1 files changed, 661 insertions, 0 deletions

diff --git a/tools/testing/selftests/kvm/demand_paging_test.c b/tools/testing/selftests/kvm/demand_paging_test.c
new file mode 100644
index 000000000000..360cd3ea4cd6
--- /dev/null
+++ b/tools/testing/selftests/kvm/demand_paging_test.c
@@ -0,0 +1,661 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * KVM demand paging test
+ * Adapted from dirty_log_test.c
+ *
+ * Copyright (C) 2018, Red Hat, Inc.
+ * Copyright (C) 2019, Google, Inc.
+ */
+
+#define _GNU_SOURCE /* for program_invocation_name */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/syscall.h>
+#include <unistd.h>
+#include <asm/unistd.h>
+#include <time.h>
+#include <poll.h>
+#include <pthread.h>
+#include <linux/bitmap.h>
+#include <linux/bitops.h>
+#include <linux/userfaultfd.h>
+
+#include "test_util.h"
+#include "kvm_util.h"
+#include "processor.h"
+
+#ifdef __NR_userfaultfd
+
+/* The memory slot index demand page */
+#define TEST_MEM_SLOT_INDEX		1
+
+/* Default guest test virtual memory offset */
+#define DEFAULT_GUEST_TEST_MEM		0xc0000000
+
+#define DEFAULT_GUEST_TEST_MEM_SIZE (1 << 30) /* 1G */
+
+#ifdef PRINT_PER_PAGE_UPDATES
+#define PER_PAGE_DEBUG(...) printf(__VA_ARGS__)
+#else
+#define PER_PAGE_DEBUG(...) _no_printf(__VA_ARGS__)
+#endif
+
+#ifdef PRINT_PER_VCPU_UPDATES
+#define PER_VCPU_DEBUG(...) printf(__VA_ARGS__)
+#else
+#define PER_VCPU_DEBUG(...) _no_printf(__VA_ARGS__)
+#endif
+
+#define MAX_VCPUS 512
+
+/*
+ * Guest/Host shared variables. Ensure addr_gva2hva() and/or
+ * sync_global_to/from_guest() are used when accessing from
+ * the host. READ/WRITE_ONCE() should also be used with anything
+ * that may change.
+ */
+static uint64_t host_page_size;
+static uint64_t guest_page_size;
+
+static char *guest_data_prototype;
+
+/*
+ * Guest physical memory offset of the testing memory slot.
+ * This will be set to the topmost valid physical address minus
+ * the test memory size.
+ */
+static uint64_t guest_test_phys_mem;
+
+/*
+ * 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_args {
+	uint64_t gva;
+	uint64_t pages;
+
+	/* Only used by the host userspace part of the vCPU thread */
+	int vcpu_id;
+	struct kvm_vm *vm;
+};
+
+static struct vcpu_args vcpu_args[MAX_VCPUS];
+
+/*
+ * Continuously write to the first 8 bytes of each page in the demand paging
+ * memory region.
