[Qemu-devel] [PATCH 0/5] vhost-scsi: Add support for host virtualized target

[Qemu-devel] [PATCH 0/5] vhost-scsi: Add support for host virtualized target

[Nicholas A. Bellinger]

From: Nicholas Bellinger <nab@linux-iscsi.org>

Hello Anthony & Co,

This is the fourth installment to add host virtualized target support for
the mainline tcm_vhost fabric driver using Linux v3.6-rc into QEMU 1.3.0-rc.

The series is available directly from the following git branch:

   git://git.kernel.org/pub/scm/virt/kvm/nab/qemu-kvm.git vhost-scsi-for-1.3

Note the code is cut against yesterday's QEMU head, and dispite the name
of the tree is based upon mainline qemu.org git code + has thus far been
running overnight with > 100K IOPs small block 4k workloads using v3.6-rc2+
based target code with RAMDISK_DR backstores.

Other than some minor fuzz between jumping from QEMU 1.2.0 -> 1.2.50, this
series is functionally identical to what's been posted for vhost-scsi RFC-v3
to qemu-devel.

Please consider applying these patches for an initial vhost-scsi merge into
QEMU 1.3.0-rc code, or let us know what else you'd like to see addressed for
this series to in order to merge.

Thank you!

--nab

Nicholas Bellinger (2):
  monitor: Rename+move net_handle_fd_param -> monitor_handle_fd_param
  virtio-scsi: Set max_target=0 during vhost-scsi operation

Stefan Hajnoczi (3):
  vhost: Pass device path to vhost_dev_init()
  vhost-scsi: add -vhost-scsi host device for use with tcm-vhost
  virtio-scsi: Add start/stop functionality for vhost-scsi

 configure            |   10 +++
 hw/Makefile.objs     |    1 +
 hw/qdev-properties.c |   41 +++++++++++
 hw/vhost-scsi.c      |  190 ++++++++++++++++++++++++++++++++++++++++++++++++++
 hw/vhost-scsi.h      |   62 ++++++++++++++++
 hw/vhost.c           |    5 +-
 hw/vhost.h           |    3 +-
 hw/vhost_net.c       |    2 +-
 hw/virtio-pci.c      |    2 +
 hw/virtio-scsi.c     |   55 ++++++++++++++-
 hw/virtio-scsi.h     |    1 +
 monitor.c            |   18 +++++
 monitor.h            |    1 +
 net.c                |   18 -----
 net.h                |    2 -
 net/socket.c         |    2 +-
 net/tap.c            |    4 +-
 qemu-common.h        |    1 +
 qemu-config.c        |   19 +++++
 qemu-options.hx      |    4 +
 vl.c                 |   18 +++++
 21 files changed, 431 insertions(+), 28 deletions(-)
 create mode 100644 hw/vhost-scsi.c
 create mode 100644 hw/vhost-scsi.h

-- 
1.7.2.5

[Qemu-devel] [PATCH 1/5] monitor: Rename+move net_handle_fd_param -> monitor_handle_fd_param

[Nicholas A. Bellinger]

From: Nicholas Bellinger <nab@linux-iscsi.org>

This patch renames+moves the net_handle_fd_param() caller used to
obtain a file descriptor from either qemu_parse_fd() (the normal case)
or from monitor_get_fd() (migration case) into a generically prefixed
monitor_handle_fd_param() to be used by vhost-scsi code.

Also update net/[socket,tap].c consumers to use the new prefix.

Reported-by: Michael S. Tsirkin <mst@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
 monitor.c    |   18 ++++++++++++++++++
 monitor.h    |    1 +
 net.c        |   18 ------------------
 net.h        |    2 --
 net/socket.c |    2 +-
 net/tap.c    |    4 ++--
 6 files changed, 22 insertions(+), 23 deletions(-)

diff --git a/monitor.c b/monitor.c
index 49dccfe..0641efe 100644
--- a/monitor.c
+++ b/monitor.c
@@ -2389,6 +2389,24 @@ int monitor_get_fd(Monitor *mon, const char *fdname)
     return -1;
 }
 
+int monitor_handle_fd_param(Monitor *mon, const char *fdname)
+{
+    int fd;
+
+    if (!qemu_isdigit(fdname[0]) && mon) {
+
+        fd = monitor_get_fd(mon, fdname);
+        if (fd == -1) {
+            error_report("No file descriptor named %s found", fdname);
+            return -1;
+        }
+    } else {
+        fd = qemu_parse_fd(fdname);
+    }
+
+    return fd;
+}
+
 /* mon_cmds and info_cmds would be sorted at runtime */
 static mon_cmd_t mon_cmds[] = {
 #include "hmp-commands.h"
diff --git a/monitor.h b/monitor.h
index 5f4de1b..d557e97 100644
--- a/monitor.h
+++ b/monitor.h
@@ -65,6 +65,7 @@ int monitor_read_block_device_key(Monitor *mon, const char *device,
                                   void *opaque);
 
 int monitor_get_fd(Monitor *mon, const char *fdname);
+int monitor_handle_fd_param(Monitor *mon, const char *fdname);
 
 void monitor_vprintf(Monitor *mon, const char *fmt, va_list ap)
     GCC_FMT_ATTR(2, 0);
diff --git a/net.c b/net.c
index 60043dd..e5d25d4 100644
--- a/net.c
+++ b/net.c
@@ -522,24 +522,6 @@ int qemu_find_nic_model(NICInfo *nd, const char * const *models,
     return -1;
 }
 
-int net_handle_fd_param(Monitor *mon, const char *param)
-{
-    int fd;
-
-    if (!qemu_isdigit(param[0]) && mon) {
-
-        fd = monitor_get_fd(mon, param);
-        if (fd == -1) {
-            error_report("No file descriptor named %s found", param);
-            return -1;
-        }
-    } else {
-        fd = qemu_parse_fd(param);
-    }
-
-    return fd;
-}
-
 static int net_init_nic(const NetClientOptions *opts, const char *name,
                         NetClientState *peer)
 {
diff --git a/net.h b/net.h
index 2975056..04fda1d 100644
--- a/net.h
+++ b/net.h
@@ -168,8 +168,6 @@ int qmp_netdev_add(Monitor *mon, const QDict *qdict, QObject **ret);
 
 void qdev_set_nic_properties(DeviceState *dev, NICInfo *nd);
 
-int net_handle_fd_param(Monitor *mon, const char *param);
-
 #define POLYNOMIAL 0x04c11db6
 unsigned compute_mcast_idx(const uint8_t *ep);
 
diff --git a/net/socket.c b/net/socket.c
index c172c24..7c602e4 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -629,7 +629,7 @@ int net_init_socket(const NetClientOptions *opts, const char *name,
     if (sock->has_fd) {
         int fd;
 
-        fd = net_handle_fd_param(cur_mon, sock->fd);
+        fd = monitor_handle_fd_param(cur_mon, sock->fd);
         if (fd == -1 || !net_socket_fd_init(peer, "socket", name, fd, 1)) {
             return -1;
         }
diff --git a/net/tap.c b/net/tap.c
index 1971525..a88ae8f 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -610,7 +610,7 @@ int net_init_tap(const NetClientOptions *opts, const char *name,
             return -1;
         }
 
-        fd = net_handle_fd_param(cur_mon, tap->fd);
+        fd = monitor_handle_fd_param(cur_mon, tap->fd);
         if (fd == -1) {
             return -1;
         }
@@ -686,7 +686,7 @@ int net_init_tap(const NetClientOptions *opts, const char *name,
         int vhostfd;
 
         if (tap->has_vhostfd) {
-            vhostfd = net_handle_fd_param(cur_mon, tap->vhostfd);
+            vhostfd = monitor_handle_fd_param(cur_mon, tap->vhostfd);
             if (vhostfd == -1) {
                 return -1;
             }
-- 
1.7.2.5

[Qemu-devel] [PATCH 2/5] vhost: Pass device path to vhost_dev_init()

[Nicholas A. Bellinger]

From: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>

The path to /dev/vhost-net is currently hardcoded in vhost_dev_init().
This needs to be changed so that /dev/vhost-scsi can be used.  Pass in
the device path instead of hardcoding it.

