qemu/hw/scsi/vhost-user-scsi.c
Felipe Franciosi f12c1ebddf vhost-user-scsi: Introduce vhost-user-scsi host device
This commit introduces a vhost-user device for SCSI. This is based
on the existing vhost-scsi implementation, but done over vhost-user
instead. It also uses a chardev to connect to the backend. Unlike
vhost-scsi (today), VMs using vhost-user-scsi can be live migrated.

To use it, start Qemu with a command line equivalent to:

qemu-system-x86_64 \
       -chardev socket,id=vus0,path=/tmp/vus.sock \
       -device vhost-user-scsi-pci,chardev=vus0,bus=pci.0,addr=...

A separate commit presents a sample application linked with libiscsi to
provide a backend for vhost-user-scsi.

Signed-off-by: Felipe Franciosi <felipe@nutanix.com>
Message-Id: <1488479153-21203-4-git-send-email-felipe@nutanix.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2017-06-15 11:18:40 +02:00

206 lines
6.2 KiB
C

/*
* vhost-user-scsi host device
*
* Copyright (c) 2016 Nutanix Inc. All rights reserved.
*
* Author:
* Felipe Franciosi <felipe@nutanix.com>
*
* This work is largely based on the "vhost-scsi" implementation by:
* Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
* Nicholas Bellinger <nab@risingtidesystems.com>
*
* This work is licensed under the terms of the GNU LGPL, version 2 or later.
* See the COPYING.LIB file in the top-level directory.
*
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "qemu/error-report.h"
#include "qemu/typedefs.h"
#include "qom/object.h"
#include "hw/fw-path-provider.h"
#include "hw/qdev-core.h"
#include "hw/virtio/vhost.h"
#include "hw/virtio/vhost-backend.h"
#include "hw/virtio/vhost-user-scsi.h"
#include "hw/virtio/virtio.h"
#include "hw/virtio/virtio-access.h"
#include "chardev/char-fe.h"
/* Features supported by the host application */
static const int user_feature_bits[] = {
VIRTIO_F_NOTIFY_ON_EMPTY,
VIRTIO_RING_F_INDIRECT_DESC,
VIRTIO_RING_F_EVENT_IDX,
VIRTIO_SCSI_F_HOTPLUG,
VHOST_INVALID_FEATURE_BIT
};
static void vhost_user_scsi_set_status(VirtIODevice *vdev, uint8_t status)
{
VHostUserSCSI *s = (VHostUserSCSI *)vdev;
VHostSCSICommon *vsc = VHOST_SCSI_COMMON(s);
bool start = (status & VIRTIO_CONFIG_S_DRIVER_OK) && vdev->vm_running;
if (vsc->dev.started == start) {
return;
}
if (start) {
int ret;
ret = vhost_scsi_common_start(vsc);
if (ret < 0) {
error_report("unable to start vhost-user-scsi: %s", strerror(-ret));
exit(1);
}
} else {
vhost_scsi_common_stop(vsc);
}
}
static void vhost_dummy_handle_output(VirtIODevice *vdev, VirtQueue *vq)
{
}
static void vhost_user_scsi_realize(DeviceState *dev, Error **errp)
{
VirtIOSCSICommon *vs = VIRTIO_SCSI_COMMON(dev);
VHostUserSCSI *s = VHOST_USER_SCSI(dev);
VHostSCSICommon *vsc = VHOST_SCSI_COMMON(s);
Error *err = NULL;
int ret;
if (!vs->conf.chardev.chr) {
error_setg(errp, "vhost-user-scsi: missing chardev");
return;
}
virtio_scsi_common_realize(dev, vhost_dummy_handle_output,
vhost_dummy_handle_output,
vhost_dummy_handle_output, &err);
if (err != NULL) {
error_propagate(errp, err);
return;
}
vsc->dev.nvqs = 2 + vs->conf.num_queues;
vsc->dev.vqs = g_new(struct vhost_virtqueue, vsc->dev.nvqs);
vsc->dev.vq_index = 0;
vsc->dev.backend_features = 0;
