1 files changed, 398 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/lib/memstress.c b/tools/testing/selftests/kvm/lib/memstress.c
new file mode 100644
index 000000000000..cf2c73971308
--- /dev/null
+++ b/tools/testing/selftests/kvm/lib/memstress.c
@@ -0,0 +1,398 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020, Google LLC.
+ */
+#define _GNU_SOURCE
+
+#include <inttypes.h>
+#include <linux/bitmap.h>
+
+#include "kvm_util.h"
+#include "memstress.h"
+#include "processor.h"
+
+struct memstress_args memstress_args;
+
+/*
+ * Guest virtual memory offset of the testing memory slot.
+ * Must not conflict with identity mapped test code.
+ */
+static uint64_t guest_test_virt_mem = DEFAULT_GUEST_TEST_MEM;
+
+struct vcpu_thread {
+	/* The index of the vCPU. */
+	int vcpu_idx;
+
+	/* The pthread backing the vCPU. */
+	pthread_t thread;
+
+	/* Set to true once the vCPU thread is up and running. */
+	bool running;
+};
+
+/* The vCPU threads involved in this test. */
+static struct vcpu_thread vcpu_threads[KVM_MAX_VCPUS];
+
+/* The function run by each vCPU thread, as provided by the test. */
+static void (*vcpu_thread_fn)(struct memstress_vcpu_args *);
+
+/* Set to true once all vCPU threads are up and running. */
+static bool all_vcpu_threads_running;
+
+static struct kvm_vcpu *vcpus[KVM_MAX_VCPUS];
+
+/*
+ * Continuously write to the first 8 bytes of each page in the
+ * specified region.
+ */
+void memstress_guest_code(uint32_t vcpu_idx)
+{
+	struct memstress_args *args = &memstress_args;
+	struct memstress_vcpu_args *vcpu_args = &args->vcpu_args[vcpu_idx];
+	struct guest_random_state rand_state;
+	uint64_t gva;
+	uint64_t pages;
+	uint64_t addr;
+	uint64_t page;
+	int i;
+
+	rand_state = new_guest_random_state(args->random_seed + vcpu_idx);
+
+	gva = vcpu_args->gva;
+	pages = vcpu_args->pages;
+
+	/* Make sure vCPU args data structure is not corrupt. */
+	GUEST_ASSERT(vcpu_args->vcpu_idx == vcpu_idx);
+
+	while (true) {
+		for (i = 0; i < sizeof(memstress_args); i += args->guest_page_size)
+			(void) *((volatile char *)args + i);
+
+		for (i = 0; i < pages; i++) {
+			if (args->random_access)
+				page = guest_random_u32(&rand_state) % pages;
+			else
+				page = i;
+
+			addr = gva + (page * args->guest_page_size);
+
+			if (guest_random_u32(&rand_state) % 100 < args->write_percent)
+				*(uint64_t *)addr = 0x0123456789ABCDEF;
+			else
+				READ_ONCE(*(uint64_t *)addr);
+		}
+
+		GUEST_SYNC(1);
+	}
+}
+
+void memstress_setup_vcpus(struct kvm_vm *vm, int nr_vcpus,
+			   struct kvm_vcpu *vcpus[],
+			   uint64_t vcpu_memory_bytes,
+			   bool partition_vcpu_memory_access)
+{
+	struct memstress_args *args = &memstress_args;
+	struct memstress_vcpu_args *vcpu_args;
+	int i;
+
+	for (i = 0; i < nr_vcpus; i++) {
+		vcpu_args = &args->vcpu_args[i];
+
+		vcpu_args->vcpu = vcpus[i];
+		vcpu_args->vcpu_idx = i;
+
+		if (partition_vcpu_memory_access) {
+			vcpu_args->gva = guest_test_virt_mem +
+					 (i * vcpu_memory_bytes);
+			vcpu_args->pages = vcpu_memory_bytes /
+					   args->guest_page_size;
+			vcpu_args->gpa = args->gpa + (i * vcpu_memory_bytes);
+		} else {
+			vcpu_args->gva = guest_test_virt_mem;
+			vcpu_args->pages = (nr_vcpus * vcpu_memory_bytes) /
+					   args->guest_page_size;
+			vcpu_args->gpa = args->gpa;
+		}
+
+		vcpu_args_set(vcpus[i], 1, i);
+
+		pr_debug("Added VCPU %d with test mem gpa [%lx, %lx)\n",
+			 i, vcpu_args->gpa, vcpu_args->gpa +
+			 (vcpu_args->pages * args->guest_page_size));
+	}
+}
+
+struct kvm_vm *memstress_create_vm(enum vm_guest_mode mode, int nr_vcpus,
+				   uint64_t vcpu_memory_bytes, int slots,
+				   enum vm_mem_backing_src_type backing_src,
+				   bool partition_vcpu_memory_access)
+{
+	struct memstress_args *args = &memstress_args;
+	struct kvm_vm *vm;
+	uint64_t guest_num_pages, slot0_pages = 0;
+	uint64_t backing_src_pagesz = get_backing_src_pagesz(backing_src);
+	uint64_t region_end_gfn;
+	int i;
+
+	pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode));
+
+	/* By default vCPUs will write to memory. */
+	args->write_percent = 100;
+
+	/*
+	 * Snapshot the non-huge page size.  This is used by the guest code to
+	 * access/dirty pages at the logging granularity.
