Re: [PATCH v9 01/19] vfio/platform: initial skeleton of VFIO support for platform devices

[Antonios Motakis]

On Wed, Nov 12, 2014 at 5:49 PM, Alex Williamson
<alex.williamson@xxxxxxxxxx> wrote:
>
> On Wed, 2014-11-12 at 11:05 +0100, Eric Auger wrote:
> > Hi Antonios,
> >
> > On 10/27/2014 07:07 PM, Antonios Motakis wrote:
> > > This patch forms the common skeleton code for platform devices support
> > > with VFIO. This will include the core functionality of VFIO_PLATFORM,
> > > however binding to the device and discovering the device resources will
> > > be done with the help of a separate file where any Linux platform bus
> > > specific code will reside.
> > >
> > > This will allow us to implement support for also discovering AMBA devices
> > > and their resources, but still reuse a large part of the VFIO_PLATFORM
> > > implementation.
> > >
> > > Signed-off-by: Antonios Motakis <a.motakis@xxxxxxxxxxxxxxxxxxxxxx>
> > > ---
> > >  drivers/vfio/platform/vfio_platform_common.c  | 126 ++++++++++++++++++++++++++
> > >  drivers/vfio/platform/vfio_platform_private.h |  36 ++++++++
> > >  2 files changed, 162 insertions(+)
> > >  create mode 100644 drivers/vfio/platform/vfio_platform_common.c
> > >  create mode 100644 drivers/vfio/platform/vfio_platform_private.h
> > >
> > > diff --git a/drivers/vfio/platform/vfio_platform_common.c b/drivers/vfio/platform/vfio_platform_common.c
> > > new file mode 100644
> > > index 0000000..e0fdbc8
> > > --- /dev/null
> > > +++ b/drivers/vfio/platform/vfio_platform_common.c
> > > @@ -0,0 +1,126 @@
> > > +/*
> > > + * Copyright (C) 2013 - Virtual Open Systems
> > > + * Author: Antonios Motakis <a.motakis@xxxxxxxxxxxxxxxxxxxxxx>
> > > + *
> > > + * This program is free software; you can redistribute it and/or modify
> > > + * it under the terms of the GNU General Public License, version 2, as
> > > + * published by the Free Software Foundation.
> > > + *
> > > + * This program is distributed in the hope that it will be useful,
> > > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > > + * GNU General Public License for more details.
> > > + */
> > > +
> > > +#include <linux/device.h>
> > > +#include <linux/interrupt.h>
> > > +#include <linux/iommu.h>
> > > +#include <linux/module.h>
> > > +#include <linux/mutex.h>
> > > +#include <linux/notifier.h>
> > > +#include <linux/pm_runtime.h>
> > > +#include <linux/slab.h>
> > > +#include <linux/types.h>
> > > +#include <linux/uaccess.h>
> > > +#include <linux/vfio.h>
> > > +#include <linux/io.h>
> > not sure at that state all the above includes are needed.
> > > +
> > > +#include "vfio_platform_private.h"
> > > +
> > > +static void vfio_platform_release(void *device_data)
> > > +{
> > > +   module_put(THIS_MODULE);
> > > +}
> > > +
> > > +static int vfio_platform_open(void *device_data)
> > > +{
> > > +   if (!try_module_get(THIS_MODULE))
> > > +           return -ENODEV;
> > > +
> > > +   return 0;
> > > +}
> > > +
> > > +static long vfio_platform_ioctl(void *device_data,
> > > +                      unsigned int cmd, unsigned long arg)
> > a minor style comment/question that applies on all the series. Shouldn't
> > subsequent argument lines rather be aligned with the first char after
> > "(", as done in PCI code?
>
> It's also my preferred style to indent to just after the open paren on
> wrapped lines where possible, but I don't think there are hard rules in
> CodingStyle or checkpatch that enforce this, so I often let it slide.
> Thanks,
>

You're right that there are no hard coding style rules for this, but I
also like this style so I'll apply it more consistently.

