1 files changed, 218 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/x86/kvm_pv_test.c b/tools/testing/selftests/kvm/x86/kvm_pv_test.c
new file mode 100644
index 000000000000..1b805cbdb47b
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86/kvm_pv_test.c
@@ -0,0 +1,218 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2020, Google LLC.
+ *
+ * Tests for KVM paravirtual feature disablement
+ */
+#include <asm/kvm_para.h>
+#include <linux/kvm_para.h>
+#include <stdint.h>
+
+#include "test_util.h"
+#include "kvm_util.h"
+#include "processor.h"
+
+struct msr_data {
+	uint32_t idx;
+	const char *name;
+};
+
+#define TEST_MSR(msr) { .idx = msr, .name = #msr }
+#define UCALL_PR_MSR 0xdeadbeef
+#define PR_MSR(msr) ucall(UCALL_PR_MSR, 1, msr)
+
+/*
+ * KVM paravirtual msrs to test. Expect a #GP if any of these msrs are read or
+ * written, as the KVM_CPUID_FEATURES leaf is cleared.
+ */
+static struct msr_data msrs_to_test[] = {
+	TEST_MSR(MSR_KVM_SYSTEM_TIME),
+	TEST_MSR(MSR_KVM_SYSTEM_TIME_NEW),
+	TEST_MSR(MSR_KVM_WALL_CLOCK),
+	TEST_MSR(MSR_KVM_WALL_CLOCK_NEW),
+	TEST_MSR(MSR_KVM_ASYNC_PF_EN),
+	TEST_MSR(MSR_KVM_STEAL_TIME),
+	TEST_MSR(MSR_KVM_PV_EOI_EN),
+	TEST_MSR(MSR_KVM_POLL_CONTROL),
+	TEST_MSR(MSR_KVM_ASYNC_PF_INT),
+	TEST_MSR(MSR_KVM_ASYNC_PF_ACK),
+};
+
+static void test_msr(struct msr_data *msr)
+{
+	uint64_t ignored;
+	uint8_t vector;
+
+	PR_MSR(msr);
+
+	vector = rdmsr_safe(msr->idx, &ignored);
+	GUEST_ASSERT_EQ(vector, GP_VECTOR);
+
+	vector = wrmsr_safe(msr->idx, 0);
+	GUEST_ASSERT_EQ(vector, GP_VECTOR);
+}
+
+struct hcall_data {
+	uint64_t nr;
+	const char *name;
+};
+
+#define TEST_HCALL(hc) { .nr = hc, .name = #hc }
+#define UCALL_PR_HCALL 0xdeadc0de
+#define PR_HCALL(hc) ucall(UCALL_PR_HCALL, 1, hc)
+
+/*
+ * KVM hypercalls to test. Expect -KVM_ENOSYS when called, as the corresponding
+ * features have been cleared in KVM_CPUID_FEATURES.
+ */
+static struct hcall_data hcalls_to_test[] = {
+	TEST_HCALL(KVM_HC_KICK_CPU),
+	TEST_HCALL(KVM_HC_SEND_IPI),
+	TEST_HCALL(KVM_HC_SCHED_YIELD),
+};
+
+static void test_hcall(struct hcall_data *hc)
+{
+	uint64_t r;
+
+	PR_HCALL(hc);
+	r = kvm_hypercall(hc->nr, 0, 0, 0, 0);
+	GUEST_ASSERT_EQ(r, -KVM_ENOSYS);
+}
+
+static void guest_main(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(msrs_to_test); i++) {
+		test_msr(&msrs_to_test[i]);
+	}
+
+	for (i = 0; i < ARRAY_SIZE(hcalls_to_test); i++) {
+		test_hcall(&hcalls_to_test[i]);
+	}
+
+	GUEST_DONE();
+}
+
+static void pr_msr(struct ucall *uc)
+{
+	struct msr_data *msr = (struct msr_data *)uc->args[0];
+
+	pr_info("testing msr: %s (%#x)\n", msr->name, msr->idx);
+}
+
+static void pr_hcall(struct ucall *uc)
+{
+	struct hcall_data *hc = (struct hcall_data *)uc->args[0];
+
+	pr_info("testing hcall: %s (%lu)\n", hc->name, hc->nr);
+}
+
+static void enter_guest(struct kvm_vcpu *vcpu)
+{
+	struct ucall uc;
+
+	while (true) {
