linux-kernel - [PATCH 1/4] iommu: Introduce iotlb_sync

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Date:   Mon, 19 Oct 2020 19:30:57 +0800
From:   Chao Hao <chao.hao@...iatek.com>
To:     Joerg Roedel <joro@...tes.org>,
        Matthias Brugger <matthias.bgg@...il.com>
CC:     <iommu@...ts.linux-foundation.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>, <wsd_upstream@...iatek.com>,
        Yong Wu <yong.wu@...iatek.com>, FY Yang <fy.yang@...iatek.com>,
        Jun Wen <jun.wen@...iatek.com>,
        Mingyuan Ma <mingyuan.ma@...iatek.com>,
        Chao Hao <chao.hao@...iatek.com>
Subject: [PATCH 1/4] iommu: Introduce iotlb_sync_range callback

Add iotlb_sync_range callback to support that driver can appoint iova
and size to do tlb sync.
Iommu will call iotlb_sync_range() after the whole mapping/unmapping
is completed, and the iova and size of iotlb_sync_range() are start_iova
and buffer total_size respectively. At the same time, iotlb_sync() and
tlb_flush_walk/leaf() can be skipped. So iotlb_sync_range() will enhance
performance by reducing the time of tlb sync.

Signed-off-by: Chao Hao <chao.hao@...iatek.com>
---
 drivers/iommu/dma-iommu.c | 9 +++++++++
 drivers/iommu/iommu.c     | 7 +++++++
 include/linux/iommu.h     | 2 ++
 3 files changed, 18 insertions(+)

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 4959f5df21bd..e2e9114c4ae2 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -479,6 +479,7 @@ static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
 		size_t size, int prot, u64 dma_mask)
 {
 	struct iommu_domain *domain = iommu_get_dma_domain(dev);
+	const struct iommu_ops *ops = domain->ops;
 	struct iommu_dma_cookie *cookie = domain->iova_cookie;
 	struct iova_domain *iovad = &cookie->iovad;
 	size_t iova_off = iova_offset(iovad, phys);
@@ -497,6 +498,10 @@ static dma_addr_t __iommu_dma_map(struct device *dev, phys_addr_t phys,
 		iommu_dma_free_iova(cookie, iova, size);
 		return DMA_MAPPING_ERROR;
 	}
+
+	if (ops->iotlb_sync_range)
+		ops->iotlb_sync_range(iova, size);
+
 	return iova + iova_off;
 }
 
@@ -1165,6 +1170,7 @@ void iommu_setup_dma_ops(struct device *dev, u64 dma_base, u64 size)
 static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
 		phys_addr_t msi_addr, struct iommu_domain *domain)
 {
+	const struct iommu_ops *ops = domain->ops;
 	struct iommu_dma_cookie *cookie = domain->iova_cookie;
 	struct iommu_dma_msi_page *msi_page;
 	dma_addr_t iova;
@@ -1187,6 +1193,9 @@ static struct iommu_dma_msi_page *iommu_dma_get_msi_page(struct device *dev,
 	if (iommu_map(domain, iova, msi_addr, size, prot))
 		goto out_free_iova;
 
+	if (ops->iotlb_sync_range)
+		ops->iotlb_sync_range(iova, size);
+
 	INIT_LIST_HEAD(&msi_page->list);
 	msi_page->phys = msi_addr;
 	msi_page->iova = iova;
diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 609bd25bf154..e399a238d1e9 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2304,6 +2304,9 @@ static size_t __iommu_unmap(struct iommu_domain *domain,
 		unmapped += unmapped_page;
 	}
 
+	if (ops->iotlb_sync_range)
+		ops->iotlb_sync_range(iova, size);
+
 	trace_unmap(orig_iova, size, unmapped);
 	return unmapped;
 }
@@ -2334,6 +2337,7 @@ static size_t __iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
 			     struct scatterlist *sg, unsigned int nents, int prot,
 			     gfp_t gfp)
 {
+	const struct iommu_ops *ops = domain->ops;
 	size_t len = 0, mapped = 0;
 	phys_addr_t start;
 	unsigned int i = 0;
@@ -2364,6 +2368,9 @@ static size_t __iommu_map_sg(struct iommu_domain *domain, unsigned long iova,
 			sg = sg_next(sg);
 	}
 
+	if (ops->iotlb_sync_range)
+		ops->iotlb_sync_range(iova, mapped);
+
 	return mapped;
 
 out_err:
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index fee209efb756..4be90324bd23 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -192,6 +192,7 @@ struct iommu_iotlb_gather {
  * @map: map a physically contiguous memory region to an iommu domain
  * @unmap: unmap a physically contiguous memory region from an iommu domain
  * @flush_iotlb_all: Synchronously flush all hardware TLBs for this domain
+ * @iotlb_sync_range: Sync specific iova and size mappings to the hardware
  * @iotlb_sync_map: Sync mappings created recently using @map to the hardware
  * @iotlb_sync: Flush all queued ranges from the hardware TLBs and empty flush
  *            queue
@@ -244,6 +245,7 @@ struct iommu_ops {
 	size_t (*unmap)(struct iommu_domain *domain, unsigned long iova,
 		     size_t size, struct iommu_iotlb_gather *iotlb_gather);
 	void (*flush_iotlb_all)(struct iommu_domain *domain);
+	void (*iotlb_sync_range)(unsigned long iova, size_t size);
 	void (*iotlb_sync_map)(struct iommu_domain *domain);
 	void (*iotlb_sync)(struct iommu_domain *domain,
 			   struct iommu_iotlb_gather *iotlb_gather);
-- 
2.18.0