RE: [PATCH v11 13/23] vfio-iommufd: Add detach_ioas support for physical VFIO devices

Liu, Yi L
2023-05-23T01:35:00Z

> From: Alex Williamson <alex.williamson@redhat.com>
> Sent: Tuesday, May 23, 2023 4:59 AM
>
> On Mon, 22 May 2023 14:46:17 -0600
> Alex Williamson <alex.williamson@redhat.com> wrote:
>
> > On Sat, 13 May 2023 06:28:17 -0700
> > Yi Liu <yi.l.liu@intel.com> wrote:
> >
> > > this prepares for adding DETACH ioctl for physical VFIO devices.
> > >
> > > Reviewed-by: Kevin Tian <kevin.tian@intel.com>
> > > Tested-by: Terrence Xu <terrence.xu@intel.com>
> > > Tested-by: Nicolin Chen <nicolinc@nvidia.com>
> > > Tested-by: Matthew Rosato <mjrosato@linux.ibm.com>
> > > Tested-by: Yanting Jiang <yanting.jiang@intel.com>
> > > Tested-by: Shameer Kolothum <shameerali.kolothum.thodi@huawei.com>
> > > Signed-off-by: Yi Liu <yi.l.liu@intel.com>
> > > ---
> > > Documentation/driver-api/vfio.rst | 8 +++++---
> > > drivers/vfio/fsl-mc/vfio_fsl_mc.c | 1 +
> > > drivers/vfio/iommufd.c | 20 +++++++++++++++++++
> > > .../vfio/pci/hisilicon/hisi_acc_vfio_pci.c | 2 ++
> > > drivers/vfio/pci/mlx5/main.c | 1 +
> > > drivers/vfio/pci/vfio_pci.c | 1 +
> > > drivers/vfio/platform/vfio_amba.c | 1 +
> > > drivers/vfio/platform/vfio_platform.c | 1 +
> > > drivers/vfio/vfio_main.c | 3 ++-
> > > include/linux/vfio.h | 8 +++++++-
> > > 10 files changed, 41 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/Documentation/driver-api/vfio.rst b/Documentation/driver-api/vfio.rst
> > > index 68abc089d6dd..363e12c90b87 100644
> > > --- a/Documentation/driver-api/vfio.rst
> > > +++ b/Documentation/driver-api/vfio.rst
> > > @@ -279,6 +279,7 @@ similar to a file operations structure::
> > > struct iommufd_ctx *ictx, u32 *out_device_id);
> > > void (*unbind_iommufd)(struct vfio_device *vdev);
> > > int (*attach_ioas)(struct vfio_device *vdev, u32 *pt_id);
> > > + void (*detach_ioas)(struct vfio_device *vdev);
> > > int (*open_device)(struct vfio_device *vdev);
> > > void (*close_device)(struct vfio_device *vdev);
> > > ssize_t (*read)(struct vfio_device *vdev, char __user *buf,
> > > @@ -315,9 +316,10 @@ container_of().
> > > - The [un]bind_iommufd callbacks are issued when the device is bound to
> > > and unbound from iommufd.
> > >
> > > - - The attach_ioas callback is issued when the device is attached to an
> > > - IOAS managed by the bound iommufd. The attached IOAS is automatically
> > > - detached when the device is unbound from iommufd.
> > > + - The [de]attach_ioas callback is issued when the device is attached to
> > > + and detached from an IOAS managed by the bound iommufd. However, the
> > > + attached IOAS can also be automatically detached when the device is
> > > + unbound from iommufd.
> > >
> > > - The read/write/mmap callbacks implement the device region access defined
> > > by the device's own VFIO_DEVICE_GET_REGION_INFO ioctl.
> > > diff --git a/drivers/vfio/fsl-mc/vfio_fsl_mc.c b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
> > > index c89a047a4cd8..d540cf683d93 100644
> > > --- a/drivers/vfio/fsl-mc/vfio_fsl_mc.c
> > > +++ b/drivers/vfio/fsl-mc/vfio_fsl_mc.c
> > > @@ -594,6 +594,7 @@ static const struct vfio_device_ops vfio_fsl_mc_ops = {
> > > .bind_iommufd = vfio_iommufd_physical_bind,
> > > .unbind_iommufd = vfio_iommufd_physical_unbind,
> > > .attach_ioas = vfio_iommufd_physical_attach_ioas,
> > > + .detach_ioas = vfio_iommufd_physical_detach_ioas,
> > > };
> > >
> > > static struct fsl_mc_driver vfio_fsl_mc_driver = {
> > > diff --git a/drivers/vfio/iommufd.c b/drivers/vfio/iommufd.c
> > > index 07b58c4625b5..e3953e1617a5 100644
> > > --- a/drivers/vfio/iommufd.c
> > > +++ b/drivers/vfio/iommufd.c
> > > @@ -167,6 +167,14 @@ int vfio_iommufd_physical_attach_ioas(struct vfio_device
> *vdev, u32 *pt_id)
> > > {
> > > int rc;
> > >
> > > + lockdep_assert_held(&vdev->dev_set->lock);
> > > +
> > > + if (WARN_ON(!vdev->iommufd_device))
> > > + return -EINVAL;
> > > +
> > > + if (vdev->iommufd_attached)
> > > + return -EBUSY;
> > > +
> > > rc = iommufd_device_attach(vdev->iommufd_device, pt_id);
> > > if (rc)
> > > return rc;
> > > @@ -175,6 +183,18 @@ int vfio_iommufd_physical_attach_ioas(struct vfio_device
> *vdev, u32 *pt_id)
> > > }
> > > EXPORT_SYMBOL_GPL(vfio_iommufd_physical_attach_ioas);
> > >
> > > +void vfio_iommufd_physical_detach_ioas(struct vfio_device *vdev)
> > > +{
> > > + lockdep_assert_held(&vdev->dev_set->lock);
> > > +
> > > + if (WARN_ON(!vdev->iommufd_device) || !vdev->iommufd_attached)
> > > + return;
> > > +
> > > + iommufd_device_detach(vdev->iommufd_device);
> > > + vdev->iommufd_attached = false;
> > > +}
> > > +EXPORT_SYMBOL_GPL(vfio_iommufd_physical_detach_ioas);
> >
> > Can't a user trigger this WARN_ON by simply repeatedly calling the
> > to-be-added detach ioctl? Thanks,
>
> Oops, didn't track the close paren correctly, disregard. Thanks,

