
> > > > > subprojects/libvduse/include/atomic.h | 1 +
> > > > > subprojects/libvduse/libvduse.c | 1152 +++++++++++++++++++
> > > > > subprojects/libvduse/libvduse.h | 225 ++++
> > > > > subprojects/libvduse/linux-headers/linux | 1 +
> > > > > subprojects/libvduse/meson.build | 10 +
> > > > > subprojects/libvduse/standard-headers/linux | 1 +
> > > > > 9 files changed, 1410 insertions(+)
> > > > > create mode 120000 subprojects/libvduse/include/atomic.h
> > > > > create mode 100644 subprojects/libvduse/libvduse.c
> > > > > create mode 100644 subprojects/libvduse/libvduse.h
> > > > > create mode 120000 subprojects/libvduse/linux-headers/linux
> > > > > create mode 100644 subprojects/libvduse/meson.build
> > > > > create mode 120000 subprojects/libvduse/standard-headers/linux
> > > >
> > > > Please update the ./MAINTAINERS file when adding new source files.
> > >
> > > OK, sure. And would you mind being one of the maintainers since I'm
> > > not sure if I can do this job well.
> >
> > You're welcome to become the maintainer. It means that you will be CCed
> > on patches affecting this code and sometimes people might send you
> > questions about VDUSE exports.
> >
>
> I see. I will try my best.
>
> > Is the issue lack of time?
> >
>
> I think the time is enough. But since I have no experience, I'm not
> sure if I can do this well.
Great! Don't worry there will probably not be much you need to do.
If someone submits a patch they'll CC you and you can post your
"Reviewed-by:". Kevin or I can pick up the patches you've reviewed and
send them with our pull requests to the qemu.git maintainer.
Stefan
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^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v2 3/6] libvduse: Add VDUSE (vDPA Device in Userspace) library
2022-03-16 15:51 ` Stefan Hajnoczi
@ 2022-03-17 2:15 ` Yongji Xie
0 siblings, 0 replies; 27+ messages in thread
From: Yongji Xie @ 2022-03-17 2:15 UTC (permalink / raw)
To: Stefan Hajnoczi
Cc: Kevin Wolf, qemu-block, Michael S. Tsirkin, Jason Wang,
qemu-devel, mreitz, mlureau, Stefano Garzarella
On Wed, Mar 16, 2022 at 11:51 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
>
> On Wed, Mar 16, 2022 at 09:49:19PM +0800, Yongji Xie wrote:
> > On Wed, Mar 16, 2022 at 9:28 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
> > >
> > > On Tue, Mar 15, 2022 at 07:38:12PM +0800, Yongji Xie wrote:
> > > > On Tue, Mar 15, 2022 at 5:48 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
> > > > >
> > > > > On Tue, Feb 15, 2022 at 06:59:40PM +0800, Xie Yongji wrote:
> > > > > > VDUSE [1] is a linux framework that makes it possible to implement
> > > > > > software-emulated vDPA devices in userspace. This adds a library
> > > > > > as a subproject to help implementing VDUSE backends in QEMU.
> > > > > >
> > > > > > [1] https://www.kernel.org/doc/html/latest/userspace-api/vduse.html
> > > > > >
> > > > > > Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> > > > > > ---
> > > > > > meson.build | 15 +
> > > > > > meson_options.txt | 2 +
> > > > > > scripts/meson-buildoptions.sh | 3 +
> > > > > > subprojects/libvduse/include/atomic.h | 1 +
> > > > > > subprojects/libvduse/libvduse.c | 1152 +++++++++++++++++++
> > > > > > subprojects/libvduse/libvduse.h | 225 ++++
> > > > > > subprojects/libvduse/linux-headers/linux | 1 +
> > > > > > subprojects/libvduse/meson.build | 10 +
> > > > > > subprojects/libvduse/standard-headers/linux | 1 +
> > > > > > 9 files changed, 1410 insertions(+)
> > > > > > create mode 120000 subprojects/libvduse/include/atomic.h
> > > > > > create mode 100644 subprojects/libvduse/libvduse.c
> > > > > > create mode 100644 subprojects/libvduse/libvduse.h
> > > > > > create mode 120000 subprojects/libvduse/linux-headers/linux
> > > > > > create mode 100644 subprojects/libvduse/meson.build
> > > > > > create mode 120000 subprojects/libvduse/standard-headers/linux
> > > > >
> > > > > Please update the ./MAINTAINERS file when adding new source files.
> > > >
> > > > OK, sure. And would you mind being one of the maintainers since I'm
> > > > not sure if I can do this job well.
> > >
> > > You're welcome to become the maintainer. It means that you will be CCed
> > > on patches affecting this code and sometimes people might send you
> > > questions about VDUSE exports.