+ */
+static void guest_code(uint32_t vcpu_id)
+{
+	uint64_t gva;
+	uint64_t pages;
+	int i;
+
+	/* Make sure vCPU args data structure is not corrupt. */
+	GUEST_ASSERT(vcpu_args[vcpu_id].vcpu_id == vcpu_id);
+
+	gva = vcpu_args[vcpu_id].gva;
+	pages = vcpu_args[vcpu_id].pages;
+
+	for (i = 0; i < pages; i++) {
+		uint64_t addr = gva + (i * guest_page_size);
+
+		addr &= ~(host_page_size - 1);
+		*(uint64_t *)addr = 0x0123456789ABCDEF;
+	}
+
+	GUEST_SYNC(1);
+}
+
+static void *vcpu_worker(void *data)
+{
+	int ret;
+	struct vcpu_args *args = (struct vcpu_args *)data;
+	struct kvm_vm *vm = args->vm;
+	int vcpu_id = args->vcpu_id;
+	struct kvm_run *run;
+	struct timespec start, end, ts_diff;
+
+	vcpu_args_set(vm, vcpu_id, 1, vcpu_id);
+	run = vcpu_state(vm, vcpu_id);
+
+	clock_gettime(CLOCK_MONOTONIC, &start);
+
+	/* Let the guest access its memory */
+	ret = _vcpu_run(vm, vcpu_id);
+	TEST_ASSERT(ret == 0, "vcpu_run failed: %d\n", ret);
+	if (get_ucall(vm, vcpu_id, NULL) != UCALL_SYNC) {
+		TEST_ASSERT(false,
+			    "Invalid guest sync status: exit_reason=%s\n",
+			    exit_reason_str(run->exit_reason));
+	}
+
+	clock_gettime(CLOCK_MONOTONIC, &end);
+	ts_diff = timespec_sub(end, start);
+	PER_VCPU_DEBUG("vCPU %d execution time: %ld.%.9lds\n", vcpu_id,
+		       ts_diff.tv_sec, ts_diff.tv_nsec);
+
+	return NULL;
+}
+
+#define PAGE_SHIFT_4K  12
+#define PTES_PER_4K_PT 512
+
+static struct kvm_vm *create_vm(enum vm_guest_mode mode, int vcpus,
+				uint64_t vcpu_memory_bytes)
+{
+	struct kvm_vm *vm;
+	uint64_t pages = DEFAULT_GUEST_PHY_PAGES;
+
+	/* Account for a few pages per-vCPU for stacks */
+	pages += DEFAULT_STACK_PGS * vcpus;
+
+	/*
+	 * Reserve twice the ammount of memory needed to map the test region and
+	 * the page table / stacks region, at 4k, for page tables. Do the
+	 * calculation with 4K page size: the smallest of all archs. (e.g., 64K
+	 * page size guest will need even less memory for page tables).
+	 */
+	pages += (2 * pages) / PTES_PER_4K_PT;
+	pages += ((2 * vcpus * vcpu_memory_bytes) >> PAGE_SHIFT_4K) /
+		 PTES_PER_4K_PT;
+	pages = vm_adjust_num_guest_pages(mode, pages);
+
+	pr_info("Testing guest mode: %s\n", vm_guest_mode_string(mode));
+
+	vm = _vm_create(mode, pages, O_RDWR);
+	kvm_vm_elf_load(vm, program_invocation_name, 0, 0);
+#ifdef __x86_64__
+	vm_create_irqchip(vm);
+#endif
+	return vm;
+}
+
+static int handle_uffd_page_request(int uffd, uint64_t addr)
+{
+	pid_t tid;
+	struct timespec start;
+	struct timespec end;
+	struct uffdio_copy copy;
+	int r;
+
+	tid = syscall(__NR_gettid);
+
+	copy.src = (uint64_t)guest_data_prototype;
+	copy.dst = addr;
+	copy.len = host_page_size;
+	copy.mode = 0;
+
+	clock_gettime(CLOCK_MONOTONIC, &start);
+
+	r = ioctl(uffd, UFFDIO_COPY, &copy);
+	if (r == -1) {
+		pr_info("Failed Paged in 0x%lx from thread %d with errno: %d\n",
+			addr, tid, errno);
+		return r;
+	}
+
+	clock_gettime(CLOCK_MONOTONIC, &end);
+
+	PER_PAGE_DEBUG("UFFDIO_COPY %d \t%ld ns\n", tid,
+		       timespec_to_ns(timespec_sub(end, start)));
+	PER_PAGE_DEBUG("Paged in %ld bytes at 0x%lx from thread %d\n",
+		       host_page_size, addr, tid);
+
+	return 0;
+}
+
+bool quit_uffd_thread;
+
+struct uffd_handler_args {
+	int uffd;
+	int pipefd;
