From: Leon Romanovsky <leonro@nvidia.com>
Date: Thu, 18 Jul 2024 18:16:04 +0000 (+0300)
Subject: iommu/dma: Add check if IOVA can be used
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=9ad04dff674c66f95684015ae81ae2d40d1b757c;p=users%2Fhch%2Fblock.git

iommu/dma: Add check if IOVA can be used

This patch adds a check if IOVA can be used for the page and size.

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
---

diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c
index 87bd706075d1..99af34871e9f 100644
--- a/drivers/iommu/dma-iommu.c
+++ b/drivers/iommu/dma-iommu.c
@@ -11,6 +11,7 @@
 #include <linux/acpi_iort.h>
 #include <linux/atomic.h>
 #include <linux/crash_dump.h>
+#include <linux/cc_platform.h>
 #include <linux/device.h>
 #include <linux/dma-direct.h>
 #include <linux/dma-map-ops.h>
@@ -1863,6 +1864,26 @@ void iommu_dma_unlink_range(struct device *dev, dma_addr_t start, size_t size,
 		iommu_iotlb_sync(domain, &iotlb_gather);
 }
 
+bool iommu_can_use_iova(struct device *dev, struct page *page, size_t size,
+			enum dma_data_direction dir)
+{
+	enum pci_p2pdma_map_type map;
+
+	if (is_swiotlb_force_bounce(dev) || dev_use_swiotlb(dev, size, dir))
+		return false;
+
+	/* TODO: Rewrite this check to rely on specific struct page flags */
+	if (cc_platform_has(CC_ATTR_MEM_ENCRYPT))
+		return false;
+
+	if (page && is_pci_p2pdma_page(page)) {
+		map = pci_p2pdma_map_type(page->pgmap, dev);
+		return map == PCI_P2PDMA_MAP_THRU_HOST_BRIDGE;
+	}
+
+	return true;
+}
+
 void iommu_setup_dma_ops(struct device *dev)
 {
 	struct iommu_domain *domain = iommu_get_domain_for_dev(dev);
diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 4f47a13cb500..6ceea32bb041 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -964,8 +964,8 @@ void pci_p2pmem_publish(struct pci_dev *pdev, bool publish)
 }
 EXPORT_SYMBOL_GPL(pci_p2pmem_publish);
 
-static enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap,
-						    struct device *dev)
+enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap,
+					     struct device *dev)
 {
 	enum pci_p2pdma_map_type type = PCI_P2PDMA_MAP_NOT_SUPPORTED;
 	struct pci_dev *provider = to_p2p_pgmap(pgmap)->provider;
diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h
index b7773201414c..894e74ba178b 100644
--- a/include/linux/dma-map-ops.h
+++ b/include/linux/dma-map-ops.h
@@ -479,6 +479,8 @@ struct pci_p2pdma_map_state {
 enum pci_p2pdma_map_type
 pci_p2pdma_map_segment(struct pci_p2pdma_map_state *state, struct device *dev,
 		       struct scatterlist *sg);
+enum pci_p2pdma_map_type pci_p2pdma_map_type(struct dev_pagemap *pgmap,
+					     struct device *dev);
 #else /* CONFIG_PCI_P2PDMA */
 static inline enum pci_p2pdma_map_type
 pci_p2pdma_map_segment(struct pci_p2pdma_map_state *state, struct device *dev,
@@ -486,6 +488,11 @@ pci_p2pdma_map_segment(struct pci_p2pdma_map_state *state, struct device *dev,
 {
 	return PCI_P2PDMA_MAP_NOT_SUPPORTED;
 }
+static inline enum pci_p2pdma_map_type
+pci_p2pdma_map_type(struct dev_pagemap *pgmap, struct device *dev)
+{
+	return PCI_P2PDMA_MAP_NOT_SUPPORTED;
+}
 #endif /* CONFIG_PCI_P2PDMA */
 
 #endif /* _LINUX_DMA_MAP_OPS_H */
diff --git a/include/linux/iommu-dma.h b/include/linux/iommu-dma.h
index 4e0a8e38237e..0832b115a436 100644
--- a/include/linux/iommu-dma.h
+++ b/include/linux/iommu-dma.h
@@ -75,4 +75,6 @@ dma_addr_t iommu_dma_link_range(struct dma_iova_state *state, phys_addr_t phys,
 		size_t size, unsigned long attrs);
 void iommu_dma_unlink_range(struct device *dev, dma_addr_t start, size_t size,
 		enum dma_data_direction dir, unsigned long attrs);
+bool iommu_can_use_iova(struct device *dev, struct page *page, size_t size,
+		enum dma_data_direction dir);
 #endif /* _LINUX_IOMMU_DMA_H */