Re: [Qemu-devel] [RFC-v3 3/5] vhost-scsi: add -vhost-scsi host device for use with tcm-vhost

[Michael S. Tsirkin]

On Tue, Aug 21, 2012 at 08:52:09PM +0000, Nicholas A. Bellinger wrote:
> From: Stefan Hajnoczi <address@hidden>
> 
> This patch adds a new type of host device that drives the vhost_scsi
> device.  The syntax to add vhost-scsi is:
> 
>   qemu -vhost-scsi id=vhost-scsi0,wwpn=...,tpgt=123
> 
> The virtio-scsi emulated device will make use of vhost-scsi to process
> virtio-scsi requests inside the kernel and hand them to the in-kernel
> SCSI target stack using the tcm_vhost fabric driver.
> 
> The tcm_vhost driver was merged into the upstream linux kernel for 3.6-rc2,
> and the commit can be found here:
> 
> http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=057cbf49a1f08297
> 

In the future, please put changelog after --- or in the cover
letter: we do not need it in git history.
I fixed this up.

> Changelog v2 -> v3:
> 
> - Move qdev_prop_vhost_scsi + DEFINE_PROP_VHOST_SCSI defs into 
> vhost-scsi.[c,h]
>   (reported by MST)
> - Add enum vhost_scsi_vq_list for VHostSCSI->vqs[] enumeration (reported by 
> MST)
> - Add missing braces around single like if statement to following QEMU
>   style (reported by Blue Swirl)
> - Change vhost_scsi_target->vhost_wwpn to char *, in order to drop casts to
>   pstrcpy in vhost_scsi_start() + vhost_scsi_stop() (reported by Blue Swirl)
> - Change VHOST_SCSI_GET_ABI_VERSION to 'int' type (MST)
> - Fix 4 byte alignment of vhost_scsi_target (MST)
> - Convert fprintf(stderr, ...) usage to -> error_report() (reported by MST)
> - Do explict memset of backend before calling VHOST_SCSI_CLEAR_ENDPOINT
>   in vhost_scsi_stop() (reported by MST)
> - Add support for vhostfd passing in vhost_scsi_add() (reported by MST)
> - Change vhost_scsi_add() to use monitor_handle_fd_param() (reported by MST)
> 
> Changelog v1 -> v2:
> 
> - Expose ABI version via VHOST_SCSI_GET_ABI_VERSION + use Rev 0 as
>   starting point for v3.6-rc code (Stefan + ALiguori + nab)
> - Fix upstream qemu conflict in hw/qdev-properties.c
> - Make GET_ABI_VERSION use int (nab + mst)
> - Fix vhost-scsi case lables in configure (reported by paolo)
> - Convert qdev_prop_vhost_scsi to use ->get() + ->set() following
>   qdev_prop_netdev (reported by paolo)
> - Fix typo in qemu-options.hx definition of vhost-scsi (reported by paolo)
> 
> Changelog v0 -> v1:
> 
> - Add VHOST_SCSI_SET_ENDPOINT call (stefan)
> - Enable vhost notifiers for multiple queues (Zhi)
> - clear vhost-scsi endpoint on stopped (Zhi)
> - Add CONFIG_VHOST_SCSI for QEMU build configure (nab)
> - Rename vhost_vring_target -> vhost_scsi_target (mst + nab)
> - Add support for VHOST_SCSI_GET_ABI_VERSION ioctl (aliguori + nab)
> 
> Cc: Stefan Hajnoczi <address@hidden>
> Cc: Zhi Yong Wu <address@hidden>
> Cc: Anthony Liguori <address@hidden>
> Cc: Paolo Bonzini <address@hidden>
> Cc: Michael S. Tsirkin <address@hidden>
