On Mon, Feb 07 2022 at 15:02, Fenghua Yu wrote: > A new mm doesn't have a PASID yet when it's created. Initialize > the mm's PASID on fork() or for init_mm to INVALID_IOASID (-1). > > INIT_PASID (0) is reserved for kernel legacy DMA PASID. It cannot be > allocated to a user process. Initializing the process's PASID to 0 may > cause confusion that why the process uses the reserved kernel legacy DMA > PASID. Initializing the PASID to INVALID_IOASID (-1) explicitly > tells the process doesn't have a valid PASID yet. > > Even though the only user of mm_pasid_init() is in fork.c, define it > in <linux/sched/mm.h> as the first of three mm/pasid life cycle > functions (init/set/drop) to keep these all together. > > Suggested-by: Dave Hansen <[email protected]> > Signed-off-by: Fenghua Yu <[email protected]> > Reviewed-by: Tony Luck <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]> _______________________________________________ iommu mailing list [email protected] https://lists.linuxfoundation.org/mailman/listinfo/iommu