Not sure ill it be clearer to have !vdev->iommufd_attached in the next
line? 😊

Regards,
Yi Liu

> Alex
>
> > > +
> > > /*
> > > * The emulated standard ops mean that vfio_device is going to use the
> > > * "mdev path" and will call vfio_pin_pages()/vfio_dma_rw(). Drivers using this
> > > diff --git a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> > > index a117eaf21c14..b2f9778c8366 100644
> > > --- a/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> > > +++ b/drivers/vfio/pci/hisilicon/hisi_acc_vfio_pci.c
> > > @@ -1373,6 +1373,7 @@ static const struct vfio_device_ops
> hisi_acc_vfio_pci_migrn_ops = {
> > > .bind_iommufd = vfio_iommufd_physical_bind,
> > > .unbind_iommufd = vfio_iommufd_physical_unbind,
> > > .attach_ioas = vfio_iommufd_physical_attach_ioas,
> > > + .detach_ioas = vfio_iommufd_physical_detach_ioas,
> > > };
> > >
> > > static const struct vfio_device_ops hisi_acc_vfio_pci_ops = {
> > > @@ -1391,6 +1392,7 @@ static const struct vfio_device_ops hisi_acc_vfio_pci_ops =
> {
> > > .bind_iommufd = vfio_iommufd_physical_bind,
> > > .unbind_iommufd = vfio_iommufd_physical_unbind,
> > > .attach_ioas = vfio_iommufd_physical_attach_ioas,
> > > + .detach_ioas = vfio_iommufd_physical_detach_ioas,
> > > };
> > >
> > > static int hisi_acc_vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id
> *id)
> > > diff --git a/drivers/vfio/pci/mlx5/main.c b/drivers/vfio/pci/mlx5/main.c
> > > index d95fd382814c..42ec574a8622 100644
> > > --- a/drivers/vfio/pci/mlx5/main.c
> > > +++ b/drivers/vfio/pci/mlx5/main.c
> > > @@ -1320,6 +1320,7 @@ static const struct vfio_device_ops mlx5vf_pci_ops = {
> > > .bind_iommufd = vfio_iommufd_physical_bind,
> > > .unbind_iommufd = vfio_iommufd_physical_unbind,
> > > .attach_ioas = vfio_iommufd_physical_attach_ioas,
> > > + .detach_ioas = vfio_iommufd_physical_detach_ioas,
> > > };
> > >
> > > static int mlx5vf_pci_probe(struct pci_dev *pdev,
> > > diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
> > > index 29091ee2e984..cb5b7f865d58 100644
> > > --- a/drivers/vfio/pci/vfio_pci.c
> > > +++ b/drivers/vfio/pci/vfio_pci.c
> > > @@ -141,6 +141,7 @@ static const struct vfio_device_ops vfio_pci_ops = {
> > > .bind_iommufd = vfio_iommufd_physical_bind,
> > > .unbind_iommufd = vfio_iommufd_physical_unbind,
> > > .attach_ioas = vfio_iommufd_physical_attach_ioas,
> > > + .detach_ioas = vfio_iommufd_physical_detach_ioas,
> > > };
> > >
> > > static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
> > > diff --git a/drivers/vfio/platform/vfio_amba.c b/drivers/vfio/platform/vfio_amba.c
> > > index 83fe54015595..6464b3939ebc 100644
> > > --- a/drivers/vfio/platform/vfio_amba.c
> > > +++ b/drivers/vfio/platform/vfio_amba.c
> > > @@ -119,6 +119,7 @@ static const struct vfio_device_ops vfio_amba_ops = {
> > > .bind_iommufd = vfio_iommufd_physical_bind,
> > > .unbind_iommufd = vfio_iommufd_physical_unbind,
> > > .attach_ioas = vfio_iommufd_physical_attach_ioas,
> > > + .detach_ioas = vfio_iommufd_physical_detach_ioas,
> > > };
> > >
> > > static const struct amba_id pl330_ids[] = {
> > > diff --git a/drivers/vfio/platform/vfio_platform.c
> b/drivers/vfio/platform/vfio_platform.c
> > > index 22a1efca32a8..8cf22fa65baa 100644
> > > --- a/drivers/vfio/platform/vfio_platform.c