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
 hw/vhost.c     |    5 +++--
 hw/vhost.h     |    3 ++-
 hw/vhost_net.c |    2 +-
 3 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/hw/vhost.c b/hw/vhost.c
index 0fd8da8..d0ce5aa 100644
--- a/hw/vhost.c
+++ b/hw/vhost.c
@@ -747,14 +747,15 @@ static void vhost_eventfd_del(MemoryListener *listener,
 {
 }
 
-int vhost_dev_init(struct vhost_dev *hdev, int devfd, bool force)
+int vhost_dev_init(struct vhost_dev *hdev, int devfd, const char *devpath,
+                   bool force)
 {
     uint64_t features;
     int r;
     if (devfd >= 0) {
         hdev->control = devfd;
     } else {
-        hdev->control = open("/dev/vhost-net", O_RDWR);
+        hdev->control = open(devpath, O_RDWR);
         if (hdev->control < 0) {
             return -errno;
         }
diff --git a/hw/vhost.h b/hw/vhost.h
index 80e64df..0c47229 100644
--- a/hw/vhost.h
+++ b/hw/vhost.h
@@ -44,7 +44,8 @@ struct vhost_dev {
     bool force;
 };
 
-int vhost_dev_init(struct vhost_dev *hdev, int devfd, bool force);
+int vhost_dev_init(struct vhost_dev *hdev, int devfd, const char *devpath,
+                   bool force);
 void vhost_dev_cleanup(struct vhost_dev *hdev);
 bool vhost_dev_query(struct vhost_dev *hdev, VirtIODevice *vdev);
 int vhost_dev_start(struct vhost_dev *hdev, VirtIODevice *vdev);
diff --git a/hw/vhost_net.c b/hw/vhost_net.c
index ecaa22d..df2c4a3 100644
--- a/hw/vhost_net.c
+++ b/hw/vhost_net.c
@@ -109,7 +109,7 @@ struct vhost_net *vhost_net_init(NetClientState *backend, int devfd,
         (1 << VHOST_NET_F_VIRTIO_NET_HDR);
     net->backend = r;
 
-    r = vhost_dev_init(&net->dev, devfd, force);
+    r = vhost_dev_init(&net->dev, devfd, "/dev/vhost-net", force);
     if (r < 0) {
         goto fail;
     }
-- 
1.7.2.5

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

[Nicholas A. Bellinger]

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 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 <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>
---
 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   <stefanha@linux.vnet.ibm.com>
+ *
+ * Changes for QEMU mainline + tcm_vhost kernel upstream:
+ *  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 <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   <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.
+ *
+ */
+
+#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

[Qemu-devel] [PATCH 4/5] virtio-scsi: Add start/stop functionality for vhost-scsi

[Nicholas A. Bellinger]

From: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>

This patch starts and stops vhost as the virtio device transitions
through its status phases.  Vhost can only be started once the guest
reports its driver has successfully initialized, which means the
virtqueues have been set up by the guest.

v3: - Add vhost-scsi.h include for DEFINE_PROP_VHOST_SCSI (mst + nab)
    - Move vhost-scsi related struct members ahead of *cmd_vqs[0] within
      VirtIOSCSI definition.  (paolo + nab)

v2: - Squash virtio-scsi: use the vhost-scsi host device from stefan (nab)
    - Fix up virtio_scsi_properties[] conflict w/ upstream qemu (nab)
    - Drop usage of to_virtio_scsi() in virtio_scsi_set_status()
      (reported by paolo)
    - Use modern VirtIOSCSIConf define in virtio-scsi.h (reported by paolo)
    - Use s->conf->vhost_scsi instead of proxyconf->vhost_scsi in
      virtio_scsi_init() (reported by paolo)
    - Only register QEMU SCSI bus is vhost-scsi is not active (reported
      by paolo)

Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Cc: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Cc: Michael S. Tsirkin <mst@redhat.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
 hw/virtio-pci.c  |    2 ++
 hw/virtio-scsi.c |   49 +++++++++++++++++++++++++++++++++++++++++++++++++
 hw/virtio-scsi.h |    1 +
 3 files changed, 52 insertions(+), 0 deletions(-)

diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index 125eded..8ec7cf1 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -22,6 +22,7 @@
 #include "virtio-net.h"
 #include "virtio-serial.h"
 #include "virtio-scsi.h"
+#include "vhost-scsi.h"
 #include "pci.h"
 #include "qemu-error.h"
 #include "msi.h"
@@ -1036,6 +1037,7 @@ static void virtio_scsi_exit_pci(PCIDevice *pci_dev)
 }
 
 static Property virtio_scsi_properties[] = {
+    DEFINE_PROP_VHOST_SCSI("vhost-scsi", VirtIOPCIProxy, scsi.vhost_scsi),
     DEFINE_PROP_BIT("ioeventfd", VirtIOPCIProxy, flags, VIRTIO_PCI_FLAG_USE_IOEVENTFD_BIT, true),
     DEFINE_PROP_UINT32("vectors", VirtIOPCIProxy, nvectors, DEV_NVECTORS_UNSPECIFIED),
     DEFINE_VIRTIO_SCSI_PROPERTIES(VirtIOPCIProxy, host_features, scsi),
diff --git a/hw/virtio-scsi.c b/hw/virtio-scsi.c
index 5f737ac..edda097 100644
--- a/hw/virtio-scsi.c
+++ b/hw/virtio-scsi.c
@@ -13,9 +13,13 @@
  *
  */
 
+#include "qemu-common.h"
+#include "qemu-error.h"
+#include "vhost-scsi.h"
 #include "virtio-scsi.h"
 #include <hw/scsi.h>
 #include <hw/scsi-defs.h>
+#include "vhost.h"
 
 #define VIRTIO_SCSI_VQ_SIZE     128
 #define VIRTIO_SCSI_CDB_SIZE    32
@@ -144,6 +148,10 @@ typedef struct {
     uint32_t cdb_size;
     int resetting;
     bool events_dropped;
+
+    bool vhost_started;
+    VHostSCSI *vhost_scsi;
+
     VirtQueue *ctrl_vq;
     VirtQueue *event_vq;
     VirtQueue *cmd_vqs[0];
@@ -699,6 +707,38 @@ static struct SCSIBusInfo virtio_scsi_scsi_info = {
     .load_request = virtio_scsi_load_request,
 };
 
+static bool virtio_scsi_started(VirtIOSCSI *s, uint8_t val)
+{
+    return (val & VIRTIO_CONFIG_S_DRIVER_OK) && s->vdev.vm_running;
+}
+
+static void virtio_scsi_set_status(VirtIODevice *vdev, uint8_t val)
+{
+    VirtIOSCSI *s = (VirtIOSCSI *)vdev;
+    bool start = virtio_scsi_started(s, val);
+
+    if (s->vhost_started == start) {
+        return;
+    }
+
+    if (start) {
+        int ret;
+
+        ret = vhost_scsi_start(s->vhost_scsi, vdev);
+        if (ret < 0) {
+            error_report("virtio-scsi: unable to start vhost: %s\n",
+                         strerror(-ret));
+
+            /* There is no userspace virtio-scsi fallback so exit */
+            exit(1);
+        }
+    } else {
+        vhost_scsi_stop(s->vhost_scsi, vdev);
+    }
+
+    s->vhost_started = start;
+}
+
 VirtIODevice *virtio_scsi_init(DeviceState *dev, VirtIOSCSIConf *proxyconf)
 {
     VirtIOSCSI *s;
@@ -712,12 +752,17 @@ VirtIODevice *virtio_scsi_init(DeviceState *dev, VirtIOSCSIConf *proxyconf)
 
     s->qdev = dev;
     s->conf = proxyconf;
+    s->vhost_started = false;
+    s->vhost_scsi = s->conf->vhost_scsi;
 
     /* TODO set up vdev function pointers */
     s->vdev.get_config = virtio_scsi_get_config;
     s->vdev.set_config = virtio_scsi_set_config;
     s->vdev.get_features = virtio_scsi_get_features;
     s->vdev.reset = virtio_scsi_reset;
+    if (s->vhost_scsi) {
+        s->vdev.set_status = virtio_scsi_set_status;
+    }
 
     s->ctrl_vq = virtio_add_queue(&s->vdev, VIRTIO_SCSI_VQ_SIZE,
                                    virtio_scsi_handle_ctrl);
@@ -743,5 +788,9 @@ void virtio_scsi_exit(VirtIODevice *vdev)
 {
     VirtIOSCSI *s = (VirtIOSCSI *)vdev;
     unregister_savevm(s->qdev, "virtio-scsi", s);
+
+    /* This will stop vhost backend if appropriate. */
+    virtio_scsi_set_status(vdev, 0);
+
     virtio_cleanup(vdev);
 }
diff --git a/hw/virtio-scsi.h b/hw/virtio-scsi.h
index 4bc889d..74e9422 100644
--- a/hw/virtio-scsi.h
+++ b/hw/virtio-scsi.h
@@ -22,6 +22,7 @@
 #define VIRTIO_SCSI_F_CHANGE                   2
 
 struct VirtIOSCSIConf {
+    VHostSCSI *vhost_scsi;
     uint32_t num_queues;
     uint32_t max_sectors;
     uint32_t cmd_per_lun;
-- 
1.7.2.5

Re: [Qemu-devel] [PATCH 4/5] virtio-scsi: Add start/stop functionality for vhost-scsi

[Paolo Bonzini]

Il 07/09/2012 08:48, Nicholas A. Bellinger ha scritto:
> Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
> Cc: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
> ---
>  hw/virtio-pci.c  |    2 ++
>  hw/virtio-scsi.c |   49 +++++++++++++++++++++++++++++++++++++++++++++++++
>  hw/virtio-scsi.h |    1 +
>  3 files changed, 52 insertions(+), 0 deletions(-)

Please create a completely separate device vhost-scsi-pci instead (or
virtio-scsi-tcm-pci, or something like that).  It is used completely
differently from virtio-scsi-pci, it does not make sense to conflate the
two.