> Signed-off-by: Nicholas Bellinger <address@hidden>
> ---
>  configure            |   10 +++
>  hw/Makefile.objs     |    1 +
>  hw/qdev-properties.c |   41 +++++++++++
>  hw/vhost-scsi.c      |  190 
> ++++++++++++++++++++++++++++++++++++++++++++++++++
>  hw/vhost-scsi.h      |   62 ++++++++++++++++
>  qemu-common.h        |    1 +
>  qemu-config.c        |   19 +++++
>  qemu-options.hx      |    4 +
>  vl.c                 |   18 +++++
>  9 files changed, 346 insertions(+), 0 deletions(-)
>  create mode 100644 hw/vhost-scsi.c
>  create mode 100644 hw/vhost-scsi.h
> 
> diff --git a/configure b/configure
> index f0dbc03..1f03202 100755
> --- a/configure
> +++ b/configure
> @@ -168,6 +168,7 @@ libattr=""
>  xfs=""
>  
>  vhost_net="no"
> +vhost_scsi="no"
>  kvm="no"
>  gprof="no"
>  debug_tcg="no"
> @@ -513,6 +514,7 @@ Haiku)
>    usb="linux"
>    kvm="yes"
>    vhost_net="yes"
> +  vhost_scsi="yes"
>    if [ "$cpu" = "i386" -o "$cpu" = "x86_64" ] ; then
>      audio_possible_drivers="$audio_possible_drivers fmod"
>    fi
> @@ -818,6 +820,10 @@ for opt do
>    ;;
>    --enable-vhost-net) vhost_net="yes"
>    ;;
> +  --disable-vhost-scsi) vhost_scsi="no"
> +  ;;
> +  --enable-vhost-scsi) vhost_scsi="yes"
> +  ;;
>    --disable-opengl) opengl="no"
>    ;;
>    --enable-opengl) opengl="yes"
> @@ -3116,6 +3122,7 @@ echo "posix_madvise     $posix_madvise"
>  echo "uuid support      $uuid"
>  echo "libcap-ng support $cap_ng"
>  echo "vhost-net support $vhost_net"
> +echo "vhost-scsi support $vhost_scsi"
>  echo "Trace backend     $trace_backend"
>  echo "Trace output file $trace_file-<pid>"
>  echo "spice support     $spice"
> @@ -3828,6 +3835,9 @@ case "$target_arch2" in
>        if test "$vhost_net" = "yes" ; then
>          echo "CONFIG_VHOST_NET=y" >> $config_target_mak
>        fi
> +      if test "$vhost_scsi" = "yes" ; then
> +        echo "CONFIG_VHOST_SCSI=y" >> $config_target_mak
> +      fi
>      fi
>  esac
>  case "$target_arch2" in
> diff --git a/hw/Makefile.objs b/hw/Makefile.objs
> index 3ba5dd0..6ab75ec 100644
> --- a/hw/Makefile.objs
> +++ b/hw/Makefile.objs
> @@ -169,6 +169,7 @@ obj-$(CONFIG_VIRTIO) += virtio.o virtio-blk.o 
> virtio-balloon.o virtio-net.o
>  obj-$(CONFIG_VIRTIO) += virtio-serial-bus.o virtio-scsi.o
>  obj-$(CONFIG_SOFTMMU) += vhost_net.o
>  obj-$(CONFIG_VHOST_NET) += vhost.o
> +obj-$(CONFIG_VHOST_SCSI) += vhost-scsi.o
>  obj-$(CONFIG_REALLY_VIRTFS) += 9pfs/
>  obj-$(CONFIG_NO_PCI) += pci-stub.o
>  obj-$(CONFIG_VGA) += vga.o
> diff --git a/hw/qdev-properties.c b/hw/qdev-properties.c
> index 8aca0d4..8b505ca 100644
> --- a/hw/qdev-properties.c
> +++ b/hw/qdev-properties.c
> @@ -4,6 +4,7 @@
>  #include "blockdev.h"
>  #include "hw/block-common.h"
>  #include "net/hub.h"
> +#include "vhost-scsi.h"
>  
>  void *qdev_get_prop_ptr(DeviceState *dev, Property *prop)
>  {
> @@ -696,6 +697,46 @@ PropertyInfo qdev_prop_vlan = {
>      .set   = set_vlan,
>  };
>  
> +/* --- vhost-scsi --- */
