[lkml]   [2022]   [Feb]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH v4 04/11] kernel/fork: Initialize mm's PASID
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 <>
> Signed-off-by: Fenghua Yu <>
> Reviewed-by: Tony Luck <>

Reviewed-by: Thomas Gleixner <>

 \ /
  Last update: 2022-02-14 18:25    [W:0.206 / U:0.540 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site