iommu/io-pgtable-arm: Add coverage for different OAS in selftest

Run selftests with different OAS values intead of hardcoding it to 48
bits.

We always keep OAS >= IAS to make the config valid for stage-2.

This can be further improved, if we split IAS/OAS configuration for
stage-1 and stage-2 (to use input sizes compatible with VA_BITS as
SMMUv3 does, or IAS > OAS which is valid for stage-1).

However, that adds more complexity, and the current change improves
coverage and makes it possible to test all concatenation cases.

Signed-off-by: Mostafa Saleh <smostafa@google.com>
Link: https://lore.kernel.org/r/20241202140604.422235-3-smostafa@google.com
Signed-off-by: Will Deacon <will@kernel.org>

Author: misaleh

drivers/iommu/io-pgtable-arm.c

@@ -1385,15 +1385,14 @@ static int __init arm_lpae_do_selftests(void)
 		SZ_64K | SZ_512M,
 	};
 
-	static const unsigned int ias[] __initconst = {
+	static const unsigned int address_size[] __initconst = {
 		32, 36, 40, 42, 44, 48,
 	};
 
-	int i, j, pass = 0, fail = 0;
+	int i, j, k, pass = 0, fail = 0;
 	struct device dev;
 	struct io_pgtable_cfg cfg = {
 		.tlb = &dummy_tlb_ops,
-		.oas = 48,
 		.coherent_walk = true,
 		.iommu_dev = &dev,
 	};
@@ -1402,15 +1401,19 @@ static int __init arm_lpae_do_selftests(void)
 	set_dev_node(&dev, NUMA_NO_NODE);
 
 	for (i = 0; i < ARRAY_SIZE(pgsize); ++i) {
-		for (j = 0; j < ARRAY_SIZE(ias); ++j) {
-			cfg.pgsize_bitmap = pgsize[i];
-			cfg.ias = ias[j];
-			pr_info("selftest: pgsize_bitmap 0x%08lx, IAS %u\n",
-				pgsize[i], ias[j]);
-			if (arm_lpae_run_tests(&cfg))
-				fail++;
-			else
-				pass++;
+		for (j = 0; j < ARRAY_SIZE(address_size); ++j) {
+			/* Don't use ias > oas as it is not valid for stage-2. */
+			for (k = 0; k <= j; ++k) {
+				cfg.pgsize_bitmap = pgsize[i];
+				cfg.ias = address_size[k];
+				cfg.oas = address_size[j];
+				pr_info("selftest: pgsize_bitmap 0x%08lx, IAS %u OAS %u\n",
+					pgsize[i], cfg.ias, cfg.oas);
+				if (arm_lpae_run_tests(&cfg))
+					fail++;
+				else
+					pass++;
+			}
 		}
 	}