> +
> +static int parse_vhost_scsi_dev(DeviceState *dev, const char *str, void 
> **ptr)
> +{
> +   VHostSCSI *p;
> +
> +   p = find_vhost_scsi(str);
> +   if (p == NULL) {
> +       return -ENOENT;
> +   }
> +
> +   *ptr = p;
> +   return 0;
> +}
> +
> +static const char *print_vhost_scsi_dev(void *ptr)
> +{
> +    VHostSCSI *p = ptr;
> +
> +    return (p) ? vhost_scsi_get_id(p) : "<null>";
> +}
> +
> +static void get_vhost_scsi_dev(Object *obj, Visitor *v, void *opaque,
> +                       const char *name, Error **errp)
> +{
> +    get_pointer(obj, v, opaque, print_vhost_scsi_dev, name, errp);
> +}
> +
> +static void set_vhost_scsi_dev(Object *obj, Visitor *v, void *opaque,
> +                               const char *name, Error **errp)
> +{
> +    set_pointer(obj, v, opaque, parse_vhost_scsi_dev, name, errp);
> +}
> +
> +PropertyInfo qdev_prop_vhost_scsi = {
> +     .name = "vhost-scsi",
> +     .get  = get_vhost_scsi_dev,
> +     .set  = set_vhost_scsi_dev,
> +};
> +
>  /* --- pointer --- */
>  
>  /* Not a proper property, just for dirty hacks.  TODO Remove it!  */
> diff --git a/hw/vhost-scsi.c b/hw/vhost-scsi.c
> new file mode 100644
> index 0000000..96da2fc
> --- /dev/null
> +++ b/hw/vhost-scsi.c
> @@ -0,0 +1,190 @@
> +/*
> + * vhost_scsi host device
> + *
> + * Copyright IBM, Corp. 2011
> + *
> + * Authors:
> + *  Stefan Hajnoczi   <address@hidden>
> + *
> + * Changes for QEMU mainline + tcm_vhost kernel upstream:
> + *  Nicholas Bellinger <address@hidden>
> + *
> + * 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 <sys/ioctl.h>
> +#include "config.h"
> +#include "qemu-queue.h"
> +#include "monitor.h"
> +#include "vhost-scsi.h"
> +#include "vhost.h"
> +
> +struct VHostSCSI {
> +    const char *id;
> +    const char *wwpn;
> +    uint16_t tpgt;
> +    int vhostfd;
> +    struct vhost_dev dev;
> +    struct vhost_virtqueue vqs[VHOST_SCSI_VQ_NUM];
> +    QLIST_ENTRY(VHostSCSI) list;
> +};
> +
> +static QLIST_HEAD(, VHostSCSI) vhost_scsi_list =
> +    QLIST_HEAD_INITIALIZER(vhost_scsi_list);
> +
> +VHostSCSI *find_vhost_scsi(const char *id)
> +{
> +    VHostSCSI *vs;
> +
> +    QLIST_FOREACH(vs, &vhost_scsi_list, list) {
> +        if (!strcmp(id, vs->id)) {
> +            return vs;
> +        }
> +    }
> +    return NULL;
> +}
> +
> +const char *vhost_scsi_get_id(VHostSCSI *vs)
> +{
> +    return vs->id;
> +}
> +
> +int vhost_scsi_start(VHostSCSI *vs, VirtIODevice *vdev)
> +{
> +    int ret, abi_version;
> +    struct vhost_scsi_target backend;
> +
> +    if (!vhost_dev_query(&vs->dev, vdev)) {
> +        return -ENOTSUP;
> +    }
> +
> +    vs->dev.nvqs = VHOST_SCSI_VQ_NUM;
> +    vs->dev.vqs = vs->vqs;
> +
> +    ret = vhost_dev_enable_notifiers(&vs->dev, vdev);
> +    if (ret < 0) {
> +        return ret;
> +    }
> +
> +    ret = vhost_dev_start(&vs->dev, vdev);
> +    if (ret < 0) {
> +        return ret;
> +    }
> +
> +    ret = ioctl(vs->dev.control, VHOST_SCSI_GET_ABI_VERSION, &abi_version);
