From mboxrd@z Thu Jan  1 00:00:00 1970
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [PATCH for-4.5] libxl: remove existence check for
 PCI device hotplug
Date: Wed, 19 Nov 2014 16:28:53 -0500
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To: Wei Liu <wei.liu2@citrix.com>
Cc: liang.z.li@intel.com, Ian Jackson <ian.jackson@eu.citrix.com>, Ian Campbell <ian.campbell@citrix.com>, xen-devel@lists.xen.org
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On Wed, Nov 19, 2014 at 09:21:23PM +0000, Wei Liu wrote:
> On Wed, Nov 19, 2014 at 04:01:54PM -0500, Konrad Rzeszutek Wilk wrote:
> > On Mon, Nov 17, 2014 at 12:10:34PM +0000, Wei Liu wrote:
> > > The existence check is to make sure a device is not added to a guest
> > > multiple times.
> > > 
> > > PCI device backend path has different rules from vif, disk etc. For
> > > example:
> > > /local/domain/0/backend/pci/9/0/dev-1/0000:03:10.1
> > > /local/domain/0/backend/pci/9/0/key-1/0000:03:10.1
> > > /local/domain/0/backend/pci/9/0/dev-2/0000:03:10.2
> > > /local/domain/0/backend/pci/9/0/key-2/0000:03:10.2
> > > 
> > > The devid for PCI devices is hardcoded 0. libxl__device_exists only
> > > checks up to /local/.../9/0 so it always returns true even the device is
> > > assignable.
> > > 
> > > Remove invocation of libxl__device_exists. We're sure at this point that
> > > the PCI device is assignable (hence no xenstore entry or JSON entry).
> > > The check is done before hand. For HVM guest it's done by calling
> > > xc_test_assign_device and for PV guest it's done by calling
> > > pciback_dev_is_assigned.
> > > 
> > > Reported-by: Li, Liang Z <liang.z.li@intel.com>
> > > Signed-off-by: Wei Liu <wei.liu2@citrix.com>
> > > Cc: Ian Campbell <ian.campbell@citrix.com>
> > > Cc: Ian Jackson <ian.jackson@eu.citrix.com>
> > > Cc: Konrad Wilk <konrad.wilk@oracle.com>
> > > ---
> > > This patch fixes a regression in 4.5.
> > 
> > Ouch! That needs then to be fixed.
> > 
> > Is the version you would want to commit? I did test it - and it
> 
> Yes.

Then Release-Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
> 
> > looked to do the right thing - thought the xen-pciback is stuck in the
> > 7 state. However that is a seperate issue that I believe is due to
> > Xen pciback not your patches.
> > 
> 
> Thanks for testing.
> 
> Wei.