[PATCH 2/5] KVM: selftests: Use the shared memslot base in memslot_perf_test

[Tharit Tangkijwanichakul <tharitt97@gmail.com>]

Use TEST_MEM_SLOT_BASE for test memslot IDs and account for the
reserved slots when calculating the available slot count. This
prepares memslot_perf_test for reserving slot 1 for library use.

Signed-off-by: Tharit Tangkijwanichakul <tharitt97@gmail.com>
---
 .../testing/selftests/kvm/memslot_perf_test.c | 62 +++++++++++--------
 1 file changed, 35 insertions(+), 27 deletions(-)

diff --git a/tools/testing/selftests/kvm/memslot_perf_test.c b/tools/testing/selftests/kvm/memslot_perf_test.c
index e1299611be32..cbb900ab58af 100644
--- a/tools/testing/selftests/kvm/memslot_perf_test.c
+++ b/tools/testing/selftests/kvm/memslot_perf_test.c
@@ -60,7 +60,7 @@
  * other memslot(s).
  *
  * We have different number of memory slots, excluding the reserved
- * memory slot 0, on various architectures and configurations. The
+ * memory slots 0 and 1, on various architectures and configurations. The
  * memory size in this test is calculated by picking the maximal
  * last memory slot's memory size, with alignment to the largest
  * supported page size (64KB). In this way, the selected memory
@@ -68,9 +68,9 @@
  *
  * architecture   slots    memory-per-slot    memory-on-last-slot
  * --------------------------------------------------------------
- * x86-4KB        32763    16KB               160KB
- * arm64-4KB      32766    16KB               112KB
- * arm64-16KB     32766    16KB               112KB
+ * x86-4KB        32762    16KB               176KB
+ * arm64-4KB      32765    16KB               128KB
+ * arm64-16KB     32765    16KB               128KB
  * arm64-64KB     8192     64KB               128KB
  */
 #define MEM_TEST_MOVE_SIZE		(3 * SZ_64K)
@@ -276,7 +276,7 @@ static u64 get_max_slots(struct vm_data *data, u32 host_page_size)
 		rempages = mempages % pages_per_slot;
 		if (check_slot_pages(host_page_size, guest_page_size,
 				     pages_per_slot, rempages))
-			return slots + 1;	/* slot 0 is reserved */
+			return slots + TEST_MEM_SLOT_BASE;
 	}
 
 	return 0;
@@ -313,38 +313,42 @@ static bool prepare_vm(struct vm_data *data, int nslots, u64 *maxslots,
 	data->hva_slots = malloc(sizeof(*data->hva_slots) * data->nslots);
 	TEST_ASSERT(data->hva_slots, "malloc() fail");
 
-	pr_info_v("Adding slots 1..%i, each slot with %"PRIu64" pages + %"PRIu64" extra pages last\n",
-		data->nslots, data->pages_per_slot, rempages);
+	pr_info_v("Adding slots %u..%u, each slot with %" PRIu64
+		  " pages + %" PRIu64 " extra pages last\n",
+		  (u32)TEST_MEM_SLOT_BASE,
+		  TEST_MEM_SLOT_BASE + data->nslots - 1,
+		  data->pages_per_slot, rempages);
 
 	clock_gettime(CLOCK_MONOTONIC, &tstart);
-	for (slot = 1, guest_addr = MEM_GPA; slot <= data->nslots; slot++) {
+	for (slot = 0, guest_addr = MEM_GPA; slot < data->nslots; slot++) {
 		u64 npages;
 
 		npages = data->pages_per_slot;
-		if (slot == data->nslots)
+		if (slot == data->nslots - 1)
 			npages += rempages;
 
 		vm_userspace_mem_region_add(data->vm, VM_MEM_SRC_ANONYMOUS,
-					    guest_addr, slot, npages,
-					    0);
+					    guest_addr, TEST_MEM_SLOT_BASE + slot,
+					    npages, 0);
 		guest_addr += npages * guest_page_size;
 	}
 	*slot_runtime = timespec_elapsed(tstart);
 
