[PATCH v6 11/12] sched: Define and initialize a flag to identify valid PASID in the task

Fenghua Yu
2020-07-13T23:48:56Z

From: Peter Zijlstra <peterz@infradead.org>

The flag is defined for the task to identify if the task has a valid
PASID. Its initial value is 0 when the task is forked/cloned. It will
be used shortly.

Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Co-developed-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
---
v2:
- Add this patch to define the flag to identify valid PASID MSR (PeterZ)

include/linux/sched.h | 3 +++
kernel/fork.c | 4 ++++
2 files changed, 7 insertions(+)

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 692e327d7455..042d6f5cde6a 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -800,6 +800,9 @@ struct task_struct {
/* Stalled due to lack of memory */
unsigned in_memstall:1;
#endif
+#ifdef CONFIG_IOMMU_SUPPORT
+ unsigned has_valid_pasid:1;
+#endif

unsigned long atomic_flags; /* Flags requiring atomic access. */

diff --git a/kernel/fork.c b/kernel/fork.c
index 43b5f112604d..0a962bebdf88 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -955,6 +955,10 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
tsk->use_memdelay = 0;
#endif

+#ifdef CONFIG_IOMMU_SUPPORT
+ tsk->has_valid_pasid = 0;
+#endif
+
#ifdef CONFIG_MEMCG
tsk->active_memcg = NULL;
#endif
--
2.19.1