> > >
> >
> > I see. I will try my best.
> >
> > > Is the issue lack of time?
> > >
> >
> > I think the time is enough. But since I have no experience, I'm not
> > sure if I can do this well.
>
> Great! Don't worry there will probably not be much you need to do.
>
> If someone submits a patch they'll CC you and you can post your
> "Reviewed-by:". Kevin or I can pick up the patches you've reviewed and
> send them with our pull requests to the qemu.git maintainer.
>
OK, I got it. Thank you!
Thanks,
Yongji
^ permalink raw reply [flat|nested] 27+ messages in thread
* Re: [PATCH v2 1/6] block: Support passing NULL ops to blk_set_dev_ops()
2022-03-16 12:18 ` Stefan Hajnoczi
@ 2022-03-17 8:57 ` Kevin Wolf
0 siblings, 0 replies; 27+ messages in thread
From: Kevin Wolf @ 2022-03-17 8:57 UTC (permalink / raw)
To: Stefan Hajnoczi
Cc: Sergio Lopez Pascual, Qemu-block, Michael Tsirkin, eblake,
Jason Wang, qemu-devel, Hanna Reitz, Xie Yongji, mlureau,
John Snow, sgarzare
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Am 16.03.2022 um 13:18 hat Stefan Hajnoczi geschrieben:
> On Tue, Mar 15, 2022 at 03:30:22PM -0400, John Snow wrote:
> > On Tue, Mar 15, 2022 at 4:47 AM Stefan Hajnoczi <stefanha@redhat.com> wrote:
> > >
> > > On Mon, Mar 14, 2022 at 03:09:35PM -0400, John Snow wrote:
> > > > On Mon, Mar 14, 2022 at 1:23 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
> > > > >
> > > > > On Tue, Feb 15, 2022 at 06:59:38PM +0800, Xie Yongji wrote:
> > > > > > This supports passing NULL ops to blk_set_dev_ops()
> > > > > > so that we can remove stale ops in some cases.
> > > > > >
> > > > > > Signed-off-by: Xie Yongji <xieyongji@bytedance.com>
> > > > > > ---
> > > > > > block/block-backend.c | 2 +-
> > > > > > 1 file changed, 1 insertion(+), 1 deletion(-)
> > > > > >
> > > > > > diff --git a/block/block-backend.c b/block/block-backend.c
> > > > > > index 4ff6b4d785..08dd0a3093 100644
> > > > > > --- a/block/block-backend.c
> > > > > > +++ b/block/block-backend.c
> > > > > > @@ -1015,7 +1015,7 @@ void blk_set_dev_ops(BlockBackend *blk, const BlockDevOps *ops,
> > > > > > blk->dev_opaque = opaque;
> > > > > >
> > > > > > /* Are we currently quiesced? Should we enforce this right now? */
> > > > > > - if (blk->quiesce_counter && ops->drained_begin) {
> > > > > > + if (blk->quiesce_counter && ops && ops->drained_begin) {
> > > > > > ops->drained_begin(opaque);
> > > > > > }
> > > > > > }
> > > > >
> > > > > John: You added this code in f4d9cc88ee6. Does blk_set_dev_ops() need to
> > > > > call ->drained_end() when ops is set to NULL?
> > > > >
> > > > > Stefan
> > > >
> > > > I'm not sure I trust my memory from five years ago.
> > > >
> > > > From what I recall, the problem was that block jobs weren't getting
> > > > drained/paused when the backend was getting quiesced -- we wanted to
> > > > be sure that a blockjob wasn't continuing to run and submit requests
> > > > against a backend we wanted to have on ice during a sensitive
> > > > operation. This conditional stanza here is meant to check if the node
> > > > we're already attached to is *already quiesced* and we missed the
> > > > signal (so-to-speak), so we replay the drained_begin() request right
> > > > there.
> > > >
> > > > i.e. there was some case where blockjobs were getting added to an
> > > > already quiesced node, and this code here post-hoc relays that drain
> > > > request to the blockjob. This gets used in
> > > > 600ac6a0ef5c06418446ef2f37407bddcc51b21c to pause/unpause jobs.
> > > > Original thread is here:
> > > > https://lists.gnu.org/archive/html/qemu-devel/2017-03/msg03416.html
> > > >
> > > > Now, I'm not sure why you want to set ops to NULL here. If we're in a
> > > > drained section, that sounds like it might be potentially bad because
> > > > we lose track of the operation to end the drained section. If your
> > > > intent is to destroy the thing that we'd need to call drained_end on,
> > > > I guess it doesn't matter -- provided you've cleaned up the target
> > > > object correctly. Just calling drained_end() pre-emptively seems like
> > > > it might be bad, what if it unpauses something you're in the middle of
> > > > trying to delete?
