From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
To: Dan Streetman <ddstreet@ieee.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
jgross@suse.com, Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Dan Streetman <dan.streetman@canonical.com>,
Bjorn Helgaas <bhelgaas@google.com>,
xen-devel@lists.xenproject.org,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-pci@vger.kernel.org
Subject: Re: [PATCH] xen: do not re-use pirq number cached in pci device msi msg data
Date: Fri, 13 Jan 2017 17:30:35 -0500 [thread overview]
Message-ID: <20170113223035.GE23066@char.us.oracle.com> (raw)
In-Reply-To: <20170113200751.20125-1-ddstreet@ieee.org>
On Fri, Jan 13, 2017 at 03:07:51PM -0500, Dan Streetman wrote:
> Revert the main part of commit:
> af42b8d12f8a ("xen: fix MSI setup and teardown for PV on HVM guests")
>
> That commit introduced reading the pci device's msi message data to see
> if a pirq was previously configured for the device's msi/msix, and re-use
> that pirq. At the time, that was the correct behavior. However, a
> later change to Qemu caused it to call into the Xen hypervisor to unmap
> all pirqs for a pci device, when the pci device disables its MSI/MSIX
> vectors; specifically the Qemu commit:
> c976437c7dba9c7444fb41df45468968aaa326ad
> ("qemu-xen: free all the pirqs for msi/msix when driver unload")
>
> Once Qemu added this pirq unmapping, it was no longer correct for the
> kernel to re-use the pirq number cached in the pci device msi message
> data. All Qemu releases since 2.1.0 contain the patch that unmaps the
> pirqs when the pci device disables its MSI/MSIX vectors.
>
> This bug is causing failures to initialize multiple NVMe controllers
> under Xen, because the NVMe driver sets up a single MSIX vector for
> each controller (concurrently), and then after using that to talk to
> the controller for some configuration data, it disables the single MSIX
> vector and re-configures all the MSIX vectors it needs. So the MSIX
> setup code tries to re-use the cached pirq from the first vector
> for each controller, but the hypervisor has already given away that
> pirq to another controller, and its initialization fails.
>
> This is discussed in more detail at:
> https://lists.xen.org/archives/html/xen-devel/2017-01/msg00447.html
>
> Fixes: af42b8d12f8a ("xen: fix MSI setup and teardown for PV on HVM guests")
> Signed-off-by: Dan Streetman <dan.streetman@canonical.com>
Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
next prev parent reply other threads:[~2017-01-13 22:32 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-05 19:28 [PATCH] xen: do not re-use pirq number cached in pci device msi msg data Dan Streetman
2017-01-07 1:06 ` Konrad Rzeszutek Wilk
2017-01-09 14:59 ` Boris Ostrovsky
2017-01-09 15:42 ` [Xen-devel] " Dan Streetman
2017-01-09 15:59 ` Konrad Rzeszutek Wilk
2017-01-09 19:30 ` Stefano Stabellini
2017-01-10 15:57 ` Dan Streetman
2017-01-10 18:41 ` Dan Streetman
2017-01-10 19:03 ` Stefano Stabellini
2017-01-10 21:32 ` Dan Streetman
2017-01-10 23:28 ` Boris Ostrovsky
2017-01-11 1:25 ` Stefano Stabellini
2017-01-11 15:26 ` Dan Streetman
2017-01-11 18:46 ` Stefano Stabellini
2017-01-11 23:25 ` Dan Streetman
2017-01-13 18:31 ` Dan Streetman
2017-01-13 18:44 ` Stefano Stabellini
2017-01-13 20:00 ` Boris Ostrovsky
2017-01-13 20:07 ` Dan Streetman
2017-01-13 20:54 ` Stefano Stabellini
2017-01-13 21:49 ` Boris Ostrovsky
2017-01-13 22:30 ` Konrad Rzeszutek Wilk [this message]
2017-02-21 15:31 ` Dan Streetman
2017-02-21 15:45 ` Juergen Gross
2017-02-21 15:58 ` Boris Ostrovsky
2017-02-22 14:28 ` Bjorn Helgaas
2017-02-22 15:14 ` Boris Ostrovsky
2017-05-03 18:19 ` [Xen-devel] " David Woodhouse
2017-05-03 18:43 ` Boris Ostrovsky
2017-05-03 22:59 ` Stefano Stabellini
2017-05-03 23:06 ` Greg KH
2017-05-03 23:12 ` Stefano Stabellini
2017-05-03 23:19 ` Greg KH
2017-01-13 20:13 ` Dan Streetman
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