+	useconds_t delay;
+};
+
+static void *uffd_handler_thread_fn(void *arg)
+{
+	struct uffd_handler_args *uffd_args = (struct uffd_handler_args *)arg;
+	int uffd = uffd_args->uffd;
+	int pipefd = uffd_args->pipefd;
+	useconds_t delay = uffd_args->delay;
+	int64_t pages = 0;
+	struct timespec start, end, ts_diff;
+
+	clock_gettime(CLOCK_MONOTONIC, &start);
+	while (!quit_uffd_thread) {
+		struct uffd_msg msg;
+		struct pollfd pollfd[2];
+		char tmp_chr;
+		int r;
+		uint64_t addr;
+
+		pollfd[0].fd = uffd;
+		pollfd[0].events = POLLIN;
+		pollfd[1].fd = pipefd;
+		pollfd[1].events = POLLIN;
+
+		r = poll(pollfd, 2, -1);
+		switch (r) {
+		case -1:
+			pr_info("poll err");
+			continue;
+		case 0:
+			continue;
+		case 1:
+			break;
+		default:
+			pr_info("Polling uffd returned %d", r);
+			return NULL;
+		}
+
+		if (pollfd[0].revents & POLLERR) {
+			pr_info("uffd revents has POLLERR");
+			return NULL;
+		}
+
+		if (pollfd[1].revents & POLLIN) {
+			r = read(pollfd[1].fd, &tmp_chr, 1);
+			TEST_ASSERT(r == 1,
+				    "Error reading pipefd in UFFD thread\n");
+			return NULL;
+		}
+
+		if (!pollfd[0].revents & POLLIN)
+			continue;
+
+		r = read(uffd, &msg, sizeof(msg));
+		if (r == -1) {
+			if (errno == EAGAIN)
+				continue;
+			pr_info("Read of uffd gor errno %d", errno);
+			return NULL;
+		}
+
+		if (r != sizeof(msg)) {
+			pr_info("Read on uffd returned unexpected size: %d bytes", r);
+			return NULL;
+		}
+
+		if (!(msg.event & UFFD_EVENT_PAGEFAULT))
+			continue;
+
+		if (delay)
+			usleep(delay);
+		addr =  msg.arg.pagefault.address;
+		r = handle_uffd_page_request(uffd, addr);
+		if (r < 0)
+			return NULL;
+		pages++;
+	}
+
+	clock_gettime(CLOCK_MONOTONIC, &end);
+	ts_diff = timespec_sub(end, start);
+	PER_VCPU_DEBUG("userfaulted %ld pages over %ld.%.9lds. (%f/sec)\n",
+		       pages, ts_diff.tv_sec, ts_diff.tv_nsec,
+		       pages / ((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / 100000000.0));
+
+	return NULL;
+}
+
+static int setup_demand_paging(struct kvm_vm *vm,
+			       pthread_t *uffd_handler_thread, int pipefd,
+			       useconds_t uffd_delay,
+			       struct uffd_handler_args *uffd_args,
+			       void *hva, uint64_t len)
+{
+	int uffd;
+	struct uffdio_api uffdio_api;
+	struct uffdio_register uffdio_register;
+
+	uffd = syscall(__NR_userfaultfd, O_CLOEXEC | O_NONBLOCK);
+	if (uffd == -1) {
+		pr_info("uffd creation failed\n");
+		return -1;
+	}
+
+	uffdio_api.api = UFFD_API;
+	uffdio_api.features = 0;
+	if (ioctl(uffd, UFFDIO_API, &uffdio_api) == -1) {
+		pr_info("ioctl uffdio_api failed\n");
+		return -1;
+	}
+
+	uffdio_register.range.start = (uint64_t)hva;
+	uffdio_register.range.len = len;
+	uffdio_register.mode = UFFDIO_REGISTER_MODE_MISSING;
+	if (ioctl(uffd, UFFDIO_REGISTER, &uffdio_register) == -1) {
+		pr_info("ioctl uffdio_register failed\n");
+		return -1;
+	}
+
+	if ((uffdio_register.ioctls & UFFD_API_RANGE_IOCTLS) !=
+			UFFD_API_RANGE_IOCTLS) {
+		pr_info("unexpected userfaultfd ioctl set\n");
+		return -1;
+	}
+
+	uffd_args->uffd = uffd;
+	uffd_args->pipefd = pipefd;
+	uffd_args->delay = uffd_delay;
+	pthread_create(uffd_handler_thread, NULL, uffd_handler_thread_fn,
+		       uffd_args);
+