ret = vhost_dev_init(&vsc->dev, (void *)&vs->conf.chardev,
VHOST_BACKEND_TYPE_USER, 0);
if (ret < 0) {
error_setg(errp, "vhost-user-scsi: vhost initialization failed: %s",
strerror(-ret));
return;
}
/* Channel and lun both are 0 for bootable vhost-user-scsi disk */
vsc->channel = 0;
vsc->lun = 0;
vsc->target = vs->conf.boot_tpgt;
}
static void vhost_user_scsi_unrealize(DeviceState *dev, Error **errp)
{
VirtIODevice *vdev = VIRTIO_DEVICE(dev);
VHostUserSCSI *s = VHOST_USER_SCSI(dev);
VHostSCSICommon *vsc = VHOST_SCSI_COMMON(s);
/* This will stop the vhost backend. */
vhost_user_scsi_set_status(vdev, 0);
vhost_dev_cleanup(&vsc->dev);
g_free(vsc->dev.vqs);
virtio_scsi_common_unrealize(dev, errp);
}
static uint64_t vhost_user_scsi_get_features(VirtIODevice *vdev,
uint64_t features, Error **errp)
{
VHostUserSCSI *s = VHOST_USER_SCSI(vdev);
/* Turn on predefined features supported by this device */
features |= s->host_features;
return vhost_scsi_common_get_features(vdev, features, errp);
}
static Property vhost_user_scsi_properties[] = {
DEFINE_PROP_CHR("chardev", VirtIOSCSICommon, conf.chardev),
DEFINE_PROP_UINT32("boot_tpgt", VirtIOSCSICommon, conf.boot_tpgt, 0),
DEFINE_PROP_UINT32("num_queues", VirtIOSCSICommon, conf.num_queues, 1),
DEFINE_PROP_UINT32("max_sectors", VirtIOSCSICommon, conf.max_sectors,
0xFFFF),
DEFINE_PROP_UINT32("cmd_per_lun", VirtIOSCSICommon, conf.cmd_per_lun, 128),
DEFINE_PROP_BIT64("hotplug", VHostUserSCSI, host_features,
VIRTIO_SCSI_F_HOTPLUG,
true),
DEFINE_PROP_BIT64("param_change", VHostUserSCSI, host_features,
VIRTIO_SCSI_F_CHANGE,
true),
DEFINE_PROP_END_OF_LIST(),
};
static const VMStateDescription vmstate_vhost_scsi = {
.name = "virtio-scsi",
.minimum_version_id = 1,
.version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_VIRTIO_DEVICE,
VMSTATE_END_OF_LIST()
},
};
static void vhost_user_scsi_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
VirtioDeviceClass *vdc = VIRTIO_DEVICE_CLASS(klass);
FWPathProviderClass *fwc = FW_PATH_PROVIDER_CLASS(klass);
dc->props = vhost_user_scsi_properties;
dc->vmsd = &vmstate_vhost_scsi;
set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
vdc->realize = vhost_user_scsi_realize;
vdc->unrealize = vhost_user_scsi_unrealize;
vdc->get_features = vhost_user_scsi_get_features;
vdc->set_config = vhost_scsi_common_set_config;
vdc->set_status = vhost_user_scsi_set_status;
fwc->get_dev_path = vhost_scsi_common_get_fw_dev_path;
}
static void vhost_user_scsi_instance_init(Object *obj)
{
VHostSCSICommon *vsc = VHOST_SCSI_COMMON(obj);
vsc->feature_bits = user_feature_bits;
/* Add the bootindex property for this object */
device_add_bootindex_property(obj, &vsc->bootindex, "bootindex", NULL,
DEVICE(vsc), NULL);
}
static const TypeInfo vhost_user_scsi_info = {
.name = TYPE_VHOST_USER_SCSI,
.parent = TYPE_VHOST_SCSI_COMMON,
.instance_size = sizeof(VHostUserSCSI),
.class_init = vhost_user_scsi_class_init,
.instance_init = vhost_user_scsi_instance_init,
.interfaces = (InterfaceInfo[]) {
{ TYPE_FW_PATH_PROVIDER },
{ }
},
};
static void virtio_register_types(void)
{
type_register_static(&vhost_user_scsi_info);
}
type_init(virtio_register_types)