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KVM: selftests: Expand negative testing of guest writes to PERF_CAPABILITIES

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Test that the guest can't write 0 to PERF_CAPABILITIES, can't write the
current value, and can't toggle _any_ bits.  There is no reason to special
case the LBR format.

Link: https://lore.kernel.org/r/20230311004618.920745-17-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
This commit is contained in:
Sean Christopherson
2023-03-10 16:46:13 -08:00
parent a2a34d148e
commit baa36dac6c
1 changed files with 54 additions and 7 deletions
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61
tools/testing/selftests/kvm/x86_64/vmx_pmu_caps_test.c
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@@ -54,9 +54,59 @@ static const union perf_capabilities format_caps = {
.pebs_format = -1,
};
static void guest_code(void)
static void guest_code(uint64_t current_val)
{
wrmsr(MSR_IA32_PERF_CAPABILITIES, PMU_CAP_LBR_FMT);
uint8_t vector;
int i;
vector = wrmsr_safe(MSR_IA32_PERF_CAPABILITIES, current_val);
GUEST_ASSERT_2(vector == GP_VECTOR, current_val, vector);
vector = wrmsr_safe(MSR_IA32_PERF_CAPABILITIES, 0);
GUEST_ASSERT_2(vector == GP_VECTOR, 0, vector);
for (i = 0; i < 64; i++) {
vector = wrmsr_safe(MSR_IA32_PERF_CAPABILITIES,
current_val ^ BIT_ULL(i));
GUEST_ASSERT_2(vector == GP_VECTOR,
current_val ^ BIT_ULL(i), vector);
}
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;
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_2(uc, "val = 0x%lx, vector = %lu");
break;
case UCALL_DONE:
break;
default:
TEST_FAIL("Unexpected ucall: %lu", uc.cmd);
}
ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_PERF_CAPABILITIES), host_cap.capabilities);
kvm_vm_free(vm);
}
/*
@@ -79,7 +129,7 @@ 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, guest_code);
struct kvm_vm *vm = vm_create_with_one_vcpu(&vcpu, NULL);
int bit;
for_each_set_bit(bit, &fungible_caps, 64) {
@@ -89,10 +139,6 @@ static void test_fungible_perf_capabilities(union perf_capabilities host_cap)
}
vcpu_set_msr(vcpu, MSR_IA32_PERF_CAPABILITIES, host_cap.capabilities);
/* check whatever we write with KVM_SET_MSR is _not_ modified */
vcpu_run(vcpu);
ASSERT_EQ(vcpu_get_msr(vcpu, MSR_IA32_PERF_CAPABILITIES), host_cap.capabilities);
kvm_vm_free(vm);
}
@@ -153,6 +199,7 @@ int main(int argc, char *argv[])
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);
printf("Completed perf capability tests.\n");
}