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Message-Id: <20210213001452.1719001-1-marcorr@google.com>
Date: Sat, 13 Feb 2021 00:14:52 +0000
From: Marc Orr <marcorr@...gle.com>
To: ikalvarado@...gle.com, pbonzini@...hat.com, huah@...nel.org,
linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
linux-kselftest@...r.kernel.org, brijesh.singh@....com,
Thomas.Lendacky@....com, jmattson@...gle.com
Cc: Marc Orr <marcorr@...gle.com>
Subject: [PATCH] selftests: kvm: add hardware_disable test
From: Ignacio Alvarado <ikalvarado@...gle.com>
This test launches 512 VMs in serial and kills them after a random
amount of time.
The test was original written to exercise KVM user notifiers in
the context of1650b4ebc99d:
- KVM: Disable irq while unregistering user notifier
- https://lore.kernel.org/kvm/CACXrx53vkO=HKfwWwk+fVpvxcNjPrYmtDZ10qWxFvVX_PTGp3g@mail.gmail.com/
Recently, this test piqued my interest because it proved useful to
for AMD SNP in exercising the "in-use" pages, described in APM section
15.36.12, "Running SNP-Active Virtual Machines".
To run the test, first compile:
$ make "CPPFLAGS=-static -Wl,--whole-archive -lpthread -Wl,--no-whole-archive" \
-C tools/testing/selftests/kvm/
Then, copy the test over to a machine with the kernel and run:
$ ./hardware_disable_test
Signed-off-by: Ignacio Alvarado <ikalvarado@...gle.com>
Signed-off-by: Marc Orr <marcorr@...gle.com>
---
tools/testing/selftests/kvm/.gitignore | 1 +
tools/testing/selftests/kvm/Makefile | 1 +
.../selftests/kvm/hardware_disable_test.c | 165 ++++++++++++++++++
3 files changed, 167 insertions(+)
create mode 100644 tools/testing/selftests/kvm/hardware_disable_test.c
diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index ce8f4ad39684..d631e111441a 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -28,6 +28,7 @@
/demand_paging_test
/dirty_log_test
/dirty_log_perf_test
+/hardware_disable_test
/kvm_create_max_vcpus
/set_memory_region_test
/steal_time
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index fe41c6a0fa67..c1c403d878f6 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -62,6 +62,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/tsc_msrs_test
TEST_GEN_PROGS_x86_64 += demand_paging_test
TEST_GEN_PROGS_x86_64 += dirty_log_test
TEST_GEN_PROGS_x86_64 += dirty_log_perf_test
+TEST_GEN_PROGS_x86_64 += hardware_disable_test
TEST_GEN_PROGS_x86_64 += kvm_create_max_vcpus
TEST_GEN_PROGS_x86_64 += set_memory_region_test
TEST_GEN_PROGS_x86_64 += steal_time
diff --git a/tools/testing/selftests/kvm/hardware_disable_test.c b/tools/testing/selftests/kvm/hardware_disable_test.c
new file mode 100644
index 000000000000..2f2eeb8a1d86
--- /dev/null
+++ b/tools/testing/selftests/kvm/hardware_disable_test.c
@@ -0,0 +1,165 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * This test is intended to reproduce a crash that happens when
+ * kvm_arch_hardware_disable is called and it attempts to unregister the user
+ * return notifiers.
