[PATCH v7 7/9] mm: Define pasid in mm

Fenghua Yu
2020-08-27T15:07:45Z

PASID is shared by all threads in a process. So the logical place to keep
track of it is in the "mm". Both ARM and X86 need to use the PASID in the
"mm".

Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Reviewed-by: Tony Luck <tony.luck@intel.com>
---
v4:
- Change PASID type to u32 (Christoph)

v3:
- Change CONFIG_PCI_PASID to CONFIG_IOMMU_SUPPORT because non-PCI device
can have PASID in ARM (Jean)

v2:
- This new patch moves "pasid" from x86 specific mm_context_t to generic
struct mm_struct per Christopher's comment: https://lore.kernel.org/linux-iommu/20200414170252.714402-1-jean-philippe@linaro.org/T/#mb57110ffe1aaa24750eeea4f93b611f0d1913911
- Jean-Philippe Brucker released a virtually same patch. I still put this
patch in the series for better review. The upstream kernel only needs one
of the two patches eventually.
https://lore.kernel.org/linux-iommu/20200519175502.2504091-2-jean-philippe@linaro.org/
- Change CONFIG_IOASID to CONFIG_PCI_PASID (Ashok)

include/linux/mm_types.h | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 496c3ff97cce..1ff0615ef19f 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -542,6 +542,10 @@ struct mm_struct {
atomic_long_t hugetlb_usage;
#endif
struct work_struct async_put_work;
+
+#ifdef CONFIG_IOMMU_SUPPORT
+ u32 pasid;
+#endif
} __randomize_layout;

/*
--
2.19.1