From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: [PATCH 2/3] vhost-scsi: new device supporting the tcm_vhost Linux kernel module Date: Thu, 28 Mar 2013 18:54:03 +0200 Message-ID: <20130328165403.GD30508@redhat.com> References: <1364421586-29857-1-git-send-email-nab@linux-iscsi.org> <1364421586-29857-3-git-send-email-nab@linux-iscsi.org> <20130327222856.GC12518@redhat.com> <1364424342.17698.31.camel@haakon2.linux-iscsi.org> <20130327225021.GA12858@redhat.com> <20130327225349.GA12927@redhat.com> <1364426662.17698.41.camel@haakon2.linux-iscsi.org> <20130328061919.GA16678@redhat.com> <1364452136.17698.89.camel@haakon2.linux-iscsi.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <1364452136.17698.89.camel@haakon2.linux-iscsi.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: virtualization-bounces@lists.linux-foundation.org Errors-To: virtualization-bounces@lists.linux-foundation.org To: "Nicholas A. Bellinger" Cc: kvm-devel , qemu-devel , lf-virt , Anthony Liguori , target-devel , Stefan Hajnoczi , Paolo Bonzini List-Id: virtualization@lists.linuxfoundation.org On Wed, Mar 27, 2013 at 11:28:56PM -0700, Nicholas A. Bellinger wrote: > On Thu, 2013-03-28 at 08:19 +0200, Michael S. Tsirkin wrote: > > On Wed, Mar 27, 2013 at 04:24:22PM -0700, Nicholas A. Bellinger wrote: > > > On Thu, 2013-03-28 at 00:53 +0200, Michael S. Tsirkin wrote: > > > > On Thu, Mar 28, 2013 at 12:50:21AM +0200, Michael S. Tsirkin wrote: > > > > > On Wed, Mar 27, 2013 at 03:45:42PM -0700, Nicholas A. Bellinger wrote: > > > > > > On Thu, 2013-03-28 at 00:28 +0200, Michael S. Tsirkin wrote: > > > > > > > On Wed, Mar 27, 2013 at 09:59:45PM +0000, Nicholas A. Bellinger wrote: > > > > > > > > From: Paolo Bonzini > > > > > > > > > > > > > > > > The WWPN specified in configfs is passed to "-device vhost-scsi-pci". > > > > > > > > The tgpt field of the SET_ENDPOINT ioctl is obsolete now, so it is not > > > > > > > > available from the QEMU command-line. Instead, I hardcode it to zero. > > > > > > > > > > > > > > > > Changes in V4: > > > > > > > > - Set event_idx=off by default (nab, thanks asias) > > > > > > > > > > > > > > Why? What's going on here? > > > > > > > > > > > > > > > > > > > Not disabling event_idx by default, or disabling from the command line > > > > > > ends up resulting in ->handle_kick() not getting called for subsequent > > > > > > commands.. > > > > > > > > > > > > I spent some time trying to track this down recently with no luck, and > > > > > > AFAICT it's always been required in order for vhost-scsi to function. > > > > > > > > > > Hmm this is a bug in kernel then. A better work-around is > > > > > to disable EVENT_IDX in kernel. Let's do it for 3.9? > > > > > > > > But before we do, can you check that SET_FEATURES is > > > > called with this bit set if you enable event_idx? > > > > If not that's your bug then ... > > > > > > > > > > Ok, SET_FEATURES is currently not setting any bits at all based upon > > > vhost_dev->features, so it looks like a vhost-scsi-pci bug.. > > > > > > > > > > If you call SET_FEATURES, does it start working even without > > disabling EVENT_IDX in kernel? > > > > Unfortunately, no. The same strangeness persists unless event_idx=off > is passed, or EVENT_IDX is disabled in the kernel and stripped off with > the vhost_scsi_get_features() patch. > I think it's important to fix it (usually exposes other bugs) but I agree, lets get it working without first.