> > > +++ b/drivers/vfio/platform/vfio_platform.c
> > > @@ -108,6 +108,7 @@ static const struct vfio_device_ops vfio_platform_ops = {
> > > .bind_iommufd = vfio_iommufd_physical_bind,
> > > .unbind_iommufd = vfio_iommufd_physical_unbind,
> > > .attach_ioas = vfio_iommufd_physical_attach_ioas,
> > > + .detach_ioas = vfio_iommufd_physical_detach_ioas,
> > > };
> > >
> > > static struct platform_driver vfio_platform_driver = {
> > > diff --git a/drivers/vfio/vfio_main.c b/drivers/vfio/vfio_main.c
> > > index 39d552e5160b..599d551fc4b5 100644
> > > --- a/drivers/vfio/vfio_main.c
> > > +++ b/drivers/vfio/vfio_main.c
> > > @@ -273,7 +273,8 @@ static int __vfio_register_dev(struct vfio_device *device,
> > > if (WARN_ON(IS_ENABLED(CONFIG_IOMMUFD) &&
> > > (!device->ops->bind_iommufd ||
> > > !device->ops->unbind_iommufd ||
> > > - !device->ops->attach_ioas)))
> > > + !device->ops->attach_ioas ||
> > > + !device->ops->detach_ioas)))
> > > return -EINVAL;
> > >
> > > /*
> > > diff --git a/include/linux/vfio.h b/include/linux/vfio.h
> > > index 431eb82e0595..f446f5901e46 100644
> > > --- a/include/linux/vfio.h
> > > +++ b/include/linux/vfio.h
> > > @@ -74,7 +74,9 @@ struct vfio_device {
> > > * @bind_iommufd: Called when binding the device to an iommufd
> > > * @unbind_iommufd: Opposite of bind_iommufd
> > > * @attach_ioas: Called when attaching device to an IOAS/HWPT managed by the
> > > - * bound iommufd. Undo in unbind_iommufd.
> > > + * bound iommufd. Undo in unbind_iommufd if @detach_ioas is not
> > > + * called.
> > > + * @detach_ioas: Opposite of attach_ioas
> > > * @open_device: Called when the first file descriptor is opened for this device
> > > * @close_device: Opposite of open_device
> > > * @read: Perform read(2) on device file descriptor
> > > @@ -98,6 +100,7 @@ struct vfio_device_ops {
> > > struct iommufd_ctx *ictx, u32 *out_device_id);
> > > void (*unbind_iommufd)(struct vfio_device *vdev);
> > > int (*attach_ioas)(struct vfio_device *vdev, u32 *pt_id);
> > > + void (*detach_ioas)(struct vfio_device *vdev);
> > > int (*open_device)(struct vfio_device *vdev);
> > > void (*close_device)(struct vfio_device *vdev);
> > > ssize_t (*read)(struct vfio_device *vdev, char __user *buf,
> > > @@ -121,6 +124,7 @@ int vfio_iommufd_physical_bind(struct vfio_device *vdev,
> > > struct iommufd_ctx *ictx, u32 *out_device_id);
> > > void vfio_iommufd_physical_unbind(struct vfio_device *vdev);
> > > int vfio_iommufd_physical_attach_ioas(struct vfio_device *vdev, u32 *pt_id);
> > > +void vfio_iommufd_physical_detach_ioas(struct vfio_device *vdev);
> > > int vfio_iommufd_emulated_bind(struct vfio_device *vdev,
> > > struct iommufd_ctx *ictx, u32 *out_device_id);
> > > void vfio_iommufd_emulated_unbind(struct vfio_device *vdev);
> > > @@ -145,6 +149,8 @@ vfio_iommufd_physical_devid(struct vfio_device *vdev)
> > > ((void (*)(struct vfio_device *vdev)) NULL)
> > > #define vfio_iommufd_physical_attach_ioas \
> > > ((int (*)(struct vfio_device *vdev, u32 *pt_id)) NULL)
> > > +#define vfio_iommufd_physical_detach_ioas \
> > > + ((void (*)(struct vfio_device *vdev)) NULL)
> > > #define vfio_iommufd_emulated_bind \
> > > ((int (*)(struct vfio_device *vdev, struct iommufd_ctx *ictx, \
> > > u32 *out_device_id)) NULL)
> >