> +    if (ret < 0) {
> +        ret = -errno;
> +        vhost_dev_stop(&vs->dev, vdev);
> +        return ret;
> +    }
> +    if (abi_version > VHOST_SCSI_ABI_VERSION) {
> +        error_report("vhost-scsi: The running tcm_vhost kernel abi_version:"
> +             " %d is greater than vhost_scsi userspace supports: %d, please"
> +             " upgrade your version of QEMU\n", abi_version,
> +             VHOST_SCSI_ABI_VERSION);
> +        ret = -ENOSYS;
> +        vhost_dev_stop(&vs->dev, vdev);
> +        return ret;
> +    }
> +    fprintf(stdout, "TCM_vHost ABI version: %d\n", abi_version);
> +
> +    memset(&backend, 0, sizeof(backend));
> +    pstrcpy(backend.vhost_wwpn, sizeof(backend.vhost_wwpn), vs->wwpn);
> +    backend.vhost_tpgt = vs->tpgt;
> +    ret = ioctl(vs->dev.control, VHOST_SCSI_SET_ENDPOINT, &backend);
> +    if (ret < 0) {
> +        ret = -errno;
> +        vhost_dev_stop(&vs->dev, vdev);
> +        return ret;
> +    }
> +
> +    return 0;
> +}
> +
> +void vhost_scsi_stop(VHostSCSI *vs, VirtIODevice *vdev)
> +{
> +    int ret;
> +    struct vhost_scsi_target backend;
> +
> +    memset(&backend, 0, sizeof(backend));
> +    pstrcpy(backend.vhost_wwpn, sizeof(backend.vhost_wwpn), vs->wwpn);
> +    backend.vhost_tpgt = vs->tpgt;
> +    ret = ioctl(vs->dev.control, VHOST_SCSI_CLEAR_ENDPOINT, &backend);
> +    if (ret < 0) {
> +        error_report("vhost-scsi: Failed to clear endpoint\n");
> +    }
> +
> +    vhost_dev_stop(&vs->dev, vdev);
> +}
> +
> +static VHostSCSI *vhost_scsi_add(const char *id, const char *wwpn,
> +                                 uint16_t tpgt, const char *vhostfd_str)
> +{
> +    VHostSCSI *vs;
> +    int ret;
> +
> +    vs = g_malloc0(sizeof(*vs));
> +    if (!vs) {
> +        error_report("vhost-scsi: unable to allocate *vs\n");
> +        return NULL;
> +    }
> +    vs->vhostfd = -1;
> +
> +    if (vhostfd_str) {
> +        vs->vhostfd = monitor_handle_fd_param(cur_mon, vhostfd_str);
> +        if (vs->vhostfd == -1) {
> +            error_report("vhost-scsi: unable to parse vs->vhostfd\n");
> +            return NULL;
> +        }
> +    }
> +    /* TODO set up vhost-scsi device and bind to tcm_vhost/$wwpm/tpgt_$tpgt 
> */
> +    ret = vhost_dev_init(&vs->dev, vs->vhostfd, "/dev/vhost-scsi", false);
> +    if (ret < 0) {
> +        error_report("vhost-scsi: vhost initialization failed: %s\n",
> +                strerror(-ret));
> +        return NULL;
> +    }
> +    vs->dev.backend_features = 0;
> +    vs->dev.acked_features = 0;
> +
> +    vs->id = g_strdup(id);
> +    vs->wwpn = g_strdup(wwpn);
> +    vs->tpgt = tpgt;
> +    QLIST_INSERT_HEAD(&vhost_scsi_list, vs, list);
> +
> +    return vs;
> +}
> +
> +VHostSCSI *vhost_scsi_add_opts(QemuOpts *opts)
> +{
> +    const char *id;
> +    const char *wwpn, *vhostfd;
> +    uint64_t tpgt;
> +
> +    id = qemu_opts_id(opts);
> +    if (!id) {
