KVM: arm64: selftest: Expand external_aborts test to look for TTW levels

Add a basic test corrupting a level-2 table entry to check that
the resulting abort is a SEA on a PTW at level-3.

Reviewed-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Marc Zyngier <maz@kernel.org>

Author: Marc Zyngier

tools/testing/selftests/kvm/arm64/external_aborts.c

@@ -250,6 +250,47 @@ static void test_serror(void)
 	kvm_vm_free(vm);
 }
 
+static void expect_sea_s1ptw_handler(struct ex_regs *regs)
+{
+	u64 esr = read_sysreg(esr_el1);
+
+	GUEST_ASSERT_EQ(regs->pc, expected_abort_pc);
+	GUEST_ASSERT_EQ(ESR_ELx_EC(esr), ESR_ELx_EC_DABT_CUR);
+	GUEST_ASSERT_EQ((esr & ESR_ELx_FSC), ESR_ELx_FSC_SEA_TTW(3));
+
+	GUEST_DONE();
+}
+
+static noinline void test_s1ptw_abort_guest(void)
+{
+	extern char test_s1ptw_abort_insn;
+
+	WRITE_ONCE(expected_abort_pc, (u64)&test_s1ptw_abort_insn);
+
+	asm volatile("test_s1ptw_abort_insn:\n\t"
+		     "ldr x0, [%0]\n\t"
+		     : : "r" (MMIO_ADDR) : "x0", "memory");
+
+	GUEST_FAIL("Load on S1PTW abort should not retire");
+}
+
+static void test_s1ptw_abort(void)
+{
+	struct kvm_vcpu *vcpu;
+	u64 *ptep, bad_pa;
+	struct kvm_vm *vm = vm_create_with_dabt_handler(&vcpu, test_s1ptw_abort_guest,
+							expect_sea_s1ptw_handler);
+
+	ptep = virt_get_pte_hva_at_level(vm, MMIO_ADDR, 2);
+	bad_pa = BIT(vm->pa_bits) - vm->page_size;
+
+	*ptep &= ~GENMASK(47, 12);
+	*ptep |= bad_pa;
+
+	vcpu_run_expect_done(vcpu);
+	kvm_vm_free(vm);
+}
+
 static void test_serror_emulated_guest(void)
 {
 	GUEST_ASSERT(!(read_sysreg(isr_el1) & ISR_EL1_A));
@@ -327,4 +368,5 @@ int main(void)
 	test_serror_masked();
 	test_serror_emulated();
 	test_mmio_ease();
+	test_s1ptw_abort();
 }

tools/testing/selftests/kvm/include/arm64/processor.h

@@ -175,6 +175,7 @@ void vm_install_exception_handler(struct kvm_vm *vm,
 void vm_install_sync_handler(struct kvm_vm *vm,
 		int vector, int ec, handler_fn handler);
 
+uint64_t *virt_get_pte_hva_at_level(struct kvm_vm *vm, vm_vaddr_t gva, int level);
 uint64_t *virt_get_pte_hva(struct kvm_vm *vm, vm_vaddr_t gva);
 
 static inline void cpu_relax(void)

tools/testing/selftests/kvm/lib/arm64/processor.c

@@ -185,7 +185,7 @@ void virt_arch_pg_map(struct kvm_vm *vm, uint64_t vaddr, uint64_t paddr)
 	_virt_pg_map(vm, vaddr, paddr, attr_idx);
 }
 
-uint64_t *virt_get_pte_hva(struct kvm_vm *vm, vm_vaddr_t gva)
+uint64_t *virt_get_pte_hva_at_level(struct kvm_vm *vm, vm_vaddr_t gva, int level)
 {
 	uint64_t *ptep;
 
@@ -195,17 +195,23 @@ uint64_t *virt_get_pte_hva(struct kvm_vm *vm, vm_vaddr_t gva)
 	ptep = addr_gpa2hva(vm, vm->pgd) + pgd_index(vm, gva) * 8;
 	if (!ptep)
 		goto unmapped_gva;
+	if (level == 0)
+		return ptep;
 
 	switch (vm->pgtable_levels) {
 	case 4:
 		ptep = addr_gpa2hva(vm, pte_addr(vm, *ptep)) + pud_index(vm, gva) * 8;
 		if (!ptep)
 			goto unmapped_gva;
+		if (level == 1)
+			break;
 		/* fall through */
 	case 3:
 		ptep = addr_gpa2hva(vm, pte_addr(vm, *ptep)) + pmd_index(vm, gva) * 8;
 		if (!ptep)
 			goto unmapped_gva;
+		if (level == 2)
+			break;
 		/* fall through */
 	case 2:
 		ptep = addr_gpa2hva(vm, pte_addr(vm, *ptep)) + pte_index(vm, gva) * 8;
@@ -223,6 +229,11 @@ uint64_t *virt_get_pte_hva(struct kvm_vm *vm, vm_vaddr_t gva)
 	exit(EXIT_FAILURE);
 }
 
+uint64_t *virt_get_pte_hva(struct kvm_vm *vm, vm_vaddr_t gva)
+{
+	return virt_get_pte_hva_at_level(vm, gva, 3);
+}
+
 vm_paddr_t addr_arch_gva2gpa(struct kvm_vm *vm, vm_vaddr_t gva)
 {
 	uint64_t *ptep = virt_get_pte_hva(vm, gva);