Paolo

Re: [Qemu-devel] [PATCH 4/5] virtio-scsi: Add start/stop functionality for vhost-scsi

[Nicholas A. Bellinger]

On Fri, 2012-09-07 at 18:00 +0200, Paolo Bonzini wrote:
> Il 07/09/2012 08:48, Nicholas A. Bellinger ha scritto:
> > Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
> > Cc: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
> > Cc: Michael S. Tsirkin <mst@redhat.com>
> > Cc: Paolo Bonzini <pbonzini@redhat.com>
> > Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
> > ---
> >  hw/virtio-pci.c  |    2 ++
> >  hw/virtio-scsi.c |   49 +++++++++++++++++++++++++++++++++++++++++++++++++
> >  hw/virtio-scsi.h |    1 +
> >  3 files changed, 52 insertions(+), 0 deletions(-)
> 
> Please create a completely separate device vhost-scsi-pci instead (or
> virtio-scsi-tcm-pci, or something like that).  It is used completely
> differently from virtio-scsi-pci, it does not make sense to conflate the
> two.
> 

Ok, I need to figure out what this will involve over the next days, and
will likely have some more questions for you to get a standlone
vhost-scsi-pci up and running.

Also just curious (question for Anthony + QEMU folks), how long can we
expect the QEMU 1.3 merge window to be open..?

Thanks Paolo!

--nab

Re: [Qemu-devel] [PATCH 4/5] virtio-scsi: Add start/stop functionality for vhost-scsi

[Paolo Bonzini]

Il 07/09/2012 21:23, Nicholas A. Bellinger ha scritto:
>> > Please create a completely separate device vhost-scsi-pci instead (or
>> > virtio-scsi-tcm-pci, or something like that).  It is used completely
>> > differently from virtio-scsi-pci, it does not make sense to conflate the
>> > two.
>> > 
> Ok, I need to figure out what this will involve over the next days, and
> will likely have some more questions for you to get a standlone
> vhost-scsi-pci up and running.
> 
> Also just curious (question for Anthony + QEMU folks), how long can we
> expect the QEMU 1.3 merge window to be open..?

wiki.qemu.org/Planning/1.3 - no hurry, until November 15th.

Paolo

Re: [Qemu-devel] [PATCH 4/5] virtio-scsi: Add start/stop functionality for vhost-scsi

[Michael S. Tsirkin]

On Fri, Sep 07, 2012 at 06:00:50PM +0200, Paolo Bonzini wrote:
> Il 07/09/2012 08:48, Nicholas A. Bellinger ha scritto:
> > Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
> > Cc: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
> > Cc: Michael S. Tsirkin <mst@redhat.com>
> > Cc: Paolo Bonzini <pbonzini@redhat.com>
> > Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
> > ---
> >  hw/virtio-pci.c  |    2 ++
> >  hw/virtio-scsi.c |   49 +++++++++++++++++++++++++++++++++++++++++++++++++
> >  hw/virtio-scsi.h |    1 +
> >  3 files changed, 52 insertions(+), 0 deletions(-)
> 
> Please create a completely separate device vhost-scsi-pci instead (or
> virtio-scsi-tcm-pci, or something like that).  It is used completely
> differently from virtio-scsi-pci, it does not make sense to conflate the
> two.
> 
> Paolo

Ideally the name would say how it is different, not what backend it
uses. Any good suggestions?

-- 
MST

Re: [Qemu-devel] [PATCH 4/5] virtio-scsi: Add start/stop functionality for vhost-scsi

[Paolo Bonzini]

Il 09/09/2012 00:40, Michael S. Tsirkin ha scritto:
> On Fri, Sep 07, 2012 at 06:00:50PM +0200, Paolo Bonzini wrote:
>> Il 07/09/2012 08:48, Nicholas A. Bellinger ha scritto:
>>> Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
>>> Cc: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
>>> Cc: Michael S. Tsirkin <mst@redhat.com>
>>> Cc: Paolo Bonzini <pbonzini@redhat.com>
>>> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
>>> ---
>>>  hw/virtio-pci.c  |    2 ++
>>>  hw/virtio-scsi.c |   49 +++++++++++++++++++++++++++++++++++++++++++++++++
>>>  hw/virtio-scsi.h |    1 +
>>>  3 files changed, 52 insertions(+), 0 deletions(-)
>>
>> Please create a completely separate device vhost-scsi-pci instead (or
>> virtio-scsi-tcm-pci, or something like that).  It is used completely
>> differently from virtio-scsi-pci, it does not make sense to conflate the
>> two.
> 
> Ideally the name would say how it is different, not what backend it
> uses. Any good suggestions?

I chose the backend name because, ideally, there would be no other
difference.  QEMU _could_ implement all the goodies in vhost-scsi (such
as reservations or ALUA), it just doesn't do that yet.

Paolo

Re: [Qemu-devel] [PATCH 4/5] virtio-scsi: Add start/stop functionality for vhost-scsi

[Michael S. Tsirkin]

On Mon, Sep 10, 2012 at 08:16:54AM +0200, Paolo Bonzini wrote:
> Il 09/09/2012 00:40, Michael S. Tsirkin ha scritto:
> > On Fri, Sep 07, 2012 at 06:00:50PM +0200, Paolo Bonzini wrote:
> >> Il 07/09/2012 08:48, Nicholas A. Bellinger ha scritto:
> >>> Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
> >>> Cc: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
> >>> Cc: Michael S. Tsirkin <mst@redhat.com>
> >>> Cc: Paolo Bonzini <pbonzini@redhat.com>
> >>> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
> >>> ---
> >>>  hw/virtio-pci.c  |    2 ++
> >>>  hw/virtio-scsi.c |   49 +++++++++++++++++++++++++++++++++++++++++++++++++
> >>>  hw/virtio-scsi.h |    1 +
> >>>  3 files changed, 52 insertions(+), 0 deletions(-)
> >>
> >> Please create a completely separate device vhost-scsi-pci instead (or
> >> virtio-scsi-tcm-pci, or something like that).  It is used completely
> >> differently from virtio-scsi-pci, it does not make sense to conflate the
> >> two.
> > 
> > Ideally the name would say how it is different, not what backend it
> > uses. Any good suggestions?
> 
> I chose the backend name because, ideally, there would be no other
> difference.  QEMU _could_ implement all the goodies in vhost-scsi (such
> as reservations or ALUA), it just doesn't do that yet.
> 
> Paolo

Then why do you say "It is used completely differently from
virtio-scsi-pci"?  Isn't it just a different backend?

If yes then it should be a backend option, like it is
for virtio-net.

-- 
MST

Re: [Qemu-devel] [PATCH 4/5] virtio-scsi: Add start/stop functionality for vhost-scsi

[Paolo Bonzini]

Il 10/09/2012 08:24, Michael S. Tsirkin ha scritto:
>> > I chose the backend name because, ideally, there would be no other
>> > difference.  QEMU _could_ implement all the goodies in vhost-scsi (such
>> > as reservations or ALUA), it just doesn't do that yet.
>> > 
>> > Paolo
> Then why do you say "It is used completely differently from
> virtio-scsi-pci"?

It is configured differently (and I haven't seen a proposal yet for how
to bridge the two), it does not interoperate, it has right now a
different set of features.

The "does not interoperate" bit is particularly important.  Say QEMU
were to implement persistent reservations (right now only a vhost-scsi
feature).  Then QEMU and vhost-scsi PR would not be interchangeable, a
reservation made by QEMU would not be visible in vhost and vice versa.

> Isn't it just a different backend?
> 
> If yes then it should be a backend option, like it is
> for virtio-net.

You mean a -drive option?  That would mean adding the logic to configure
vhost-scsi to the QEMU block layer, that's a completely different project...

