On Fri, Aug 16, 2019 at 03:33:20PM +0100, Dr. David Alan Gilbert (git) wrote:
> From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
>
> The virtio-fs virtio device provides shared file system access using
> the FUSE protocol carried ovew virtio.
> The actual file server is implemented in an external vhost-user-fs device
> backend process.
>
> Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
> Signed-off-by: Sebastien Boeuf <sebastien.bo...@intel.com>
> Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
> ---
> configure | 13 +
> hw/virtio/Makefile.objs | 1 +
> hw/virtio/vhost-user-fs.c | 297 ++++++++++++++++++++
> include/hw/virtio/vhost-user-fs.h | 45 +++
> include/standard-headers/linux/virtio_fs.h | 41 +++
> include/standard-headers/linux/virtio_ids.h | 1 +
> 6 files changed, 398 insertions(+)
> create mode 100644 hw/virtio/vhost-user-fs.c
> create mode 100644 include/hw/virtio/vhost-user-fs.h
> create mode 100644 include/standard-headers/linux/virtio_fs.h
>
> diff --git a/configure b/configure
> index 714e7fb6a1..e7e33ee783 100755
> --- a/configure
> +++ b/configure
> @@ -382,6 +382,7 @@ vhost_crypto=""
> vhost_scsi=""
> vhost_vsock=""
> vhost_user=""
> +vhost_user_fs=""
> kvm="no"
> hax="no"
> hvf="no"
> @@ -1316,6 +1317,10 @@ for opt do
> ;;
> --enable-vhost-vsock) vhost_vsock="yes"
> ;;
> + --disable-vhost-user-fs) vhost_user_fs="no"
> + ;;
> + --enable-vhost-user-fs) vhost_user_fs="yes"
> + ;;
> --disable-opengl) opengl="no"
> ;;
> --enable-opengl) opengl="yes"
> @@ -2269,6 +2274,10 @@ test "$vhost_crypto" = "" && vhost_crypto=$vhost_user
> if test "$vhost_crypto" = "yes" && test "$vhost_user" = "no"; then
> error_exit "--enable-vhost-crypto requires --enable-vhost-user"
> fi
> +test "$vhost_user_fs" = "" && vhost_user_fs=$vhost_user
> +if test "$vhost_user_fs" = "yes" && test "$vhost_user" = "no"; then
> + error_exit "--enable-vhost-user-fs requires --enable-vhost-user"
> +fi
>
> # OR the vhost-kernel and vhost-user values for simplicity
> if test "$vhost_net" = ""; then
> @@ -6425,6 +6434,7 @@ echo "vhost-crypto support $vhost_crypto"
> echo "vhost-scsi support $vhost_scsi"
> echo "vhost-vsock support $vhost_vsock"
> echo "vhost-user support $vhost_user"
> +echo "vhost-user-fs support $vhost_user_fs"
> echo "Trace backends $trace_backends"
> if have_backend "simple"; then
> echo "Trace output file $trace_file-<pid>"
> @@ -6921,6 +6931,9 @@ fi
> if test "$vhost_user" = "yes" ; then
> echo "CONFIG_VHOST_USER=y" >> $config_host_mak
> fi
> +if test "$vhost_user_fs" = "yes" ; then
> + echo "CONFIG_VHOST_USER_FS=y" >> $config_host_mak
> +fi
> if test "$blobs" = "yes" ; then
> echo "INSTALL_BLOBS=yes" >> $config_host_mak
> fi
> diff --git a/hw/virtio/Makefile.objs b/hw/virtio/Makefile.objs
> index 964ce78607..47ffbf22c4 100644
> --- a/hw/virtio/Makefile.objs
> +++ b/hw/virtio/Makefile.objs
> @@ -11,6 +11,7 @@ common-obj-$(CONFIG_VIRTIO_PCI) += virtio-pci.o
> common-obj-$(CONFIG_VIRTIO_MMIO) += virtio-mmio.o
> obj-$(CONFIG_VIRTIO_BALLOON) += virtio-balloon.o
> obj-$(CONFIG_VIRTIO_CRYPTO) += virtio-crypto.o
> +obj-$(CONFIG_VHOST_USER_FS) += vhost-user-fs.o
> obj-$(call land,$(CONFIG_VIRTIO_CRYPTO),$(CONFIG_VIRTIO_PCI)) +=
> virtio-crypto-pci.o
> obj-$(CONFIG_VIRTIO_PMEM) += virtio-pmem.o
> common-obj-$(call land,$(CONFIG_VIRTIO_PMEM),$(CONFIG_VIRTIO_PCI)) +=
> virtio-pmem-pci.o
> diff --git a/hw/virtio/vhost-user-fs.c b/hw/virtio/vhost-user-fs.c
> new file mode 100644
> index 0000000000..2753c2c07a
> --- /dev/null
> +++ b/hw/virtio/vhost-user-fs.c
> @@ -0,0 +1,297 @@
> +/*
> + * Vhost-user filesystem virtio device
> + *
> + * Copyright 2018 Red Hat, Inc.
