From mboxrd@z Thu Jan 1 00:00:00 1970 From: Konrad Rzeszutek Wilk Subject: Re: Problems accessing passthrough PCI device Date: Thu, 13 Nov 2014 14:03:38 -0500 Message-ID: <20141113190338.GB11211@laptop.dumpdata.com> References: <198478230.20141113102921@gmail.com> <5464C971020000780004739B@mail.emea.novell.com> <196307380.20141113120732@gmail.com> <5464E1D9020000780004746B@mail.emea.novell.com> <429773295.20141113144907@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <429773295.20141113144907@gmail.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Simon Martin Cc: Jan Beulich , xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On Thu, Nov 13, 2014 at 02:49:07PM -0300, Simon Martin wrote: > Hello Jan, > > >> > >> Yes, the first thing I do in the driver is set the PCI configuration > >> access bits to 7 that should enable IO space, Memory Space and Master > >> BUS access. > >> > >> As a test I disabled this and all reads to the PCI device return -1, > >> even the first one. > > > I implied your earlier statement to mean that. But - did you also > > verify that the three flags actually end up set (ideally from both > > DomU and Dom0 perspective)? The PCI backend may be screwing > > up things... > > Yes I do verify the write. How do I check this from Dom0? You can crank up the debug volume in xen-pciback. Recompile the kernel and put '#define DEBUG 1' at the start of the .c files. Interestingly enough I saw this issue as well - and it looked to me that Xen pciback was stuck in '7' state (Reconfiguring) and never excited it. But I hadn't had a chance to dig in this. > > >> I agree, this looks more than a hang than a crash. I've just found a > >> link to the USB debug cable. I've ordered one but it will take a while > > > And I hope you first verified that your system meets the criteria > > for this to work in the first place? > > I followed the checks in the Kernel earlyprintk debugging HOWTO, i.e. > lspci -vvv to check the USB debug capability, and it verified. The > device is ordered and now just to wait.... > > > -- > Best regards, > Simon mailto:furryfuttock@gmail.com > > > _______________________________________________ > Xen-devel mailing list > Xen-devel@lists.xen.org > http://lists.xen.org/xen-devel