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From: Alex Williamson <alex.williamson@redhat.com>
To: Andreas Hartmann <andihartmann@freenet.de>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	linux-pci <linux-pci@vger.kernel.org>
Subject: Re: Hard and silent lock up since linux 3.14 with PCIe pass through (vfio)
Date: Thu, 23 Oct 2014 10:33:42 -0600
Message-ID: <1414082022.27420.39.camel@ul30vt.home> (raw)
In-Reply-To: <54492606.5090308@maya.org>

On Thu, 2014-10-23 at 18:00 +0200, Andreas Hartmann wrote:
> Alex Williamson wrote:
> > On Wed, 2014-10-22 at 18:22 +0200, Andreas Hartmann wrote:
> >> Alex Williamson wrote:
> >>> --- a/drivers/pci/pci.c
> >>> +++ b/drivers/pci/pci.c
> >>> @@ -3308,15 +3308,15 @@ static int __pci_dev_reset(struct pci_dev *dev, int prob
> >>>         if (rc != -ENOTTY)
> >>>                 goto done;
> >>>  
> >>> -       rc = pci_pm_reset(dev, probe);
> >>> +       rc = pci_dev_reset_slot_function(dev, probe);
> >>>         if (rc != -ENOTTY)
> >>>                 goto done;
> >>>  
> >>> -       rc = pci_dev_reset_slot_function(dev, probe);
> >>> +       rc = pci_parent_bus_reset(dev, probe);
> >>>         if (rc != -ENOTTY)
> >>>                 goto done;
> >>>  
> >>> -       rc = pci_parent_bus_reset(dev, probe);
> >>> +       rc = pci_pm_reset(dev, probe);
> >>>  done:
> >>>         return rc;
> >>>  }
> >>
> >> This way it's crashing with echo 1 > reset, too.
> > 
> > Ok, so it's somehow related to doing a bus reset with virtual channel
> > save/restore while PM reset with VC save/restore works ok as apparently
> > does bus reset without VC save/restore.  Let's try to do a manual bus
> > reset so we can look at the post reset state of the device before the
> > kernel tries to restore it.
> > 
> > First bind the target device 03:00.0 to pci-stub or vfio-pci so that we
> > know it's not being used.
> > 
> > Next capture lspci -xxxx -s 3:00.0 so we have the starting state.
> > 
> > Then we'll do a bus reset using setpci:
> > # setpci -s 00:05.0 3e.w=40:40
> > <if you script this, wait at least 2ms here>
> > # setpci -s 00:05.0 3e.w=00:40
> > <wait 1 second here>
> > 
> > Now re-capture lspci -xxxx -s 3:00.0
> 
> The machine is booted w/ vfio bound to 3:00.0 as usual (now for testing
> linux 3.14)
> 
> lspci -xxxx -s 3:00.0
> setpci -s 00:05.0 3e.w=40:40
> usleep 10
> setpci -s 00:05.0 3e.w=00:40
> sleep 1
> lspci -xxxx -s 3:00.0
> 
> I didn't get the second lspci because the machine already was hanging.
> The first output is attached completely.

Hmm, that doesn't make much sense.  You had found that if you disabled
the VC save/restore then QEMU works.  That should have still been using
secondary bus reset as we're trying to do here, so I don't understand
why we can't do a manual secondary bus reset now.

If you use Bjorn's previous patch to disable VC save/restore and my
patch to reorder the reset mechanisms, does echo 1 > reset for the sysfs
entry for the device also still cause a hang?

Can you provide a link to the specific model for this card?  Thanks,

Alex


  reply index

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-23 19:03 Andreas Hartmann
2014-09-23 20:07 ` Alex Williamson
2014-09-24 14:54   ` Andreas Hartmann
2014-09-24 17:16     ` Andreas Hartmann
2014-10-10  9:39   ` Andreas Hartmann
2014-10-10 14:37     ` Bjorn Helgaas
2014-10-10 14:49       ` Andreas Hartmann
2014-10-10 15:55         ` Bjorn Helgaas
2014-10-10 16:09           ` Andreas Hartmann
2014-10-10 16:41             ` Bjorn Helgaas
2014-10-10 22:32               ` Andreas Hartmann
2014-10-10 22:54                 ` Bjorn Helgaas
2014-10-11  6:20                   ` Andreas Hartmann
2014-10-15  8:04                     ` Alex Williamson
2014-10-17  1:04                       ` Andreas Hartmann
2014-10-21 21:06                         ` Alex Williamson
2014-10-21 21:32                           ` Alex Williamson
2014-10-22 16:22                             ` Andreas Hartmann
2014-10-22 20:36                               ` Alex Williamson
2014-10-23 16:00                                 ` Andreas Hartmann
2014-10-23 16:33                                   ` Alex Williamson [this message]
2014-10-23 17:12                                     ` Andreas Hartmann
2014-10-23 17:33                                     ` Andreas Hartmann
2014-10-23 19:37                                       ` Alex Williamson
2014-10-24 14:21                                         ` Andreas Hartmann
2014-10-25  6:03                                         ` Andreas Hartmann
2014-10-28 21:51                                           ` Alex Williamson
2014-10-29 16:47                                             ` Andreas Hartmann
2014-10-29 17:44                                               ` Alex Williamson
2014-10-29 17:57                                                 ` Andreas Hartmann
2014-10-29 18:16                                                   ` Alex Williamson
2014-10-29 19:43                                                     ` Andreas Hartmann
2014-10-29 20:50                                                       ` Alex Williamson
2014-10-29 21:35                                                         ` Andreas Hartmann
2014-10-30 16:35                                                         ` Andreas Hartmann
2014-10-30 16:58                                                           ` Alex Williamson
2014-10-30 19:09                                                             ` Andreas Hartmann
2014-10-30 19:45                                                               ` Alex Williamson
2014-10-30 20:21                                                                 ` Andreas Hartmann
2014-10-22 15:34                           ` Andreas Hartmann
2014-10-22 16:02                             ` Alex Williamson
2014-10-22 16:20                               ` Andreas Hartmann

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