> +        error_report("vhost-scsi: no id specified\n");
> +        return NULL;
> +    }
> +    if (find_vhost_scsi(id)) {
> +        error_report("duplicate vhost-scsi: \"%s\"\n", id);
> +        return NULL;
> +    }
> +
> +    wwpn = qemu_opt_get(opts, "wwpn");
> +    if (!wwpn) {
> +        error_report("vhost-scsi: \"%s\" missing wwpn\n", id);
> +        return NULL;
> +    }
> +
> +    tpgt = qemu_opt_get_number(opts, "tpgt", UINT64_MAX);
> +    if (tpgt > UINT16_MAX) {
> +        error_report("vhost-scsi: \"%s\" needs a 16-bit tpgt\n", id);
> +        return NULL;
> +    }
> +    vhostfd = qemu_opt_get(opts, "vhostfd");
> +
> +    return vhost_scsi_add(id, wwpn, tpgt, vhostfd);
> +}
> diff --git a/hw/vhost-scsi.h b/hw/vhost-scsi.h
> new file mode 100644
> index 0000000..68de51a
> --- /dev/null
> +++ b/hw/vhost-scsi.h
> @@ -0,0 +1,62 @@
> +/*
> + * vhost_scsi host device
> + *
> + * Copyright IBM, Corp. 2011
> + *
> + * Authors:
> + *  Stefan Hajnoczi   <address@hidden>
> + *
> + * 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.
> + *
> + */
> +
> +#ifndef VHOST_SCSI_H
> +#define VHOST_SCSI_H
> +
> +#include "qemu-common.h"
> +#include "qemu-option.h"
> +#include "qdev.h"
> +
> +/*
> + * Used by QEMU userspace to ensure a consistent vhost-scsi ABI.
> + *
> + * ABI Rev 0: July 2012 version starting point for v3.6-rc merge candidate +
> + *            RFC-v2 vhost-scsi userspace.  Add GET_ABI_VERSION ioctl usage
> + */
> +
> +#define VHOST_SCSI_ABI_VERSION       0
> +
> +/* TODO #include <linux/vhost.h> properly */
> +/* For VHOST_SCSI_SET_ENDPOINT/VHOST_SCSI_CLEAR_ENDPOINT ioctl */
> +struct vhost_scsi_target {
> +    int abi_version;
> +    char vhost_wwpn[224];
> +    unsigned short vhost_tpgt;
> +    unsigned short reserved;
> +};
> +
> +enum vhost_scsi_vq_list {
> +    VHOST_SCSI_VQ_CTL = 0,
> +    VHOST_SCSI_VQ_EVT = 1,
> +    VHOST_SCSI_VQ_IO = 2,
> +    VHOST_SCSI_VQ_NUM = 3,
> +};
> +
> +#define VHOST_VIRTIO 0xAF
> +#define VHOST_SCSI_SET_ENDPOINT _IOW(VHOST_VIRTIO, 0x40, struct 
> vhost_scsi_target)
> +#define VHOST_SCSI_CLEAR_ENDPOINT _IOW(VHOST_VIRTIO, 0x41, struct 
> vhost_scsi_target)
> +#define VHOST_SCSI_GET_ABI_VERSION _IOW(VHOST_VIRTIO, 0x42, int)
> +
> +extern PropertyInfo qdev_prop_vhost_scsi;
> +
> +#define DEFINE_PROP_VHOST_SCSI(_n, _s, _f) \
> +    DEFINE_PROP(_n, _s, _f, qdev_prop_vhost_scsi, VHostSCSI*)
> +
> +VHostSCSI *find_vhost_scsi(const char *id);
> +const char *vhost_scsi_get_id(VHostSCSI *vs);
> +VHostSCSI *vhost_scsi_add_opts(QemuOpts *opts);
> +int vhost_scsi_start(VHostSCSI *vs, VirtIODevice *vdev);
> +void vhost_scsi_stop(VHostSCSI *vs, VirtIODevice *vdev);
> +
> +#endif
> diff --git a/qemu-common.h b/qemu-common.h
> index f9deca6..ec36002 100644
> --- a/qemu-common.h
> +++ b/qemu-common.h
> @@ -280,6 +280,7 @@ typedef struct EventNotifier EventNotifier;
>  typedef struct VirtIODevice VirtIODevice;
>  typedef struct QEMUSGList QEMUSGList;
>  typedef struct SHPCDevice SHPCDevice;
