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

Emanuele Giuseppe Esposito eesposit@redhat.com writes:

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 | 183 ++++++++++++++++++ 3 files changed, 185 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..f5294dc4b8ff --- /dev/null +++ b/tools/testing/selftests/kvm/x86_64/get_emulated_cpuid.c @@ -0,0 +1,183 @@ +// 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]);
  

+}

CPUID comparison here seems to be borrowed from get_cpuid_test.c, I think we can either put it to a library or (my preference) just merge these two selftests together. 'get_cpuid_test' name is generic enough to be used for KVM_GET_EMULATED_CPUID too.

+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 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");
  

• /* high nent, set the entries and adjust */
• cpuid->nent = MAX_NENT;
• res = _kvm_ioctl(vm, KVM_GET_EMULATED_CPUID, cpuid);
• printf("%d %d\n", res, errno);
• TEST_ASSERT(res == 0,

• 	"KVM_GET_EMULATED_CPUID should not fail with nent > actual nent");
  

• right_nent = cpuid->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");
  

• /* 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");
  

• }
• /* 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");
  

• free(cpuid);

+}

+// emulated is all emulated +// supported is only hw + kvm

/* * ... */

comments please

+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);

+}