By default, HLT instruction executed by guest is intercepted by hypervisor.
However, KVM_CAP_X86_DISABLE_EXITS capability can be used to not intercept
HLT by setting KVM_X86_DISABLE_EXITS_HLT.
Add a test case to test KVM_X86_DISABLE_EXITS_HLT functionality.
Suggested-by: Sean Christopherson <sea...@google.com>
Signed-off-by: Manali Shukla <manali.shu...@amd.com>
---
tools/testing/selftests/kvm/Makefile | 1 +
.../kvm/x86_64/halt_disable_exit_test.c | 113 ++++++++++++++++++
2 files changed, 114 insertions(+)
create mode 100644 tools/testing/selftests/kvm/x86_64/halt_disable_exit_test.c
diff --git a/tools/testing/selftests/kvm/Makefile
b/tools/testing/selftests/kvm/Makefile
index c75251d5c97c..9f72abb95d2e 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -89,6 +89,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/set_sregs_test
TEST_GEN_PROGS_x86_64 += x86_64/smaller_maxphyaddr_emulation_test
TEST_GEN_PROGS_x86_64 += x86_64/smm_test
TEST_GEN_PROGS_x86_64 += x86_64/state_test
+TEST_GEN_PROGS_x86_64 += x86_64/halt_disable_exit_test
TEST_GEN_PROGS_x86_64 += x86_64/vmx_preemption_timer_test
TEST_GEN_PROGS_x86_64 += x86_64/svm_vmcall_test
TEST_GEN_PROGS_x86_64 += x86_64/svm_int_ctl_test
diff --git a/tools/testing/selftests/kvm/x86_64/halt_disable_exit_test.c
b/tools/testing/selftests/kvm/x86_64/halt_disable_exit_test.c
new file mode 100644
index 000000000000..b7279dd0eaff
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/halt_disable_exit_test.c
@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * KVM disable halt exit test
+ *
+ * Copyright (C) 2024 Advanced Micro Devices, Inc.
+ */
+#include <pthread.h>
+#include <signal.h>
+#include "kvm_util.h"
+#include "svm_util.h"
+#include "processor.h"
+#include "test_util.h"
+
+pthread_t task_thread, vcpu_thread;
+#define SIG_IPI SIGUSR1
+
+static void guest_code(uint8_t is_hlt_exec)
+{
+ while (!READ_ONCE(is_hlt_exec))
+ ;
+
+ safe_halt();
+ GUEST_DONE();
+}
+
+static void *task_worker(void *arg)
+{
+ uint8_t *is_hlt_exec = (uint8_t *)arg;
+
+ usleep(1000);
+ WRITE_ONCE(*is_hlt_exec, 1);
+ pthread_kill(vcpu_thread, SIG_IPI);
+ return 0;
+}
+
+static void *vcpu_worker(void *arg)
+{
+ int ret;
+ int sig = -1;
+ uint8_t *is_hlt_exec = (uint8_t *)arg;
+ struct kvm_vm *vm;
+ struct kvm_run *run;
+ struct kvm_vcpu *vcpu;
+ struct kvm_signal_mask *sigmask = alloca(offsetof(struct
kvm_signal_mask, sigset)
+ + sizeof(sigset_t));
+ sigset_t *sigset = (sigset_t *) &sigmask->sigset;
+
+ /* Create a VM without in kernel APIC support */
+ vm = __vm_create(VM_SHAPE_DEFAULT, 1, 0, false);
+ vm_enable_cap(vm, KVM_CAP_X86_DISABLE_EXITS, KVM_X86_DISABLE_EXITS_HLT);
+ vcpu = vm_vcpu_add(vm, 0, guest_code);
+ vcpu_args_set(vcpu, 1, *is_hlt_exec);
+
+ /*
+ * SIG_IPI is unblocked atomically while in KVM_RUN. It causes the
+ * ioctl to return with -EINTR, but it is still pending and we need
+ * to accept it with the sigwait.
+ */
+ sigmask->len = 8;
+ pthread_sigmask(0, NULL, sigset);
+ sigdelset(sigset, SIG_IPI);
+ vcpu_ioctl(vcpu, KVM_SET_SIGNAL_MASK, sigmask);
+ sigemptyset(sigset);
+ sigaddset(sigset, SIG_IPI);
+ run = vcpu->run;
+
+again:
+ ret = __vcpu_run(vcpu);
+ TEST_ASSERT_EQ(errno, EINTR);
+
+ if (ret == -1 && errno == EINTR) {
+ sigwait(sigset, &sig);
+ assert(sig == SIG_IPI);
+ TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_INTR);
+ goto again;
+ }
+
+ if (run->exit_reason == KVM_EXIT_HLT)
+ TEST_FAIL("Expected KVM_EXIT_INTR, got KVM_EXIT_HLT");
+
+ TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
+ kvm_vm_free(vm);
+ return 0;
+}
+
+int main(int argc, char *argv[])
+{
+ int ret;
+ void *retval;
+ uint8_t is_halt_exec;
+ sigset_t sigset;
+
+ TEST_REQUIRE(kvm_has_cap(KVM_CAP_X86_DISABLE_EXITS));
+
+ /* Ensure that vCPU threads start with SIG_IPI blocked. */
+ sigemptyset(&sigset);
+ sigaddset(&sigset, SIG_IPI);
+ pthread_sigmask(SIG_BLOCK, &sigset, NULL);
+
+ ret = pthread_create(&vcpu_thread, NULL, vcpu_worker, &is_halt_exec);
+ TEST_ASSERT(ret == 0, "pthread_create vcpu thread failed errno=%d",
errno);
+
+ ret = pthread_create(&task_thread, NULL, task_worker, &is_halt_exec);
+ TEST_ASSERT(ret == 0, "pthread_create task thread failed errno=%d",
errno);
+
+ pthread_join(vcpu_thread, &retval);
+ TEST_ASSERT(ret == 0, "pthread_join on vcpu thread failed with
errno=%d", ret);
+
+ pthread_join(task_thread, &retval);
+ TEST_ASSERT(ret == 0, "pthread_join on task thread failed with
errno=%d", ret);
+
+ return 0;
+}
--
2.34.1
