From: Fenghua Yu fenghua.yu@intel.com
[ Upstream commit 82e69a121be4b1597ce758534816a8ee04c8b761 ]
When a new mm is created, its PASID should be cleared, i.e. the PASID is initialized to its init state 0 on both ARM and X86.
This patch was part of the series introducing mm->pasid, but got lost along the way [1]. It still makes sense to have it, because each address space has a different PASID. And the IOMMU code in iommu_sva_alloc_pasid() expects the pasid field of a new mm struct to be cleared.
[1] https://lore.kernel.org/linux-iommu/YDgh53AcQHT+T3L0@otcwcpicx3.sc.intel.com...
Link: https://lkml.kernel.org/r/20210302103837.2562625-1-jean-philippe@linaro.org Signed-off-by: Fenghua Yu fenghua.yu@intel.com Signed-off-by: Jean-Philippe Brucker jean-philippe@linaro.org Reviewed-by: Tony Luck tony.luck@intel.com Cc: Jacob Pan jacob.jun.pan@intel.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- include/linux/mm_types.h | 1 + kernel/fork.c | 8 ++++++++ 2 files changed, 9 insertions(+)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h index 07d9acb5b19c..61c77cfff8c2 100644 --- a/include/linux/mm_types.h +++ b/include/linux/mm_types.h @@ -23,6 +23,7 @@ #endif #define AT_VECTOR_SIZE (2*(AT_VECTOR_SIZE_ARCH + AT_VECTOR_SIZE_BASE + 1))
+#define INIT_PASID 0
struct address_space; struct mem_cgroup; diff --git a/kernel/fork.c b/kernel/fork.c index d66cd1014211..808af2cc8ab6 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -994,6 +994,13 @@ static void mm_init_owner(struct mm_struct *mm, struct task_struct *p) #endif }
+static void mm_init_pasid(struct mm_struct *mm) +{ +#ifdef CONFIG_IOMMU_SUPPORT + mm->pasid = INIT_PASID; +#endif +} + static void mm_init_uprobes_state(struct mm_struct *mm) { #ifdef CONFIG_UPROBES @@ -1024,6 +1031,7 @@ static struct mm_struct *mm_init(struct mm_struct *mm, struct task_struct *p, mm_init_cpumask(mm); mm_init_aio(mm); mm_init_owner(mm, p); + mm_init_pasid(mm); RCU_INIT_POINTER(mm->exe_file, NULL); mmu_notifier_subscriptions_init(mm); init_tlb_flush_pending(mm);