> + *
> + * Authors:
> + * Stefan Hajnoczi <stefa...@redhat.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or
> + * (at your option) any later version. See the COPYING file in the
> + * top-level directory.
> + */
> +
> +#include "qemu/osdep.h"
> +#include <sys/ioctl.h>
> +#include "standard-headers/linux/virtio_fs.h"
> +#include "qapi/error.h"
> +#include "hw/virtio/virtio-bus.h"
> +#include "hw/virtio/virtio-access.h"
> +#include "qemu/error-report.h"
> +#include "hw/virtio/vhost-user-fs.h"
> +#include "monitor/monitor.h"
> +
> +static void vuf_get_config(VirtIODevice *vdev, uint8_t *config)
> +{
> + VHostUserFS *fs = VHOST_USER_FS(vdev);
> + struct virtio_fs_config fscfg = {};
> +
> + memcpy((char *)fscfg.tag, fs->conf.tag,
> + MIN(strlen(fs->conf.tag) + 1, sizeof(fscfg.tag)));
> +
> + virtio_stl_p(vdev, &fscfg.num_queues, fs->conf.num_queues);
> +
> + memcpy(config, &fscfg, sizeof(fscfg));
> +}
> +
> +static void vuf_start(VirtIODevice *vdev)
> +{
> + VHostUserFS *fs = VHOST_USER_FS(vdev);
> + BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
> + VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> + int ret;
> + int i;
> +
> + if (!k->set_guest_notifiers) {
> + error_report("binding does not support guest notifiers");
> + return;
> + }
> +
> + ret = vhost_dev_enable_notifiers(&fs->vhost_dev, vdev);
> + if (ret < 0) {
> + error_report("Error enabling host notifiers: %d", -ret);
> + return;
> + }
> +
> + ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, true);
> + if (ret < 0) {
> + error_report("Error binding guest notifier: %d", -ret);
> + goto err_host_notifiers;
> + }
> +
> + fs->vhost_dev.acked_features = vdev->guest_features;
> + ret = vhost_dev_start(&fs->vhost_dev, vdev);
> + if (ret < 0) {
> + error_report("Error starting vhost: %d", -ret);
> + goto err_guest_notifiers;
> + }
> +
> + /*
> + * guest_notifier_mask/pending not used yet, so just unmask
> + * everything here. virtio-pci will do the right thing by
> + * enabling/disabling irqfd.