Paolo

Re: [Qemu-devel] [PATCH 4/5] virtio-scsi: Add start/stop functionality for vhost-scsi

[Michael S. Tsirkin]

On Mon, Sep 10, 2012 at 08:42:15AM +0200, Paolo Bonzini wrote:
> Il 10/09/2012 08:24, Michael S. Tsirkin ha scritto:
> >> > I chose the backend name because, ideally, there would be no other
> >> > difference.  QEMU _could_ implement all the goodies in vhost-scsi (such
> >> > as reservations or ALUA), it just doesn't do that yet.
> >> > 
> >> > Paolo
> > Then why do you say "It is used completely differently from
> > virtio-scsi-pci"?
> 
> It is configured differently (and I haven't seen a proposal yet for how
> to bridge the two), it does not interoperate, it has right now a
> different set of features.
> 
> The "does not interoperate" bit is particularly important.  Say QEMU
> were to implement persistent reservations (right now only a vhost-scsi
> feature).  Then QEMU and vhost-scsi PR would not be interchangeable, a
> reservation made by QEMU would not be visible in vhost and vice versa.

So this is backend stuff, right?

> > Isn't it just a different backend?
> > 
> > If yes then it should be a backend option, like it is
> > for virtio-net.
> 
> You mean a -drive option?

Yes.

> That would mean adding the logic to configure
> vhost-scsi to the QEMU block layer, that's a completely different project...
> 
> Paolo

This is an implementation detail. You can make it -drive option
but still have all the actual logic outside block layer.
All you need in block is option parsing code.
Please take a look at how -net does this:
we did *not* add all logic to qemu net layer.

Re: [Qemu-devel] [PATCH 4/5] virtio-scsi: Add start/stop functionality for vhost-scsi

[Anthony Liguori]

On 09/10/2012 01:24 AM, Michael S. Tsirkin wrote:
> On Mon, Sep 10, 2012 at 08:16:54AM +0200, Paolo Bonzini wrote:
>> Il 09/09/2012 00:40, Michael S. Tsirkin ha scritto:
>>> On Fri, Sep 07, 2012 at 06:00:50PM +0200, Paolo Bonzini wrote:
>>>> Il 07/09/2012 08:48, Nicholas A. Bellinger ha scritto:
>>>>> Cc: Stefan Hajnoczi<stefanha@linux.vnet.ibm.com>
>>>>> Cc: Zhi Yong Wu<wuzhy@linux.vnet.ibm.com>
>>>>> Cc: Michael S. Tsirkin<mst@redhat.com>
>>>>> Cc: Paolo Bonzini<pbonzini@redhat.com>
>>>>> Signed-off-by: Nicholas Bellinger<nab@linux-iscsi.org>
>>>>> ---
>>>>>   hw/virtio-pci.c  |    2 ++
>>>>>   hw/virtio-scsi.c |   49 +++++++++++++++++++++++++++++++++++++++++++++++++
>>>>>   hw/virtio-scsi.h |    1 +
>>>>>   3 files changed, 52 insertions(+), 0 deletions(-)
>>>>
>>>> Please create a completely separate device vhost-scsi-pci instead (or
>>>> virtio-scsi-tcm-pci, or something like that).  It is used completely
>>>> differently from virtio-scsi-pci, it does not make sense to conflate the
>>>> two.
>>>
>>> Ideally the name would say how it is different, not what backend it
>>> uses. Any good suggestions?
>>
>> I chose the backend name because, ideally, there would be no other
>> difference.  QEMU _could_ implement all the goodies in vhost-scsi (such
>> as reservations or ALUA), it just doesn't do that yet.
>>
>> Paolo
>
> Then why do you say "It is used completely differently from
> virtio-scsi-pci"?  Isn't it just a different backend?
>
> If yes then it should be a backend option, like it is
> for virtio-net.

I don't mean to bike shed here so don't take this as a nack on making it a 
backend option, but in retrospect, the way we did vhost-net was a mistake even 
though I strongly advocated for it to be a backend option.

The code to do it is really, really ugly.  I think it would have made a lot more 
sense to just make it a device and then have it not use a netdev backend or any 
other kind of backend split.

For instance:

qemu -device vhost-net-pci,tapfd=X

I know this breaks the model of separate backends and frontends but since 
vhost-net absolutely requires a tap fd, I think it's better in the long run to 
not abuse the netdev backend to prevent user confusion.  Having a dedicated 
backend type that only has one possible option and can only be used by one 
device is a bit silly too.

So I would be in favor of dropping/squashing 3/5 and radically simplifying how 
this was exposed to the user.

I would just take qemu_vhost_scsi_opts and make them device properties.

Regards,

Anthony Liguori

>

Re: [Qemu-devel] [PATCH 4/5] virtio-scsi: Add start/stop functionality for vhost-scsi

[Michael S. Tsirkin]

On Tue, Sep 11, 2012 at 08:46:34AM -0500, Anthony Liguori wrote:
> On 09/10/2012 01:24 AM, Michael S. Tsirkin wrote:
> >On Mon, Sep 10, 2012 at 08:16:54AM +0200, Paolo Bonzini wrote:
> >>Il 09/09/2012 00:40, Michael S. Tsirkin ha scritto:
> >>>On Fri, Sep 07, 2012 at 06:00:50PM +0200, Paolo Bonzini wrote:
> >>>>Il 07/09/2012 08:48, Nicholas A. Bellinger ha scritto:
> >>>>>Cc: Stefan Hajnoczi<stefanha@linux.vnet.ibm.com>
> >>>>>Cc: Zhi Yong Wu<wuzhy@linux.vnet.ibm.com>
> >>>>>Cc: Michael S. Tsirkin<mst@redhat.com>
> >>>>>Cc: Paolo Bonzini<pbonzini@redhat.com>
> >>>>>Signed-off-by: Nicholas Bellinger<nab@linux-iscsi.org>
> >>>>>---
> >>>>>  hw/virtio-pci.c  |    2 ++
> >>>>>  hw/virtio-scsi.c |   49 +++++++++++++++++++++++++++++++++++++++++++++++++
> >>>>>  hw/virtio-scsi.h |    1 +
> >>>>>  3 files changed, 52 insertions(+), 0 deletions(-)
> >>>>
> >>>>Please create a completely separate device vhost-scsi-pci instead (or
> >>>>virtio-scsi-tcm-pci, or something like that).  It is used completely
> >>>>differently from virtio-scsi-pci, it does not make sense to conflate the
> >>>>two.
> >>>
> >>>Ideally the name would say how it is different, not what backend it
> >>>uses. Any good suggestions?
> >>
> >>I chose the backend name because, ideally, there would be no other
> >>difference.  QEMU _could_ implement all the goodies in vhost-scsi (such
> >>as reservations or ALUA), it just doesn't do that yet.
> >>
> >>Paolo
> >
> >Then why do you say "It is used completely differently from
> >virtio-scsi-pci"?  Isn't it just a different backend?
> >
> >If yes then it should be a backend option, like it is
> >for virtio-net.
> 
> I don't mean to bike shed here so don't take this as a nack on
> making it a backend option, but in retrospect, the way we did
> vhost-net was a mistake even though I strongly advocated for it to
> be a backend option.
> 
> The code to do it is really, really ugly.  I think it would have
> made a lot more sense to just make it a device and then have it not
> use a netdev backend or any other kind of backend split.
> 
> For instance:
> 
> qemu -device vhost-net-pci,tapfd=X
> 
> I know this breaks the model of separate backends and frontends but
> since vhost-net absolutely requires a tap fd, I think it's better in
> the long run to not abuse the netdev backend to prevent user
> confusion.  Having a dedicated backend type that only has one
> possible option and can only be used by one device is a bit silly
> too.
> 
> So I would be in favor of dropping/squashing 3/5 and radically
> simplifying how this was exposed to the user.
> 
> I would just take qemu_vhost_scsi_opts and make them device properties.
> 
> Regards,
> 
> Anthony Liguori

I'd like to clarify that I'm fine with either approach.
Even a separate device is OK if this is what others want
though I like it the least.

