1 files changed, 156 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/x86/kvm_clock_test.c b/tools/testing/selftests/kvm/x86/kvm_clock_test.c
new file mode 100644
index 000000000000..5bc12222d87a
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86/kvm_clock_test.c
@@ -0,0 +1,156 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2021, Google LLC.
+ *
+ * Tests for adjusting the KVM clock from userspace
+ */
+#include <asm/kvm_para.h>
+#include <asm/pvclock.h>
+#include <asm/pvclock-abi.h>
+#include <stdint.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <time.h>
+
+#include "test_util.h"
+#include "kvm_util.h"
+#include "processor.h"
+
+struct test_case {
+	uint64_t kvmclock_base;
+	int64_t realtime_offset;
+};
+
+static struct test_case test_cases[] = {
+	{ .kvmclock_base = 0 },
+	{ .kvmclock_base = 180 * NSEC_PER_SEC },
+	{ .kvmclock_base = 0, .realtime_offset = -180 * NSEC_PER_SEC },
+	{ .kvmclock_base = 0, .realtime_offset = 180 * NSEC_PER_SEC },
+};
+
+#define GUEST_SYNC_CLOCK(__stage, __val)			\
+		GUEST_SYNC_ARGS(__stage, __val, 0, 0, 0)
+
+static void guest_main(vm_paddr_t pvti_pa, struct pvclock_vcpu_time_info *pvti)
+{
+	int i;
+
+	wrmsr(MSR_KVM_SYSTEM_TIME_NEW, pvti_pa | KVM_MSR_ENABLED);
+	for (i = 0; i < ARRAY_SIZE(test_cases); i++)
+		GUEST_SYNC_CLOCK(i, __pvclock_read_cycles(pvti, rdtsc()));
+}
+
+#define EXPECTED_FLAGS (KVM_CLOCK_REALTIME | KVM_CLOCK_HOST_TSC)
+
+static inline void assert_flags(struct kvm_clock_data *data)
+{
+	TEST_ASSERT((data->flags & EXPECTED_FLAGS) == EXPECTED_FLAGS,
+		    "unexpected clock data flags: %x (want set: %x)",
+		    data->flags, EXPECTED_FLAGS);
+}
+
+static void handle_sync(struct ucall *uc, struct kvm_clock_data *start,
+			struct kvm_clock_data *end)
+{
+	uint64_t obs, exp_lo, exp_hi;
+
+	obs = uc->args[2];
+	exp_lo = start->clock;
+	exp_hi = end->clock;
+
+	assert_flags(start);
+	assert_flags(end);
+
+	TEST_ASSERT(exp_lo <= obs && obs <= exp_hi,
+		    "unexpected kvm-clock value: %"PRIu64" expected range: [%"PRIu64", %"PRIu64"]",
+		    obs, exp_lo, exp_hi);
+
+	pr_info("kvm-clock value: %"PRIu64" expected range [%"PRIu64", %"PRIu64"]\n",
+		obs, exp_lo, exp_hi);
+}
+
+static void handle_abort(struct ucall *uc)
+{
+	REPORT_GUEST_ASSERT(*uc);
+}
+
+static void setup_clock(struct kvm_vm *vm, struct test_case *test_case)
+{
+	struct kvm_clock_data data;
+
+	memset(&data, 0, sizeof(data));
+
+	data.clock = test_case->kvmclock_base;
+	if (test_case->realtime_offset) {
+		struct timespec ts;
+		int r;
+
+		data.flags |= KVM_CLOCK_REALTIME;
+		do {
+			r = clock_gettime(CLOCK_REALTIME, &ts);
+			if (!r)
+				break;
+		} while (errno == EINTR);
+
+		TEST_ASSERT(!r, "clock_gettime() failed: %d", r);
+
+		data.realtime = ts.tv_sec * NSEC_PER_SEC;
+		data.realtime += ts.tv_nsec;
+		data.realtime += test_case->realtime_offset;
+	}
+
+	vm_ioctl(vm, KVM_SET_CLOCK, &data);
+}
+
+static void enter_guest(struct kvm_vcpu *vcpu)
+{
+	struct kvm_clock_data start, end;
+	struct kvm_vm *vm = vcpu->vm;
+	struct ucall uc;
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(test_cases); i++) {
+		setup_clock(vm, &test_cases[i]);
+
+		vm_ioctl(vm, KVM_GET_CLOCK, &start);
+
+		vcpu_run(vcpu);
+		vm_ioctl(vm, KVM_GET_CLOCK, &end);
+
+		TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
+
+		switch (get_ucall(vcpu, &uc)) {
+		case UCALL_SYNC:
+			handle_sync(&uc, &start, &end);
+			break;
+		case UCALL_ABORT:
+			handle_abort(&uc);
+			return;
+		default:
+			TEST_ASSERT(0, "unhandled ucall: %ld", uc.cmd);
+		}
+	}
+}
+
+int main(void)
+{
+	struct kvm_vcpu *vcpu;
+	vm_vaddr_t pvti_gva;
+	vm_paddr_t pvti_gpa;
+	struct kvm_vm *vm;
+	int flags;
+
+	flags = kvm_check_cap(KVM_CAP_ADJUST_CLOCK);
+	TEST_REQUIRE(flags & KVM_CLOCK_REALTIME);
+
+	TEST_REQUIRE(sys_clocksource_is_based_on_tsc());
+
+	vm = vm_create_with_one_vcpu(&vcpu, guest_main);
+
+	pvti_gva = vm_vaddr_alloc(vm, getpagesize(), 0x10000);
+	pvti_gpa = addr_gva2gpa(vm, pvti_gva);
+	vcpu_args_set(vcpu, 2, pvti_gpa, pvti_gva);
+
+	enter_guest(vcpu);
+	kvm_vm_free(vm);
+}