> + */
> + for (i = 0; i < fs->vhost_dev.nvqs; i++) {
> + vhost_virtqueue_mask(&fs->vhost_dev, vdev, i, false);
> + }
> +
> + return;
> +
> +err_guest_notifiers:
> + k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
> +err_host_notifiers:
> + vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
> +}
> +
> +static void vuf_stop(VirtIODevice *vdev)
> +{
> + VHostUserFS *fs = VHOST_USER_FS(vdev);
> + BusState *qbus = BUS(qdev_get_parent_bus(DEVICE(vdev)));
> + VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
> + int ret;
> +
> + if (!k->set_guest_notifiers) {
> + return;
> + }
> +
> + vhost_dev_stop(&fs->vhost_dev, vdev);
> +
> + ret = k->set_guest_notifiers(qbus->parent, fs->vhost_dev.nvqs, false);
> + if (ret < 0) {
> + error_report("vhost guest notifier cleanup failed: %d", ret);
> + return;
> + }
> +
> + vhost_dev_disable_notifiers(&fs->vhost_dev, vdev);
> +}
> +
> +static void vuf_set_status(VirtIODevice *vdev, uint8_t status)
> +{
> + VHostUserFS *fs = VHOST_USER_FS(vdev);
> + bool should_start = status & VIRTIO_CONFIG_S_DRIVER_OK;
> +
> + if (!vdev->vm_running) {
> + should_start = false;
> + }
> +
> + if (fs->vhost_dev.started == should_start) {
> + return;
> + }
> +
> + if (should_start) {
> + vuf_start(vdev);
> + } else {
> + vuf_stop(vdev);
> + }
> +}
> +
> +static uint64_t vuf_get_features(VirtIODevice *vdev,
> + uint64_t requested_features,
> + Error **errp)
> +{
> + /* No feature bits used yet */
> + return requested_features;
> +}
> +
> +static void vuf_handle_output(VirtIODevice *vdev, VirtQueue *vq)
> +{
> + /* Do nothing */
Why is this safe? Is this because this never triggers? assert(0) then?
If it triggers then backend won't be notified, which might
cause it to get stuck.
> +}
> +
> +static void vuf_guest_notifier_mask(VirtIODevice *vdev, int idx,
> + bool mask)
> +{
> + VHostUserFS *fs = VHOST_USER_FS(vdev);
> +
> + vhost_virtqueue_mask(&fs->vhost_dev, vdev, idx, mask);
> +}
> +
> +static bool vuf_guest_notifier_pending(VirtIODevice *vdev, int idx)
> +{
> + VHostUserFS *fs = VHOST_USER_FS(vdev);
> +
> + return vhost_virtqueue_pending(&fs->vhost_dev, idx);
> +}
> +
> +static void vuf_device_realize(DeviceState *dev, Error **errp)
> +{
> + VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> + VHostUserFS *fs = VHOST_USER_FS(dev);
> + unsigned int i;
> + size_t len;
> + int ret;
> +
> + if (!fs->conf.chardev.chr) {
> + error_setg(errp, "missing chardev");
> + return;
> + }
> +
> + if (!fs->conf.tag) {
> + error_setg(errp, "missing tag property");
> + return;
> + }
> + len = strlen(fs->conf.tag);
> + if (len == 0) {
> + error_setg(errp, "tag property cannot be empty");
> + return;
> + }
> + if (len > sizeof_field(struct virtio_fs_config, tag)) {
> + error_setg(errp, "tag property must be %zu bytes or less",
> + sizeof_field(struct virtio_fs_config, tag));
> + return;
> + }
> +
> + if (fs->conf.num_queues == 0) {
> + error_setg(errp, "num-queues property must be larger than 0");
> + return;
> + }
The strange thing is that actual # of queues is this number + 2.
And this affects an optimal number of vectors (see patch 2).
Not sure what a good solution is - include the
mandatory queues in the number?
Needs to be documented in some way.
> +
> + if (!is_power_of_2(fs->conf.queue_size)) {
> + error_setg(errp, "queue-size property must be a power of 2");
> + return;
> + }
Hmm packed ring allows non power of 2 ...
We need to look into a generic helper to support VQ
size checks.
> +
> + if (fs->conf.queue_size > VIRTQUEUE_MAX_SIZE) {
> + error_setg(errp, "queue-size property must be %u or smaller",
> + VIRTQUEUE_MAX_SIZE);
> + return;
> + }
> +
> + if (!vhost_user_init(&fs->vhost_user, &fs->conf.chardev, errp)) {
> + return;
> + }
> +
> + virtio_init(vdev, "vhost-user-fs", VIRTIO_ID_FS,
> + sizeof(struct virtio_fs_config));
> +
> + /* Notifications queue */
> + virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
> +
> + /* Hiprio queue */
> + virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
>
Weird, spec patch v6 says:
+\item[0] hiprio
+\item[1\ldots n] request queues
where's the Notifications queue coming from?