+	 */
+	args->guest_page_size = vm_guest_mode_params[mode].page_size;
+
+	guest_num_pages = vm_adjust_num_guest_pages(mode,
+				(nr_vcpus * vcpu_memory_bytes) / args->guest_page_size);
+
+	TEST_ASSERT(vcpu_memory_bytes % getpagesize() == 0,
+		    "Guest memory size is not host page size aligned.");
+	TEST_ASSERT(vcpu_memory_bytes % args->guest_page_size == 0,
+		    "Guest memory size is not guest page size aligned.");
+	TEST_ASSERT(guest_num_pages % slots == 0,
+		    "Guest memory cannot be evenly divided into %d slots.",
+		    slots);
+
+	/*
+	 * If using nested, allocate extra pages for the nested page tables and
+	 * in-memory data structures.
+	 */
+	if (args->nested)
+		slot0_pages += memstress_nested_pages(nr_vcpus);
+
+	/*
+	 * Pass guest_num_pages to populate the page tables for test memory.
+	 * The memory is also added to memslot 0, but that's a benign side
+	 * effect as KVM allows aliasing HVAs in meslots.
+	 */
+	vm = __vm_create_with_vcpus(VM_SHAPE(mode), nr_vcpus,
+				    slot0_pages + guest_num_pages,
+				    memstress_guest_code, vcpus);
+
+	args->vm = vm;
+
+	/* Put the test region at the top guest physical memory. */
+	region_end_gfn = vm->max_gfn + 1;
+
+#ifdef __x86_64__
+	/*
+	 * When running vCPUs in L2, restrict the test region to 48 bits to
+	 * avoid needing 5-level page tables to identity map L2.
+	 */
+	if (args->nested)
+		region_end_gfn = min(region_end_gfn, (1UL << 48) / args->guest_page_size);
+#endif
+	/*
+	 * If there should be more memory in the guest test region than there
+	 * can be pages in the guest, it will definitely cause problems.
+	 */
+	TEST_ASSERT(guest_num_pages < region_end_gfn,
+		    "Requested more guest memory than address space allows.\n"
+		    "    guest pages: %" PRIx64 " max gfn: %" PRIx64
+		    " nr_vcpus: %d wss: %" PRIx64 "]",
+		    guest_num_pages, region_end_gfn - 1, nr_vcpus, vcpu_memory_bytes);
+
+	args->gpa = (region_end_gfn - guest_num_pages - 1) * args->guest_page_size;
+	args->gpa = align_down(args->gpa, backing_src_pagesz);
+#ifdef __s390x__
+	/* Align to 1M (segment size) */
+	args->gpa = align_down(args->gpa, 1 << 20);
+#endif
+	args->size = guest_num_pages * args->guest_page_size;
+	pr_info("guest physical test memory: [0x%lx, 0x%lx)\n",
+		args->gpa, args->gpa + args->size);
+
+	/* Add extra memory slots for testing */
+	for (i = 0; i < slots; i++) {
+		uint64_t region_pages = guest_num_pages / slots;
+		vm_paddr_t region_start = args->gpa + region_pages * args->guest_page_size * i;
+
+		vm_userspace_mem_region_add(vm, backing_src, region_start,
+					    MEMSTRESS_MEM_SLOT_INDEX + i,
+					    region_pages, 0);
+	}
+
+	/* Do mapping for the demand paging memory slot */
+	virt_map(vm, guest_test_virt_mem, args->gpa, guest_num_pages);
+
+	memstress_setup_vcpus(vm, nr_vcpus, vcpus, vcpu_memory_bytes,
+			      partition_vcpu_memory_access);
+
+	if (args->nested) {
+		pr_info("Configuring vCPUs to run in L2 (nested).\n");
+		memstress_setup_nested(vm, nr_vcpus, vcpus);
+	}
+
+	/* Export the shared variables to the guest. */
+	sync_global_to_guest(vm, memstress_args);
+
+	return vm;
+}
+
+void memstress_destroy_vm(struct kvm_vm *vm)
+{
+	kvm_vm_free(vm);
+}
+
+void memstress_set_write_percent(struct kvm_vm *vm, uint32_t write_percent)
+{
+	memstress_args.write_percent = write_percent;
+	sync_global_to_guest(vm, memstress_args.write_percent);
+}
+
+void memstress_set_random_seed(struct kvm_vm *vm, uint32_t random_seed)
+{
+	memstress_args.random_seed = random_seed;
+	sync_global_to_guest(vm, memstress_args.random_seed);
+}
+
+void memstress_set_random_access(struct kvm_vm *vm, bool random_access)
+{
+	memstress_args.random_access = random_access;
+	sync_global_to_guest(vm, memstress_args.random_access);
+}
+
+uint64_t __weak memstress_nested_pages(int nr_vcpus)
+{
+	return 0;
+}
+
+void __weak memstress_setup_nested(struct kvm_vm *vm, int nr_vcpus, struct kvm_vcpu **vcpus)
+{
+	pr_info("%s() not support on this architecture, skipping.\n", __func__);
+	exit(KSFT_SKIP);
+}
+
+static void *vcpu_thread_main(void *data)
+{
+	struct vcpu_thread *vcpu = data;
+	int vcpu_idx = vcpu->vcpu_idx;
+
+	if (memstress_args.pin_vcpus)
+		kvm_pin_this_task_to_pcpu(memstress_args.vcpu_to_pcpu[vcpu_idx]);
+
+	WRITE_ONCE(vcpu->running, true);
+
+	/*
+	 * Wait for all vCPU threads to be up and running before calling the test-
+	 * provided vCPU thread function. This prevents thread creation (which
+	 * requires taking the mmap_sem in write mode) from interfering with the
+	 * guest faulting in its memory.
