Re: [RFC PATCH v3 6/9] vfio/pci: export vfio_pci_setup_barmap

Yan Zhao
2020-02-21T06:29:48Z

On Fri, Feb 21, 2020 at 05:00:13AM +0800, Alex Williamson wrote:
> On Tue, 11 Feb 2020 05:14:19 -0500
> Yan Zhao <yan.y.zhao@intel.com> wrote:
>
> > This allows vendor driver to read/write to bars directly which is useful
> > in security checking condition.
> >
> > Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
> > ---
> > drivers/vfio/pci/vfio_pci_rdwr.c | 26 +++++++++++++-------------
> > include/linux/vfio.h | 2 ++
> > 2 files changed, 15 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/vfio/pci/vfio_pci_rdwr.c b/drivers/vfio/pci/vfio_pci_rdwr.c
> > index a0ef1de4f74a..3ba85fb2af5b 100644
> > --- a/drivers/vfio/pci/vfio_pci_rdwr.c
> > +++ b/drivers/vfio/pci/vfio_pci_rdwr.c
> > @@ -129,7 +129,7 @@ static ssize_t do_io_rw(void __iomem *io, char __user *buf,
> > return done;
> > }
> >
> > -static int vfio_pci_setup_barmap(struct vfio_pci_device *vdev, int bar)
> > +void __iomem *vfio_pci_setup_barmap(struct vfio_pci_device *vdev, int bar)
> > {
> > struct pci_dev *pdev = vdev->pdev;
> > struct vfio_pci_device_private *priv = VDEV_TO_PRIV(vdev);
> > @@ -137,22 +137,23 @@ static int vfio_pci_setup_barmap(struct vfio_pci_device *vdev, int bar)
> > void __iomem *io;
> >
> > if (priv->barmap[bar])
> > - return 0;
> > + return priv->barmap[bar];
> >
> > ret = pci_request_selected_regions(pdev, 1 << bar, "vfio");
> > if (ret)
> > - return ret;
> > + return NULL;
> >
> > io = pci_iomap(pdev, bar, 0);
> > if (!io) {
> > pci_release_selected_regions(pdev, 1 << bar);
> > - return -ENOMEM;
> > + return NULL;
> > }
> >
> > priv->barmap[bar] = io;
> >
> > - return 0;
> > + return io;
> > }
> > +EXPORT_SYMBOL_GPL(vfio_pci_setup_barmap);
>
> This should instead become a vfio_pci_get_barmap() function that tests
> for an optionally calls vfio_pci_setup_barmap before returning the
> pointer. I'm now willing to lose the better error returns in the
> original. Thanks,
>
Got it. will change it.
Thanks!

Yan