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

Liu, Yi L
2023-04-04T14:25:15Z

> 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