1 files changed, 105 insertions, 0 deletions
diff --git a/tools/testing/selftests/kvm/x86/smaller_maxphyaddr_emulation_test.c b/tools/testing/selftests/kvm/x86/smaller_maxphyaddr_emulation_test.c
new file mode 100644
index 000000000000..fabeeaddfb3a
--- /dev/null
+++ b/tools/testing/selftests/kvm/x86/smaller_maxphyaddr_emulation_test.c
@@ -0,0 +1,105 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2020, Google LLC.
+ *
+ * Test that KVM emulates instructions in response to EPT violations when
+ * allow_smaller_maxphyaddr is enabled and guest.MAXPHYADDR < host.MAXPHYADDR.
+ */
+#include "flds_emulation.h"
+
+#include "test_util.h"
+#include "kvm_util.h"
+#include "vmx.h"
+
+#define MAXPHYADDR 36
+
+#define MEM_REGION_GVA	0x0000123456789000
+#define MEM_REGION_GPA	0x0000000700000000
+#define MEM_REGION_SLOT	10
+#define MEM_REGION_SIZE PAGE_SIZE
+
+static void guest_code(bool tdp_enabled)
+{
+	uint64_t error_code;
+	uint64_t vector;
+
+	vector = kvm_asm_safe_ec(FLDS_MEM_EAX, error_code, "a"(MEM_REGION_GVA));
+
+	/*
+	 * When TDP is enabled, flds will trigger an emulation failure, exit to
+	 * userspace, and then the selftest host "VMM" skips the instruction.
+	 *
+	 * When TDP is disabled, no instruction emulation is required so flds
+	 * should generate #PF(RSVD).
+	 */
+	if (tdp_enabled) {
+		GUEST_ASSERT(!vector);
+	} else {
+		GUEST_ASSERT_EQ(vector, PF_VECTOR);
+		GUEST_ASSERT(error_code & PFERR_RSVD_MASK);
+	}
+
+	GUEST_DONE();
+}
+
+int main(int argc, char *argv[])
+{
+	struct kvm_vcpu *vcpu;
+	struct kvm_vm *vm;
+	struct ucall uc;
+	uint64_t *pte;
+	uint64_t *hva;
+	uint64_t gpa;
+	int rc;
+
+	TEST_REQUIRE(kvm_has_cap(KVM_CAP_SMALLER_MAXPHYADDR));
+
+	vm = vm_create_with_one_vcpu(&vcpu, guest_code);
+	vcpu_args_set(vcpu, 1, kvm_is_tdp_enabled());
+
+	vcpu_set_cpuid_property(vcpu, X86_PROPERTY_MAX_PHY_ADDR, MAXPHYADDR);
+
+	rc = kvm_check_cap(KVM_CAP_EXIT_ON_EMULATION_FAILURE);
+	TEST_ASSERT(rc, "KVM_CAP_EXIT_ON_EMULATION_FAILURE is unavailable");
+	vm_enable_cap(vm, KVM_CAP_EXIT_ON_EMULATION_FAILURE, 1);
+
+	vm_userspace_mem_region_add(vm, VM_MEM_SRC_ANONYMOUS,
+				    MEM_REGION_GPA, MEM_REGION_SLOT,
+				    MEM_REGION_SIZE / PAGE_SIZE, 0);
+	gpa = vm_phy_pages_alloc(vm, MEM_REGION_SIZE / PAGE_SIZE,
+				 MEM_REGION_GPA, MEM_REGION_SLOT);
+	TEST_ASSERT(gpa == MEM_REGION_GPA, "Failed vm_phy_pages_alloc");
+	virt_map(vm, MEM_REGION_GVA, MEM_REGION_GPA, 1);
+	hva = addr_gpa2hva(vm, MEM_REGION_GPA);
+	memset(hva, 0, PAGE_SIZE);
+
+	pte = vm_get_page_table_entry(vm, MEM_REGION_GVA);
+	*pte |= BIT_ULL(MAXPHYADDR);
+
+	vcpu_run(vcpu);
+
+	/*
+	 * When TDP is enabled, KVM must emulate in response the guest physical
+	 * address that is illegal from the guest's perspective, but is legal
+	 * from hardware's perspeective.  This should result in an emulation
+	 * failure exit to userspace since KVM doesn't support emulating flds.
+	 */
+	if (kvm_is_tdp_enabled()) {
+		handle_flds_emulation_failure_exit(vcpu);
+		vcpu_run(vcpu);
+	}
+
+	switch (get_ucall(vcpu, &uc)) {
+	case UCALL_ABORT:
+		REPORT_GUEST_ASSERT(uc);
+		break;
+	case UCALL_DONE:
+		break;
+	default:
+		TEST_FAIL("Unrecognized ucall: %lu", uc.cmd);
+	}
+
+	kvm_vm_free(vm);
+
+	return 0;
+}