> +typedef struct VHostSCSI VHostSCSI;
>  
>  typedef uint64_t pcibus_t;
>  
> diff --git a/qemu-config.c b/qemu-config.c
> index 5c3296b..2d4884c 100644
> --- a/qemu-config.c
> +++ b/qemu-config.c
> @@ -626,6 +626,24 @@ QemuOptsList qemu_boot_opts = {
>      },
>  };
>  
> +QemuOptsList qemu_vhost_scsi_opts = {
> +    .name = "vhost-scsi",
> +    .head = QTAILQ_HEAD_INITIALIZER(qemu_vhost_scsi_opts.head),
> +    .desc = {
> +        {
> +            .name = "wwpn",
> +            .type = QEMU_OPT_STRING,
> +        }, {
> +            .name = "tpgt",
> +            .type = QEMU_OPT_NUMBER,
> +        }, {
> +            .name = "vhostfd",
> +            .type = QEMU_OPT_STRING,
> +        },
> +        { /* end of list */ }
> +    },
> +};
> +
>  static QemuOptsList *vm_config_groups[32] = {
>      &qemu_drive_opts,
>      &qemu_chardev_opts,
> @@ -641,6 +659,7 @@ static QemuOptsList *vm_config_groups[32] = {
>      &qemu_machine_opts,
>      &qemu_boot_opts,
>      &qemu_iscsi_opts,
> +    &qemu_vhost_scsi_opts,
>      NULL,
>  };
>  
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 47cb5bd..4e7a03c 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -565,6 +565,10 @@ possible drivers and properties, use @code{-device ?} and
>  ETEXI
>  
>  DEFHEADING()
> +DEF("vhost-scsi", HAS_ARG, QEMU_OPTION_vhost_scsi,
> +    "-vhost-scsi wwpn=string0,tpgt=number0\n"
> +    "                add vhost-scsi device\n",
> +    QEMU_ARCH_ALL)
>  
>  DEFHEADING(File system options:)
>  
> diff --git a/vl.c b/vl.c
> index 91076f0..61c8284 100644
> --- a/vl.c
> +++ b/vl.c
> @@ -144,6 +144,7 @@ int main(int argc, char **argv)
>  #include "qemu-options.h"
>  #include "qmp-commands.h"
>  #include "main-loop.h"
> +#include "hw/vhost-scsi.h"
>  #ifdef CONFIG_VIRTFS
>  #include "fsdev/qemu-fsdev.h"
>  #endif
> @@ -1858,6 +1859,14 @@ static int fsdev_init_func(QemuOpts *opts, void 
> *opaque)
>  }
>  #endif
>  
> +static int vhost_scsi_init_func(QemuOpts *opts, void *opaque)
> +{
> +    if (!vhost_scsi_add_opts(opts)) {
> +        return -1;
> +    }
> +    return 0;
> +}
> +
>  static int mon_init_func(QemuOpts *opts, void *opaque)
>  {
>      CharDriverState *chr;
> @@ -2617,6 +2626,11 @@ int main(int argc, char **argv, char **envp)
>                  }
>                  break;
>  #endif
> +            case QEMU_OPTION_vhost_scsi:
> +                if (!qemu_opts_parse(qemu_find_opts("vhost-scsi"), optarg, 
> 0)) {
> +                    exit(1);
> +                }
> +                break;
>  #ifdef CONFIG_SLIRP
>              case QEMU_OPTION_tftp:
>                  legacy_tftp_prefix = optarg;
> @@ -3337,6 +3351,10 @@ int main(int argc, char **argv, char **envp)
>          exit(1);
>      }
>  #endif
> +    if (qemu_opts_foreach(qemu_find_opts("vhost-scsi"),
> +                          vhost_scsi_init_func, NULL, 1)) {
> +        exit(1);
> +    }
>  
>      os_daemonize();
>  
> -- 
> 1.7.2.5