diff mbox series

[v7,01/24] mm: Add a PASID field to mm_struct

Message ID 20200519175502.2504091-2-jean-philippe@linaro.org (mailing list archive)
State New, archived
Headers show
Series iommu: Shared Virtual Addressing for SMMUv3 | expand

Commit Message

Jean-Philippe Brucker May 19, 2020, 5:54 p.m. UTC 
Some devices can tag their DMA requests with a 20-bit Process Address
Space ID (PASID), allowing them to access multiple address spaces. In
combination with recoverable I/O page faults (for example PCIe PRI),
PASID allows the IOMMU to share page tables with the MMU.

To make sure that a single PASID is allocated for each address space, as
required by Intel ENQCMD, store the PASID in the mm_struct. The IOMMU
driver is in charge of serializing modifications to the PASID field.

Signed-off-by: Jean-Philippe Brucker <jean-philippe@linaro.org>
---
 include/linux/mm_types.h | 4 ++++
 1 file changed, 4 insertions(+)
diff mbox series

Patch

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 4aba6c0c2ba8..8db647275817 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -534,6 +534,10 @@  struct mm_struct {
 		atomic_long_t hugetlb_usage;
 #endif
 		struct work_struct async_put_work;
+#ifdef CONFIG_IOMMU_SUPPORT
+		/* Address space ID used by device DMA */
+		unsigned int pasid;
+#endif
 	} __randomize_layout;
 
 	/*