Messages in this thread | | | Subject | Re: [Xen-devel] [PATCH] Xen/pciback: Implement PCI slot or bus reset with 'do_flr' SysFS attribute | From | Govinda Tatti <> | Date | Wed, 29 Nov 2017 13:51:06 -0600 |
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On 11/29/2017 12:05 PM, Pasi Kärkkäinen wrote: > On Wed, Nov 29, 2017 at 11:25:09AM -0600, Govinda Tatti wrote: >>>>> Furthermore, contrary to what you claim in >>>>> your reply to Pasi, I can't see where you try an actual FLR first - >>>>> you go straight to pci_probe_reset_{slot,bus}(). If you actually >>>>> tried FLR first, only falling back to the other methods as "emulation", >>>>> I could certainly agree with the file name chosen. >>>> Currently, multiple resets are being invoked (independently) in the context >>>> of "xl attach/detach/shutdown/reboot". >>>> >>>> - pci_reset_function_locked (invoked by pcistub_put_pci_dev()) >>>> This function tries various PCI reset methods including FLR. >>>> - pcistub_reset_dev (called by toolsstack based on "do_flr" attribute) >>> While related in a certain way, I can't really see how this addresses >>> the comment. >> pcistub_reset_dev() just tries slot or bus reset but not FLR since it is >> being >> checked and executed by pci_reset_function_locked() if supported. May be we >> can >> add FLR reset code to pcistub_reset_dev() and try FLR first before fall-back >> to >> slot/bus reset. >> > Hmm.. is the suitable reset method something that can be figured out automatically? > > I mean if FLR is tried first, but it isn't supported by the device, is it OK to go ahead and do a slot/bus reset automatically? Yes, we are moving in the same direction.
> What if there are other devices in the same bus, wouldn't automatic bus reset be a bad thing? We will perform BUS or SLOT reset only if all device/functions behind the bus/slot are owned by pcistub. Otherwise, we will skipthis reset.
> Or should the reset-method be configured by the user for the VM / PCI device ? > > Just thinking out loud here.. >
Cheers GOVINDA
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