On Mon, Sep 17, 2012 at 01:42:54PM +0100, Ian Campbell wrote:
> On Mon, 2012-09-17 at 13:32 +0100, Pasi Kärkkäinen wrote:
>> On Mon, Sep 17, 2012 at 01:51:03PM +0200, Robin Axelsson wrote:
>>> There is one thing I wonder though when it comes to PCI passthrough:
>>>
>>> Can Xen reset hardware through the d3d0 in the ACPI interface and/or
>>> through a 'bus reset' or a 'link reset'? Or can it reset
hardware
>>> that is marked for passthrough only through FLR?
>>>
>>> For details see e.g.
>>>
http://www.vmware.com/files/pdf/techpaper/vsp_4_vmdirectpath_host.pdf
>>>
>> I added xen-devel to the CC-list.
>> Hopefully someone there can reply this question.
> With a pvops dom0 Xen resets devices by writing to its "reset" node in
> sysfs so it will reset the device using whatever method the dom0 kernel
> supports for that device.
And if you use Xen PCI-back it has this enabled so you don't even
need the 'reset' functionality.
> The version of Linux I have to hand has, in __pci_dev_reset, calls to
> the following in this order and stops after the first one which
> succeeds:
> * pci_dev_specific_reset (AKA per device quirks)
> * pcie_flr
> * pci_af_flr
> * pci_pm_reset
> * pci_parent_bus_reset
>
> See drivers/pci/pci.c in the kernel for more info.
>
> IIRC classic Xen kernels had similar code in pciback, although I don't
> know which specific sets of actions or in which order they were tried.
>
> Ian.
>
>
> _______________________________________________
> Xen-devel mailing list
> Xen-devel(a)lists.xen.org
>
http://lists.xen.org/xen-devel
>
.
That sounds like great news, that means that FLR is not a requirement to
successfully pass through hardware without errors, as is stated in the
VTdHowTo page. So it seems that the VTdHowTo page needs to be updated
with this information.