-	for (slot = 1, guest_addr = MEM_GPA; slot <= data->nslots; slot++) {
+	for (slot = 0, guest_addr = MEM_GPA; slot < data->nslots; slot++) {
 		u64 npages;
 		gpa_t gpa;
 
 		npages = data->pages_per_slot;
-		if (slot == data->nslots)
+		if (slot == data->nslots - 1)
 			npages += rempages;
 
-		gpa = vm_phy_pages_alloc(data->vm, npages, guest_addr, slot);
+		gpa = vm_phy_pages_alloc(data->vm, npages, guest_addr,
+					 TEST_MEM_SLOT_BASE + slot);
 		TEST_ASSERT(gpa == guest_addr,
 			    "vm_phy_pages_alloc() failed");
 
-		data->hva_slots[slot - 1] = addr_gpa2hva(data->vm, guest_addr);
-		memset(data->hva_slots[slot - 1], 0, npages * guest_page_size);
+		data->hva_slots[slot] = addr_gpa2hva(data->vm, guest_addr);
+		memset(data->hva_slots[slot], 0, npages * guest_page_size);
 
 		guest_addr += npages * guest_page_size;
 	}
@@ -631,9 +635,10 @@ static void test_memslot_move_loop(struct vm_data *data, struct sync_area *sync)
 	u64 movesrcgpa;
 
 	movesrcgpa = vm_slot2gpa(data, data->nslots - 1);
-	vm_mem_region_move(data->vm, data->nslots - 1 + 1,
+	vm_mem_region_move(data->vm, TEST_MEM_SLOT_BASE + data->nslots - 1,
 			   MEM_TEST_MOVE_GPA_DEST);
-	vm_mem_region_move(data->vm, data->nslots - 1 + 1, movesrcgpa);
+	vm_mem_region_move(data->vm, TEST_MEM_SLOT_BASE + data->nslots - 1,
+			   movesrcgpa);
 }
 
 static void test_memslot_do_unmap(struct vm_data *data,
@@ -988,8 +993,10 @@ static bool parse_args(int argc, char *argv[],
 #endif
 		case 's':
 			targs->nslots = atoi_paranoid(optarg);
-			if (targs->nslots <= 1 && targs->nslots != -1) {
-				pr_info("Slot count cap must be larger than 1 or -1 for no cap\n");
+			if (targs->nslots <= TEST_MEM_SLOT_BASE &&
+			    targs->nslots != -1) {
+				pr_info("Slot count cap must be larger than %d or -1 for no cap\n",
+					TEST_MEM_SLOT_BASE);
 				return false;
 			}
 			break;
@@ -1027,20 +1034,21 @@ static bool parse_args(int argc, char *argv[],
 	}
 
 	max_mem_slots = kvm_check_cap(KVM_CAP_NR_MEMSLOTS);
-	if (max_mem_slots <= 1) {
-		pr_info("KVM_CAP_NR_MEMSLOTS should be greater than 1\n");
+	if (max_mem_slots <= TEST_MEM_SLOT_BASE) {
+		pr_info("KVM_CAP_NR_MEMSLOTS should be greater than %d\n",
+			TEST_MEM_SLOT_BASE);
 		return false;
 	}
 
-	/* Memory slot 0 is reserved */
+	/* Memory slots below TEST_MEM_SLOT_BASE are reserved. */
 	if (targs->nslots == -1)
-		targs->nslots = max_mem_slots - 1;
+		targs->nslots = max_mem_slots - TEST_MEM_SLOT_BASE;
 	else
-		targs->nslots = min_t(int, targs->nslots, max_mem_slots) - 1;
+		targs->nslots = min_t(int, targs->nslots, max_mem_slots)
+				- TEST_MEM_SLOT_BASE;
 
 	pr_info_v("Allowed Number of memory slots: %"PRIu32"\n",
-		  targs->nslots + 1);
-
+		 (u32)(targs->nslots + TEST_MEM_SLOT_BASE));
 	return true;
 }
 
-- 
2.53.0