Re: [Intel-gfx] [PATCH v3 03/12] vfio/pci: Move the existing hot reset logic to be a helper

["Liu, Yi L" <yi.l.liu@intel.com>]

> From: Eric Auger <eric.auger@redhat.com>
> Sent: Tuesday, April 4, 2023 10:00 PM
> 
> Hi Yi,
> 
> On 4/1/23 16:44, Yi Liu wrote:
> > This prepares to add another method for hot reset. The major hot reset logic
> > are moved to vfio_pci_ioctl_pci_hot_reset_groups().
> >
> > No functional change is intended.
> >
> > Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
> > Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
> > Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
> > Tested-by: Yanting Jiang <yanting.jiang@intel.com>
> > Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> > ---
> >  drivers/vfio/pci/vfio_pci_core.c | 56 +++++++++++++++++++-------------
> >  1 file changed, 33 insertions(+), 23 deletions(-)
> >
> > diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> > index 5d745c9abf05..3696b8e58445 100644
> > --- a/drivers/vfio/pci/vfio_pci_core.c
> > +++ b/drivers/vfio/pci/vfio_pci_core.c
> > @@ -1255,29 +1255,17 @@ static int vfio_pci_ioctl_get_pci_hot_reset_info(
> >  	return ret;
> >  }
> >
> > -static int vfio_pci_ioctl_pci_hot_reset(struct vfio_pci_core_device *vdev,
> > -					struct vfio_pci_hot_reset __user *arg)
> > +static int
> > +vfio_pci_ioctl_pci_hot_reset_groups(struct vfio_pci_core_device *vdev,
> > +				    struct vfio_pci_hot_reset *hdr,
> nit why don't you simply pass the user group count as decoded earlier.
> hdr sounds like a dup of arg.

indeed. only hdr->count is needed.

> > +				    bool slot,
> > +				    struct vfio_pci_hot_reset __user *arg)
> >  {
> > -	unsigned long minsz = offsetofend(struct vfio_pci_hot_reset, count);
> > -	struct vfio_pci_hot_reset hdr;
> >  	int32_t *group_fds;
> >  	struct file **files;
> >  	struct vfio_pci_group_info info;
> > -	bool slot = false;
> >  	int file_idx, count = 0, ret = 0;
> >
> > -	if (copy_from_user(&hdr, arg, minsz))
> > -		return -EFAULT;
> > -
> > -	if (hdr.argsz < minsz || hdr.flags)
> > -		return -EINVAL;
> > -
> > -	/* Can we do a slot or bus reset or neither? */
> > -	if (!pci_probe_reset_slot(vdev->pdev->slot))
> > -		slot = true;
> > -	else if (pci_probe_reset_bus(vdev->pdev->bus))
> > -		return -ENODEV;
> > -
> >  	/*
> >  	 * We can't let userspace give us an arbitrarily large buffer to copy,
> >  	 * so verify how many we think there could be.  Note groups can have
> > @@ -1289,11 +1277,11 @@ static int vfio_pci_ioctl_pci_hot_reset(struct
> vfio_pci_core_device *vdev,
> >  		return ret;
> >
> >  	/* Somewhere between 1 and count is OK */
> > -	if (!hdr.count || hdr.count > count)
> > +	if (!hdr->count || hdr->count > count)
> >  		return -EINVAL;
> >
> > -	group_fds = kcalloc(hdr.count, sizeof(*group_fds), GFP_KERNEL);
> > -	files = kcalloc(hdr.count, sizeof(*files), GFP_KERNEL);
> > +	group_fds = kcalloc(hdr->count, sizeof(*group_fds), GFP_KERNEL);
> > +	files = kcalloc(hdr->count, sizeof(*files), GFP_KERNEL);
> >  	if (!group_fds || !files) {
> >  		kfree(group_fds);
> >  		kfree(files);
> > @@ -1301,7 +1289,7 @@ static int vfio_pci_ioctl_pci_hot_reset(struct
> vfio_pci_core_device *vdev,
> >  	}
> >
> >  	if (copy_from_user(group_fds, arg->group_fds,
> > -			   hdr.count * sizeof(*group_fds))) {
> > +			   hdr->count * sizeof(*group_fds))) {
> >  		kfree(group_fds);
> >  		kfree(files);
> >  		return -EFAULT;
> > @@ -1311,7 +1299,7 @@ static int vfio_pci_ioctl_pci_hot_reset(struct
> vfio_pci_core_device *vdev,
> >  	 * Get the group file for each fd to ensure the group held across
> >  	 * the reset
> >  	 */
> > -	for (file_idx = 0; file_idx < hdr.count; file_idx++) {
> > +	for (file_idx = 0; file_idx < hdr->count; file_idx++) {
> >  		struct file *file = fget(group_fds[file_idx]);
> >
> >  		if (!file) {
> > @@ -1335,7 +1323,7 @@ static int vfio_pci_ioctl_pci_hot_reset(struct
> vfio_pci_core_device *vdev,
> >  	if (ret)
> >  		goto hot_reset_release;
> >
> > -	info.count = hdr.count;
> > +	info.count = hdr->count;
> >  	info.files = files;
> >
> >  	ret = vfio_pci_dev_set_hot_reset(vdev->vdev.dev_set, &info);
> > @@ -1348,6 +1336,28 @@ static int vfio_pci_ioctl_pci_hot_reset(struct
> vfio_pci_core_device *vdev,
> >  	return ret;
> >  }
> >
> > +static int vfio_pci_ioctl_pci_hot_reset(struct vfio_pci_core_device *vdev,
> > +					struct vfio_pci_hot_reset __user *arg)
> > +{
> > +	unsigned long minsz = offsetofend(struct vfio_pci_hot_reset, count);
> > +	struct vfio_pci_hot_reset hdr;
> > +	bool slot = false;
> > +
> > +	if (copy_from_user(&hdr, arg, minsz))
> > +		return -EFAULT;
> > +
> > +	if (hdr.argsz < minsz || hdr.flags)
> > +		return -EINVAL;
> > +
> > +	/* Can we do a slot or bus reset or neither? */
> > +	if (!pci_probe_reset_slot(vdev->pdev->slot))
> > +		slot = true;
> > +	else if (pci_probe_reset_bus(vdev->pdev->bus))
> > +		return -ENODEV;
> > +
> > +	return vfio_pci_ioctl_pci_hot_reset_groups(vdev, &hdr, slot, arg);
> > +}
> > +
> >  static int vfio_pci_ioctl_ioeventfd(struct vfio_pci_core_device *vdev,
> >  				    struct vfio_device_ioeventfd __user *arg)
> >  {
> Besides
> Reviewed-by: Eric Auger <eric.auger@redhat.com>

Thanks,
Yi Liu