diff --git a/drivers/iommu/amd/init.c b/drivers/iommu/amd/init.c
index 8ec8a6fccaaf..1d7b9fe305ac 100644
--- a/drivers/iommu/amd/init.c
+++ b/drivers/iommu/amd/init.c
@@ -389,7 +389,13 @@ static void iommu_set_device_table(struct amd_iommu *iommu)
 
 	BUG_ON(iommu->mmio_base == NULL);
 
-	if (is_kdump_kernel())
+	/*
+	 * A kdump kernel that reuses the previous kernel's device table must
+	 * leave the base register alone. It already points at that table, and
+	 * with SNP enabled the register is locked. If reuse failed, program
+	 * the freshly allocated table like a normal boot.
+	 */
+	if (iommu->pci_seg->old_dev_tbl_cpy)
 		return;
 
 	entry = iommu_virt_to_phys(dev_table);