> + /* Request queues */
> + for (i = 0; i < fs->conf.num_queues; i++) {
> + virtio_add_queue(vdev, fs->conf.queue_size, vuf_handle_output);
> + }
> +
> + /* 1 high prio queue, plus the number configured */
> + fs->vhost_dev.nvqs = 1 + fs->conf.num_queues;
> + fs->vhost_dev.vqs = g_new0(struct vhost_virtqueue, fs->vhost_dev.nvqs);
> + ret = vhost_dev_init(&fs->vhost_dev, &fs->vhost_user,
> + VHOST_BACKEND_TYPE_USER, 0);
> + if (ret < 0) {
> + error_setg_errno(errp, -ret, "vhost_dev_init failed");
> + goto err_virtio;
> + }
> +
> + return;
> +
> +err_virtio:
> + vhost_user_cleanup(&fs->vhost_user);
> + virtio_cleanup(vdev);
> + g_free(fs->vhost_dev.vqs);
> + return;
> +}
> +
> +static void vuf_device_unrealize(DeviceState *dev, Error **errp)
> +{
> + VirtIODevice *vdev = VIRTIO_DEVICE(dev);
> + VHostUserFS *fs = VHOST_USER_FS(dev);
> +
> + /* This will stop vhost backend if appropriate. */
> + vuf_set_status(vdev, 0);
> +
> + vhost_dev_cleanup(&fs->vhost_dev);
> +
> + vhost_user_cleanup(&fs->vhost_user);
> +
> + virtio_cleanup(vdev);
> + g_free(fs->vhost_dev.vqs);
> + fs->vhost_dev.vqs = NULL;
> +}
> +
> +static const VMStateDescription vuf_vmstate = {
> + .name = "vhost-user-fs",
> + .unmigratable = 1,
> +};
> +
> +static Property vuf_properties[] = {
> + DEFINE_PROP_CHR("chardev", VHostUserFS, conf.chardev),
> + DEFINE_PROP_STRING("tag", VHostUserFS, conf.tag),
> + DEFINE_PROP_UINT16("num-queues", VHostUserFS, conf.num_queues, 1),
> + DEFINE_PROP_UINT16("queue-size", VHostUserFS, conf.queue_size, 128),
> + DEFINE_PROP_STRING("vhostfd", VHostUserFS, conf.vhostfd),
> + DEFINE_PROP_END_OF_LIST(),
> +};
> +
> +static void vuf_class_init(ObjectClass *klass, void *data)
> +{
> + DeviceClass *dc = DEVICE_CLASS(klass);
> + VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
> +
> + dc->props = vuf_properties;
> + dc->vmsd = &vuf_vmstate;
> + set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
> + vdc->realize = vuf_device_realize;
> + vdc->unrealize = vuf_device_unrealize;
> + vdc->get_features = vuf_get_features;
> + vdc->get_config = vuf_get_config;
> + vdc->set_status = vuf_set_status;
> + vdc->guest_notifier_mask = vuf_guest_notifier_mask;
> + vdc->guest_notifier_pending = vuf_guest_notifier_pending;
> +}
> +
> +static const TypeInfo vuf_info = {
> + .name = TYPE_VHOST_USER_FS,
> + .parent = TYPE_VIRTIO_DEVICE,
> + .instance_size = sizeof(VHostUserFS),
> + .class_init = vuf_class_init,
> +};
> +
> +static void vuf_register_types(void)
> +{
> + type_register_static(&vuf_info);
> +}
> +
> +type_init(vuf_register_types)
> diff --git a/include/hw/virtio/vhost-user-fs.h
> b/include/hw/virtio/vhost-user-fs.h
> new file mode 100644
> index 0000000000..d07ab134b9
> --- /dev/null
> +++ b/include/hw/virtio/vhost-user-fs.h
> @@ -0,0 +1,45 @@
> +/*
> + * Vhost-user filesystem virtio device
> + *
> + * Copyright 2018 Red Hat, Inc.
> + *
> + * Authors:
> + * Stefan Hajnoczi <stefa...@redhat.com>
> + *
> + * This work is licensed under the terms of the GNU GPL, version 2 or
> + * (at your option) any later version. See the COPYING file in the
> + * top-level directory.
