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Message-ID: <87k0pms6no.fsf@vitty.brq.redhat.com>
Date: Thu, 01 Apr 2021 11:20:11 +0200
From: Vitaly Kuznetsov <vkuznets@...hat.com>
To: Emanuele Giuseppe Esposito <eesposit@...hat.com>,
kvm@...r.kernel.org
Cc: Paolo Bonzini <pbonzini@...hat.com>,
Jonathan Corbet <corbet@....net>,
Sean Christopherson <seanjc@...gle.com>,
Jim Mattson <jmattson@...gle.com>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
"H. Peter Anvin" <hpa@...or.com>, Shuah Khan <shuah@...nel.org>,
Alexander Graf <graf@...zon.com>,
Andrew Jones <drjones@...hat.com>, linux-doc@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-kselftest@...r.kernel.org
Subject: Re: [PATCH 4/4] selftests: kvm: add get_emulated_cpuid test
Emanuele Giuseppe Esposito <eesposit@...hat.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@...hat.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);
> +}
--
Vitaly
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