[PATCH v2 4/4] selftests: kvm: add get_emulated_cpuid test

[Emanuele Giuseppe Esposito <eesposit@redhat.com>]

Introduce a new selftest for the KVM_GET_EMULATED_CPUID
ioctl. Since the behavior and functionality is similar to
get_cpuid_test, the test checks:

1) checks for corner case in the nent field of the struct kvm_cpuid2.
2) sets and gets it as cpuid from the guest VM

Signed-off-by: Emanuele Giuseppe Esposito <eesposit@redhat.com>
---
 tools/testing/selftests/kvm/.gitignore        |   1 +
 tools/testing/selftests/kvm/Makefile          |   1 +
 .../selftests/kvm/x86_64/get_emulated_cpuid.c | 198 ++++++++++++++++++
 3 files changed, 200 insertions(+)
 create mode 100644 tools/testing/selftests/kvm/x86_64/get_emulated_cpuid.c

diff --git a/tools/testing/selftests/kvm/.gitignore b/tools/testing/selftests/kvm/.gitignore
index 7bd7e776c266..f1523f3bfd04 100644
--- a/tools/testing/selftests/kvm/.gitignore
+++ b/tools/testing/selftests/kvm/.gitignore
@@ -8,6 +8,7 @@
 /x86_64/debug_regs
 /x86_64/evmcs_test
 /x86_64/get_cpuid_test
+x86_64/get_emulated_cpuid
 /x86_64/get_msr_index_features
 /x86_64/kvm_pv_test
 /x86_64/hyperv_clock
diff --git a/tools/testing/selftests/kvm/Makefile b/tools/testing/selftests/kvm/Makefile
index 67eebb53235f..0d8d3bd5a7c7 100644
--- a/tools/testing/selftests/kvm/Makefile
+++ b/tools/testing/selftests/kvm/Makefile
@@ -40,6 +40,7 @@ LIBKVM_s390x = lib/s390x/processor.c lib/s390x/ucall.c lib/s390x/diag318_test_ha
 
