KVM: selftests: Add hyperv_cpuid test

Add a simple (and stupid) hyperv_cpuid test: check that we got the
expected number of entries with and without Enlightened VMCS enabled
and that all currently reserved fields are zeroed.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

tools/testing/selftests/kvm/Makefile

@@ -15,6 +15,7 @@ TEST_GEN_PROGS_x86_64 += x86_64/vmx_tsc_adjust_test
 TEST_GEN_PROGS_x86_64 += x86_64/cr4_cpuid_sync_test
 TEST_GEN_PROGS_x86_64 += x86_64/state_test
 TEST_GEN_PROGS_x86_64 += x86_64/evmcs_test
+TEST_GEN_PROGS_x86_64 += x86_64/hyperv_cpuid
 TEST_GEN_PROGS_x86_64 += dirty_log_test
 TEST_GEN_PROGS_x86_64 += clear_dirty_log_test
 

tools/testing/selftests/kvm/x86_64/hyperv_cpuid.c

@@ -0,0 +1,157 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Test for x86 KVM_CAP_HYPERV_CPUID
+ *
+ * Copyright (C) 2018, Red Hat, Inc.
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2.
+ *
+ */
+
+#define _GNU_SOURCE /* for program_invocation_short_name */
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+
+#include "test_util.h"
+#include "kvm_util.h"
+#include "processor.h"
+
+#define VCPU_ID 0
+
+static void guest_code(void)
+{
+}
+
+static void test_hv_cpuid(struct kvm_cpuid2 *hv_cpuid_entries,
+			  int evmcs_enabled)
+{
+	int i;
+
+	if (!evmcs_enabled)
+		TEST_ASSERT(hv_cpuid_entries->nent == 6,
+			    "KVM_GET_SUPPORTED_HV_CPUID should return 6 entries"
+			    " when Enlightened VMCS is disabled (returned %d)",
+			    hv_cpuid_entries->nent);
+	else
+		TEST_ASSERT(hv_cpuid_entries->nent == 7,
+			    "KVM_GET_SUPPORTED_HV_CPUID should return 7 entries"
+			    " when Enlightened VMCS is enabled (returned %d)",
+			    hv_cpuid_entries->nent);
+
+	for (i = 0; i < hv_cpuid_entries->nent; i++) {
+		struct kvm_cpuid_entry2 *entry = &hv_cpuid_entries->entries[i];
+
+		TEST_ASSERT((entry->function >= 0x40000000) &&
+			    (entry->function <= 0x4000000A),
+			    "function %lx is our of supported range",
+			    entry->function);
+
+		TEST_ASSERT(entry->index == 0,
+			    ".index field should be zero");
+
+		TEST_ASSERT(entry->index == 0,
+			    ".index field should be zero");
+
+		TEST_ASSERT(entry->flags == 0,
+			    ".flags field should be zero");
+
+		TEST_ASSERT(entry->padding[0] == entry->padding[1]
+			    == entry->padding[2] == 0,
+			    ".index field should be zero");
+
+		/*
+		 * If needed for debug:
+		 * fprintf(stdout,
+		 *	"CPUID%lx EAX=0x%lx EBX=0x%lx ECX=0x%lx EDX=0x%lx\n",
+		 *	entry->function, entry->eax, entry->ebx, entry->ecx,
+		 *	entry->edx);
+		 */
+	}
+
+}
+
+void test_hv_cpuid_e2big(struct kvm_vm *vm)
+{
+	static struct kvm_cpuid2 cpuid = {.nent = 0};
+	int ret;
+
+	ret = _vcpu_ioctl(vm, VCPU_ID, KVM_GET_SUPPORTED_HV_CPUID, &cpuid);
+
+	TEST_ASSERT(ret == -1 && errno == E2BIG,
+		    "KVM_GET_SUPPORTED_HV_CPUID didn't fail with -E2BIG when"
+		    " it should have: %d %d", ret, errno);
+}
+
+
+struct kvm_cpuid2 *kvm_get_supported_hv_cpuid(struct kvm_vm *vm)
+{
+	int nent = 20; /* should be enough */
+	static struct kvm_cpuid2 *cpuid;
+	int ret;
+
+	cpuid = malloc(sizeof(*cpuid) + nent * sizeof(struct kvm_cpuid_entry2));
+
+	if (!cpuid) {
+		perror("malloc");
+		abort();
+	}
+
+	cpuid->nent = nent;
+
+	vcpu_ioctl(vm, VCPU_ID, KVM_GET_SUPPORTED_HV_CPUID, cpuid);
+
+	return cpuid;
+}
+
+
+int main(int argc, char *argv[])
+{
+	struct kvm_vm *vm;
+	int rv;
+	uint16_t evmcs_ver;
+	struct kvm_cpuid2 *hv_cpuid_entries;
+	struct kvm_enable_cap enable_evmcs_cap = {
+		.cap = KVM_CAP_HYPERV_ENLIGHTENED_VMCS,
+		 .args[0] = (unsigned long)&evmcs_ver
+	};
+
+	/* Tell stdout not to buffer its content */
+	setbuf(stdout, NULL);
+
+	rv = kvm_check_cap(KVM_CAP_HYPERV_CPUID);
+	if (!rv) {
+		fprintf(stderr,
+			"KVM_CAP_HYPERV_CPUID not supported, skip test\n");
+		exit(KSFT_SKIP);
+	}
+
+	/* Create VM */
+	vm = vm_create_default(VCPU_ID, 0, guest_code);
+
+	test_hv_cpuid_e2big(vm);
+
+	hv_cpuid_entries = kvm_get_supported_hv_cpuid(vm);
+	if (!hv_cpuid_entries)
+		return 1;
+
+	test_hv_cpuid(hv_cpuid_entries, 0);
+
+	free(hv_cpuid_entries);
+
+	vcpu_ioctl(vm, VCPU_ID, KVM_ENABLE_CAP, &enable_evmcs_cap);
+
+	hv_cpuid_entries = kvm_get_supported_hv_cpuid(vm);
+	if (!hv_cpuid_entries)
+		return 1;
+
+	test_hv_cpuid(hv_cpuid_entries, 1);
+
+	free(hv_cpuid_entries);
+
+	kvm_vm_free(vm);
+
+	return 0;
+}