On Wed, 2017-02-22 at 10:14 -0500, Boris Ostrovsky wrote: > On 02/22/2017 09:28 AM, Bjorn Helgaas wrote: > > > > On Tue, Feb 21, 2017 at 10:58:39AM -0500, Boris Ostrovsky wrote: > > > > > > On 02/21/2017 10:45 AM, Juergen Gross wrote: > > > > > > > > On 21/02/17 16:31, Dan Streetman wrote: > > > > > > > > > > On Fri, Jan 13, 2017 at 5:30 PM, Konrad Rzeszutek Wilk > > > > > <konrad.wilk@xxxxxxxxxx> wrote: > > > > > > > > > > > > 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@xxxxxxxxxxxxx> > > > > > > Acked-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx> > > > > > This doesn't seem to be applied yet, is it still waiting on another > > > > > ack? Or maybe I'm looking at the wrong git tree... > > > > Am I wrong or shouldn't this go through the PCI tree? Konrad? > > > Konrad is away this week but since pull request for Xen tree just went > > > out we should probably wait until rc1 anyway (unless something big comes > > > up before that). > > I assume this should go via the Xen or x86 tree, since that's how most > > arch/x86/pci/xen.c patches have been handled, including af42b8d12f8a. > > If you think otherwise, let me know. > > OK, I applied it to Xen tree's for-linus-4.11. Hm, we want this (c74fd80f2f4) in stable too, don't we?
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