 TEST_GEN_PROGS_x86_64 = x86_64/cr4_cpuid_sync_test
 TEST_GEN_PROGS_x86_64 += x86_64/get_msr_index_features
+TEST_GEN_PROGS_x86_64 += x86_64/get_emulated_cpuid
 TEST_GEN_PROGS_x86_64 += x86_64/evmcs_test
 TEST_GEN_PROGS_x86_64 += x86_64/get_cpuid_test
 TEST_GEN_PROGS_x86_64 += x86_64/hyperv_clock
diff --git a/tools/testing/selftests/kvm/x86_64/get_emulated_cpuid.c b/tools/testing/selftests/kvm/x86_64/get_emulated_cpuid.c
new file mode 100644
index 000000000000..79fdbf4a1df1
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86_64/get_emulated_cpuid.c
@@ -0,0 +1,198 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2021, Red Hat Inc.
+ *
+ * Generic tests for KVM CPUID set/get ioctls
+ */
+#include <asm/kvm_para.h>
+#include <linux/kvm_para.h>
+#include <stdint.h>
+
+#include "test_util.h"
+#include "kvm_util.h"
+#include "processor.h"
+
+#define VCPU_ID 0
+#define MAX_NENT 1000
+
+/* CPUIDs known to differ */
+struct {
+	u32 function;
+	u32 index;
+} mangled_cpuids[] = {
+	{.function = 0xd, .index = 0},
+};
+
+static void guest_main(void)
+{
+
+}
+
+static bool is_cpuid_mangled(struct kvm_cpuid_entry2 *entrie)
+{
+	int i;
+
+	for (i = 0; i < sizeof(mangled_cpuids); i++) {
+		if (mangled_cpuids[i].function == entrie->function &&
+		    mangled_cpuids[i].index == entrie->index)
+			return true;
+	}
+
+	return false;
+}
+
+static void check_cpuid(struct kvm_cpuid2 *cpuid, struct kvm_cpuid_entry2 *entrie)
+{
+	int i;
+
+	for (i = 0; i < cpuid->nent; i++) {
+		if (cpuid->entries[i].function == entrie->function &&
+		    cpuid->entries[i].index == entrie->index) {
+			if (is_cpuid_mangled(entrie))
+				return;
+
+			TEST_ASSERT(cpuid->entries[i].eax == entrie->eax &&
+				    cpuid->entries[i].ebx == entrie->ebx &&
+				    cpuid->entries[i].ecx == entrie->ecx &&
+				    cpuid->entries[i].edx == entrie->edx,
+				    "CPUID 0x%x.%x differ: 0x%x:0x%x:0x%x:0x%x vs 0x%x:0x%x:0x%x:0x%x",
+				    entrie->function, entrie->index,
+				    cpuid->entries[i].eax, cpuid->entries[i].ebx,
+				    cpuid->entries[i].ecx, cpuid->entries[i].edx,
+				    entrie->eax, entrie->ebx, entrie->ecx, entrie->edx);
+			return;
+		}
+	}
+
+	TEST_ASSERT(false, "CPUID 0x%x.%x not found", entrie->function, entrie->index);
+}
+
+static void compare_cpuids(struct kvm_cpuid2 *cpuid1,
+						   struct kvm_cpuid2 *cpuid2)
+{
+	int i;
+
+	for (i = 0; i < cpuid1->nent; i++)
+		check_cpuid(cpuid2, &cpuid1->entries[i]);
+
+	for (i = 0; i < cpuid2->nent; i++)
+		check_cpuid(cpuid1, &cpuid2->entries[i]);
+}
+
+struct kvm_cpuid2 *vcpu_alloc_cpuid(struct kvm_vm *vm, vm_vaddr_t *p_gva, struct kvm_cpuid2 *cpuid)
+{
+	int size = sizeof(*cpuid) + cpuid->nent * sizeof(cpuid->entries[0]);
+	vm_vaddr_t gva = vm_vaddr_alloc(vm, size,
+					getpagesize(), 0, 0);
+	struct kvm_cpuid2 *guest_cpuids = addr_gva2hva(vm, gva);
+
+	memcpy(guest_cpuids, cpuid, size);
+
+	*p_gva = gva;
+	return guest_cpuids;
+}
+
+static struct kvm_cpuid2 *alloc_custom_kvm_cpuid2(int nent)
+{
+	struct kvm_cpuid2 *cpuid;
+	size_t size;
+
+	size = sizeof(*cpuid);
+	size += nent * sizeof(struct kvm_cpuid_entry2);
+	cpuid = calloc(1, size);
+	if (!cpuid) {
+		perror("malloc");
+		abort();
+	}
+
+	cpuid->nent = nent;
+
+	return cpuid;
+}
+
+static void clean_entries_kvm_cpuid2(struct kvm_cpuid2 *cpuid, int nent)
+{
+	size_t size;
+	int old_nent;
+
+	size = sizeof(*cpuid);
+	size += nent * sizeof(struct kvm_cpuid_entry2);
+
+	old_nent = cpuid->nent;
+	memset(cpuid, 0, size);
+	cpuid->nent = old_nent;
+}
+
+static void test_emulated_entries(struct kvm_vm *vm)
+{
+	int res, right_nent;
+	struct kvm_cpuid2 *cpuid;
+
+	cpuid = alloc_custom_kvm_cpuid2(MAX_NENT);
+
+	/* 0 nent, return E2BIG */
+	cpuid->nent = 0;
+	res = _kvm_ioctl(vm, KVM_GET_EMULATED_CPUID, cpuid);
+	TEST_ASSERT(res == -1 && errno == E2BIG,
+				"KVM_GET_EMULATED_CPUID should fail E2BIG with nent=0");
+	clean_entries_kvm_cpuid2(cpuid, MAX_NENT);
+
+	/* high nent, set the entries and adjust */
+	cpuid->nent = MAX_NENT;
+	res = _kvm_ioctl(vm, KVM_GET_EMULATED_CPUID, cpuid);
+	TEST_ASSERT(res == 0,
+			"KVM_GET_EMULATED_CPUID should not fail with nent > actual nent");
+	right_nent = cpuid->nent;
+	clean_entries_kvm_cpuid2(cpuid, MAX_NENT);
+
+	/* high nent, set the entries and adjust */
+	cpuid->nent++;
+	res = _kvm_ioctl(vm, KVM_GET_EMULATED_CPUID, cpuid);
+	TEST_ASSERT(res == 0,
+			"KVM_GET_EMULATED_CPUID should not fail with nent > actual nent");
+	TEST_ASSERT(right_nent == cpuid->nent,
+				"KVM_GET_EMULATED_CPUID nent should be always the same");
+	clean_entries_kvm_cpuid2(cpuid, MAX_NENT);
+
+	/* low nent, return E2BIG */
+	if (right_nent > 1) {
+		cpuid->nent = 1;
+		res = _kvm_ioctl(vm, KVM_GET_EMULATED_CPUID, cpuid);
+		TEST_ASSERT(res == -1 && errno == E2BIG,
+					"KVM_GET_EMULATED_CPUID should fail with nent=1");
+		clean_entries_kvm_cpuid2(cpuid, MAX_NENT);
+	}
+
+	/* exact nent */
+	cpuid->nent = right_nent;
+	res = _kvm_ioctl(vm, KVM_GET_EMULATED_CPUID, cpuid);
+	TEST_ASSERT(res == 0,
+			"KVM_GET_EMULATED_CPUID should not fail with nent == actual nent");
+	TEST_ASSERT(cpuid->nent == right_nent,
+			"KVM_GET_EMULATED_CPUID should be invaried when nent is exact");
+	clean_entries_kvm_cpuid2(cpuid, MAX_NENT);
+
+	free(cpuid);
+}
+
+int main(void)
+{
+	struct kvm_cpuid2 *emul_cpuid, *cpuid2;
+	struct kvm_vm *vm;
+
+	if (!kvm_check_cap(KVM_CAP_EXT_EMUL_CPUID)) {
+		print_skip("KVM_GET_EMULATED_CPUID not available");
+		return 0;
+	}
+
+	vm = vm_create_default(VCPU_ID, 0, guest_main);
+
+	emul_cpuid = kvm_get_emulated_cpuid();
+	vcpu_set_cpuid(vm, VCPU_ID, emul_cpuid);
+	cpuid2 = vcpu_get_cpuid(vm, VCPU_ID);
+
+	test_emulated_entries(vm);
+	compare_cpuids(emul_cpuid, cpuid2);
+
+	kvm_vm_free(vm);
+}
-- 
2.30.2