[PATCH 6/6] KVM: selftests: smm_test: Test SMM enter from L2

From: Vitaly Kuznetsov
Date: Mon Jun 28 2021 - 06:45:23 EST


Two additional tests are added:
- SMM triggered from L2 does not currupt L1 host state.
- Save/restore during SMM triggered from L2 does not corrupt guest/host
state.

Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
---
tools/testing/selftests/kvm/x86_64/smm_test.c | 70 +++++++++++++++++--
1 file changed, 64 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/kvm/x86_64/smm_test.c b/tools/testing/selftests/kvm/x86_64/smm_test.c
index c1f831803ad2..d0fe2fdce58c 100644
--- a/tools/testing/selftests/kvm/x86_64/smm_test.c
+++ b/tools/testing/selftests/kvm/x86_64/smm_test.c
@@ -53,15 +53,28 @@ static inline void sync_with_host(uint64_t phase)
: "+a" (phase));
}

-void self_smi(void)
+static void self_smi(void)
{
x2apic_write_reg(APIC_ICR,
APIC_DEST_SELF | APIC_INT_ASSERT | APIC_DM_SMI);
}

-void guest_code(void *arg)
+static void l2_guest_code(void)
{
+ sync_with_host(8);
+
+ sync_with_host(10);
+
+ vmcall();
+}
+
+static void guest_code(void *arg)
+{
+ #define L2_GUEST_STACK_SIZE 64
+ unsigned long l2_guest_stack[L2_GUEST_STACK_SIZE];
uint64_t apicbase = rdmsr(MSR_IA32_APICBASE);
+ struct svm_test_data *svm = arg;
+ struct vmx_pages *vmx_pages = arg;

sync_with_host(1);

@@ -74,21 +87,50 @@ void guest_code(void *arg)
sync_with_host(4);

if (arg) {
- if (cpu_has_svm())
- generic_svm_setup(arg, NULL, NULL);
- else
- GUEST_ASSERT(prepare_for_vmx_operation(arg));
+ if (cpu_has_svm()) {
+ generic_svm_setup(svm, l2_guest_code,
+ &l2_guest_stack[L2_GUEST_STACK_SIZE]);
+ } else {
+ GUEST_ASSERT(prepare_for_vmx_operation(vmx_pages));
+ GUEST_ASSERT(load_vmcs(vmx_pages));
+ prepare_vmcs(vmx_pages, l2_guest_code,
+ &l2_guest_stack[L2_GUEST_STACK_SIZE]);
+ }

sync_with_host(5);

self_smi();

sync_with_host(7);
+
+ if (cpu_has_svm()) {
+ run_guest(svm->vmcb, svm->vmcb_gpa);
+ svm->vmcb->save.rip += 3;
+ run_guest(svm->vmcb, svm->vmcb_gpa);
+ } else {
+ vmlaunch();
+ vmresume();
+ }
+
+ /* Stages 8-11 are eaten by SMM (SMRAM_STAGE reported instead) */
+ sync_with_host(12);
}

sync_with_host(DONE);
}

+void inject_smi(struct kvm_vm *vm)
+{
+ struct kvm_vcpu_events events;
+
+ vcpu_events_get(vm, VCPU_ID, &events);
+
+ events.smi.pending = 1;
+ events.flags |= KVM_VCPUEVENT_VALID_SMM;
+
+ vcpu_events_set(vm, VCPU_ID, &events);
+}
+
int main(int argc, char *argv[])
{
vm_vaddr_t nested_gva = 0;
@@ -147,6 +189,22 @@ int main(int argc, char *argv[])
"Unexpected stage: #%x, got %x",
stage, stage_reported);

+ /*
+ * Enter SMM during L2 execution and check that we correctly
+ * return from it. Do not perform save/restore while in SMM yet.
+ */
+ if (stage == 8) {
+ inject_smi(vm);
+ continue;
+ }
+
+ /*
+ * Perform save/restore while the guest is in SMM triggered
+ * during L2 execution.
+ */
+ if (stage == 10)
+ inject_smi(vm);
+
state = vcpu_save_state(vm, VCPU_ID);
kvm_vm_release(vm);
kvm_vm_restart(vm, O_RDWR);
--
2.31.1