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// SPDX-License-Identifier: GPL-2.0
/*
* Test for VMX-pmu perf capability msr
*
* Copyright (C) 2021 Intel Corporation
*
* Test to check the effect of various CPUID settings on
* MSR_IA32_PERF_CAPABILITIES MSR, and check that what
* we write with KVM_SET_MSR is _not_ modified by the guest
* and check it can be retrieved with KVM_GET_MSR, also test
* the invalid LBR formats are rejected.
*/
#define _GNU_SOURCE /* for program_invocation_short_name */
#include <sys/ioctl.h>
#include <linux/bitmap.h>
#include "kvm_util.h"
#include "vmx.h"
union perf_capabilities {
struct {
u64 lbr_format:6;
u64 pebs_trap:1;
u64 pebs_arch_reg:1;
u64 pebs_format:4;
u64 smm_freeze:1;
u64 full_width_write:1;
u64 pebs_baseline:1;
u64 perf_metrics:1;
u64 pebs_output_pt_available:1;
u64 anythread_deprecated:1;
};
u64 capabilities;
};
/*
* The LBR format and most PEBS features are immutable, all other features are
* fungible (if supported by the host and KVM).
*/
static const union perf_capabilities immutable_caps = {
.lbr_format = -1,
.pebs_trap = 1,
.pebs_arch_reg = 1,
.pebs_format = -1,
.pebs_baseline = 1,
};
static const union perf_capabilities format_caps = {
.lbr_format = -1,
.pebs_format = -1,
};
static void guest_test_perf_capabilities_gp(uint64_t val)
{
uint8_t vector = wrmsr_safe(MSR_IA32_PERF_CAPABILITIES, val);
__GUEST_ASSERT(vector == GP_VECTOR,
"Expected #GP for value '0x%lx', got vector '0x%x'",
val, vector);
}
static void guest_code(uint64_t current_val)
{
int i;
guest_test_perf_capabilities_gp(current_val);
guest_test_perf_capabilities_gp(0);
for (i = 0; i < 64; i++)
guest_test_perf_capabilities_gp(current_val ^ BIT_ULL(i));
GUEST_DONE();
}
/*
* Verify that guest WRMSRs to PERF_CAPABILITIES #GP regardless of the value
* written, that the guest always sees the userspace controlled value, and that
* PERF_CAPABILITIES is immutable after KVM_RUN.
*/
static void test_guest_wrmsr_perf_capabilities(union perf_capabilities host_cap)
{
struct kvm_vcpu *vcpu;
struct kvm_vm *vm = vm_create_with_one_vcpu(&vcpu, guest_code);
struct ucall uc;
int r, i;
vm_init_descriptor_tables(vm);
vcpu_init_descriptor_tables(vcpu);
vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, host_cap.capabilities);
vcpu_args_set(vcpu, 1, host_cap.capabilities);
vcpu_run(vcpu);
switch (get_ucall(vcpu, &uc)) {
case UCALL_ABORT:
REPORT_GUEST_ASSERT(uc);
break;
case UCALL_DONE:
break;
default:
TEST_FAIL("Unexpected ucall: %lu", uc.cmd);
}
TEST_ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_PERF_CAPABILITIES),
host_cap.capabilities);
vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, host_cap.capabilities);
r = _vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, 0);
TEST_ASSERT(!r, "Post-KVM_RUN write '0' didn't fail");
for (i = 0; i < 64; i++) {
r = _vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES,
host_cap.capabilities ^ BIT_ULL(i));
TEST_ASSERT(!r, "Post-KVM_RUN write '0x%llx'didn't fail",
host_cap.capabilities ^ BIT_ULL(i));
}
kvm_vm_free(vm);
}
/*
* Verify KVM allows writing PERF_CAPABILITIES with all KVM-supported features
* enabled, as well as '0' (to disable all features).