+	 */
+	while (!READ_ONCE(all_vcpu_threads_running))
+		;
+
+	vcpu_thread_fn(&memstress_args.vcpu_args[vcpu_idx]);
+
+	return NULL;
+}
+
+void memstress_start_vcpu_threads(int nr_vcpus,
+				  void (*vcpu_fn)(struct memstress_vcpu_args *))
+{
+	int i;
+
+	vcpu_thread_fn = vcpu_fn;
+	WRITE_ONCE(all_vcpu_threads_running, false);
+	WRITE_ONCE(memstress_args.stop_vcpus, false);
+
+	for (i = 0; i < nr_vcpus; i++) {
+		struct vcpu_thread *vcpu = &vcpu_threads[i];
+
+		vcpu->vcpu_idx = i;
+		WRITE_ONCE(vcpu->running, false);
+
+		pthread_create(&vcpu->thread, NULL, vcpu_thread_main, vcpu);
+	}
+
+	for (i = 0; i < nr_vcpus; i++) {
+		while (!READ_ONCE(vcpu_threads[i].running))
+			;
+	}
+
+	WRITE_ONCE(all_vcpu_threads_running, true);
+}
+
+void memstress_join_vcpu_threads(int nr_vcpus)
+{
+	int i;
+
+	WRITE_ONCE(memstress_args.stop_vcpus, true);
+
+	for (i = 0; i < nr_vcpus; i++)
+		pthread_join(vcpu_threads[i].thread, NULL);
+}
+
+static void toggle_dirty_logging(struct kvm_vm *vm, int slots, bool enable)
+{
+	int i;
+
+	for (i = 0; i < slots; i++) {
+		int slot = MEMSTRESS_MEM_SLOT_INDEX + i;
+		int flags = enable ? KVM_MEM_LOG_DIRTY_PAGES : 0;
+
+		vm_mem_region_set_flags(vm, slot, flags);
+	}
+}
+
+void memstress_enable_dirty_logging(struct kvm_vm *vm, int slots)
+{
+	toggle_dirty_logging(vm, slots, true);
+}
+
+void memstress_disable_dirty_logging(struct kvm_vm *vm, int slots)
+{
+	toggle_dirty_logging(vm, slots, false);
+}
+
+void memstress_get_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[], int slots)
+{
+	int i;
+
+	for (i = 0; i < slots; i++) {
+		int slot = MEMSTRESS_MEM_SLOT_INDEX + i;
+
+		kvm_vm_get_dirty_log(vm, slot, bitmaps[i]);
+	}
+}
+
+void memstress_clear_dirty_log(struct kvm_vm *vm, unsigned long *bitmaps[],
+			       int slots, uint64_t pages_per_slot)
+{
+	int i;
+
+	for (i = 0; i < slots; i++) {
+		int slot = MEMSTRESS_MEM_SLOT_INDEX + i;
+
+		kvm_vm_clear_dirty_log(vm, slot, bitmaps[i], 0, pages_per_slot);
+	}
+}
+
+unsigned long **memstress_alloc_bitmaps(int slots, uint64_t pages_per_slot)
+{
+	unsigned long **bitmaps;
+	int i;
+
+	bitmaps = malloc(slots * sizeof(bitmaps[0]));
+	TEST_ASSERT(bitmaps, "Failed to allocate bitmaps array.");
+
+	for (i = 0; i < slots; i++) {
+		bitmaps[i] = bitmap_zalloc(pages_per_slot);
+		TEST_ASSERT(bitmaps[i], "Failed to allocate slot bitmap.");
+	}
+
+	return bitmaps;
+}
+
+void memstress_free_bitmaps(unsigned long *bitmaps[], int slots)
+{
+	int i;
+
+	for (i = 0; i < slots; i++)
+		free(bitmaps[i]);
+
+	free(bitmaps);
+}