From 2325d4dd7321cd569f996c5d091f4f83efb25693 Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 8 Jun 2022 22:45:16 +0000 Subject: KVM: selftests: Add MONITOR/MWAIT quirk test Add a test to verify the "MONITOR/MWAIT never fault" quirk, and as a bonus, also verify the related "MISC_ENABLES ignores ENABLE_MWAIT" quirk. If the "never fault" quirk is enabled, MONITOR/MWAIT should always be emulated as NOPs, even if they're reported as disabled in guest CPUID. Use the MISC_ENABLES quirk to coerce KVM into toggling the MWAIT CPUID enable, as KVM now disallows manually toggling CPUID bits after running the vCPU. Signed-off-by: Sean Christopherson Message-Id: <20220608224516.3788274-6-seanjc@google.com> Signed-off-by: Paolo Bonzini --- tools/testing/selftests/kvm/.gitignore | 1 + tools/testing/selftests/kvm/Makefile | 1 + .../selftests/kvm/x86_64/monitor_mwait_test | Bin 1485656 -> 0 bytes .../selftests/kvm/x86_64/monitor_mwait_test.c | 137 +++++++++++++++++++++ 4 files changed, 139 insertions(+) delete mode 100755 tools/testing/selftests/kvm/x86_64/monitor_mwait_test create mode 100644 tools/testing/selftests/kvm/x86_64/monitor_mwait_test.c (limited to 'tools/testing/selftests') diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore index dd5c88c11059..f3c2f074b948 100644 --- a/tools/testing/selftests/kvm/.gitignore +++ b/tools/testing/selftests/kvm/.gitignore @@ -28,6 +28,7 @@ /x86_64/max_vcpuid_cap_test /x86_64/mmio_warning_test /x86_64/mmu_role_test +/x86_64/monitor_mwait_test /x86_64/platform_info_test /x86_64/pmu_event_filter_test /x86_64/set_boot_cpu_id diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile index b52c130f7b2f..ad1634e5659f 100644 --- a/tools/testing/selftests/kvm/Makefile +++ b/tools/testing/selftests/kvm/Makefile @@ -84,6 +84,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/kvm_clock_test TEST_GEN_PROGS_x86_64 += x86_64/kvm_pv_test TEST_GEN_PROGS_x86_64 += x86_64/mmio_warning_test TEST_GEN_PROGS_x86_64 += x86_64/mmu_role_test +TEST_GEN_PROGS_x86_64 += x86_64/monitor_mwait_test TEST_GEN_PROGS_x86_64 += x86_64/platform_info_test TEST_GEN_PROGS_x86_64 += x86_64/pmu_event_filter_test TEST_GEN_PROGS_x86_64 += x86_64/set_boot_cpu_id diff --git a/tools/testing/selftests/kvm/x86_64/monitor_mwait_test b/tools/testing/selftests/kvm/x86_64/monitor_mwait_test deleted file mode 100755 index 598b597e1eec..000000000000 Binary files a/tools/testing/selftests/kvm/x86_64/monitor_mwait_test and /dev/null differ diff --git a/tools/testing/selftests/kvm/x86_64/monitor_mwait_test.c b/tools/testing/selftests/kvm/x86_64/monitor_mwait_test.c new file mode 100644 index 000000000000..49f2ed1c53fe --- /dev/null +++ b/tools/testing/selftests/kvm/x86_64/monitor_mwait_test.c @@ -0,0 +1,137 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include + +#include "kvm_util.h" +#include "processor.h" + +#define X86_FEATURE_MWAIT (1u << 3) + +enum monitor_mwait_testcases { + MWAIT_QUIRK_DISABLED = BIT(0), + MISC_ENABLES_QUIRK_DISABLED = BIT(1), + MWAIT_DISABLED = BIT(2), +}; + +static void guest_monitor_wait(int testcase) +{ + /* + * If both MWAIT and