> >

Re: [Qemu-devel] [PATCH 4/5] virtio-scsi: Add start/stop functionality for vhost-scsi

[Nicholas A. Bellinger]

On Tue, 2012-09-11 at 18:07 +0300, Michael S. Tsirkin wrote:
> On Tue, Sep 11, 2012 at 08:46:34AM -0500, Anthony Liguori wrote:
> > On 09/10/2012 01:24 AM, Michael S. Tsirkin wrote:
> > >On Mon, Sep 10, 2012 at 08:16:54AM +0200, Paolo Bonzini wrote:
> > >>Il 09/09/2012 00:40, Michael S. Tsirkin ha scritto:
> > >>>On Fri, Sep 07, 2012 at 06:00:50PM +0200, Paolo Bonzini wrote:

<SNIP>

> > >>>>Please create a completely separate device vhost-scsi-pci instead (or
> > >>>>virtio-scsi-tcm-pci, or something like that).  It is used completely
> > >>>>differently from virtio-scsi-pci, it does not make sense to conflate the
> > >>>>two.
> > >>>
> > >>>Ideally the name would say how it is different, not what backend it
> > >>>uses. Any good suggestions?
> > >>
> > >>I chose the backend name because, ideally, there would be no other
> > >>difference.  QEMU _could_ implement all the goodies in vhost-scsi (such
> > >>as reservations or ALUA), it just doesn't do that yet.
> > >>
> > >>Paolo
> > >
> > >Then why do you say "It is used completely differently from
> > >virtio-scsi-pci"?  Isn't it just a different backend?
> > >
> > >If yes then it should be a backend option, like it is
> > >for virtio-net.
> > 
> > I don't mean to bike shed here so don't take this as a nack on
> > making it a backend option, but in retrospect, the way we did
> > vhost-net was a mistake even though I strongly advocated for it to
> > be a backend option.
> > 
> > The code to do it is really, really ugly.  I think it would have
> > made a lot more sense to just make it a device and then have it not
> > use a netdev backend or any other kind of backend split.
> > 
> > For instance:
> > 
> > qemu -device vhost-net-pci,tapfd=X
> > 
> > I know this breaks the model of separate backends and frontends but
> > since vhost-net absolutely requires a tap fd, I think it's better in
> > the long run to not abuse the netdev backend to prevent user
> > confusion.  Having a dedicated backend type that only has one
> > possible option and can only be used by one device is a bit silly
> > too.
> > 
> > So I would be in favor of dropping/squashing 3/5 and radically
> > simplifying how this was exposed to the user.
> > 
> > I would just take qemu_vhost_scsi_opts and make them device properties.
> > 
> > Regards,
> > 
> > Anthony Liguori
> 
> I'd like to clarify that I'm fine with either approach.
> Even a separate device is OK if this is what others want
> though I like it the least.
> 

Hi MST, Paolo & Co,

I've been out the better part of the week with the flu, and am just now
catching up on emails from the last days..

So to better understand the reasoning for adding an separate PCI device
for vhost-scsi ahead of implementing the code changes, here are main
points from folk's comments:

*) Convert vhost-scsi into a separate standalone vhost-scsi-pci device

  - Lets userspace know that virtio-scsi + QEMU block and virtio-scsi + 
    tcm_vhost do not track SCSI state (such as reservations + ALUA), and
    hence are not interchangeable during live-migration.
  
  - Reduces complexity of adding vhost-scsi related logic into existing
    virtio-scsi-pci code path.

  - Having backends with one possible option doesn’t make much sense.

*) Keep vhost-scsi as a backend to virtio-scsi-pci

  - Reduces duplicated code amongst multiple virtio-scsi backends.
  
  - Follows the split for what existing vhost-net code already does.

So that said, two quick questions for Paolo & Co..

For the standalone vhost-scsi-pci device case, can you give a brief idea
as to what extent you'd like to see virtio-scsi.c code/defs duplicated
and/or shared amongst a new vhost-scsi-pci device..?

Also to help me along, can you give an example based on the current
usage below how the QEMU command line arguments would change with a
standalone vhost-scsi-pci device..?

./x86_64-softmmu/qemu-system-x86_64 -enable-kvm -smp 4 -m 2048 \
    -hda /usr/src/qemu-vhost.git/debian_squeeze_amd64_standard-old.qcow2 \
    -vhost-scsi id=vhost-scsi0,wwpn=naa.600140579ad21088,tpgt=1 \
    -device virtio-scsi-pci,vhost-scsi=vhost-scsi0,event_idx=off

Thank you!

--nab

Re: [Qemu-devel] [PATCH 4/5] virtio-scsi: Add start/stop functionality for vhost-scsi

[Paolo Bonzini]

Il 14/09/2012 00:27, Nicholas A. Bellinger ha scritto:
> *) Keep vhost-scsi as a backend to virtio-scsi-pci
> 
>   - Reduces duplicated code amongst multiple virtio-scsi backends.
>   
>   - Follows the split for what existing vhost-net code already does.
> 
> So that said, two quick questions for Paolo & Co..
> 
> For the standalone vhost-scsi-pci device case, can you give a brief idea
> as to what extent you'd like to see virtio-scsi.c code/defs duplicated
> and/or shared amongst a new vhost-scsi-pci device..?

Not much, in the end, would be shared; it could end up being just
parts of virtio_scsi_init and virtio_scsi_exit, and virtio_scsi_get_config.

Almost all the other code is to implement the SCSI bus interface,
which you do not need.

I don't remember if and how vhost handles configuration changes.  If you
need any struct in virtio-scsi.c, either move it to virtio-scsi.h or
add the new device in the same file.

> Also to help me along, can you give an example based on the current
> usage below how the QEMU command line arguments would change with a
> standalone vhost-scsi-pci device..?
> 
> ./x86_64-softmmu/qemu-system-x86_64 -enable-kvm -smp 4 -m 2048 \
>     -hda /usr/src/qemu-vhost.git/debian_squeeze_amd64_standard-old.qcow2 \
>     -vhost-scsi id=vhost-scsi0,wwpn=naa.600140579ad21088,tpgt=1 \
>     -device virtio-scsi-pci,vhost-scsi=vhost-scsi0,event_idx=off

Two possibilities.  Either simply do s/virtio-scsi-pci/vhost-scsi-pci/ or do

./x86_64-softmmu/qemu-system-x86_64 -enable-kvm -smp 4 -m 2048 \
    -hda /usr/src/qemu-vhost.git/debian_squeeze_amd64_standard-old.qcow2 \
    -device virtio-scsi-pci,wwpn=naa.600140579ad21088,tpgt=1,event_idx=off

Re: [Qemu-devel] [PATCH 4/5] virtio-scsi: Add start/stop functionality for vhost-scsi

[Michael S. Tsirkin]

On Fri, Sep 14, 2012 at 08:45:11AM +0200, Paolo Bonzini wrote:
> Il 14/09/2012 00:27, Nicholas A. Bellinger ha scritto:
> > *) Keep vhost-scsi as a backend to virtio-scsi-pci
> > 
> >   - Reduces duplicated code amongst multiple virtio-scsi backends.
> >   
> >   - Follows the split for what existing vhost-net code already does.
> > 
> > So that said, two quick questions for Paolo & Co..
> > 
> > For the standalone vhost-scsi-pci device case, can you give a brief idea
> > as to what extent you'd like to see virtio-scsi.c code/defs duplicated
> > and/or shared amongst a new vhost-scsi-pci device..?
> 
> Not much, in the end, would be shared; it could end up being just
> parts of virtio_scsi_init and virtio_scsi_exit, and virtio_scsi_get_config.
> 
> Almost all the other code is to implement the SCSI bus interface,
> which you do not need.
> 
> I don't remember if and how vhost handles configuration changes.

All configuration changes are handled in userspace.

>  If you
> need any struct in virtio-scsi.c, either move it to virtio-scsi.h or
> add the new device in the same file.
> 
> > Also to help me along, can you give an example based on the current
> > usage below how the QEMU command line arguments would change with a
> > standalone vhost-scsi-pci device..?
> > 
> > ./x86_64-softmmu/qemu-system-x86_64 -enable-kvm -smp 4 -m 2048 \
> >     -hda /usr/src/qemu-vhost.git/debian_squeeze_amd64_standard-old.qcow2 \
> >     -vhost-scsi id=vhost-scsi0,wwpn=naa.600140579ad21088,tpgt=1 \
> >     -device virtio-scsi-pci,vhost-scsi=vhost-scsi0,event_idx=off
> 
> Two possibilities.  Either simply do s/virtio-scsi-pci/vhost-scsi-pci/ or do
> 
> ./x86_64-softmmu/qemu-system-x86_64 -enable-kvm -smp 4 -m 2048 \
>     -hda /usr/src/qemu-vhost.git/debian_squeeze_amd64_standard-old.qcow2 \
>     -device virtio-scsi-pci,wwpn=naa.600140579ad21088,tpgt=1,event_idx=off

I think I like the second option better.

