Messages in this thread | | | Date | Tue, 21 May 2013 17:31:48 -0400 | From | Don Dutile <> | Subject | Re: [PATCH 6/7] PCI: Make sure VF's driver get attached after PF's |
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On 05/21/2013 05:30 PM, Don Dutile wrote: > On 05/14/2013 05:39 PM, Alexander Duyck wrote: >> On 05/14/2013 12:59 PM, Yinghai Lu wrote: >>> On Tue, May 14, 2013 at 12:45 PM, Alexander Duyck >>> <alexander.h.duyck@intel.com> wrote: >>>> On 05/14/2013 11:44 AM, Yinghai Lu wrote: >>>>> On Tue, May 14, 2013 at 9:00 AM, Alexander Duyck >>>>> <alexander.h.duyck@intel.com> wrote: >>>>>> I'm sorry, but what is the point of this patch? With device assignment >>>>>> it is always possible to have VFs loaded and the PF driver unloaded >>>>>> since you cannot remove the VFs if they are assigned to a VM. >>>>> unload PF driver will not call pci_disable_sriov? >>>> You cannot call pci_disable_sriov because you will panic all of the >>>> guests that have devices assigned. >>> ixgbe_remove did call pci_disable_sriov... >>> >>> for guest panic, that is another problem. >>> just like you pci passthrough with real pci device and hotremove the >>> card in host. >>> >>> ... >> >> I suggest you take another look. In ixgbe_disable_sriov, which is the >> function that is called we do a check for assigned VFs. If they are >> assigned then we do not call pci_disable_sriov. >> >>> >>>> So how does your patch actually fix this problem? It seems like it is >>>> just avoiding it. >>> yes, until the first one is done. >> >> Avoiding the issue doesn't fix the underlying problem and instead you >> are likely just introducing more bugs as a result. >> >>>> From what I can tell your problem is originating in pci_call_probe. I >>>> believe it is calling work_on_cpu and that doesn't seem correct since >>>> the work should be taking place on a CPU already local to the PF. You >>>> might want to look there to see why you are trying to schedule work on a >>>> CPU which should be perfectly fine for you to already be doing your work on. >>> it always try to go with local cpu with same pxm. >> >> The problem is we really shouldn't be calling work_for_cpu in this case >> since we are already on the correct CPU. What probably should be >> happening is that pci_call_probe should be doing a check to see if the >> current CPU is already contained within the device node map and if so >> just call local_pci_probe directly. That way you can avoid deadlocking >> the system by trying to flush the CPU queue of the CPU you are currently on. >> > That's the patch that Michael Tsirkin posted for a fix, > but it was noted that if you have the case where the _same_ driver is used for vf & pf, > other deadlocks may occur. > It would work in the case of ixgbe/ixgbevf, but not for something like > the Mellanox pf/vf driver (which is the same). > apologies; here's the thread the discussed the issue: https://patchwork.kernel.org/patch/2458681/
>> >> Alex >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-pci" in >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html >
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