KVM: selftests: Add CPUID tests for Hyper-V features that need in-kernel APIC

Add testcases to x86's Hyper-V CPUID test to verify that KVM advertises
support for features that require an in-kernel local APIC appropriately,
i.e. that KVM hides support from the vCPU-scoped ioctl if the VM doesn't
have an in-kernel local APIC.

Cc: Vitaly Kuznetsov <vkuznets@redhat.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20250118003454.2619573-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>

diff --git a/tools/testing/selftests/kvm/x86/hyperv_cpuid.c b/tools/testing/selftests/kvm/x86/hyperv_cpuid.c
index 3188749ec6e12211d97eb0db57a81cafdafc8930..4e920705681aef6b9311287ce3dfcf6b00d3a62a 100644 (file)
--- a/tools/testing/selftests/kvm/x86/hyperv_cpuid.c
+++ b/tools/testing/selftests/kvm/x86/hyperv_cpuid.c
@@ -43,6 +43,7 @@ static bool smt_possible(void)
 
 static void test_hv_cpuid(struct kvm_vcpu *vcpu, bool evmcs_expected)
 {
+       const bool has_irqchip = !vcpu || vcpu->vm->has_irqchip;
        const struct kvm_cpuid2 *hv_cpuid_entries;
        int i;
        int nent_expected = 10;
@@ -85,12 +86,19 @@ static void test_hv_cpuid(struct kvm_vcpu *vcpu, bool evmcs_expected)
                                    entry->eax, evmcs_expected
                                );
                        break;
+               case 0x40000003:
+                       TEST_ASSERT(has_irqchip || !(entry->edx & BIT(19)),
+                                   "\"Direct\" Synthetic Timers should require in-kernel APIC");
+                       break;
                case 0x40000004:
                        test_val = entry->eax & (1UL << 18);
 
                        TEST_ASSERT(!!test_val == !smt_possible(),
                                    "NoNonArchitecturalCoreSharing bit"
                                    " doesn't reflect SMT setting");
+
+                       TEST_ASSERT(has_irqchip || !(entry->eax & BIT(10)),
+                                   "Cluster IPI (i.e. SEND_IPI) should require in-kernel APIC");
                        break;
                case 0x4000000A:
                        TEST_ASSERT(entry->eax & (1UL << 19),
@@ -145,9 +153,14 @@ int main(int argc, char *argv[])
 
        TEST_REQUIRE(kvm_has_cap(KVM_CAP_HYPERV_CPUID));
 
-       vm = vm_create_with_one_vcpu(&vcpu, guest_code);
+       /* Test the vCPU ioctl without an in-kernel local APIC. */
+       vm = vm_create_barebones();
+       vcpu = __vm_vcpu_add(vm, 0);
+       test_hv_cpuid(vcpu, false);
+       kvm_vm_free(vm);
 
        /* Test vCPU ioctl version */
+       vm = vm_create_with_one_vcpu(&vcpu, guest_code);
        test_hv_cpuid_e2big(vm, vcpu);
        test_hv_cpuid(vcpu, false);