+		vcpu_run(vcpu);
+		TEST_ASSERT_KVM_EXIT_REASON(vcpu, KVM_EXIT_IO);
+
+		switch (get_ucall(vcpu, &uc)) {
+		case UCALL_PR_MSR:
+			pr_msr(&uc);
+			break;
+		case UCALL_PR_HCALL:
+			pr_hcall(&uc);
+			break;
+		case UCALL_ABORT:
+			REPORT_GUEST_ASSERT(uc);
+			return;
+		case UCALL_DONE:
+			return;
+		}
+	}
+}
+
+static void test_pv_unhalt(void)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+	struct kvm_cpuid_entry2 *ent;
+	u32 kvm_sig_old;
+	int r;
+
+	if (!(kvm_check_cap(KVM_CAP_X86_DISABLE_EXITS) & KVM_X86_DISABLE_EXITS_HLT))
+		return;
+
+	pr_info("testing KVM_FEATURE_PV_UNHALT\n");
+
+	/* KVM_PV_UNHALT test */
+	vm = vm_create_with_one_vcpu(&vcpu, guest_main);
+	vcpu_set_cpuid_feature(vcpu, X86_FEATURE_KVM_PV_UNHALT);
+
+	TEST_ASSERT(vcpu_cpuid_has(vcpu, X86_FEATURE_KVM_PV_UNHALT),
+		    "Enabling X86_FEATURE_KVM_PV_UNHALT had no effect");
+
+	/* Verify KVM disallows disabling exits after vCPU creation. */
+	r = __vm_enable_cap(vm, KVM_CAP_X86_DISABLE_EXITS, KVM_X86_DISABLE_EXITS_HLT);
+	TEST_ASSERT(r && errno == EINVAL,
+		    "Disabling exits after vCPU creation didn't fail as expected");
+
+	kvm_vm_free(vm);
+
+	/* Verify that KVM clear PV_UNHALT from guest CPUID. */
+	vm = vm_create(1);
+	vm_enable_cap(vm, KVM_CAP_X86_DISABLE_EXITS, KVM_X86_DISABLE_EXITS_HLT);
+
+	vcpu = vm_vcpu_add(vm, 0, NULL);
+	TEST_ASSERT(!vcpu_cpuid_has(vcpu, X86_FEATURE_KVM_PV_UNHALT),
+		    "vCPU created with PV_UNHALT set by default");
+
+	vcpu_set_cpuid_feature(vcpu, X86_FEATURE_KVM_PV_UNHALT);
+	TEST_ASSERT(!vcpu_cpuid_has(vcpu, X86_FEATURE_KVM_PV_UNHALT),
+		    "PV_UNHALT set in guest CPUID when HLT-exiting is disabled");
+
+	/*
+	 * Clobber the KVM PV signature and verify KVM does NOT clear PV_UNHALT
+	 * when KVM PV is not present, and DOES clear PV_UNHALT when switching
+	 * back to the correct signature..
+	 */
+	ent = vcpu_get_cpuid_entry(vcpu, KVM_CPUID_SIGNATURE);
+	kvm_sig_old = ent->ebx;
+	ent->ebx = 0xdeadbeef;
+	vcpu_set_cpuid(vcpu);
+
+	vcpu_set_cpuid_feature(vcpu, X86_FEATURE_KVM_PV_UNHALT);
+	TEST_ASSERT(vcpu_cpuid_has(vcpu, X86_FEATURE_KVM_PV_UNHALT),
+		    "PV_UNHALT cleared when using bogus KVM PV signature");
+
+	ent = vcpu_get_cpuid_entry(vcpu, KVM_CPUID_SIGNATURE);
+	ent->ebx = kvm_sig_old;
+	vcpu_set_cpuid(vcpu);
+
+	TEST_ASSERT(!vcpu_cpuid_has(vcpu, X86_FEATURE_KVM_PV_UNHALT),
+		    "PV_UNHALT set in guest CPUID when HLT-exiting is disabled");
+
+	/* FIXME: actually test KVM_FEATURE_PV_UNHALT feature */
+
+	kvm_vm_free(vm);
+}
+
+int main(void)
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+
+	TEST_REQUIRE(kvm_has_cap(KVM_CAP_ENFORCE_PV_FEATURE_CPUID));
+
+	vm = vm_create_with_one_vcpu(&vcpu, guest_main);
+
+	vcpu_enable_cap(vcpu, KVM_CAP_ENFORCE_PV_FEATURE_CPUID, 1);
+
+	vcpu_clear_cpuid_entry(vcpu, KVM_CPUID_FEATURES);
+
+	enter_guest(vcpu);
+	kvm_vm_free(vm);
+
+	test_pv_unhalt();
+}