memslot_modification_stress_test.c

  1// SPDX-License-Identifier: GPL-2.0
  2/*
  3 * KVM memslot modification stress test
  4 * Adapted from demand_paging_test.c
  5 *
  6 * Copyright (C) 2018, Red Hat, Inc.
  7 * Copyright (C) 2020, Google, Inc.
  8 */
  9#include <stdio.h>
 10#include <stdlib.h>
 11#include <sys/syscall.h>
 12#include <unistd.h>
 13#include <asm/unistd.h>
 14#include <time.h>
 15#include <poll.h>
 16#include <pthread.h>
 17#include <linux/bitmap.h>
 18#include <linux/bitops.h>
 19#include <linux/userfaultfd.h>
 20
 21#include "memstress.h"
 22#include "processor.h"
 23#include "test_util.h"
 24#include "guest_modes.h"
 25#include "ucall_common.h"
 26
 27#define DUMMY_MEMSLOT_INDEX 7
 28
 29#define DEFAULT_MEMSLOT_MODIFICATION_ITERATIONS 10
 30
 31
 32static int nr_vcpus = 1;
 33static uint64_t guest_percpu_mem_size = DEFAULT_PER_VCPU_MEM_SIZE;
 34
 35static void vcpu_worker(struct memstress_vcpu_args *vcpu_args)
 36{
 37	struct kvm_vcpu *vcpu = vcpu_args->vcpu;
 38	struct kvm_run *run;
 39	int ret;
 40
 41	run = vcpu->run;
 42
 43	/* Let the guest access its memory until a stop signal is received */
 44	while (!READ_ONCE(memstress_args.stop_vcpus)) {
 45		ret = _vcpu_run(vcpu);
 46		TEST_ASSERT(ret == 0, "vcpu_run failed: %d", ret);
 47
 48		if (get_ucall(vcpu, NULL) == UCALL_SYNC)
 49			continue;
 50
 51		TEST_ASSERT(false,
 52			    "Invalid guest sync status: exit_reason=%s\n",
 53			    exit_reason_str(run->exit_reason));
 54	}
 55}
 56
 57static void add_remove_memslot(struct kvm_vm *vm, useconds_t delay,
 58			       uint64_t nr_modifications)
 59{
 60	uint64_t pages = max_t(int, vm->page_size, getpagesize()) / vm->page_size;
 61	uint64_t gpa;
 62	int i;
 63
 64	/*
 65	 * Add the dummy memslot just below the memstress memslot, which is
 66	 * at the top of the guest physical address space.
 67	 */
 68	gpa = memstress_args.gpa - pages * vm->page_size;
 69
 70	for (i = 0; i < nr_modifications; i++) {
 71		usleep(delay);
 72		vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS, gpa,
 73					    DUMMY_MEMSLOT_INDEX, pages, 0);
 74
 75		vm_mem_region_delete(vm, DUMMY_MEMSLOT_INDEX);
 76	}
 77}
 78
 79struct test_params {
 80	useconds_t delay;
 81	uint64_t nr_iterations;
 82	bool partition_vcpu_memory_access;
 83	bool disable_slot_zap_quirk;
 84};
 85
 86static void run_test(enum vm_guest_mode mode, void *arg)
 87{
 88	struct test_params *p = arg;
 89	struct kvm_vm *vm;
 90
 91	vm = memstress_create_vm(mode, nr_vcpus, guest_percpu_mem_size, 1,
 92				 VM_MEM_SRC_ANONYMOUS,
 93				 p->partition_vcpu_memory_access);
 94#ifdef __x86_64__
 95	if (p->disable_slot_zap_quirk)
 96		vm_enable_cap(vm, KVM_CAP_DISABLE_QUIRKS2, KVM_X86_QUIRK_SLOT_ZAP_ALL);
 97
 98	pr_info("Memslot zap quirk %s\n", p->disable_slot_zap_quirk ?
 99		"disabled" : "enabled");
100#endif
101
102	pr_info("Finished creating vCPUs\n");
103
104	memstress_start_vcpu_threads(nr_vcpus, vcpu_worker);
105
106	pr_info("Started all vCPUs\n");
107
108	add_remove_memslot(vm, p->delay, p->nr_iterations);
109
110	memstress_join_vcpu_threads(nr_vcpus);
111	pr_info("All vCPU threads joined\n");
112
113	memstress_destroy_vm(vm);
114}
115
116static void help(char *name)
117{
118	puts("");
119	printf("usage: %s [-h] [-m mode] [-d delay_usec] [-q]\n"
120	       "          [-b memory] [-v vcpus] [-o] [-i iterations]\n", name);
121	guest_modes_help();
122	printf(" -d: add a delay between each iteration of adding and\n"
123	       "     deleting a memslot in usec.\n");
124	printf(" -q: Disable memslot zap quirk.\n");
125	printf(" -b: specify the size of the memory region which should be\n"
126	       "     accessed by each vCPU. e.g. 10M or 3G.\n"
127	       "     Default: 1G\n");
128	printf(" -v: specify the number of vCPUs to run.\n");
129	printf(" -o: Overlap guest memory accesses instead of partitioning\n"
130	       "     them into a separate region of memory for each vCPU.\n");
131	printf(" -i: specify the number of iterations of adding and removing\n"
132	       "     a memslot.\n"
133	       "     Default: %d\n", DEFAULT_MEMSLOT_MODIFICATION_ITERATIONS);
134	puts("");
135	exit(0);
136}
137
138int main(int argc, char *argv[])
139{
140	int max_vcpus = kvm_check_cap(KVM_CAP_MAX_VCPUS);
141	int opt;
142	struct test_params p = {
143		.delay = 0,
144		.nr_iterations = DEFAULT_MEMSLOT_MODIFICATION_ITERATIONS,
145		.partition_vcpu_memory_access = true
146	};
147
148	guest_modes_append_default();
149
150	while ((opt = getopt(argc, argv, "hm:d:qb:v:oi:")) != -1) {
151		switch (opt) {
152		case 'm':
153			guest_modes_cmdline(optarg);
154			break;
155		case 'd':
156			p.delay = atoi_non_negative("Delay", optarg);
157			break;
158		case 'b':
159			guest_percpu_mem_size = parse_size(optarg);
160			break;
161		case 'v':
162			nr_vcpus = atoi_positive("Number of vCPUs", optarg);
163			TEST_ASSERT(nr_vcpus <= max_vcpus,
164				    "Invalid number of vcpus, must be between 1 and %d",
165				    max_vcpus);
166			break;
167		case 'o':
168			p.partition_vcpu_memory_access = false;
169			break;
170		case 'i':
171			p.nr_iterations = atoi_positive("Number of iterations", optarg);
172			break;
173#ifdef __x86_64__
174		case 'q':
175			p.disable_slot_zap_quirk = true;
176
177			TEST_REQUIRE(kvm_check_cap(KVM_CAP_DISABLE_QUIRKS2) &
178				     KVM_X86_QUIRK_SLOT_ZAP_ALL);
179			break;
180#endif
181		case 'h':
182		default:
183			help(argv[0]);
184			break;
185		}
186	}
187
188	for_each_guest_mode(run_test, &p);
189
190	return 0;
191}