On Mon, 5 Nov 2018 15:34:06 +0800
Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx> wrote:
> A parent device might create different types of mediated
> devices. For example, a mediated device could be created
> by the parent device with full isolation and protection
> provided by the IOMMU. One usage case could be found on
> Intel platforms where a mediated device is an assignable
> subset of a PCI, the DMA requests on behalf of it are all
> tagged with a PASID. Since IOMMU supports PASID-granular
> translations (scalable mode in vt-d 3.0), this mediated
> device could be individually protected and isolated by an
> IOMMU.
>
> This patch adds two new members in struct mdev_device:
> * iommu_device
> - This, if set, indicates that the mediated device could
> be fully isolated and protected by IOMMU via attaching
> an iommu domain to this device. If empty, it indicates
> using vendor defined isolation.
>
> * iommu_domain
> - This is a place holder for an iommu domain. A domain
> could be store here for later use once it has been
> attached to the iommu_device of this mdev.
>
> Below helpers are added to set and get above iommu device
> and iommu domain pointers.
>
> * mdev_set/get_iommu_device(dev, iommu_device)
> - Set or get the iommu device which represents this mdev
> in IOMMU's device scope. Drivers don't need to set the
> iommu device if it uses vendor defined isolation.
>
> * mdev_set/get_iommu_domain(domain)
> - A iommu domain which has been attached to the iommu
> device in order to protect and isolate the mediated
> device will be kept in the mdev data structure and
> could be retrieved later.
>
> Cc: Ashok Raj <ashok.raj@xxxxxxxxx>
> Cc: Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx>
> Cc: Kevin Tian <kevin.tian@xxxxxxxxx>
> Cc: Liu Yi L <yi.l.liu@xxxxxxxxx>
> Suggested-by: Kevin Tian <kevin.tian@xxxxxxxxx>
> Suggested-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
> Signed-off-by: Lu Baolu <baolu.lu@xxxxxxxxxxxxxxx>
> ---
> drivers/vfio/mdev/mdev_core.c | 36 ++++++++++++++++++++++++++++++++
> drivers/vfio/mdev/mdev_private.h | 2 ++
> include/linux/mdev.h | 23 ++++++++++++++++++++
> 3 files changed, 61 insertions(+)
>
> diff --git a/drivers/vfio/mdev/mdev_core.c b/drivers/vfio/mdev/mdev_core.c
> index 0212f0ee8aea..5119809225c5 100644
> --- a/drivers/vfio/mdev/mdev_core.c
> +++ b/drivers/vfio/mdev/mdev_core.c
> @@ -390,6 +390,42 @@ int mdev_device_remove(struct device *dev, bool force_remove)
> return 0;
> }
>
> +int mdev_set_iommu_device(struct device *dev, struct device *iommu_device)
> +{
> + struct mdev_device *mdev = to_mdev_device(dev);
> +
> + mdev->iommu_device = iommu_device;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(mdev_set_iommu_device);
> +
> +struct device *mdev_get_iommu_device(struct device *dev)
> +{
> + struct mdev_device *mdev = to_mdev_device(dev);
> +
> + return mdev->iommu_device;
> +}
> +EXPORT_SYMBOL(mdev_get_iommu_device);
> +
> +int mdev_set_iommu_domain(struct device *dev, void *domain)
> +{
> + struct mdev_device *mdev = to_mdev_device(dev);
> +
> + mdev->iommu_domain = domain;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(mdev_set_iommu_domain);
> +
> +void *mdev_get_iommu_domain(struct device *dev)
> +{
> + struct mdev_device *mdev = to_mdev_device(dev);
> +
> + return mdev->iommu_domain;
> +}
> +EXPORT_SYMBOL(mdev_get_iommu_domain);
> +
> static int __init mdev_init(void)
> {
> return mdev_bus_register();
> diff --git a/drivers/vfio/mdev/mdev_private.h b/drivers/vfio/mdev/mdev_private.h
> index b5819b7d7ef7..c01518068e84 100644
> --- a/drivers/vfio/mdev/mdev_private.h
> +++ b/drivers/vfio/mdev/mdev_private.h
> @@ -34,6 +34,8 @@ struct mdev_device {
> struct list_head next;
> struct kobject *type_kobj;
> bool active;
> + struct device *iommu_device;
> + void *iommu_domain;
> };
>
> #define to_mdev_device(dev) container_of(dev, struct mdev_device, dev)
> diff --git a/include/linux/mdev.h b/include/linux/mdev.h
> index b6e048e1045f..c46777d3e568 100644
> --- a/include/linux/mdev.h
> +++ b/include/linux/mdev.h
> @@ -14,6 +14,29 @@
> #define MDEV_H
>
> struct mdev_device;
> +struct iommu_domain;
> +
> +/*
> + * Called by the parent device driver to set the PCI device which represents
s/PCI //
There is no requirement or expectation that the device is PCI.
> + * this mdev in iommu protection scope. By default, the iommu device is NULL,
> + * that indicates using vendor defined isolation.
> + *
> + * @dev: the mediated device that iommu will isolate.
> + * @iommu_device: a pci device which represents the iommu for @dev.
> + *
> + * Return 0 for success, otherwise negative error value.
> + */
> +int mdev_set_iommu_device(struct device *dev, struct device *iommu_device);
> +
> +struct device *mdev_get_iommu_device(struct device *dev);
> +
> +/*
> + * Called by vfio iommu modules to save the iommu domain after a domain being
> + * attached to the mediated device.
> + */
> +int mdev_set_iommu_domain(struct device *dev, void *domain);
> +
> +void *mdev_get_iommu_domain(struct device *dev);
I can't say I really understand the purpose of this, the cover letter
indicates this is a placeholder, should we add it separately when we
have a requirement for it? Thanks,
Alex