+	PER_VCPU_DEBUG("Created uffd thread for HVA range [%p, %p)\n",
+		       hva, hva + len);
+
+	return 0;
+}
+
+static void run_test(enum vm_guest_mode mode, bool use_uffd,
+		     useconds_t uffd_delay, int vcpus,
+		     uint64_t vcpu_memory_bytes)
+{
+	pthread_t *vcpu_threads;
+	pthread_t *uffd_handler_threads = NULL;
+	struct uffd_handler_args *uffd_args = NULL;
+	struct timespec start, end, ts_diff;
+	int *pipefds = NULL;
+	struct kvm_vm *vm;
+	uint64_t guest_num_pages;
+	int vcpu_id;
+	int r;
+
+	vm = create_vm(mode, vcpus, vcpu_memory_bytes);
+
+	guest_page_size = vm_get_page_size(vm);
+
+	TEST_ASSERT(vcpu_memory_bytes % guest_page_size == 0,
+		    "Guest memory size is not guest page size aligned.");
+
+	guest_num_pages = (vcpus * vcpu_memory_bytes) / guest_page_size;
+	guest_num_pages = vm_adjust_num_guest_pages(mode, guest_num_pages);
+
+	/*
+	 * 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 < vm_get_max_gfn(vm),
+		    "Requested more guest memory than address space allows.\n"
+		    "    guest pages: %lx max gfn: %x vcpus: %d wss: %lx]\n",
+		    guest_num_pages, vm_get_max_gfn(vm), vcpus,
+		    vcpu_memory_bytes);
+
+	host_page_size = getpagesize();
+	TEST_ASSERT(vcpu_memory_bytes % host_page_size == 0,
+		    "Guest memory size is not host page size aligned.");
+
+	guest_test_phys_mem = (vm_get_max_gfn(vm) - guest_num_pages) *
+			      guest_page_size;
+	guest_test_phys_mem &= ~(host_page_size - 1);
+
+#ifdef __s390x__
+	/* Align to 1M (segment size) */
+	guest_test_phys_mem &= ~((1 << 20) - 1);
+#endif
+
+	pr_info("guest physical test memory offset: 0x%lx\n", guest_test_phys_mem);
+
+	/* Add an extra memory slot for testing demand paging */
+	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
+				    guest_test_phys_mem,
+				    TEST_MEM_SLOT_INDEX,
+				    guest_num_pages, 0);
+
+	/* Do mapping for the demand paging memory slot */
+	virt_map(vm, guest_test_virt_mem, guest_test_phys_mem, guest_num_pages, 0);
+
+	ucall_init(vm, NULL);
+
+	guest_data_prototype = malloc(host_page_size);
+	TEST_ASSERT(guest_data_prototype,
+		    "Failed to allocate buffer for guest data pattern");
+	memset(guest_data_prototype, 0xAB, host_page_size);
+
+	vcpu_threads = malloc(vcpus * sizeof(*vcpu_threads));
+	TEST_ASSERT(vcpu_threads, "Memory allocation failed");
+
+	if (use_uffd) {
+		uffd_handler_threads =
+			malloc(vcpus * sizeof(*uffd_handler_threads));
+		TEST_ASSERT(uffd_handler_threads, "Memory allocation failed");
+
+		uffd_args = malloc(vcpus * sizeof(*uffd_args));
+		TEST_ASSERT(uffd_args, "Memory allocation failed");
+
+		pipefds = malloc(sizeof(int) * vcpus * 2);
+		TEST_ASSERT(pipefds, "Unable to allocate memory for pipefd");
+	}
+
+	for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
+		vm_paddr_t vcpu_gpa;
+		void *vcpu_hva;
+
+		vm_vcpu_add_default(vm, vcpu_id, guest_code);
+
+		vcpu_gpa = guest_test_phys_mem + (vcpu_id * vcpu_memory_bytes);
+		PER_VCPU_DEBUG("Added VCPU %d with test mem gpa [%lx, %lx)\n",
+			       vcpu_id, vcpu_gpa, vcpu_gpa + vcpu_memory_bytes);
+
+		/* Cache the HVA pointer of the region */
+		vcpu_hva = addr_gpa2hva(vm, vcpu_gpa);
+
+		if (use_uffd) {
+			/*
+			 * Set up user fault fd to handle demand paging
+			 * requests.