> Alex
>
> > > +{
> > > +   if (cmd == VFIO_DEVICE_GET_INFO)
> > > +           return -EINVAL;
> > > +
> > > +   else if (cmd == VFIO_DEVICE_GET_REGION_INFO)
> > > +           return -EINVAL;
> > > +
> > > +   else if (cmd == VFIO_DEVICE_GET_IRQ_INFO)
> > > +           return -EINVAL;
> > > +
> > > +   else if (cmd == VFIO_DEVICE_SET_IRQS)
> > > +           return -EINVAL;
> > > +
> > > +   else if (cmd == VFIO_DEVICE_RESET)
> > > +           return -EINVAL;
> > > +
> > > +   return -ENOTTY;
> > > +}
> > > +
> > > +static ssize_t vfio_platform_read(void *device_data, char __user *buf,
> > > +                             size_t count, loff_t *ppos)
> > > +{
> > > +   return -EINVAL;
> > > +}
> > > +
> > > +static ssize_t vfio_platform_write(void *device_data, const char __user *buf,
> > > +                              size_t count, loff_t *ppos)
> > > +{
> > > +   return -EINVAL;
> > > +}
> > > +
> > > +static int vfio_platform_mmap(void *device_data, struct vm_area_struct *vma)
> > > +{
> > > +   return -EINVAL;
> > > +}
> > > +
> > > +static const struct vfio_device_ops vfio_platform_ops = {
> > > +   .name           = "vfio-platform",
> > > +   .open           = vfio_platform_open,
> > > +   .release        = vfio_platform_release,
> > > +   .ioctl          = vfio_platform_ioctl,
> > > +   .read           = vfio_platform_read,
> > > +   .write          = vfio_platform_write,
> > > +   .mmap           = vfio_platform_mmap,
> > > +};
> > > +
> > > +int vfio_platform_probe_common(struct vfio_platform_device *vdev,
> > > +                          struct device *dev)
> > > +{
> > > +   struct iommu_group *group;
> > > +   int ret;
> > > +
> > > +   if (!vdev)
> > > +           return -EINVAL;
> > > +
> > > +   group = iommu_group_get(dev);
> > > +   if (!group) {
> > > +           pr_err("VFIO: No IOMMU group for device %s\n", vdev->name);
> > > +           return -EINVAL;
> > > +   }
> > I saw the above check also is done at beginning of vfio_add_group_dev.
> > Added value however is pr_err which is useful and PCI code does the
> > check too.
> >
> > Eric
> > > +
> > > +   ret = vfio_add_group_dev(dev, &vfio_platform_ops, vdev);
> > > +   if (ret) {
> > > +           iommu_group_put(group);
> > > +           return ret;
> > > +   }
> > > +
> > > +   return 0;
> > > +}
> > > +EXPORT_SYMBOL_GPL(vfio_platform_probe_common);
> > > +
> > > +struct vfio_platform_device *vfio_platform_remove_common(struct device *dev)
> > > +{
> > > +   struct vfio_platform_device *vdev;
> > > +
> > > +   vdev = vfio_del_group_dev(dev);
> > > +   if (vdev)
> > > +           iommu_group_put(dev->iommu_group);
> > > +
> > > +   return vdev;
> > > +}
> > > +EXPORT_SYMBOL_GPL(vfio_platform_remove_common);
> > > diff --git a/drivers/vfio/platform/vfio_platform_private.h b/drivers/vfio/platform/vfio_platform_private.h
> > > new file mode 100644
> > > index 0000000..062b92d
> > > --- /dev/null
> > > +++ b/drivers/vfio/platform/vfio_platform_private.h
> > > @@ -0,0 +1,36 @@
> > > +/*
> > > + * Copyright (C) 2013 - Virtual Open Systems
> > > + * Author: Antonios Motakis <a.motakis@xxxxxxxxxxxxxxxxxxxxxx>
> > > + *
> > > + * This program is free software; you can redistribute it and/or modify
> > > + * it under the terms of the GNU General Public License, version 2, as
> > > + * published by the Free Software Foundation.
> > > + *
> > > + * This program is distributed in the hope that it will be useful,
> > > + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> > > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> > > + * GNU General Public License for more details.
> > > + */
> > > +
> > > +#ifndef VFIO_PLATFORM_PRIVATE_H
> > > +#define VFIO_PLATFORM_PRIVATE_H
> > > +
> > > +struct vfio_platform_device {
> > > +   /*
> > > +    * These fields should be filled by the bus specific binder
> > > +    */
> > > +   void            *opaque;
> > > +   const char      *name;
> > > +   uint32_t        flags;
> > > +   /* callbacks to discover device resources */
> > > +   struct resource*
> > > +           (*get_resource)(struct vfio_platform_device *vdev, int i);
> > > +   int     (*get_irq)(struct vfio_platform_device *vdev, int i);
> > > +};
> > > +
> > > +extern int vfio_platform_probe_common(struct vfio_platform_device *vdev,
> > > +                                 struct device *dev);
> > > +extern struct vfio_platform_device *vfio_platform_remove_common
> > > +                                (struct device *dev);
> > > +
> > > +#endif /* VFIO_PLATFORM_PRIVATE_H */
> > >
> >
>
>
>
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