> > > >
> > > > I might need slightly more context to know what you're hoping to
> > > > accomplish, but I hope this info helps contextualize this code
> > > > somewhat.
> > >
> > > Setting to NULL in this patch is a subset of blk_detach_dev(), which
> > > gets called when a storage controller is hot unplugged.
> > >
> > > In this patch series there is no DeviceState because a VDUSE export is
> > > not a device. The VDUSE code calls blk_set_dev_ops() to
> > > register/unregister callbacks (e.g. ->resize_cb()).
> > >
> > > The reason I asked about ->drained_end() is for symmetry. If the
> > > device's ->drained_begin() callback changed state or allocated resources
> > > then they may need to be freed/reset. On the other hand, the
> > > blk_set_dev_ops(blk, NULL, NULL) call should be made by the dev_ops
> > > owner so they can clean up without a ->drained_end() call.
> >
> > OK, got it... Hm, we don't actually use these for BlockJobs anymore.
> > It looks like the only user of these callbacks now is the NBD driver.
> >
> > ad90febaf22d95e49fb6821bfb3ebd05b4919417 followed not long after my
> > initial patch and removed my intended user. I tried just removing the
> > fields, but the build chokes on NBD.
> > It looks like these usages are pretty modern, Sergio added them in
> > fd6afc50 (2021-06-02). So, I guess we do actually still use these
> > hooks. (After a period of maybe not using them for 4 years? Wow.)
> >
> > I'm not clear on what we *want* to happen here, though. It doesn't
> > sound like NBD is the anticipated use case, so maybe just make the
> > removal fail if the drained section is active and callbacks are
> > defined? That's the safe thing to do, probably.
>
> I'm not sure either. CCing Eric. Maybe the answer is to just leave it
> as-is.
NBD never calls blk_set_dev_ops(NULL), so does the specific case matter?
I guess the question is when blk_set_dev_ops(NULL) should be called in
general and what that means for draining. blk_set_dev_ops() is currently
taken as attaching a new user, and if its BlockBackend is drained, the
user needs to be aware of that because it should not send requests until
the node is undrained.
What does blk_set_dev_ops(NULL) mean, though? That the user has gone
away? If so, it doesn't make a difference because it won't send requests
anyway. If it's only about to go away, calling .drained_end() might make
it send requests even though the node is still drained. This would be a
bug.
It looks to me as if it's not necessary to balance .drain_begin/end on
the BlockDevOps level to get some counter back to zero. A user can
safely go away while the node is still drained.
Kevin
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^ permalink raw reply [flat|nested] 27+ messages in thread
end of thread, other threads:[~2022-03-17 8:59 UTC | newest]
Thread overview: 27+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-02-15 10:59 [PATCH v2 0/6] Support exporting BDSs via VDUSE Xie Yongji
2022-02-15 10:59 ` [PATCH v2 1/6] block: Support passing NULL ops to blk_set_dev_ops() Xie Yongji
2022-03-14 17:23 ` Stefan Hajnoczi
2022-03-14 19:09 ` John Snow
2022-03-15 8:47 ` Stefan Hajnoczi
2022-03-15 19:30 ` John Snow
2022-03-16 12:18 ` Stefan Hajnoczi
2022-03-17 8:57 ` Kevin Wolf
2022-02-15 10:59 ` [PATCH v2 2/6] linux-headers: Add vduse.h Xie Yongji
2022-02-15 10:59 ` [PATCH v2 3/6] libvduse: Add VDUSE (vDPA Device in Userspace) library Xie Yongji
2022-03-15 9:48 ` Stefan Hajnoczi
2022-03-15 11:38 ` Yongji Xie
2022-03-16 13:28 ` Stefan Hajnoczi
2022-03-16 13:49 ` Yongji Xie
2022-03-16 15:51 ` Stefan Hajnoczi
2022-03-17 2:15 ` Yongji Xie
2022-02-15 10:59 ` [PATCH v2 4/6] vduse-blk: implements vduse-blk export Xie Yongji
2022-03-15 11:08 ` Stefan Hajnoczi
2022-03-15 11:52 ` Yongji Xie
2022-03-16 12:16 ` Stefan Hajnoczi
2022-03-16 13:24 ` Yongji Xie
2022-02-15 10:59 ` [PATCH v2 5/6] vduse-blk: Add vduse-blk resize support Xie Yongji
2022-03-15 13:36 ` Stefan Hajnoczi
2022-02-15 10:59 ` [PATCH v2 6/6] libvduse: Add support for reconnecting Xie Yongji
2022-03-15 13:48 ` Stefan Hajnoczi
2022-03-16 2:33 ` Yongji Xie
2022-03-09 15:37 ` [PATCH v2 0/6] Support exporting BDSs via VDUSE Stefan Hajnoczi
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