From: Jason Gunthorpe jgg@nvidia.com Sent: Thursday, August 22, 2024 10:46 PM
This results in passing 0 or just IOMMU_CACHE to iommu_map(). Most of the page table formats don't like this:
amdv1 - -EINVAL armv7s - returns 0, doesn't update mapped arm-lpae - returns 0 doesn't update mapped dart - returns 0, doesn't update mapped VT-D - returns -EINVAL
Unfortunately the three formats that return 0 cause serious problems:
Returning ret = but not uppdating mapped from domain->map_pages() causes an infinite loop in __iommu_map()
Not writing ioptes means that VFIO/iommufd have no way to recover them and we will have memory leaks and worse during unmap
Since almost nothing can support this, and it is a useless thing to do, block it early in iommufd.
Cc: stable@kernel.org Fixes: aad37e71d5c4 ("iommufd: IOCTLs for the io_pagetable") Signed-off-by: Jason Gunthorpe jgg@nvidia.com
Reviewed-by: Kevin Tian kevin.tian@intel.com