linux-kernel - [PATCH v6 06/15] iommu: Split 'addr_merge' argument to iommu

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Date:   Tue, 15 Jun 2021 10:08:24 -0700
From:   Georgi Djakov <quic_c_gdjako@...cinc.com>
To:     <will@...nel.org>, <robin.murphy@....com>
CC:     <joro@...tes.org>, <isaacm@...eaurora.org>,
        <baolu.lu@...ux.intel.com>, <pratikp@...eaurora.org>,
        <iommu@...ts.linux-foundation.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <djakov@...nel.org>
Subject: [PATCH v6 06/15] iommu: Split 'addr_merge' argument to iommu_pgsize() into separate parts

From: Will Deacon <will@...nel.org>

The 'addr_merge' parameter to iommu_pgsize() is a fabricated address
intended to describe the alignment requirements to consider when
choosing an appropriate page size. On the iommu_map() path, this address
is the logical OR of the virtual and physical addresses.

Subsequent improvements to iommu_pgsize() will need to check the
alignment of the virtual and physical components of 'addr_merge'
independently, so pass them in as separate parameters and reconstruct
'addr_merge' locally.

No functional change.

Signed-off-by: Will Deacon <will@...nel.org>
Signed-off-by: Isaac J. Manjarres <isaacm@...eaurora.org>
Signed-off-by: Georgi Djakov <quic_c_gdjako@...cinc.com>
---
 drivers/iommu/iommu.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c
index 80e471ada358..80e14c139d40 100644
--- a/drivers/iommu/iommu.c
+++ b/drivers/iommu/iommu.c
@@ -2375,12 +2375,13 @@ phys_addr_t iommu_iova_to_phys(struct iommu_domain *domain, dma_addr_t iova)
 }
 EXPORT_SYMBOL_GPL(iommu_iova_to_phys);
 
-static size_t iommu_pgsize(struct iommu_domain *domain,
-			   unsigned long addr_merge, size_t size)
+static size_t iommu_pgsize(struct iommu_domain *domain, unsigned long iova,
+			   phys_addr_t paddr, size_t size)
 {
 	unsigned int pgsize_idx;
 	unsigned long pgsizes;
 	size_t pgsize;
+	unsigned long addr_merge = paddr | iova;
 
 	/* Page sizes supported by the hardware and small enough for @size */
 	pgsizes = domain->pgsize_bitmap & GENMASK(__fls(size), 0);
@@ -2433,7 +2434,7 @@ static int __iommu_map(struct iommu_domain *domain, unsigned long iova,
 	pr_debug("map: iova 0x%lx pa %pa size 0x%zx\n", iova, &paddr, size);
 
 	while (size) {
-		size_t pgsize = iommu_pgsize(domain, iova | paddr, size);
+		size_t pgsize = iommu_pgsize(domain, iova, paddr, size);
 
 		pr_debug("mapping: iova 0x%lx pa %pa pgsize 0x%zx\n",
 			 iova, &paddr, pgsize);
@@ -2521,8 +2522,9 @@ static size_t __iommu_unmap(struct iommu_domain *domain,
 	 * or we hit an area that isn't mapped.
 	 */
 	while (unmapped < size) {
-		size_t pgsize = iommu_pgsize(domain, iova, size - unmapped);
+		size_t pgsize;
 
+		pgsize = iommu_pgsize(domain, iova, iova, size - unmapped);
 		unmapped_page = ops->unmap(domain, iova, pgsize, iotlb_gather);
 		if (!unmapped_page)
 			break;