Re: [RFC-v2 3/6] vhost-scsi: add -vhost-scsi host device for use with tcm-vhost

["Michael S. Tsirkin" <mst@redhat.com>]

On Tue, Aug 14, 2012 at 02:12:29PM -0700, Nicholas A. Bellinger wrote:
> On Mon, 2012-08-13 at 11:59 +0300, Michael S. Tsirkin wrote:
> > On Mon, Aug 13, 2012 at 08:35:14AM +0000, Nicholas A. Bellinger wrote:
> > > From: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
> > > 
> > > 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
> > > 
> > > 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 <stefanha@linux.vnet.ibm.com>
> > > Cc: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
> > > Cc: Anthony Liguori <aliguori@us.ibm.com>
> > > Cc: Paolo Bonzini <pbonzini@redhat.com>
> > > Cc: Michael S. Tsirkin <mst@redhat.com>
> > > Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
> > 
> > 
> > Sent mail too fast, sorry. More comments below.
> > 
> > > ---
> > >  configure            |   10 +++
> > >  hw/Makefile.objs     |    1 +
> > >  hw/qdev-properties.c |   40 ++++++++++++
> > >  hw/qdev.h            |    3 +
> > >  hw/vhost-scsi.c      |  170 ++++++++++++++++++++++++++++++++++++++++++++++++++
> > >  hw/vhost-scsi.h      |   50 +++++++++++++++
> > >  qemu-common.h        |    1 +
> > >  qemu-config.c        |   16 +++++
> > >  qemu-options.hx      |    4 +
> > >  vl.c                 |   18 +++++
> > >  10 files changed, 313 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..0266266 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 +697,45 @@ 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!  */
> > 
> > Why does this make sense in the generic qdev-properties?
> > There's exactly one device that can use this, no?
> > 
> 
> Mmmm, not sure on this one either..  Stefan..?
> 
> > > diff --git a/hw/qdev.h b/hw/qdev.h
> > > index d699194..d5873bb 100644
> > > --- a/hw/qdev.h
> > > +++ b/hw/qdev.h
> > > @@ -238,6 +238,7 @@ extern PropertyInfo qdev_prop_vlan;
> > >  extern PropertyInfo qdev_prop_pci_devfn;
> > >  extern PropertyInfo qdev_prop_blocksize;
> > >  extern PropertyInfo qdev_prop_pci_host_devaddr;
> > > +extern PropertyInfo qdev_prop_vhost_scsi;
> > >  
> > >  #define DEFINE_PROP(_name, _state, _field, _prop, _type) { \
> > >          .name      = (_name),                                    \
> > > @@ -305,6 +306,8 @@ extern PropertyInfo qdev_prop_pci_host_devaddr;
> > >      DEFINE_PROP_DEFAULT(_n, _s, _f, _d, qdev_prop_blocksize, uint16_t)
> > >  #define DEFINE_PROP_PCI_HOST_DEVADDR(_n, _s, _f) \
> > >      DEFINE_PROP(_n, _s, _f, qdev_prop_pci_host_devaddr, PCIHostDeviceAddress)
> > > +#define DEFINE_PROP_VHOST_SCSI(_n, _s, _f)       \
> > > +    DEFINE_PROP(_n, _s, _f, qdev_prop_vhost_scsi, VHostSCSI*)
> > >
> > 
> > Can this move to vhost-scsi.c?
> >   
> 
> Done
> 
> > >  #define DEFINE_PROP_END_OF_LIST()               \
> > >      {}
> > > diff --git a/hw/vhost-scsi.c b/hw/vhost-scsi.c
> > > new file mode 100644
> > > index 0000000..7145b2d
> > > --- /dev/null
> > > +++ b/hw/vhost-scsi.c
> > > @@ -0,0 +1,170 @@
> > > +/*
> > > + * vhost_scsi host device
> > > + *
> > > + * Copyright IBM, Corp. 2011
> > > + *
> > > + * Authors:
> > > + *  Stefan Hajnoczi   <stefanha@linux.vnet.ibm.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 <sys/ioctl.h>
> > > +#include "config.h"
> > > +#include "qemu-queue.h"
> > > +#include "vhost-scsi.h"
> > > +#include "vhost.h"
> > > +
> > > +struct VHostSCSI {
> > > +    const char *id;
> > > +    const char *wwpn;
> > > +    uint16_t tpgt;
> > > +    struct vhost_dev dev;
> > > +    struct vhost_virtqueue vqs[3];
> > 
> > Could you add enum for vq numbers pls?
> > 
> 
> Done
> 
> > > +    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) == 0) {
> > 
> > !strcmp
> > 
> 
> Done
> 
> > > +            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 = 3;
> > > +    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;
> > > +    }
> > > +
> > > +    memset(&backend, 0, sizeof(backend));
> > > +    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) {
> > > +        fprintf(stderr, "The running tcm_vhost kernel abi_version: %d is greater"
> > > +		" than vhost_scsi userspace supports: %d\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);
> > > +
> > > +    pstrcpy((char *)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;
> > > +
> > > +    pstrcpy((char *)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) {
> > > +        fprintf(stderr, "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)
> > > +{
> > > +    VHostSCSI *vs = g_malloc0(sizeof(*vs));
> > > +    int ret;
> > > +
> > > +    /* TODO set up vhost-scsi device and bind to tcm_vhost/$wwpm/tpgt_$tpgt */
> > > +    fprintf(stderr, "wwpn = \"%s\" tpgt = \"%u\"\n", id, tpgt);
> > > +
> > 
> > Please do not keep debugging fprintfs around.
> > 
> 
> Dropped
> 
> > > +    ret = vhost_dev_init(&vs->dev, -1, "/dev/vhost-scsi", false);
> > 
> > commented on this separately
> > 
> 
> ...
> 
> > > +    if (ret < 0) {
> > > +        fprintf(stderr, "vhost-scsi: vhost initialization failed: %s\n",
> > > +                strerror(-ret));
> > 
> > errors should go to monitor, here and elsewhere.
> > 
> 
> I think this means using monitor_printf() right..?
> 
> Looking at that now..


error_report is handier.