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Re: [PATCH] uio/uio_pci_generic: Add SR-IOV support

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On 09/28/2017 09:46 AM, David Woodhouse wrote:
> On Thu, 2017-09-28 at 08:22 -0400, Don Dutile wrote:
>>
>> After reading Alex's response, I now understand Dave's question
>> better and why the patch won't work in general.
>
> UIO doesn't work "in general". It requires a very *specific* userspace
> driver for the hardware in question, which needs to know what it's
> doing.
>
>> In every SRIOV capable device I've run into to date, the PF has
>> to know the VFs are being assigned due to some resource mgmt, if not
>> internal (e.g., switch) configuration reasons.
>> The reasons are often subtle.
>
> Sure. If there's actually a userspace driver (which in my case there
> isn't), and if that's needed for the hardware ins question (which in my
> case it isn't), then it'd need to do that before enabling the VFs via
> the user-level sysfs interface of which you speak.
>
>>  From the context of the patches (uio), why aren't VFs enabled via
>> user-level sysfs interface? That was provided for user-mgmt apps
>> to have a PCIe-generic/common, device-independent method of VF
>> enablement
>
> That is *precisely* what we're doing. But the user-space sysfs
> interface doesn't actually *exist* unless a driver is bound to the
> device in question, with a .sriov-configure method. Which is where I
> came in... :)
>
ah, nickel summary: no in-kernel driver w/.sriov-configure method.
if so, now I'm up to speed with you....
hmmmm....
so, that would imply we need an in-kernel, pcie-common, .sriov-configure method
that's invoked if a driver isn't bound to a device? ... yes?

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[PATCH] uio/uio_pci_generic: Add SR-IOV support David Woodhouse <dwmw2@infradead.org> - 2017-09-27 15:20 +0200
  Re: [PATCH] uio/uio_pci_generic: Add SR-IOV support Bjorn Helgaas <helgaas@kernel.org> - 2017-09-28 00:10 +0200
    Re: [PATCH] uio/uio_pci_generic: Add SR-IOV support David Woodhouse <dwmw2@infradead.org> - 2017-09-28 00:30 +0200
      Re: [PATCH] uio/uio_pci_generic: Add SR-IOV support Alexander Duyck <alexander.duyck@gmail.com> - 2017-09-28 01:10 +0200
        Re: [PATCH] uio/uio_pci_generic: Add SR-IOV support Don Dutile <ddutile@redhat.com> - 2017-09-28 14:30 +0200
          Re: [PATCH] uio/uio_pci_generic: Add SR-IOV support David Woodhouse <dwmw2@infradead.org> - 2017-09-28 15:50 +0200
            Re: [PATCH] uio/uio_pci_generic: Add SR-IOV support Don Dutile <ddutile@redhat.com> - 2017-09-28 17:10 +0200
              Re: [PATCH] uio/uio_pci_generic: Add SR-IOV support David Woodhouse <dwmw2@infradead.org> - 2017-09-28 18:00 +0200
                Re: [PATCH] uio/uio_pci_generic: Add SR-IOV support Don Dutile <ddutile@redhat.com> - 2017-09-28 19:00 +0200
                Re: [PATCH] uio/uio_pci_generic: Add SR-IOV support David Woodhouse <dwmw2@infradead.org> - 2017-10-02 14:40 +0200
                Re: [PATCH] uio/uio_pci_generic: Add SR-IOV support Don Dutile <ddutile@redhat.com> - 2017-10-02 22:50 +0200
    Re: [PATCH] uio/uio_pci_generic: Add SR-IOV support Don Dutile <ddutile@redhat.com> - 2017-09-28 14:20 +0200

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