Re: [RFC PATCH v3 1/9] vfio/pci: export vfio_pci_device public and add vfio_pci_device_private

Yan Zhao
2020-02-21T06:28:56Z

On Fri, Feb 21, 2020 at 05:00:11AM +0800, Alex Williamson wrote:
> On Tue, 11 Feb 2020 05:10:38 -0500
> Yan Zhao <yan.y.zhao@intel.com> wrote:
>
> > (1) make vfio_pci_device public, so it is accessible from external code.
> > (2) add a private struct vfio_pci_device_private, which is only accessible
> > from internal code. It extends struct vfio_pci_device.
> >
> > Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
> > ---
> > drivers/vfio/pci/vfio_pci.c | 256 +++++++++++++++-------------
> > drivers/vfio/pci/vfio_pci_config.c | 186 ++++++++++++--------
> > drivers/vfio/pci/vfio_pci_igd.c | 19 ++-
> > drivers/vfio/pci/vfio_pci_intrs.c | 186 +++++++++++---------
> > drivers/vfio/pci/vfio_pci_nvlink2.c | 22 +--
> > drivers/vfio/pci/vfio_pci_private.h | 7 +-
> > drivers/vfio/pci/vfio_pci_rdwr.c | 40 +++--
> > include/linux/vfio.h | 5 +
> > 8 files changed, 408 insertions(+), 313 deletions(-)
>
> [SNIP!]
>
> > diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> > index e42a711a2800..70a2b8fb6179 100644
> > --- a/include/linux/vfio.h
> > +++ b/include/linux/vfio.h
> > @@ -195,4 +195,9 @@ extern int vfio_virqfd_enable(void *opaque,
> > void *data, struct virqfd **pvirqfd, int fd);
> > extern void vfio_virqfd_disable(struct virqfd **pvirqfd);
> >
> > +struct vfio_pci_device {
> > + struct pci_dev *pdev;
> > + int num_regions;
> > + int irq_type;
> > +};
> > #endif /* VFIO_H */
>
> Hi Yan,
>
> Sorry for the delay. I'm still not very happy with this result, I was
> hoping the changes could be done less intrusively. Maybe here's
> another suggestion, why can't the vendor driver use a struct
> vfio_pci_device* as an opaque pointer? If you only want these three
> things initially, I think this whole massive patch can be reduced to:
>
> struct pci_dev *vfio_pci_pdev(struct vfio_pci_device *vdev)
> {
> return vdev->pdev;
> }
> EXPORT_SYMBOL_GPL(vfio_pci_dev);
>
> int vfio_pci_num_regions(struct vfio_pci_device *vdev)
> {
> return vdev->num_regions;
> }
> EXPORT_SYMBOL_GPL(vfio_pci_num_region);
>
> int vfio_pci_irq_type(struct vfio_pci_device *vdev)
> {
> return vdev->irq_type;
> }
> EXPORT_SYMBOL_GPL(vfio_pci_irq_type);
>
> This is how vfio-pci works with vfio, we don't know a struct
> vfio_device as anything other than an opaque pointer and we have access
> function where we need to see some property of that object.
>
> Patch 5/9 would become a vfio_pci_set_vendor_regions() interface.
>
you are right!
I'll change it to this way. Thanks.

Yan