> + */
> +
> +#ifndef _QEMU_VHOST_USER_FS_H
> +#define _QEMU_VHOST_USER_FS_H
> +
> +#include "hw/virtio/virtio.h"
> +#include "hw/virtio/vhost.h"
> +#include "hw/virtio/vhost-user.h"
> +#include "chardev/char-fe.h"
> +
> +#define TYPE_VHOST_USER_FS "x-vhost-user-fs-device"
> +#define VHOST_USER_FS(obj) \
> + OBJECT_CHECK(VHostUserFS, (obj), TYPE_VHOST_USER_FS)
> +
> +typedef struct {
> + CharBackend chardev;
> + char *tag;
> + uint16_t num_queues;
> + uint16_t queue_size;
> + char *vhostfd;
> +} VHostUserFSConf;
> +
> +typedef struct {
> + /*< private >*/
> + VirtIODevice parent;
> + VHostUserFSConf conf;
> + struct vhost_virtqueue *vhost_vqs;
> + struct vhost_dev vhost_dev;
> + VhostUserState vhost_user;
> +
> + /*< public >*/
> +} VHostUserFS;
> +
> +#endif /* _QEMU_VHOST_USER_FS_H */
> diff --git a/include/standard-headers/linux/virtio_fs.h
> b/include/standard-headers/linux/virtio_fs.h
> new file mode 100644
> index 0000000000..4f811a0b70
> --- /dev/null
> +++ b/include/standard-headers/linux/virtio_fs.h
> @@ -0,0 +1,41 @@
> +#ifndef _LINUX_VIRTIO_FS_H
> +#define _LINUX_VIRTIO_FS_H
> +/* This header is BSD licensed so anyone can use the definitions to implement
> + * compatible drivers/servers.
> + *
> + * Redistribution and use in source and binary forms, with or without
> + * modification, are permitted provided that the following conditions
> + * are met:
> + * 1. Redistributions of source code must retain the above copyright
> + * notice, this list of conditions and the following disclaimer.
> + * 2. Redistributions in binary form must reproduce the above copyright
> + * notice, this list of conditions and the following disclaimer in the
> + * documentation and/or other materials provided with the distribution.
> + * 3. Neither the name of IBM nor the names of its contributors
> + * may be used to endorse or promote products derived from this software
> + * without specific prior written permission.
> + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS
> IS'' AND
> + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
> + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
> + * ARE DISCLAIMED. IN NO EVENT SHALL IBM OR CONTRIBUTORS BE LIABLE
> + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
> + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
> + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
> + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
> + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
> + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
> + * SUCH DAMAGE. */
> +#include "standard-headers/linux/types.h"
> +#include "standard-headers/linux/virtio_ids.h"
> +#include "standard-headers/linux/virtio_config.h"
> +#include "standard-headers/linux/virtio_types.h"
> +
> +struct virtio_fs_config {
> + /* Filesystem name (UTF-8, not NUL-terminated, padded with NULs) */
> + uint8_t tag[36];
> +
> + /* Number of request queues */
> + uint32_t num_queues;
> +} QEMU_PACKED;
> +
> +#endif /* _LINUX_VIRTIO_FS_H */
> diff --git a/include/standard-headers/linux/virtio_ids.h
> b/include/standard-headers/linux/virtio_ids.h
> index 32b2f94d1f..73fc004807 100644
> --- a/include/standard-headers/linux/virtio_ids.h
> +++ b/include/standard-headers/linux/virtio_ids.h
> @@ -43,6 +43,7 @@
> #define VIRTIO_ID_INPUT 18 /* virtio input */
> #define VIRTIO_ID_VSOCK 19 /* virtio vsock transport */
> #define VIRTIO_ID_CRYPTO 20 /* virtio crypto */
> +#define VIRTIO_ID_FS 26 /* virtio filesystem */
> #define VIRTIO_ID_PMEM 27 /* virtio pmem */
>
> #endif /* _LINUX_VIRTIO_IDS_H */
> --
> 2.21.0
