Introduce Virtio-loopback epsilon release:

Epsilon release introduces a new compatibility layer which make virtio-loopback
design to work with QEMU and rust-vmm vhost-user backend without require any
changes.

Signed-off-by: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Change-Id: I52e57563e08a7d0bdc002f8e928ee61ba0c53dd9

1 files changed, 61 insertions, 0 deletions

diff --git a/target/nios2/op_helper.c b/target/nios2/op_helper.c
new file mode 100644
index 000000000..a59003855
--- /dev/null
+++ b/target/nios2/op_helper.c
@@ -0,0 +1,61 @@
+/*
+ * Altera Nios II helper routines.
+ *
+ * Copyright (C) 2012 Chris Wulff <crwulff@gmail.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see
+ * <http://www.gnu.org/licenses/lgpl-2.1.html>
+ */
+
+#include "qemu/osdep.h"
+#include "cpu.h"
+#include "exec/helper-proto.h"
+#include "exec/cpu_ldst.h"
+#include "exec/exec-all.h"
+#include "qemu/main-loop.h"
+
+#if !defined(CONFIG_USER_ONLY)
+void helper_mmu_read_debug(CPUNios2State *env, uint32_t rn)
+{
+    mmu_read_debug(env, rn);
+}
+
+void helper_mmu_write(CPUNios2State *env, uint32_t rn, uint32_t v)
+{
+    mmu_write(env, rn, v);
+}
+
+static void nios2_check_interrupts(CPUNios2State *env)
+{
+    if (env->irq_pending &&
+        (env->regs[CR_STATUS] & CR_STATUS_PIE)) {
+        env->irq_pending = 0;
+        cpu_interrupt(env_cpu(env), CPU_INTERRUPT_HARD);
+    }
+}
+
+void helper_check_interrupts(CPUNios2State *env)
+{
+    qemu_mutex_lock_iothread();
+    nios2_check_interrupts(env);
+    qemu_mutex_unlock_iothread();
+}
+#endif /* !CONFIG_USER_ONLY */
+
+void helper_raise_exception(CPUNios2State *env, uint32_t index)
+{
+    CPUState *cs = env_cpu(env);
+    cs->exception_index = index;
+    cpu_loop_exit(cs);
+}