[PATCH 7/7] iommu/amd: Fully decode all combinations of alloc_paging_flags

[Jason Gunthorpe <jgg@nvidia.com>]

Currently AMD does not support IOMMU_HWPT_ALLOC_PASID |
IOMMU_HWPT_ALLOC_DIRTY_TRACKING, it should be rejected. Instead it creates
a V1 domain without dirty tracking support.

Use a switch to fully decode the flags.

Fixes: ce2cd175469f ("iommu/amd: Enhance amd_iommu_domain_alloc_user()")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
---
 drivers/iommu/amd/iommu.c | 31 ++++++++++++++++---------------
 1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/drivers/iommu/amd/iommu.c b/drivers/iommu/amd/iommu.c
index c84eb3e7bd8bef..a418a1f48e7fa7 100644
--- a/drivers/iommu/amd/iommu.c
+++ b/drivers/iommu/amd/iommu.c
@@ -2375,24 +2375,25 @@ amd_iommu_domain_alloc_paging_flags(struct device *dev, u32 flags,
 	if ((flags & ~supported_flags) || user_data)
 		return ERR_PTR(-EOPNOTSUPP);
 
-	/* Allocate domain with v2 page table if IOMMU supports PASID. */
-	if (flags & IOMMU_HWPT_ALLOC_PASID) {
+	switch (flags &
+		(IOMMU_HWPT_ALLOC_PASID | IOMMU_HWPT_ALLOC_DIRTY_TRACKING)) {
+	case IOMMU_HWPT_ALLOC_DIRTY_TRACKING:
+		/* Allocate domain with v1 page table for dirty tracking */
+		if (!amd_iommu_hd_support(iommu))
+			break;
+		return do_iommu_domain_alloc(dev, flags, PD_MODE_V1);
+	case IOMMU_HWPT_ALLOC_PASID:
+		/* Allocate domain with v2 page table if IOMMU supports PASID. */
 		if (!amd_iommu_pasid_supported())
-			return ERR_PTR(-EOPNOTSUPP);
-
+			break;
 		return do_iommu_domain_alloc(dev, flags, PD_MODE_V2);
+	case 0:
+		/* If nothing specific is required use the kernel commandline default */
+		return do_iommu_domain_alloc(dev, 0, amd_iommu_pgtable);
+	default:
+		break;
 	}
-
-	/* Allocate domain with v1 page table for dirty tracking */
-	if (flags & IOMMU_HWPT_ALLOC_DIRTY_TRACKING) {
-		if (amd_iommu_hd_support(iommu))
-			return do_iommu_domain_alloc(dev, flags, PD_MODE_V1);
-
-		return ERR_PTR(-EOPNOTSUPP);
-	}
-
-	/* If nothing specific is required use the kernel commandline default */
-	return do_iommu_domain_alloc(dev, 0, amd_iommu_pgtable);
+	return ERR_PTR(-EOPNOTSUPP);
 }
 
 void amd_iommu_domain_free(struct iommu_domain *dom)
-- 
2.43.0