its quirk are disabled, MONITOR/MWAIT should #UD, + * in all other scenarios KVM should emulate them as nops. + */ + bool fault_wanted = (testcase & MWAIT_QUIRK_DISABLED) && + (testcase & MWAIT_DISABLED); + u8 vector; + + GUEST_SYNC(testcase); + + vector = kvm_asm_safe("monitor"); + if (fault_wanted) + GUEST_ASSERT_2(vector == UD_VECTOR, testcase, vector); + else + GUEST_ASSERT_2(!vector, testcase, vector); + + vector = kvm_asm_safe("monitor"); + if (fault_wanted) + GUEST_ASSERT_2(vector == UD_VECTOR, testcase, vector); + else + GUEST_ASSERT_2(!vector, testcase, vector); +} + +static void guest_code(void) +{ + guest_monitor_wait(MWAIT_DISABLED); + + guest_monitor_wait(MWAIT_QUIRK_DISABLED | MWAIT_DISABLED); + + guest_monitor_wait(MISC_ENABLES_QUIRK_DISABLED | MWAIT_DISABLED); + guest_monitor_wait(MISC_ENABLES_QUIRK_DISABLED); + + guest_monitor_wait(MISC_ENABLES_QUIRK_DISABLED | MWAIT_QUIRK_DISABLED | MWAIT_DISABLED); + guest_monitor_wait(MISC_ENABLES_QUIRK_DISABLED | MWAIT_QUIRK_DISABLED); + + GUEST_DONE(); +} + +int main(int argc, char *argv[]) +{ + uint64_t disabled_quirks; + struct kvm_cpuid2 *cpuid; + struct kvm_cpuid_entry2 *entry; + struct kvm_vcpu *vcpu; + struct kvm_run *run; + struct kvm_vm *vm; + struct ucall uc; + int testcase; + + TEST_REQUIRE(kvm_has_cap(KVM_CAP_DISABLE_QUIRKS2)); + + cpuid = kvm_get_supported_cpuid(); + + entry = kvm_get_supported_cpuid_index(1, 0); + entry->ecx &= ~X86_FEATURE_MWAIT; + set_cpuid(cpuid, entry); + + vm = vm_create_with_one_vcpu(&vcpu, guest_code); + vcpu_set_cpuid(vcpu, cpuid); + + run = vcpu->run; + + vm_init_descriptor_tables(vm); + vcpu_init_descriptor_tables(vcpu); + + while (1) { + vcpu_run(vcpu); + + TEST_ASSERT(run->exit_reason == KVM_EXIT_IO, + "Unexpected exit reason: %u (%s),\n", + run->exit_reason, + exit_reason_str(run->exit_reason)); + + switch (get_ucall(vcpu, &uc)) { + case UCALL_SYNC: + testcase = uc.args[1]; + break; + case UCALL_ABORT: + TEST_FAIL("%s at %s:%ld, testcase = %lx, vector = %ld", + (const char *)uc.args[0], __FILE__, + uc.args[1], uc.args[2], uc.args[3]); + goto done; + case UCALL_DONE: + goto done; + default: + TEST_FAIL("Unknown ucall %lu", uc.cmd); + goto done; + } + + disabled_quirks = 0; + if (testcase & MWAIT_QUIRK_DISABLED) + disabled_quirks |= KVM_X86_QUIRK_MWAIT_NEVER_FAULTS; + if (testcase & MISC_ENABLES_QUIRK_DISABLED) + disabled_quirks |= KVM_X86_QUIRK_MISC_ENABLE_NO_MWAIT; + vm_enable_cap(vm, KVM_CAP_DISABLE_QUIRKS2, disabled_quirks); + + /* + * If the MISC_ENABLES quirk (KVM neglects to update CPUID to + * enable/disable MWAIT) is disabled, toggle the ENABLE_MWAIT + * bit in MISC_ENABLES accordingly. If the quirk is enabled, + * the only valid configuration is MWAIT disabled, as CPUID + * can't be manually changed after running the vCPU. + */ + if (!(testcase & MISC_ENABLES_QUIRK_DISABLED)) { + TEST_ASSERT(testcase & MWAIT_DISABLED, + "Can't toggle CPUID features after running vCPU"); + continue; + } + + vcpu_set_msr(vcpu, MSR_IA32_MISC_ENABLE, + (testcase & MWAIT_DISABLED) ? 0 : MSR_IA32_MISC_ENABLE_MWAIT); + } + +done: + kvm_vm_free(vm); + return 0; +} -- cgit