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From: Sven Peter <sven@svenpeter.dev>
To: iommu@lists.linux-foundation.org
Cc: Sven Peter <sven@svenpeter.dev>, Joerg Roedel <joro@8bytes.org>,
	Will Deacon <will@kernel.org>,
	Robin Murphy <robin.murphy@arm.com>,
	Arnd Bergmann <arnd@kernel.org>,
	Mohamed Mediouni <mohamed.mediouni@caramail.com>,
	Alexander Graf <graf@amazon.com>,
	Hector Martin <marcan@marcan.st>,
	linux-kernel@vger.kernel.org
Subject: [RFC PATCH 3/3] iommu: Introduce __IOMMU_DOMAIN_LARGE_PAGES
Date: Fri,  6 Aug 2021 17:55:23 +0200	[thread overview]
Message-ID: <20210806155523.50429-4-sven@svenpeter.dev> (raw)
In-Reply-To: <20210806155523.50429-1-sven@svenpeter.dev>

__IOMMU_DOMAIN_LARGE_PAGES indicates that a domain can handle
conditions where PAGE_SIZE might be smaller than the IOMMU page size.
Always allow attaching devices to such domains and set the flag for
IOMMU_DOMAIN_DMA, which can now handle these situations.

Signed-off-by: Sven Peter <sven@svenpeter.dev>
---
 drivers/iommu/iommu.c |  2 ++
 include/linux/iommu.h | 14 +++++++++-----
 2 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 5854a4ef5681..f0bfd76187b1 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -1970,6 +1970,8 @@ static int iommu_check_page_size(struct iommu_domain *domain)
 {
 	if (!(domain->type & __IOMMU_DOMAIN_PAGING))
 		return 0;
+	if (domain->type & __IOMMU_DOMAIN_LARGE_PAGES)
+		return 0;
 
 	if ((1 << __ffs(domain->pgsize_bitmap)) > PAGE_SIZE) {
 		pr_warn("IOMMU page size cannot represent CPU pages.\n");
diff --git a/include/linux/iommu.h b/include/linux/iommu.h
index e552ecfefcf7..1f97eac8a4b0 100644
--- a/include/linux/iommu.h
+++ b/include/linux/iommu.h
@@ -56,10 +56,13 @@ struct iommu_domain_geometry {
 };
 
 /* Domain feature flags */
-#define __IOMMU_DOMAIN_PAGING	(1U << 0)  /* Support for iommu_map/unmap */
-#define __IOMMU_DOMAIN_DMA_API	(1U << 1)  /* Domain for use in DMA-API
-					      implementation              */
-#define __IOMMU_DOMAIN_PT	(1U << 2)  /* Domain is identity mapped   */
+#define __IOMMU_DOMAIN_PAGING       (1U << 0)  /* Support for iommu_map/unmap */
+#define __IOMMU_DOMAIN_DMA_API      (1U << 1)  /* Domain for use in DMA-API
+						   implementation              */
+#define __IOMMU_DOMAIN_PT           (1U << 2)  /* Domain is identity mapped   */
+#define __IOMMU_DOMAIN_LARGE_PAGES  (1U << 3)  /* Domain can handle IOMMU page
+						  sizes larger than the CPU
+						  page size                   */
 
 /*
  * This are the possible domain-types
@@ -77,7 +80,8 @@ struct iommu_domain_geometry {
 #define IOMMU_DOMAIN_IDENTITY	(__IOMMU_DOMAIN_PT)
 #define IOMMU_DOMAIN_UNMANAGED	(__IOMMU_DOMAIN_PAGING)
 #define IOMMU_DOMAIN_DMA	(__IOMMU_DOMAIN_PAGING |	\
-				 __IOMMU_DOMAIN_DMA_API)
+				 __IOMMU_DOMAIN_DMA_API |       \
+				 __IOMMU_DOMAIN_LARGE_PAGES)
 
 struct iommu_domain {
 	unsigned type;
-- 
2.25.1


      parent reply	other threads:[~2021-08-06 15:57 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-06 15:55 [RFC PATCH 0/3] iommu/dma-iommu: Support IOMMU page size larger than the CPU page size Sven Peter
2021-08-06 15:55 ` [RFC PATCH 1/3] iommu: Move IOMMU pagesize check to attach_device Sven Peter
2021-08-06 15:55 ` [RFC PATCH 2/3] iommu/dma-iommu: Support iovad->granule > PAGE_SIZE Sven Peter
2021-08-06 18:04   ` Robin Murphy
2021-08-07  8:41     ` Sven Peter
2021-08-09 18:37       ` Robin Murphy
2021-08-09 19:57         ` Sven Peter
2021-08-07 11:47     ` Sven Peter
2021-08-09 17:41       ` Robin Murphy
2021-08-09 20:45         ` Sven Peter
2021-08-10  9:51           ` Robin Murphy
2021-08-11 20:18             ` Sven Peter
2021-08-12 12:43               ` Robin Murphy
2021-08-06 15:55 ` Sven Peter [this message]

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