[PATCH 1/3] powernv/iov: Ensure the pdn for VFs always contains a valid PE number

[Michael Ellerman]

"Oliver O'Halloran" <oohall at gmail.com> writes:
> On Tue, Oct 1, 2019 at 3:09 AM Bjorn Helgaas <helgaas at kernel.org> wrote:
>> On Mon, Sep 30, 2019 at 12:08:46PM +1000, Oliver O'Halloran wrote:
>> This is all powerpc, so I assume Michael will handle this.  Just
>> random things I noticed; ignore if they don't make sense:
>>
>> > On PowerNV we use the pcibios_sriov_enable() hook to do two things:
>> >
>> > 1. Create a pci_dn structure for each of the VFs, and
>> > 2. Configure the PHB's internal BARs that map MMIO ranges to PEs
>> >    so that each VF has it's own PE. Note that the PE also determines
>>
>> s/it's/its/
>>
>> >    the IOMMU table the HW uses for the device.
>> >
>> > Currently we do not set the pe_number field of the pci_dn immediately after
>> > assigning the PE number for the VF that it represents. Instead, we do that
>> > in a fixup (see pnv_pci_dma_dev_setup) which is run inside the
>> > pcibios_add_device() hook which is run prior to adding the device to the
>> > bus.
>> >
>> > On PowerNV we add the device to it's IOMMU group using a bus notifier and
>>
>> s/it's/its/
>>
>> > in order for this to work the PE number needs to be known when the bus
>> > notifier is run. This works today since the PE number is set in the fixup
>> > which runs before adding the device to the bus. However, if we want to move
>> > the fixup to a later stage this will break.
>> >
>> > We can fix this by setting the pdn->pe_number inside of
>> > pcibios_sriov_enable(). There's no good to avoid this since we already have
>>
>> s/no good/no good reason/ ?
>>
>> Not quite sure what "this" refers to ... "no good reason to avoid
>> setting pdn->pe_number in pcibios_sriov_enable()"?  The double
>> negative makes it a little hard to parse.
>
> I agree it's a bit vague, I'll re-word it.

So I'm expecting a v2?

cheers