+			 */
+			r = pipe2(&pipefds[vcpu_id * 2],
+				  O_CLOEXEC | O_NONBLOCK);
+			TEST_ASSERT(!r, "Failed to set up pipefd");
+
+			r = setup_demand_paging(vm,
+						&uffd_handler_threads[vcpu_id],
+						pipefds[vcpu_id * 2],
+						uffd_delay, &uffd_args[vcpu_id],
+						vcpu_hva, vcpu_memory_bytes);
+			if (r < 0)
+				exit(-r);
+		}
+
+#ifdef __x86_64__
+		vcpu_set_cpuid(vm, vcpu_id, kvm_get_supported_cpuid());
+#endif
+
+		vcpu_args[vcpu_id].vm = vm;
+		vcpu_args[vcpu_id].vcpu_id = vcpu_id;
+		vcpu_args[vcpu_id].gva = guest_test_virt_mem +
+					 (vcpu_id * vcpu_memory_bytes);
+		vcpu_args[vcpu_id].pages = vcpu_memory_bytes / guest_page_size;
+	}
+
+	/* Export the shared variables to the guest */
+	sync_global_to_guest(vm, host_page_size);
+	sync_global_to_guest(vm, guest_page_size);
+	sync_global_to_guest(vm, vcpu_args);
+
+	pr_info("Finished creating vCPUs and starting uffd threads\n");
+
+	clock_gettime(CLOCK_MONOTONIC, &start);
+
+	for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
+		pthread_create(&vcpu_threads[vcpu_id], NULL, vcpu_worker,
+			       &vcpu_args[vcpu_id]);
+	}
+
+	pr_info("Started all vCPUs\n");
+
+	/* Wait for the vcpu threads to quit */
+	for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
+		pthread_join(vcpu_threads[vcpu_id], NULL);
+		PER_VCPU_DEBUG("Joined thread for vCPU %d\n", vcpu_id);
+	}
+
+	pr_info("All vCPU threads joined\n");
+
+	clock_gettime(CLOCK_MONOTONIC, &end);
+
+	if (use_uffd) {
+		char c;
+
+		/* Tell the user fault fd handler threads to quit */
+		for (vcpu_id = 0; vcpu_id < vcpus; vcpu_id++) {
+			r = write(pipefds[vcpu_id * 2 + 1], &c, 1);
+			TEST_ASSERT(r == 1, "Unable to write to pipefd");
+
+			pthread_join(uffd_handler_threads[vcpu_id], NULL);
+		}
+	}
+
+	ts_diff = timespec_sub(end, start);
+	pr_info("Total guest execution time: %ld.%.9lds\n",
+		ts_diff.tv_sec, ts_diff.tv_nsec);
+	pr_info("Overall demand paging rate: %f pgs/sec\n",
+		guest_num_pages / ((double)ts_diff.tv_sec + (double)ts_diff.tv_nsec / 100000000.0));
+
+	ucall_uninit(vm);
+	kvm_vm_free(vm);
+
+	free(guest_data_prototype);
+	free(vcpu_threads);
+	if (use_uffd) {
+		free(uffd_handler_threads);
+		free(uffd_args);
+		free(pipefds);
+	}
+}
+
+struct guest_mode {
+	bool supported;
+	bool enabled;
+};
+static struct guest_mode guest_modes[NUM_VM_MODES];
+
+#define guest_mode_init(mode, supported, enabled) ({ \
+	guest_modes[mode] = (struct guest_mode){ supported, enabled }; \
+})
+
+static void help(char *name)
+{
+	int i;
+
+	puts("");
+	printf("usage: %s [-h] [-m mode] [-u] [-d uffd_delay_usec]\n"
+	       "          [-b memory] [-v vcpus]\n", name);
+	printf(" -m: specify the guest mode ID to test\n"
+	       "     (default: test all supported modes)\n"
+	       "     This option may be used multiple times.\n"
+	       "     Guest mode IDs:\n");
+	for (i = 0; i < NUM_VM_MODES; ++i) {