-- 
MST

Re: [Qemu-devel] [PATCH 4/5] virtio-scsi: Add start/stop functionality for vhost-scsi

[Michael S. Tsirkin]

On Tue, Sep 11, 2012 at 08:46:34AM -0500, Anthony Liguori wrote:
> On 09/10/2012 01:24 AM, Michael S. Tsirkin wrote:
> >On Mon, Sep 10, 2012 at 08:16:54AM +0200, Paolo Bonzini wrote:
> >>Il 09/09/2012 00:40, Michael S. Tsirkin ha scritto:
> >>>On Fri, Sep 07, 2012 at 06:00:50PM +0200, Paolo Bonzini wrote:
> >>>>Il 07/09/2012 08:48, Nicholas A. Bellinger ha scritto:
> >>>>>Cc: Stefan Hajnoczi<stefanha@linux.vnet.ibm.com>
> >>>>>Cc: Zhi Yong Wu<wuzhy@linux.vnet.ibm.com>
> >>>>>Cc: Michael S. Tsirkin<mst@redhat.com>
> >>>>>Cc: Paolo Bonzini<pbonzini@redhat.com>
> >>>>>Signed-off-by: Nicholas Bellinger<nab@linux-iscsi.org>
> >>>>>---
> >>>>>  hw/virtio-pci.c  |    2 ++
> >>>>>  hw/virtio-scsi.c |   49 +++++++++++++++++++++++++++++++++++++++++++++++++
> >>>>>  hw/virtio-scsi.h |    1 +
> >>>>>  3 files changed, 52 insertions(+), 0 deletions(-)
> >>>>
> >>>>Please create a completely separate device vhost-scsi-pci instead (or
> >>>>virtio-scsi-tcm-pci, or something like that).  It is used completely
> >>>>differently from virtio-scsi-pci, it does not make sense to conflate the
> >>>>two.
> >>>
> >>>Ideally the name would say how it is different, not what backend it
> >>>uses. Any good suggestions?
> >>
> >>I chose the backend name because, ideally, there would be no other
> >>difference.  QEMU _could_ implement all the goodies in vhost-scsi (such
> >>as reservations or ALUA), it just doesn't do that yet.
> >>
> >>Paolo
> >
> >Then why do you say "It is used completely differently from
> >virtio-scsi-pci"?  Isn't it just a different backend?
> >
> >If yes then it should be a backend option, like it is
> >for virtio-net.
> 
> I don't mean to bike shed here so don't take this as a nack on
> making it a backend option, but in retrospect, the way we did
> vhost-net was a mistake even though I strongly advocated for it to
> be a backend option.
> 
> The code to do it is really, really ugly.  I think it would have
> made a lot more sense to just make it a device and then have it not
> use a netdev backend or any other kind of backend split.
> 
> For instance:
> 
> qemu -device vhost-net-pci,tapfd=X

We'd have to duplicate all tap options such as upscript then,
and educate users that vhost-net-pci is in fact same as virtio-net-pci
just faster. They have enough trouble guessing "-net-pci"
in virtio-net-pci.

IMHO a simple -device virtio-net-pci,vhost=on
would have been the right thing to do in retrospect.

> since vhost-net absolutely requires a tap fd, I think it's better in
> the long run to not abuse the netdev backend to prevent user
> confusion.

In practice adding an option (even if it was in the wrong place)
did not result in user confusion. Also in practice, renaming "virtio"
to virtio-net-pci etc did create confusion.


> Having a dedicated backend type that only has one
> possible option and can only be used by one device is a bit silly
> too.

By now we can just enable it by default. This was always the
idea.

> So I would be in favor of dropping/squashing 3/5 and radically
> simplifying how this was exposed to the user.

Let's just make sure we don't have implementation tail wagging
the user interface dog :)

> 
> I would just take qemu_vhost_scsi_opts and make them device properties.
> 
> Regards,
> 
> Anthony Liguori
> 
> >

[Qemu-devel] [PATCH 5/5] virtio-scsi: Set max_target=0 during vhost-scsi operation

[Nicholas A. Bellinger]

From: Nicholas Bellinger <nab@linux-iscsi.org>

This QEMU patch sets VirtIOSCSIConfig->max_target=0 for vhost-scsi operation
to restrict virtio-scsi LLD guest scanning to max_id=0 (a single target ID
instance) when connected to individual tcm_vhost endpoints.

This ensures that virtio-scsi LLD only attempts to scan target IDs up to
VIRTIO_SCSI_MAX_TARGET when connected via virtio-scsi-raw.

Cc: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Cc: Zhi Yong Wu <wuzhy@linux.vnet.ibm.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
---
 hw/virtio-scsi.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/hw/virtio-scsi.c b/hw/virtio-scsi.c
index edda097..ab5ca72 100644
--- a/hw/virtio-scsi.c
+++ b/hw/virtio-scsi.c
@@ -546,7 +546,11 @@ static void virtio_scsi_get_config(VirtIODevice *vdev,
     stl_raw(&scsiconf->sense_size, s->sense_size);
     stl_raw(&scsiconf->cdb_size, s->cdb_size);
     stl_raw(&scsiconf->max_channel, VIRTIO_SCSI_MAX_CHANNEL);
-    stl_raw(&scsiconf->max_target, VIRTIO_SCSI_MAX_TARGET);
+    if (s->vhost_scsi) {
+        stl_raw(&scsiconf->max_target, 0);
+    } else {
+        stl_raw(&scsiconf->max_target, VIRTIO_SCSI_MAX_TARGET);
+    }
     stl_raw(&scsiconf->max_lun, VIRTIO_SCSI_MAX_LUN);
 }
 
-- 
1.7.2.5

Re: [Qemu-devel] [PATCH 0/5] vhost-scsi: Add support for host virtualized target

[Asias He]

Hello Nicholas,

On 09/07/2012 02:48 PM, Nicholas A. Bellinger wrote:
> From: Nicholas Bellinger <nab@linux-iscsi.org>
> 
> Hello Anthony & Co,
> 
> This is the fourth installment to add host virtualized target support for
> the mainline tcm_vhost fabric driver using Linux v3.6-rc into QEMU 1.3.0-rc.
> 
> The series is available directly from the following git branch:
> 
>    git://git.kernel.org/pub/scm/virt/kvm/nab/qemu-kvm.git vhost-scsi-for-1.3
> 
> Note the code is cut against yesterday's QEMU head, and dispite the name
> of the tree is based upon mainline qemu.org git code + has thus far been
> running overnight with > 100K IOPs small block 4k workloads using v3.6-rc2+
> based target code with RAMDISK_DR backstores.

Are you still seeing the performance degradation discussed in the thread

 "vhost-scsi port to v1.1.0 + MSI-X performance regression"

?

> Other than some minor fuzz between jumping from QEMU 1.2.0 -> 1.2.50, this
> series is functionally identical to what's been posted for vhost-scsi RFC-v3
> to qemu-devel.
> 
> Please consider applying these patches for an initial vhost-scsi merge into
> QEMU 1.3.0-rc code, or let us know what else you'd like to see addressed for
> this series to in order to merge.
> 
> Thank you!
> 
> --nab
> 
> Nicholas Bellinger (2):
>   monitor: Rename+move net_handle_fd_param -> monitor_handle_fd_param
>   virtio-scsi: Set max_target=0 during vhost-scsi operation
> 
> Stefan Hajnoczi (3):
>   vhost: Pass device path to vhost_dev_init()
>   vhost-scsi: add -vhost-scsi host device for use with tcm-vhost
>   virtio-scsi: Add start/stop functionality for vhost-scsi
> 
>  configure            |   10 +++
>  hw/Makefile.objs     |    1 +
>  hw/qdev-properties.c |   41 +++++++++++
>  hw/vhost-scsi.c      |  190 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  hw/vhost-scsi.h      |   62 ++++++++++++++++
>  hw/vhost.c           |    5 +-
>  hw/vhost.h           |    3 +-
>  hw/vhost_net.c       |    2 +-
>  hw/virtio-pci.c      |    2 +
>  hw/virtio-scsi.c     |   55 ++++++++++++++-
>  hw/virtio-scsi.h     |    1 +
>  monitor.c            |   18 +++++
>  monitor.h            |    1 +
>  net.c                |   18 -----
>  net.h                |    2 -
>  net/socket.c         |    2 +-
>  net/tap.c            |    4 +-
>  qemu-common.h        |    1 +
>  qemu-config.c        |   19 +++++
>  qemu-options.hx      |    4 +
>  vl.c                 |   18 +++++
>  21 files changed, 431 insertions(+), 28 deletions(-)
>  create mode 100644 hw/vhost-scsi.c
>  create mode 100644 hw/vhost-scsi.h
> 


-- 
Asias

Re: [Qemu-devel] [PATCH 0/5] vhost-scsi: Add support for host virtualized target

[Nicholas A. Bellinger]

On Tue, 2012-09-11 at 12:36 +0800, Asias He wrote:
> Hello Nicholas,
> 

Hello Asias!

