[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v5 9/9] xen/pciback: Implement PCI reset slot or bus with 'do_flr' SysFS attribute
Thursday, December 4, 2014, 2:43:06 PM, you wrote: > On 04/12/14 13:10, Sander Eikelenboom wrote: >> >> Thursday, December 4, 2014, 1:24:47 PM, you wrote: >> >>> On 04/12/14 12:06, Konrad Rzeszutek Wilk wrote: >>>> >>>> On Dec 4, 2014 6:30 AM, David Vrabel <david.vrabel@xxxxxxxxxx> wrote: >>>>> >>>>> On 03/12/14 21:40, Konrad Rzeszutek Wilk wrote: >>>>>> >>>>>> Instead of doing all this complex dance, we depend on the toolstack >>>>>> doing the right thing. As such implement the 'do_flr' SysFS attribute >>>>>> which 'xl' uses when a device is detached or attached from/to a guest. >>>>>> It bypasses the need to worry about the PCI lock. >>>>> >>>>> No. Get pciback to add its own "reset" sysfs file (as I have repeatedly >>>>> proposed). >>>>> >>>> >>>> Which does not work as the kobj will complain (as there is already an >>>> 'reset' associated with the PCI device). >> >>> It is only needed if the core won't provide one. >> >>> +static int pcistub_try_create_reset_file(struct pci_dev *pci) >>> +{ >>> + struct xen_pcibk_dev_data *dev_data = pci_get_drvdata(pci); >>> + struct device *dev = &pci->dev; >>> + int ret; >>> + >>> + /* Already have a per-function reset? */ >>> + if (pci_probe_reset_function(pci) == 0) >>> + return 0; >>> + >>> + ret = device_create_file(dev, &dev_attr_reset); >>> + if (ret < 0) >>> + return ret; >> + dev_data->>created_reset_file = true; >>> + return 0; >>> +} >> >> Wouldn't the "core-reset-sysfs-file" be still wired to the end up calling >> "pci.c:__pci_dev_reset" ? >> >> The problem with that function is that from my testing it seems that the >> first option "pci_dev_specific_reset" always seems to return succes, so all >> the >> other options are skipped (flr, pm, slot, bus). However the device it self >> is >> not properly reset enough (perhaps the pci_dev_specific_reset is good enough >> for >> none virtualization purposes and it's probably the least intrusive. For >> virtualization however it would be nice to be sure it resets properly, or >> have a >> way to force a specific reset routine.) > Then you need work with the maintainer for those specific devices or > drivers to fix their specific reset function. > I'm not adding stuff to pciback to workaround broken quirks. OK that's a pretty clear message there, so if one wants to use pci and vga passthrough one should better use KVM and vfio-pci. vfio-pci has: - logic to do the try-slot-bus-reset logic - it has quirks specific to vga passthrough implemented in from the looks of it a quite clean driver. (the main issue with it so far was you could only seize devices based on vendor and device id, which can be a problem when you have multiple devices. However that was resolved recently if i am correct.) And neither of those will be supported by xen-pciback if i get your message right ? -- Sander > David _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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