+ */
+
+#define _GNU_SOURCE
+
+#include <fcntl.h>
+#include <pthread.h>
+#include <semaphore.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <sys/wait.h>
+
+#include <test_util.h>
+
+#include "kvm_util.h"
+
+#define VCPU_NUM 4
+#define SLEEPING_THREAD_NUM (1 << 4)
+#define FORK_NUM (1ULL << 9)
+#define DELAY_US_MAX 2000
+#define GUEST_CODE_PIO_PORT 4
+
+sem_t *sem;
+
+/* Arguments for the pthreads */
+struct payload {
+ struct kvm_vm *vm;
+ uint32_t index;
+};
+
+static void guest_code(void)
+{
+ for (;;)
+ ; /* Some busy work */
+ printf("Should not be reached.\n");
+}
+
+static void *run_vcpu(void *arg)
+{
+ struct payload *payload = (struct payload *)arg;
+ struct kvm_run *state = vcpu_state(payload->vm, payload->index);
+
+ vcpu_run(payload->vm, payload->index);
+
+ TEST_ASSERT(false, "%s: exited with reason %d: %s\n",
+ __func__, state->exit_reason,
+ exit_reason_str(state->exit_reason));
+ pthread_exit(NULL);
+}
+
+static void *sleeping_thread(void *arg)
+{
+ int fd;
+
+ while (true) {
+ fd = open("/dev/null", O_RDWR);
+ close(fd);
+ }
+ TEST_ASSERT(false, "%s: exited\n", __func__);
+ pthread_exit(NULL);
+}
+
+static inline void check_create_thread(pthread_t *thread, pthread_attr_t *attr,
+ void *(*f)(void *), void *arg)
+{
+ int r;
+
+ r = pthread_create(thread, attr, f, arg);
+ TEST_ASSERT(r == 0, "%s: failed to create thread", __func__);
+}
+
+static inline void check_set_affinity(pthread_t thread, cpu_set_t *cpu_set)
+{
+ int r;
+
+ r = pthread_setaffinity_np(thread, sizeof(cpu_set_t), cpu_set);
+ TEST_ASSERT(r == 0, "%s: failed set affinity", __func__);
+}
+
+static inline void check_join(pthread_t thread, void **retval)
+{
+ int r;
+
+ r = pthread_join(thread, retval);
+ TEST_ASSERT(r == 0, "%s: failed to join thread", __func__);
+}
+
+static void run_test(uint32_t run)
+{
+ struct kvm_vm *vm;
+ cpu_set_t cpu_set;
+ pthread_t threads[VCPU_NUM];
+ pthread_t throw_away;
+ struct payload payloads[VCPU_NUM];
+ void *b;
+ uint32_t i, j;
+
+ CPU_ZERO(&cpu_set);
+ for (i = 0; i < VCPU_NUM; i++)
+ CPU_SET(i, &cpu_set);
+
+ vm = vm_create(VM_MODE_DEFAULT, DEFAULT_GUEST_PHY_PAGES, O_RDWR);
+ kvm_vm_elf_load(vm, program_invocation_name, 0, 0);
+ vm_create_irqchip(vm);
+
+ fprintf(stderr, "%s: [%d] start vcpus\n", __func__, run);
+ for (i = 0; i < VCPU_NUM; ++i) {
+ vm_vcpu_add_default(vm, i, guest_code);
+ payloads[i].vm = vm;
+ payloads[i].index = i;
+
+ check_create_thread(&threads[i], NULL, run_vcpu,
+ (void *)&payloads[i]);
+ check_set_affinity(threads[i], &cpu_set);
+
+ for (j = 0; j < SLEEPING_THREAD_NUM; ++j) {
+ check_create_thread(&throw_away, NULL, sleeping_thread,
+ (void *)NULL);
+ check_set_affinity(throw_away, &cpu_set);
+ }
+ }
+ fprintf(stderr, "%s: [%d] all threads launched\n", __func__, run);
+ sem_post(sem);
+ for (i = 0; i < VCPU_NUM; ++i)
+ check_join(threads[i], &b);
+ /* Should not be reached */
+ TEST_ASSERT(false, "%s: [%d] child escaped the ninja\n", __func__, run);
+}
+
+int main(int argc, char **argv)
+{
+ uint32_t i;
+ int s, r;
+ pid_t pid;
+
+ sem = sem_open("vm_sem", O_CREAT | O_EXCL, 0644, 0);
+ sem_unlink("vm_sem");
+
+ for (i = 0; i < FORK_NUM; ++i) {
+ pid = fork();
+ TEST_ASSERT(pid >= 0, "%s: unable to fork", __func__);
+ if (pid == 0)
+ run_test(i); /* This function always exits */
+
+ fprintf(stderr, "%s: [%d] waiting semaphore\n", __func__, i);
+ sem_wait(sem);
+ r = (rand() % DELAY_US_MAX) + 1;
+ fprintf(stderr, "%s: [%d] waiting %dus\n", __func__, i, r);
+ usleep(r);
+ r = waitpid(pid, &s, WNOHANG);
+ TEST_ASSERT(r != pid,
+ "%s: [%d] child exited unexpectedly status: [%d]",
+ __func__, i, s);
+ fprintf(stderr, "%s: [%d] killing child\n", __func__, i);
+ kill(pid, SIGKILL);
+ }
+
+ sem_destroy(sem);
+ exit(0);
+}
--
2.30.0.478.g8a0d178c01-goog
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