> On 09/07/2012 02:48 PM, Nicholas A. Bellinger wrote:
> > From: Nicholas Bellinger <nab@linux-iscsi.org>
> > 
> > Hello Anthony & Co,
> > 
> > This is the fourth installment to add host virtualized target support for
> > the mainline tcm_vhost fabric driver using Linux v3.6-rc into QEMU 1.3.0-rc.
> > 
> > The series is available directly from the following git branch:
> > 
> >    git://git.kernel.org/pub/scm/virt/kvm/nab/qemu-kvm.git vhost-scsi-for-1.3
> > 
> > Note the code is cut against yesterday's QEMU head, and dispite the name
> > of the tree is based upon mainline qemu.org git code + has thus far been
> > running overnight with > 100K IOPs small block 4k workloads using v3.6-rc2+
> > based target code with RAMDISK_DR backstores.
> 
> Are you still seeing the performance degradation discussed in the thread
> 
>  "vhost-scsi port to v1.1.0 + MSI-X performance regression"
> 

So the performance regression reported here with QEMU v1.2-rc +
virtio-scsi ended up being related to virtio interrupts being delivered
across multiple CPUs.

After explicitly setting the IRQ affinity of the virtio0-request MSI-X
vector to a specific CPU, the small block (4k) mixed random I/O
performance jumped back up to the expected ~100K IOPs for a single LUN.

FYI, I just tried this again with the most recent QEMU v1.2.50 (v1.3-rc)
code, and both cases appear to be performing as expected once again
regardless of the explicit IRQ affinity setting.

--nab

Re: [Qemu-devel] [PATCH 0/5] vhost-scsi: Add support for host virtualized target

[Paolo Bonzini]

Il 13/09/2012 22:12, Nicholas A. Bellinger ha scritto:
>> > Are you still seeing the performance degradation discussed in the thread
>> > 
>> >  "vhost-scsi port to v1.1.0 + MSI-X performance regression"
>> > 
> So the performance regression reported here with QEMU v1.2-rc +
> virtio-scsi ended up being related to virtio interrupts being delivered
> across multiple CPUs.
> 
> After explicitly setting the IRQ affinity of the virtio0-request MSI-X
> vector to a specific CPU, the small block (4k) mixed random I/O
> performance jumped back up to the expected ~100K IOPs for a single LUN.

Have you tried setting rq_affinity to 2?  Benchmarking this against
multiqueue virtio-scsi is on my todo list.

Paolo

> FYI, I just tried this again with the most recent QEMU v1.2.50 (v1.3-rc)
> code, and both cases appear to be performing as expected once again
> regardless of the explicit IRQ affinity setting.

Re: [Qemu-devel] [PATCH 0/5] vhost-scsi: Add support for host virtualized target

[Michael S. Tsirkin]

On Fri, Sep 07, 2012 at 06:48:14AM +0000, Nicholas A. Bellinger wrote:
> From: Nicholas Bellinger <nab@linux-iscsi.org>
> 
> Hello Anthony & Co,
> 
> This is the fourth installment to add host virtualized target support for
> the mainline tcm_vhost fabric driver using Linux v3.6-rc into QEMU 1.3.0-rc.
> 
> The series is available directly from the following git branch:
> 
>    git://git.kernel.org/pub/scm/virt/kvm/nab/qemu-kvm.git vhost-scsi-for-1.3
> 
> Note the code is cut against yesterday's QEMU head, and dispite the name
> of the tree is based upon mainline qemu.org git code + has thus far been
> running overnight with > 100K IOPs small block 4k workloads using v3.6-rc2+
> based target code with RAMDISK_DR backstores.
> 
> Other than some minor fuzz between jumping from QEMU 1.2.0 -> 1.2.50, this
> series is functionally identical to what's been posted for vhost-scsi RFC-v3
> to qemu-devel.
> 
> Please consider applying these patches for an initial vhost-scsi merge into
> QEMU 1.3.0-rc code, or let us know what else you'd like to see addressed for
> this series to in order to merge.
> 
> Thank you!
> 
> --nab

OK what's the status here?
We missed 1.3 but let's try not to miss 1.4?

> Nicholas Bellinger (2):
>   monitor: Rename+move net_handle_fd_param -> monitor_handle_fd_param
>   virtio-scsi: Set max_target=0 during vhost-scsi operation
> 
> Stefan Hajnoczi (3):
>   vhost: Pass device path to vhost_dev_init()
>   vhost-scsi: add -vhost-scsi host device for use with tcm-vhost
>   virtio-scsi: Add start/stop functionality for vhost-scsi
> 
>  configure            |   10 +++
>  hw/Makefile.objs     |    1 +
>  hw/qdev-properties.c |   41 +++++++++++
>  hw/vhost-scsi.c      |  190 ++++++++++++++++++++++++++++++++++++++++++++++++++
>  hw/vhost-scsi.h      |   62 ++++++++++++++++
>  hw/vhost.c           |    5 +-
>  hw/vhost.h           |    3 +-
>  hw/vhost_net.c       |    2 +-
>  hw/virtio-pci.c      |    2 +
>  hw/virtio-scsi.c     |   55 ++++++++++++++-
>  hw/virtio-scsi.h     |    1 +
>  monitor.c            |   18 +++++
>  monitor.h            |    1 +
>  net.c                |   18 -----
>  net.h                |    2 -
>  net/socket.c         |    2 +-
>  net/tap.c            |    4 +-
>  qemu-common.h        |    1 +
>  qemu-config.c        |   19 +++++
>  qemu-options.hx      |    4 +
>  vl.c                 |   18 +++++
>  21 files changed, 431 insertions(+), 28 deletions(-)
>  create mode 100644 hw/vhost-scsi.c
>  create mode 100644 hw/vhost-scsi.h
> 
> -- 
> 1.7.2.5
> 
> _______________________________________________
> Virtualization mailing list
> Virtualization@lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/virtualization

Re: [Qemu-devel] [PATCH 0/5] vhost-scsi: Add support for host virtualized target

[Nicholas A. Bellinger]

Hi MST & Co,

On Thu, 2013-01-17 at 18:43 +0200, Michael S. Tsirkin wrote:
> On Fri, Sep 07, 2012 at 06:48:14AM +0000, Nicholas A. Bellinger wrote:
> > From: Nicholas Bellinger <nab@linux-iscsi.org>
> > 
> > Hello Anthony & Co,
> > 
> > This is the fourth installment to add host virtualized target support for
> > the mainline tcm_vhost fabric driver using Linux v3.6-rc into QEMU 1.3.0-rc.
> > 
> > The series is available directly from the following git branch:
> > 
> >    git://git.kernel.org/pub/scm/virt/kvm/nab/qemu-kvm.git vhost-scsi-for-1.3
> > 
> > Note the code is cut against yesterday's QEMU head, and dispite the name
> > of the tree is based upon mainline qemu.org git code + has thus far been
> > running overnight with > 100K IOPs small block 4k workloads using v3.6-rc2+
> > based target code with RAMDISK_DR backstores.
> > 
> > Other than some minor fuzz between jumping from QEMU 1.2.0 -> 1.2.50, this
> > series is functionally identical to what's been posted for vhost-scsi RFC-v3
> > to qemu-devel.
> > 
> > Please consider applying these patches for an initial vhost-scsi merge into
> > QEMU 1.3.0-rc code, or let us know what else you'd like to see addressed for
> > this series to in order to merge.
> > 
> > Thank you!
> > 
> > --nab
> 
> OK what's the status here?
> We missed 1.3 but let's try not to miss 1.4?
> 

Unfortunately, I've not been able to get back to the conversion
requested by Paolo for a standalone vhost-scsi PCI device.

At this point my hands are still full with iSER-target for-3.9 kernel
code over the next weeks.  

What's the v1.4 feature cut-off looking like at this point..?

--nab

Re: [Qemu-devel] [PATCH 0/5] vhost-scsi: Add support for host virtualized target

[Michael S. Tsirkin]

On Thu, Jan 17, 2013 at 01:07:21PM -0800, Nicholas A. Bellinger wrote:
> Hi MST & Co,
> 
> On Thu, 2013-01-17 at 18:43 +0200, Michael S. Tsirkin wrote:
> > On Fri, Sep 07, 2012 at 06:48:14AM +0000, Nicholas A. Bellinger wrote:
> > > From: Nicholas Bellinger <nab@linux-iscsi.org>
> > > 
> > > Hello Anthony & Co,
> > > 
> > > This is the fourth installment to add host virtualized target support for
> > > the mainline tcm_vhost fabric driver using Linux v3.6-rc into QEMU 1.3.0-rc.
> > > 
> > > The series is available directly from the following git branch:
> > > 
> > >    git://git.kernel.org/pub/scm/virt/kvm/nab/qemu-kvm.git vhost-scsi-for-1.3
> > > 
> > > Note the code is cut against yesterday's QEMU head, and dispite the name
> > > of the tree is based upon mainline qemu.org git code + has thus far been
> > > running overnight with > 100K IOPs small block 4k workloads using v3.6-rc2+
> > > based target code with RAMDISK_DR backstores.
> > > 
> > > Other than some minor fuzz between jumping from QEMU 1.2.0 -> 1.2.50, this
> > > series is functionally identical to what's been posted for vhost-scsi RFC-v3
> > > to qemu-devel.
> > > 
> > > Please consider applying these patches for an initial vhost-scsi merge into
> > > QEMU 1.3.0-rc code, or let us know what else you'd like to see addressed for
> > > this series to in order to merge.
> > > 
> > > Thank you!
> > > 
> > > --nab
> > 
> > OK what's the status here?
> > We missed 1.3 but let's try not to miss 1.4?
> > 
> 
> Unfortunately, I've not been able to get back to the conversion
> requested by Paolo for a standalone vhost-scsi PCI device.

