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Diffstat (limited to '')
| -rw-r--r-- | tools/testing/selftests/kvm/x86_64/tsc_msrs_test.c | 153 |
1 files changed, 153 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/x86_64/tsc_msrs_test.c b/tools/testing/selftests/kvm/x86_64/tsc_msrs_test.c new file mode 100644 index 000000000000..22d366c697f7 --- /dev/null +++ b/tools/testing/selftests/kvm/x86_64/tsc_msrs_test.c @@ -0,0 +1,153 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Tests for MSR_IA32_TSC and MSR_IA32_TSC_ADJUST. + * + * Copyright (C) 2020, Red Hat, Inc. + */ +#include <stdio.h> +#include <string.h> +#include "kvm_util.h" +#include "processor.h" + +#define UNITY (1ull << 30) +#define HOST_ADJUST (UNITY * 64) +#define GUEST_STEP (UNITY * 4) +#define ROUND(x) ((x + UNITY / 2) & -UNITY) +#define rounded_rdmsr(x) ROUND(rdmsr(x)) +#define rounded_host_rdmsr(x) ROUND(vcpu_get_msr(vcpu, x)) + +static void guest_code(void) +{ + u64 val = 0; + + GUEST_ASSERT_EQ(rounded_rdmsr(MSR_IA32_TSC), val); + GUEST_ASSERT_EQ(rounded_rdmsr(MSR_IA32_TSC_ADJUST), val); + + /* Guest: writes to MSR_IA32_TSC affect both MSRs. */ + val = 1ull * GUEST_STEP; + wrmsr(MSR_IA32_TSC, val); + GUEST_ASSERT_EQ(rounded_rdmsr(MSR_IA32_TSC), val); + GUEST_ASSERT_EQ(rounded_rdmsr(MSR_IA32_TSC_ADJUST), val); + + /* Guest: writes to MSR_IA32_TSC_ADJUST affect both MSRs. */ + GUEST_SYNC(2); + val = 2ull * GUEST_STEP; + wrmsr(MSR_IA32_TSC_ADJUST, val); + GUEST_ASSERT_EQ(rounded_rdmsr(MSR_IA32_TSC), val); + GUEST_ASSERT_EQ(rounded_rdmsr(MSR_IA32_TSC_ADJUST), val); + + /* Host: setting the TSC offset. */ + GUEST_SYNC(3); + GUEST_ASSERT_EQ(rounded_rdmsr(MSR_IA32_TSC), HOST_ADJUST + val); + GUEST_ASSERT_EQ(rounded_rdmsr(MSR_IA32_TSC_ADJUST), val); + + /* + * Guest: writes to MSR_IA32_TSC_ADJUST do not destroy the + * host-side offset and affect both MSRs. + */ + GUEST_SYNC(4); + val = 3ull * GUEST_STEP; + wrmsr(MSR_IA32_TSC_ADJUST, val); + GUEST_ASSERT_EQ(rounded_rdmsr(MSR_IA32_TSC), HOST_ADJUST + val); + GUEST_ASSERT_EQ(rounded_rdmsr(MSR_IA32_TSC_ADJUST), val); + + /* + * Guest: writes to MSR_IA32_TSC affect both MSRs, so the host-side + * offset is now visible in MSR_IA32_TSC_ADJUST. + */ + GUEST_SYNC(5); + val = 4ull * GUEST_STEP; + wrmsr(MSR_IA32_TSC, val); + GUEST_ASSERT_EQ(rounded_rdmsr(MSR_IA32_TSC), val); + GUEST_ASSERT_EQ(rounded_rdmsr(MSR_IA32_TSC_ADJUST), val - HOST_ADJUST); + + GUEST_DONE(); +} + +static void run_vcpu(struct kvm_vcpu *vcpu, int stage) +{ + struct ucall uc; + + vcpu_run(vcpu); + + switch (get_ucall(vcpu, &uc)) { + case