+		printf("         %d:    %s%s\n", i, vm_guest_mode_string(i),
+		       guest_modes[i].supported ? " (supported)" : "");
+	}
+	printf(" -u: use User Fault FD to handle vCPU page\n"
+	       "     faults.\n");
+	printf(" -d: add a delay in usec to the User Fault\n"
+	       "     FD handler to simulate demand paging\n"
+	       "     overheads. Ignored without -u.\n");
+	printf(" -b: specify the size of the memory region which should be\n"
+	       "     demand paged by each vCPU. e.g. 10M or 3G.\n"
+	       "     Default: 1G\n");
+	printf(" -v: specify the number of vCPUs to run.\n");
+	puts("");
+	exit(0);
+}
+
+int main(int argc, char *argv[])
+{
+	bool mode_selected = false;
+	uint64_t vcpu_memory_bytes = DEFAULT_GUEST_TEST_MEM_SIZE;
+	int vcpus = 1;
+	unsigned int mode;
+	int opt, i;
+	bool use_uffd = false;
+	useconds_t uffd_delay = 0;
+
+#ifdef __x86_64__
+	guest_mode_init(VM_MODE_PXXV48_4K, true, true);
+#endif
+#ifdef __aarch64__
+	guest_mode_init(VM_MODE_P40V48_4K, true, true);
+	guest_mode_init(VM_MODE_P40V48_64K, true, true);
+	{
+		unsigned int limit = kvm_check_cap(KVM_CAP_ARM_VM_IPA_SIZE);
+
+		if (limit >= 52)
+			guest_mode_init(VM_MODE_P52V48_64K, true, true);
+		if (limit >= 48) {
+			guest_mode_init(VM_MODE_P48V48_4K, true, true);
+			guest_mode_init(VM_MODE_P48V48_64K, true, true);
+		}
+	}
+#endif
+#ifdef __s390x__
+	guest_mode_init(VM_MODE_P40V48_4K, true, true);
+#endif
+
+	while ((opt = getopt(argc, argv, "hm:ud:b:v:")) != -1) {
+		switch (opt) {
+		case 'm':
+			if (!mode_selected) {
+				for (i = 0; i < NUM_VM_MODES; ++i)
+					guest_modes[i].enabled = false;
+				mode_selected = true;
+			}
+			mode = strtoul(optarg, NULL, 10);
+			TEST_ASSERT(mode < NUM_VM_MODES,
+				    "Guest mode ID %d too big", mode);
+			guest_modes[mode].enabled = true;
+			break;
+		case 'u':
+			use_uffd = true;
+			break;
+		case 'd':
+			uffd_delay = strtoul(optarg, NULL, 0);
+			TEST_ASSERT(uffd_delay >= 0,
+				    "A negative UFFD delay is not supported.");
+			break;
+		case 'b':
+			vcpu_memory_bytes = parse_size(optarg);
+			break;
+		case 'v':
+			vcpus = atoi(optarg);
+			TEST_ASSERT(vcpus > 0,
+				    "Must have a positive number of vCPUs");
+			TEST_ASSERT(vcpus <= MAX_VCPUS,
+				    "This test does not currently support\n"
+				    "more than %d vCPUs.", MAX_VCPUS);
+			break;
+		case 'h':
+		default:
+			help(argv[0]);
+			break;
+		}
+	}
+
+	for (i = 0; i < NUM_VM_MODES; ++i) {
+		if (!guest_modes[i].enabled)
+			continue;
+		TEST_ASSERT(guest_modes[i].supported,
+			    "Guest mode ID %d (%s) not supported.",
+			    i, vm_guest_mode_string(i));
+		run_test(i, use_uffd, uffd_delay, vcpus, vcpu_memory_bytes);
+	}
+
+	return 0;
+}
+
+#else /* __NR_userfaultfd */
+
+#warning "missing __NR_userfaultfd definition"
+
+int main(void)
+{
+	print_skip("__NR_userfaultfd must be present for userfaultfd test");
+	return KSFT_SKIP;
+}
+
+#endif /* __NR_userfaultfd */