It doesn't have to be a standalone device. A vhost=on frontend
option is also OK I think. Paolo, any objections?

> At this point my hands are still full with iSER-target for-3.9 kernel
> code over the next weeks.  
> 
> What's the v1.4 feature cut-off looking like at this point..?
> 
> --nab

Not sure but soon.

Re: [Qemu-devel] [PATCH 0/5] vhost-scsi: Add support for host virtualized target

[Wenchao Xia]

Hi, Nicholas
  Have this serial been merged to qemu 1.4? If not, I am rebasing it to
upstream, hope no one else is working on that.

> From: Nicholas Bellinger <nab@linux-iscsi.org>
> 
> Hello Anthony & Co,
> 
> This is the fourth installment to add host virtualized target support for
> the mainline tcm_vhost fabric driver using Linux v3.6-rc into QEMU 1.3.0-rc.
> 
> The series is available directly from the following git branch:
> 
>     git://git.kernel.org/pub/scm/virt/kvm/nab/qemu-kvm.git vhost-scsi-for-1.3
> 
> Note the code is cut against yesterday's QEMU head, and dispite the name
> of the tree is based upon mainline qemu.org git code + has thus far been
> running overnight with > 100K IOPs small block 4k workloads using v3.6-rc2+
> based target code with RAMDISK_DR backstores.
> 
> Other than some minor fuzz between jumping from QEMU 1.2.0 -> 1.2.50, this
> series is functionally identical to what's been posted for vhost-scsi RFC-v3
> to qemu-devel.
> 
> Please consider applying these patches for an initial vhost-scsi merge into
> QEMU 1.3.0-rc code, or let us know what else you'd like to see addressed for
> this series to in order to merge.
> 
> Thank you!
> 
> --nab
> 
> Nicholas Bellinger (2):
>    monitor: Rename+move net_handle_fd_param -> monitor_handle_fd_param
>    virtio-scsi: Set max_target=0 during vhost-scsi operation
> 
> Stefan Hajnoczi (3):
>    vhost: Pass device path to vhost_dev_init()
>    vhost-scsi: add -vhost-scsi host device for use with tcm-vhost
>    virtio-scsi: Add start/stop functionality for vhost-scsi
> 
>   configure            |   10 +++
>   hw/Makefile.objs     |    1 +
>   hw/qdev-properties.c |   41 +++++++++++
>   hw/vhost-scsi.c      |  190 ++++++++++++++++++++++++++++++++++++++++++++++++++
>   hw/vhost-scsi.h      |   62 ++++++++++++++++
>   hw/vhost.c           |    5 +-
>   hw/vhost.h           |    3 +-
>   hw/vhost_net.c       |    2 +-
>   hw/virtio-pci.c      |    2 +
>   hw/virtio-scsi.c     |   55 ++++++++++++++-
>   hw/virtio-scsi.h     |    1 +
>   monitor.c            |   18 +++++
>   monitor.h            |    1 +
>   net.c                |   18 -----
>   net.h                |    2 -
>   net/socket.c         |    2 +-
>   net/tap.c            |    4 +-
>   qemu-common.h        |    1 +
>   qemu-config.c        |   19 +++++
>   qemu-options.hx      |    4 +
>   vl.c                 |   18 +++++
>   21 files changed, 431 insertions(+), 28 deletions(-)
>   create mode 100644 hw/vhost-scsi.c
>   create mode 100644 hw/vhost-scsi.h
> 


-- 
Best Regards

Wenchao Xia

Re: [Qemu-devel] [PATCH 0/5] vhost-scsi: Add support for host virtualized target

[Nicholas A. Bellinger]

Hello Wenchao,

On Tue, 2013-04-02 at 11:28 +0800, Wenchao Xia wrote:
> Hi, Nicholas
>   Have this serial been merged to qemu 1.4?

Not just yet.  Asias, MST, Paolo and myself have been working recently
on the series for qemu 1.4.

>  If not, I am rebasing it to
> upstream, hope no one else is working on that.
> 

The latest PATCH-v2 for vhost-scsi-pci against upstream qemu commit
dcadaa9b (from March 25th) is here:

http://www.spinics.net/lists/target-devel/msg04263.html

Note that you'll need this small work-around patch to avoid a bug that
we're currently tracking down:

http://www.spinics.net/lists/target-devel/msg04122.html

Also, you'll need a recent SeaBios build with the following commits:

commit 5a7730db57ab0715223421e65b54fb50d6fefe5c
Author: Asias He <asias@redhat.com>
Date:   Fri Mar 15 09:45:15 2013 +0800

    virtio-scsi: Set _DRIVER_OK flag before scsi target scanning

commit b44a7be17bdd270ea029a8e2ec0c2e80c6cd0444
Author: Asias He <asias@redhat.com>
Date:   Fri Mar 15 09:45:16 2013 +0800

    virtio-scsi: Pack struct virtio_scsi_{req_cmd,resp_cmd}

I'll be rebasing to qemu HEAD over the next few days and posting a
PATCH-v3, and would be happy to include you in the CC to follow along.

Thanks!

--nab


> > From: Nicholas Bellinger <nab@linux-iscsi.org>
> > 
> > Hello Anthony & Co,
> > 
> > This is the fourth installment to add host virtualized target support for
> > the mainline tcm_vhost fabric driver using Linux v3.6-rc into QEMU 1.3.0-rc.
> > 
> > The series is available directly from the following git branch:
> > 
> >     git://git.kernel.org/pub/scm/virt/kvm/nab/qemu-kvm.git vhost-scsi-for-1.3
> > 
> > Note the code is cut against yesterday's QEMU head, and dispite the name
> > of the tree is based upon mainline qemu.org git code + has thus far been
> > running overnight with > 100K IOPs small block 4k workloads using v3.6-rc2+
> > based target code with RAMDISK_DR backstores.
> > 
> > Other than some minor fuzz between jumping from QEMU 1.2.0 -> 1.2.50, this
> > series is functionally identical to what's been posted for vhost-scsi RFC-v3
> > to qemu-devel.
> > 
> > Please consider applying these patches for an initial vhost-scsi merge into
> > QEMU 1.3.0-rc code, or let us know what else you'd like to see addressed for
> > this series to in order to merge.
> > 
> > Thank you!
> > 
> > --nab
> > 
> > Nicholas Bellinger (2):
> >    monitor: Rename+move net_handle_fd_param -> monitor_handle_fd_param
> >    virtio-scsi: Set max_target=0 during vhost-scsi operation
> > 
> > Stefan Hajnoczi (3):
> >    vhost: Pass device path to vhost_dev_init()
> >    vhost-scsi: add -vhost-scsi host device for use with tcm-vhost
> >    virtio-scsi: Add start/stop functionality for vhost-scsi
> > 
> >   configure            |   10 +++
> >   hw/Makefile.objs     |    1 +
> >   hw/qdev-properties.c |   41 +++++++++++
> >   hw/vhost-scsi.c      |  190 ++++++++++++++++++++++++++++++++++++++++++++++++++
> >   hw/vhost-scsi.h      |   62 ++++++++++++++++
> >   hw/vhost.c           |    5 +-
> >   hw/vhost.h           |    3 +-
> >   hw/vhost_net.c       |    2 +-
> >   hw/virtio-pci.c      |    2 +
> >   hw/virtio-scsi.c     |   55 ++++++++++++++-
> >   hw/virtio-scsi.h     |    1 +
> >   monitor.c            |   18 +++++
> >   monitor.h            |    1 +
> >   net.c                |   18 -----
> >   net.h                |    2 -
> >   net/socket.c         |    2 +-
> >   net/tap.c            |    4 +-
> >   qemu-common.h        |    1 +
> >   qemu-config.c        |   19 +++++
> >   qemu-options.hx      |    4 +
> >   vl.c                 |   18 +++++
> >   21 files changed, 431 insertions(+), 28 deletions(-)
> >   create mode 100644 hw/vhost-scsi.c
> >   create mode 100644 hw/vhost-scsi.h
> > 
> 
>