*/
static void test_basic_perf_capabilities(union perf_capabilities host_cap)
{
struct kvm_vcpu *vcpu;
struct kvm_vm *vm = vm_create_with_one_vcpu(&vcpu, NULL);
vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, 0);
vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, host_cap.capabilities);
kvm_vm_free(vm);
}
static void test_fungible_perf_capabilities(union perf_capabilities host_cap)
{
const uint64_t fungible_caps = host_cap.capabilities & ~immutable_caps.capabilities;
struct kvm_vcpu *vcpu;
struct kvm_vm *vm = vm_create_with_one_vcpu(&vcpu, NULL);
int bit;
for_each_set_bit(bit, &fungible_caps, 64) {
vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, BIT_ULL(bit));
vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES,
host_cap.capabilities & ~BIT_ULL(bit));
}
vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, host_cap.capabilities);
kvm_vm_free(vm);
}
/*
* Verify KVM rejects attempts to set unsupported and/or immutable features in
* PERF_CAPABILITIES. Note, LBR format and PEBS format need to be validated
* separately as they are multi-bit values, e.g. toggling or setting a single
* bit can generate a false positive without dedicated safeguards.
*/
static void test_immutable_perf_capabilities(union perf_capabilities host_cap)
{
const uint64_t reserved_caps = (~host_cap.capabilities |
immutable_caps.capabilities) &
~format_caps.capabilities;
struct kvm_vcpu *vcpu;
struct kvm_vm *vm = vm_create_with_one_vcpu(&vcpu, NULL);
union perf_capabilities val = host_cap;
int r, bit;
for_each_set_bit(bit, &reserved_caps, 64) {
r = _vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES,
host_cap.capabilities ^ BIT_ULL(bit));
TEST_ASSERT(!r, "%s immutable feature 0x%llx (bit %d) didn't fail",
host_cap.capabilities & BIT_ULL(bit) ? "Setting" : "Clearing",
BIT_ULL(bit), bit);
}
/*
* KVM only supports the host's native LBR format, as well as '0' (to
* disable LBR support). Verify KVM rejects all other LBR formats.
*/
for (val.lbr_format = 1; val.lbr_format; val.lbr_format++) {
if (val.lbr_format == host_cap.lbr_format)
continue;
r = _vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, val.capabilities);
TEST_ASSERT(!r, "Bad LBR FMT = 0x%x didn't fail, host = 0x%x",
val.lbr_format, host_cap.lbr_format);
}
/* Ditto for the PEBS format. */
for (val.pebs_format = 1; val.pebs_format; val.pebs_format++) {
if (val.pebs_format == host_cap.pebs_format)
continue;
r = _vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, val.capabilities);
TEST_ASSERT(!r, "Bad PEBS FMT = 0x%x didn't fail, host = 0x%x",
val.pebs_format, host_cap.pebs_format);
}
kvm_vm_free(vm);
}
/*
* Test that LBR MSRs are writable when LBRs are enabled, and then verify that
* disabling the vPMU via CPUID also disables LBR support. Set bits 2:0 of
* LBR_TOS as those bits are writable across all uarch implementations (arch
* LBRs will need to poke a different MSR).
*/
static void test_lbr_perf_capabilities(union perf_capabilities host_cap)
{
struct kvm_vcpu *vcpu;
struct kvm_vm *vm;
int r;
if (!host_cap.lbr_format)
return;
vm = vm_create_with_one_vcpu(&vcpu, NULL);
vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, host_cap.capabilities);
vcpu_set_msr(vcpu, MSR_LBR_TOS, 7);
vcpu_clear_cpuid_entry(vcpu, X86_PROPERTY_PMU_VERSION.function);
r = _vcpu_set_msr(vcpu, MSR_LBR_TOS, 7);
TEST_ASSERT(!r, "Writing LBR_TOS should fail after disabling vPMU");
kvm_vm_free(vm);
}
int main(int argc, char *argv[])
{
union perf_capabilities host_cap;
TEST_REQUIRE(get_kvm_param_bool("enable_pmu"));
TEST_REQUIRE(kvm_cpu_has(X86_FEATURE_PDCM));
TEST_REQUIRE(kvm_cpu_has_p(X86_PROPERTY_PMU_VERSION));
TEST_REQUIRE(kvm_cpu_property(X86_PROPERTY_PMU_VERSION) > 0);
host_cap.capabilities = kvm_get_feature_msr(MSR_IA32_PERF_CAPABILITIES);
TEST_ASSERT(host_cap.full_width_write,
"Full-width writes should always be supported");
test_basic_perf_capabilities(host_cap);
test_fungible_perf_capabilities(host_cap);
test_immutable_perf_capabilities(host_cap);
test_guest_wrmsr_perf_capabilities(host_cap);
test_lbr_perf_capabilities(host_cap);
}
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