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author | Aaron Lewis <aaronlewis () google ! com> | 2019-05-31 14:14:52 +0000 |
---|---|---|
committer | Paolo Bonzini <pbonzini@redhat.com> | 2019-06-19 16:11:54 +0200 |
commit | 9dba988edb31d013003b7f00e82dd56f01db70c3 (patch) | |
tree | cfcd97662a21ec345c913adabdc4dd4b4d2e86af /tools/testing/selftests/kvm/x86_64/mmio_warning_test.c | |
parent | kvm: tests: Sort tests in the Makefile alphabetically (diff) | |
download | linux-dev-9dba988edb31d013003b7f00e82dd56f01db70c3.tar.xz linux-dev-9dba988edb31d013003b7f00e82dd56f01db70c3.zip |
tests: kvm: Check for a kernel warning
When running with /sys/module/kvm_intel/parameters/unrestricted_guest=N,
test that a kernel warning does not occur informing us that
vcpu->mmio_needed=1. This can happen when KVM_RUN is called after a
triple fault.
This test was made to detect a bug that was reported by Syzkaller
(https://groups.google.com/forum/#!topic/syzkaller/lHfau8E3SOE) and
fixed with commit bbeac2830f4de ("KVM: X86: Fix residual mmio emulation
request to userspace").
Signed-off-by: Aaron Lewis <aaronlewis@google.com>
Reviewed-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Peter Shier <pshier@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to '')
-rw-r--r-- | tools/testing/selftests/kvm/x86_64/mmio_warning_test.c | 126 |
1 files changed, 126 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/x86_64/mmio_warning_test.c b/tools/testing/selftests/kvm/x86_64/mmio_warning_test.c new file mode 100644 index 000000000000..00bb97d76000 --- /dev/null +++ b/tools/testing/selftests/kvm/x86_64/mmio_warning_test.c @@ -0,0 +1,126 @@ +/* + * mmio_warning_test + * + * Copyright (C) 2019, Google LLC. + * + * This work is licensed under the terms of the GNU GPL, version 2. + * + * Test that we don't get a kernel warning when we call KVM_RUN after a + * triple fault occurs. To get the triple fault to occur we call KVM_RUN + * on a VCPU that hasn't been properly setup. + * + */ + +#define _GNU_SOURCE +#include <fcntl.h> +#include <kvm_util.h> +#include <linux/kvm.h> +#include <processor.h> +#include <pthread.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <sys/ioctl.h> +#include <sys/mman.h> +#include <sys/stat.h> +#include <sys/types.h> +#include <sys/wait.h> +#include <test_util.h> +#include <unistd.h> + +#define NTHREAD 4 +#define NPROCESS 5 + +struct thread_context { + int kvmcpu; + struct kvm_run *run; +}; + +void *thr(void *arg) +{ + struct thread_context *tc = (struct thread_context *)arg; + int res; + int kvmcpu = tc->kvmcpu; + struct kvm_run *run = tc->run; + + res = ioctl(kvmcpu, KVM_RUN, 0); + printf("ret1=%d exit_reason=%d suberror=%d\n", + res, run->exit_reason, run->internal.suberror); + + return 0; +} + +void test(void) +{ + int i, kvm, kvmvm, kvmcpu; + pthread_t th[NTHREAD]; + struct kvm_run *run; + struct thread_context tc; + + kvm = open("/dev/kvm", O_RDWR); + TEST_ASSERT(kvm != -1, "failed to open /dev/kvm"); + kvmvm = ioctl(kvm, KVM_CREATE_VM, 0); + TEST_ASSERT(kvmvm != -1, "KVM_CREATE_VM failed"); + kvmcpu = ioctl(kvmvm, KVM_CREATE_VCPU, 0); + TEST_ASSERT(kvmcpu != -1, "KVM_CREATE_VCPU failed"); + run = (struct kvm_run *)mmap(0, 4096, PROT_READ|PROT_WRITE, MAP_SHARED, + kvmcpu, 0); + tc.kvmcpu = kvmcpu; + tc.run = run; + srand(getpid()); + for (i = 0; i < NTHREAD; i++) { + pthread_create(&th[i], NULL, thr, (void *)(uintptr_t)&tc); + usleep(rand() % 10000); + } + for (i = 0; i < NTHREAD; i++) + pthread_join(th[i], NULL); +} + +int get_warnings_count(void) +{ + int warnings; + FILE *f; + + f = popen("dmesg | grep \"WARNING:\" | wc -l", "r"); + fscanf(f, "%d", &warnings); + fclose(f); + + return warnings; +} + +int main(void) +{ + int warnings_before, warnings_after; + + if (!is_intel_cpu()) { + printf("Must be run on an Intel CPU, skipping test\n"); + exit(KSFT_SKIP); + } + + if (vm_is_unrestricted_guest(NULL)) { + printf("Unrestricted guest must be disabled, skipping test\n"); + exit(KSFT_SKIP); + } + + warnings_before = get_warnings_count(); + + for (int i = 0; i < NPROCESS; ++i) { + int status; + int pid = fork(); + + if (pid < 0) + exit(1); + if (pid == 0) { + test(); + exit(0); + } + while (waitpid(pid, &status, __WALL) != pid) + ; + } + + warnings_after = get_warnings_count(); + TEST_ASSERT(warnings_before == warnings_after, + "Warnings found in kernel. Run 'dmesg' to inspect them."); + + return 0; +} |