linux-kernel - [PATCH v1] iommu/s390: Declare s390 iommu reserved regions

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Date:   Tue, 15 Jan 2019 18:37:30 +0100
From:   Pierre Morel <pmorel@...ux.ibm.com>
To:     gerald.schaefer@...ibm.com
Cc:     joro@...tes.org, linux-s390@...r.kernel.org,
        iommu@...ts.linux-foundation.org, linux-kernel@...r.kernel.org,
        alex.williamson@...hat.com, shameerali.kolothum.thodi@...wei.com,
        walling@...ux.ibm.com
Subject: [PATCH v1] iommu/s390: Declare s390 iommu reserved regions

The s390 iommu can only allow DMA transactions between the zPCI device
entries start_dma and end_dma.

Let's declare the regions before start_dma and after end_dma as
reserved regions using the appropriate callback in iommu_ops.

Signed-off-by: Pierre Morel <pmorel@...ux.ibm.com>
---
 drivers/iommu/s390-iommu.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c
index 22d4db3..5ca91a1 100644
--- a/drivers/iommu/s390-iommu.c
+++ b/drivers/iommu/s390-iommu.c
@@ -363,6 +363,33 @@ void zpci_destroy_iommu(struct zpci_dev *zdev)
 	iommu_device_sysfs_remove(&zdev->iommu_dev);
 }
 
+static void s390_get_resv_regions(struct device *dev, struct list_head *head)
+{
+	struct iommu_resv_region *region;
+	struct zpci_dev *zdev = to_pci_dev(dev)->sysdata;
+
+	region = iommu_alloc_resv_region(0, zdev->start_dma,
+					 0, IOMMU_RESV_RESERVED);
+	if (!region)
+		return;
+	list_add_tail(&region->list, head);
+
+	region = iommu_alloc_resv_region(zdev->end_dma + 1,
+					 ~0UL - zdev->end_dma,
+					 0, IOMMU_RESV_RESERVED);
+	if (!region)
+		return;
+	list_add_tail(&region->list, head);
+}
+
+static void s390_put_resv_regions(struct device *dev, struct list_head *head)
+{
+	struct iommu_resv_region *entry, *next;
+
+	list_for_each_entry_safe(entry, next, head, list)
+		kfree(entry);
+}
+
 static const struct iommu_ops s390_iommu_ops = {
 	.capable = s390_iommu_capable,
 	.domain_alloc = s390_domain_alloc,
@@ -376,6 +403,8 @@ static const struct iommu_ops s390_iommu_ops = {
 	.remove_device = s390_iommu_remove_device,
 	.device_group = generic_device_group,
 	.pgsize_bitmap = S390_IOMMU_PGSIZES,
+	.get_resv_regions = s390_get_resv_regions,
+	.put_resv_regions = s390_put_resv_regions,
 };
 
 static int __init s390_iommu_init(void)
-- 
2.7.4