[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] xen: do not re-use pirq number cached in pci device msi msg data
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? Juergen _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx https://lists.xen.org/xen-devel
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