On Tue, Aug 15, 2023 at 01:42:35PM -0300, Jason Gunthorpe wrote:
On Fri, Aug 11, 2023 at 12:15:00AM -0700, Yi Liu wrote:
Under nested IOMMU translation, userspace owns the stage-1 translation table (e.g. the stage-1 page table of Intel VT-d or the context table of ARM SMMUv3, and etc.). Stage-1 translation tables are vendor specific, and need to be compatible with the underlying IOMMU hardware. Hence, userspace should know the IOMMU hardware capability before creating and configuring the stage-1 translation table to kernel.
This adds IOMMU_GET_HW_INFO ioctl to query the IOMMU hardware information (a.k.a capability) for a given device. The returned data is vendor specific, userspace needs to decode it with the structure mapped by the @out_data_type field.
As only physical devices have IOMMU hardware, so this will return error if the given device is not a physical device.
Reviewed-by: Lu Baolu baolu.lu@linux.intel.com Co-developed-by: Nicolin Chen nicolinc@nvidia.com Signed-off-by: Nicolin Chen nicolinc@nvidia.com Signed-off-by: Yi Liu yi.l.liu@intel.com
drivers/iommu/iommufd/main.c | 85 ++++++++++++++++++++++++++++++++++++ include/uapi/linux/iommufd.h | 36 +++++++++++++++ 2 files changed, 121 insertions(+)
diff --git a/drivers/iommu/iommufd/main.c b/drivers/iommu/iommufd/main.c index 94c498b8fdf6..d459811c5381 100644 --- a/drivers/iommu/iommufd/main.c +++ b/drivers/iommu/iommufd/main.c @@ -17,6 +17,7 @@
I was looking at this more and this code should be in device.c:
+static int iommufd_fill_hw_info(struct device *dev, void __user *user_ptr,
unsigned int *length, u32 *type)+{
Since it is working on devices
main.c is primarily for context related stuff
Ack for that. We'd make similar changes to the other handlers too.
Thanks Nic