Re: [PATCH v5 0/4] uio: add MSI/MSI-X support to uio_pci_generic driver

[Vlad Zolotarov]

On 10/06/15 23:35, Vlad Zolotarov wrote:
> On 10/06/15 21:27, Michael S. Tsirkin wrote:
> > On Tue, Oct 06, 2015 at 08:17:35PM +0300, Vlad Zolotarov wrote:
> > > This series add support for MSI and MSI-X interrupts to 
> > > uio_pci_generic driver.
> > >
> > > Currently uio_pci_generic demands INT#x interrupts source be 
> > > available. However
> > > there are devices that simply don't have INT#x capability, for 
> > > instance SR-IOV
> > > VF devices that simply don't have INT#x capability. For such devices
> > > uio_pci_generic will simply fail (more specifically its probe() will 
> > > fail).
> > >
> > > When IOMMU is either not available (e.g. Amazon EC2) or not 
> > > acceptable due to
> > > performance overhead and thus VFIO is not an option users that develop
> > > user-space drivers are left without any option but to develop some 
> > > proprietary
> > > UIO drivers (e.g. igb_uio driver in Intel's DPDK) just to be able to 
> > > use UIO
> > > infrastructure.
> > >
> > > This series provides a generic solution for this problem while 
> > > preserving the
> > > original behaviour for devices for which the original 
> > > uio_pci_generic had worked
> > > before (i.e. INT#x will be used by default).
> > >
> > > New in v5:
> > >     - Expanded the commitlog on PATCH1.
> > Looks like you didn't attempt to address any of my review comments.
> > I don't intend to review this until you do.
>
> So far there hasn't been any comments related to the code in these 
> patches  from your side but rather comments about the general flaws of 
> the current uio_pci_generic in particular and UIO in general that have 
> nothing to do with this series. Therefore obviously there was nothing 
> to address.
> If u have any comments related to _THIS_ series I'd be glad to 
> address. So far I was under the strong impression that u develop an 
> obviously theoretical discussion about "nice to have fixed" stuff in 
> UIO, which was obvious to everybody on this thread had nothing to do 
> with this patch series.
>
> Could it be that I've got u wrong? If so, could u, pls., clarify what 
> u'd like me to fix in these patches exactly and why?

I beg my pardon, there was one relevant comment of yours - to split the 
bars mapping into a separate patch. And this has been addressed. ;)

> thanks,
> vlad
>
> > > New in v4:
> > >     - Use portable __u32 and __s32 types from asm/types.h for
> > >       defining uio_pci_generic_irq_set fields.
> > >     - Use proper _IO macros for defining read and write ioctl()
> > >       commands.
> > >     - Moved bars mapping setting into a separate patch.
> > >     - Update uio_pci_generic example in uio-howto.tmpl.
> > >
> > > New in v3:
> > >     - Add __iomem qualifier to temp buffer receiving ioremap value.
> > >   New in v2:
> > >     - Added #include <linux/uaccess.h> to uio_pci_generic.c
> > >
> > >
> > > Vlad Zolotarov (4):
> > >    uio: add ioctl support
> > >    uio_pci_generic: properly initialize PCI bars mappings towards UIO
> > >    uio_pci_generic: add MSI/MSI-X support
> > >    Documentation: update uio-howto
> > >
> > >   Documentation/DocBook/uio-howto.tmpl | 139 ++++++++++--
> > >   drivers/uio/uio.c                    |  15 ++
> > >   drivers/uio/uio_pci_generic.c        | 409 
> > > +++++++++++++++++++++++++++++++++--
> > >   include/linux/uio_driver.h           |   3 +
> > >   include/uapi/linux/uio_pci_generic.h |  51 +++++
> > >   5 files changed, 574 insertions(+), 43 deletions(-)
> > >   create mode 100644 include/uapi/linux/uio_pci_generic.h
> > >
> > > --
> > > 2.1.0

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