Inject an Unknown Fault instead of aborting VM on unknown exception
This allows the VM to decide how to handle the fault, rather than being
forcefully aborted. It also allows us to simplify some of the secondary tests,
whereby the test can trap and observe the exception rather than abort, which
reduces the number of secondary VM services tests need to spawn.
Bug: 140916188
Change-Id: Ib2e98a6507aa15c5d805089cd28851b66c6a6379
diff --git a/test/vmapi/common/exception_handler.c b/test/vmapi/common/exception_handler.c
new file mode 100644
index 0000000..87e61ec
--- /dev/null
+++ b/test/vmapi/common/exception_handler.c
@@ -0,0 +1,109 @@
+/*
+ * Copyright 2019 The Hafnium Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "hf/dlog.h"
+
+#include "vmapi/hf/call.h"
+
+#include "../msr.h"
+#include "test/hftest.h"
+
+/**
+ * Tracks the number of times the exception handler has been invoked.
+ */
+static int exception_handler_num_exceptions = 0;
+
+/**
+ * Sends the number of exceptions handled to the Primary VM.
+ */
+void exception_handler_send_num_exceptions(void)
+{
+ void *send_buf = SERVICE_SEND_BUFFER();
+
+ dlog("Sending num_exceptions %d to primary VM\n",
+ exception_handler_num_exceptions);
+ memcpy_s(send_buf, SPCI_MSG_PAYLOAD_MAX,
+ (const void *)&exception_handler_num_exceptions,
+ sizeof(exception_handler_num_exceptions));
+ EXPECT_EQ(spci_msg_send(hf_vm_get_id(), HF_PRIMARY_VM_ID,
+ sizeof(exception_handler_num_exceptions), 0)
+ .func,
+ SPCI_SUCCESS_32);
+}
+
+/**
+ * Receives the number of exceptions handled.
+ */
+int exception_handler_receive_num_exceptions(
+ const struct spci_value *send_res,
+ const struct spci_memory_region *recv_buf)
+{
+ int num_exceptions = *((const int *)recv_buf);
+
+ EXPECT_EQ(send_res->func, SPCI_MSG_SEND_32);
+ EXPECT_EQ(spci_msg_send_size(*send_res), sizeof(num_exceptions));
+ EXPECT_EQ(spci_rx_release().func, SPCI_SUCCESS_32);
+ return num_exceptions;
+}
+
+/**
+ * EL1 exception handler to use in unit test VMs.
+ * Skips the instruction that triggered the exception.
+ */
+bool exception_handler_skip_instruction(void)
+{
+ dlog("%s function is triggered!\n", __func__);
+ ++exception_handler_num_exceptions;
+
+ /* Skip instruction that triggered the exception. */
+ uint64_t next_pc = read_msr(elr_el1);
+ next_pc += 4UL;
+ write_msr(elr_el1, next_pc);
+
+ /* Indicate that elr_el1 should not be restored. */
+ return true;
+}
+
+/**
+ * EL1 exception handler to use in unit test VMs.
+ * Yields control back to the hypervisor and sends the number of exceptions.
+ */
+bool exception_handler_yield(void)
+{
+ dlog("%s function is triggered!\n", __func__);
+ ++exception_handler_num_exceptions;
+
+ exception_handler_send_num_exceptions();
+
+ /* Indicate that elr_el1 should not be restored. */
+ return true;
+}
+
+/**
+ * Returns the number of times the instruction handler was invoked.
+ */
+int exception_handler_get_num(void)
+{
+ return exception_handler_num_exceptions;
+}
+
+/**
+ * Resets the number of exceptions counter;
+ */
+void exception_handler_reset(void)
+{
+ exception_handler_num_exceptions = 0;
+}