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From: Chuck Lever <chuck.lever@oracle.com>
To: baolu.lu@linux.intel.com
Cc: isaacm@codeaurora.org, robin.murphy@arm.com,
	iommu@lists.linux-foundation.org, will@kernel.org
Subject: [PATCH RFC 4/9] iommu/io-pgtable: Introduce map_sg() as a page table op
Date: Wed, 27 Jan 2021 15:00:46 -0500	[thread overview]
Message-ID: <161177764655.1311.6780394066063825590.stgit@manet.1015granger.net> (raw)
In-Reply-To: <161177711359.1311.417185373365934204.stgit@manet.1015granger.net>

From: Isaac J. Manjarres <isaacm@codeaurora.org>

While mapping a scatter-gather list, iommu_map_sg() calls
into the IOMMU driver through an indirect call, which can
call into the io-pgtable code through another indirect call.

This sequence of going through the IOMMU core code, the IOMMU
driver, and finally the io-pgtable code, occurs for every
element in the scatter-gather list, in the worse case, which
is not optimal.

Introduce a map_sg callback in the io-pgtable ops so that
IOMMU drivers can invoke it with the complete scatter-gather
list, so that it can be processed within the io-pgtable
code entirely, reducing the number of indirect calls, and
boosting overall iommu_map_sg() performance.

Signed-off-by: Isaac J. Manjarres <isaacm@codeaurora.org>
Tested-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
---
 include/linux/io-pgtable.h |    6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h
index ea727eb1a1a9..6d0e73172603 100644
--- a/include/linux/io-pgtable.h
+++ b/include/linux/io-pgtable.h
@@ -147,6 +147,9 @@ struct io_pgtable_cfg {
  * struct io_pgtable_ops - Page table manipulation API for IOMMU drivers.
  *
  * @map:          Map a physically contiguous memory region.
+ * @map_sg:       Map a scatter-gather list of physically contiguous memory
+ *                chunks. The mapped pointer argument is used to store how
+ *                many bytes are mapped.
  * @unmap:        Unmap a physically contiguous memory region.
  * @iova_to_phys: Translate iova to physical address.
  *
@@ -156,6 +159,9 @@ struct io_pgtable_cfg {
 struct io_pgtable_ops {
 	int (*map)(struct io_pgtable_ops *ops, unsigned long iova,
 		   phys_addr_t paddr, size_t size, int prot, gfp_t gfp);
+	int (*map_sg)(struct io_pgtable_ops *ops, unsigned long iova,
+		      struct scatterlist *sg, unsigned int nents, int prot,
+		      gfp_t gfp, size_t *mapped);
 	size_t (*unmap)(struct io_pgtable_ops *ops, unsigned long iova,
 			size_t size, struct iommu_iotlb_gather *gather);
 	phys_addr_t (*iova_to_phys)(struct io_pgtable_ops *ops,


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  parent reply	other threads:[~2021-01-27 20:00 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-27 20:00 [PATCH RFC 0/9] Possible set of VT-d optimizations Chuck Lever
2021-01-27 20:00 ` [PATCH RFC 1/9] iommu: Move iotlb_sync_map out from __iommu_map Chuck Lever
2021-01-28  2:40   ` Lu Baolu
2021-01-27 20:00 ` [PATCH RFC 2/9] iommu: Add iova and size as parameters in iotlb_sync_map Chuck Lever
2021-01-28  2:44   ` Lu Baolu
2021-01-28 12:51   ` Joerg Roedel
2021-01-28 13:19     ` Will Deacon
2021-01-28 13:26       ` Joerg Roedel
2021-01-27 20:00 ` [PATCH RFC 3/9] iommu/vt-d: Add iotlb_sync_map callback Chuck Lever
2021-01-27 20:00 ` Chuck Lever [this message]
2021-01-27 20:00 ` [PATCH RFC 5/9] iommu/io-pgtable-arm: Hook up map_sg() Chuck Lever
2021-01-28 13:53   ` Will Deacon
2021-01-27 20:01 ` [PATCH RFC 6/9] iommu/io-pgtable-arm-v7s: " Chuck Lever
2021-01-27 20:01 ` [PATCH RFC 7/9] iommu: Introduce map_sg() as an IOMMU op for IOMMU drivers Chuck Lever
2021-01-28  2:58   ` Lu Baolu
2021-01-27 20:01 ` [PATCH RFC 8/9] iommu/arm-smmu: Hook up map_sg() Chuck Lever
2021-01-27 20:01 ` [PATCH RFC 9/9] iommu/vt-d: Introduce map_sg() for Intel IOMMUs Chuck Lever
2021-01-28  2:28 ` [PATCH RFC 0/9] Possible set of VT-d optimizations Lu Baolu
2021-01-28 13:59 ` Robin Murphy
2021-01-28 14:52   ` Chuck Lever
2021-01-29 11:54     ` Lu Baolu
2021-02-01 18:08     ` Chuck Lever

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