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, 80 insertions, 0 deletions

diff --git a/linux-user/hexagon/cpu_loop.c b/linux-user/hexagon/cpu_loop.c
new file mode 100644
index 000000000..6b24cbaba
--- /dev/null
+++ b/linux-user/hexagon/cpu_loop.c
@@ -0,0 +1,80 @@
+/*
+ *  qemu user cpu loop
+ *
+ *  Copyright (c) 2003-2008 Fabrice Bellard
+ *  Copyright(c) 2019-2021 Qualcomm Innovation Center, Inc. All Rights Reserved.
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program 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 General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu.h"
+#include "user-internals.h"
+#include "cpu_loop-common.h"
+#include "signal-common.h"
+#include "internal.h"
+
+void cpu_loop(CPUHexagonState *env)
+{
+    CPUState *cs = env_cpu(env);
+    int trapnr;
+    target_ulong syscallnum;
+    target_ulong ret;
+
+    for (;;) {
+        cpu_exec_start(cs);
+        trapnr = cpu_exec(cs);
+        cpu_exec_end(cs);
+        process_queued_cpu_work(cs);
+
+        switch (trapnr) {
+        case EXCP_INTERRUPT:
+            /* just indicate that signals should be handled asap */
+            break;
+        case HEX_EXCP_TRAP0:
+            syscallnum = env->gpr[6];
+            env->gpr[HEX_REG_PC] += 4;
+            ret = do_syscall(env,
+                             syscallnum,
+                             env->gpr[0],
+                             env->gpr[1],
+                             env->gpr[2],
+                             env->gpr[3],
+                             env->gpr[4],
+                             env->gpr[5],
+                             0, 0);
+            if (ret == -TARGET_ERESTARTSYS) {
+                env->gpr[HEX_REG_PC] -= 4;
+            } else if (ret != -TARGET_QEMU_ESIGRETURN) {
+                env->gpr[0] = ret;
+            }
+            break;
+        case EXCP_ATOMIC:
+            cpu_exec_step_atomic(cs);
+            break;
+        default:
+            EXCP_DUMP(env, "\nqemu: unhandled CPU exception %#x - aborting\n",
+                     trapnr);
+            exit(EXIT_FAILURE);
+        }
+        process_pending_signals(env);
+    }
+}
+
+void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
+{
+    env->gpr[HEX_REG_PC] = regs->sepc;
+    env->gpr[HEX_REG_SP] = regs->sp;
+    env->gpr[HEX_REG_USR] = 0x56000;
+}