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

On Tue, Aug 14, 2012 at 01:31:14PM -0700, Nicholas A. Bellinger wrote:

On Mon, 2012-08-13 at 11:53 +0300, Michael S. Tsirkin wrote:

quoted

On Mon, Aug 13, 2012 at 08:35:14AM +0000, Nicholas A. Bellinger wrote:

quoted

From: Stefan Hajnoczi <redacted>

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.

<SNIP>

quoted

quoted

+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);
+
+    ret = vhost_dev_init(&vs->dev, -1, "/dev/vhost-scsi", false);

This -1 is a hack. You need to support passing in fd from
the monitor, and pass it here.

Mmm, looking at how vhost_net_init + tap.c does this, but am not quite
what fd needs to be propagated up for virtio-scsi -> vhost-scsi..

Can you please elaborate on this one a bit more..?

--nab

The idea is to allow running as a user without access to
/dev/vhost-scsi.
For this, allow passing in the fd of /dev/vhost-scsi through unix domain sockets.

-- 
MST