UCALL_SYNC: + TEST_ASSERT(!strcmp((const char *)uc.args[0], "hello") && + uc.args[1] == stage + 1, "Stage %d: Unexpected register values vmexit, got %lx", + stage + 1, (ulong)uc.args[1]); + return; + case UCALL_DONE: + return; + case UCALL_ABORT: + REPORT_GUEST_ASSERT_2(uc, "values: %#lx, %#lx"); + default: + TEST_ASSERT(false, "Unexpected exit: %s", + exit_reason_str(vcpu->run->exit_reason)); + } +} + +int main(void) +{ + struct kvm_vcpu *vcpu; + struct kvm_vm *vm; + uint64_t val; + + vm = vm_create_with_one_vcpu(&vcpu, guest_code); + + val = 0; + ASSERT_EQ(rounded_host_rdmsr(MSR_IA32_TSC), val); + ASSERT_EQ(rounded_host_rdmsr(MSR_IA32_TSC_ADJUST), val); + + /* Guest: writes to MSR_IA32_TSC affect both MSRs. */ + run_vcpu(vcpu, 1); + val = 1ull * GUEST_STEP; + ASSERT_EQ(rounded_host_rdmsr(MSR_IA32_TSC), val); + ASSERT_EQ(rounded_host_rdmsr(MSR_IA32_TSC_ADJUST), val); + + /* Guest: writes to MSR_IA32_TSC_ADJUST affect both MSRs. */ + run_vcpu(vcpu, 2); + val = 2ull * GUEST_STEP; + ASSERT_EQ(rounded_host_rdmsr(MSR_IA32_TSC), val); + ASSERT_EQ(rounded_host_rdmsr(MSR_IA32_TSC_ADJUST), val); + + /* + * Host: writes to MSR_IA32_TSC set the host-side offset + * and therefore do not change MSR_IA32_TSC_ADJUST. + */ + vcpu_set_msr(vcpu, MSR_IA32_TSC, HOST_ADJUST + val); + ASSERT_EQ(rounded_host_rdmsr(MSR_IA32_TSC), HOST_ADJUST + val); + ASSERT_EQ(rounded_host_rdmsr(MSR_IA32_TSC_ADJUST), val); + run_vcpu(vcpu, 3); + + /* Host: writes to MSR_IA32_TSC_ADJUST do not modify the TSC. */ + vcpu_set_msr(vcpu, MSR_IA32_TSC_ADJUST, UNITY * 123456); + ASSERT_EQ(rounded_host_rdmsr(MSR_IA32_TSC), HOST_ADJUST + val); + ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_TSC_ADJUST), UNITY * 123456); + + /* Restore previous value. */ + vcpu_set_msr(vcpu, MSR_IA32_TSC_ADJUST, val); + ASSERT_EQ(rounded_host_rdmsr(MSR_IA32_TSC), HOST_ADJUST + val); + ASSERT_EQ(rounded_host_rdmsr(MSR_IA32_TSC_ADJUST), val); + + /* + * Guest: writes to MSR_IA32_TSC_ADJUST do not destroy the + * host-side offset and affect both MSRs. + */ + run_vcpu(vcpu, 4); + val = 3ull * GUEST_STEP; + ASSERT_EQ(rounded_host_rdmsr(MSR_IA32_TSC), HOST_ADJUST + val); + ASSERT_EQ(rounded_host_rdmsr(MSR_IA32_TSC_ADJUST), val); + + /* + * Guest: writes to MSR_IA32_TSC affect both MSRs, so the host-side + * offset is now visible in MSR_IA32_TSC_ADJUST. + */ + run_vcpu(vcpu, 5); + val = 4ull * GUEST_STEP; + ASSERT_EQ(rounded_host_rdmsr(MSR_IA32_TSC), val); + ASSERT_EQ(rounded_host_rdmsr(MSR_IA32_TSC_ADJUST), val - HOST_ADJUST); + + kvm_vm_free(vm); + + return 0; +} |