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, 139 insertions, 0 deletions

diff --git a/linux-user/m68k/cpu_loop.c b/linux-user/m68k/cpu_loop.c
new file mode 100644
index 000000000..790bd558c
--- /dev/null
+++ b/linux-user/m68k/cpu_loop.c
@@ -0,0 +1,139 @@
+/*
+ *  qemu user cpu loop
+ *
+ *  Copyright (c) 2003-2008 Fabrice Bellard
+ *
+ *  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-common.h"
+#include "qemu.h"
+#include "user-internals.h"
+#include "cpu_loop-common.h"
+#include "signal-common.h"
+
+void cpu_loop(CPUM68KState *env)
+{
+    CPUState *cs = env_cpu(env);
+    int trapnr;
+    unsigned int n;
+    target_siginfo_t info;
+
+    for(;;) {
+        cpu_exec_start(cs);
+        trapnr = cpu_exec(cs);
+        cpu_exec_end(cs);
+        process_queued_cpu_work(cs);
+
+        switch(trapnr) {
+        case EXCP_HALT_INSN:
+            /* Semihosing syscall.  */
+            env->pc += 4;
+            do_m68k_semihosting(env, env->dregs[0]);
+            break;
+        case EXCP_ILLEGAL:
+        case EXCP_LINEA:
+        case EXCP_LINEF:
+            info.si_signo = TARGET_SIGILL;
+            info.si_errno = 0;
+            info.si_code = TARGET_ILL_ILLOPN;
+            info._sifields._sigfault._addr = env->pc;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
+            break;
+        case EXCP_CHK:
+            info.si_signo = TARGET_SIGFPE;
+            info.si_errno = 0;
+            info.si_code = TARGET_FPE_INTOVF;
+            info._sifields._sigfault._addr = env->pc;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
+            break;
+        case EXCP_DIV0:
+            info.si_signo = TARGET_SIGFPE;
+            info.si_errno = 0;
+            info.si_code = TARGET_FPE_INTDIV;
+            info._sifields._sigfault._addr = env->pc;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
+            break;
+        case EXCP_TRAP0:
+            {
+                abi_long ret;
+                n = env->dregs[0];
+                env->pc += 2;
+                ret = do_syscall(env,
+                                 n,
+                                 env->dregs[1],
+                                 env->dregs[2],
+                                 env->dregs[3],
+                                 env->dregs[4],
+                                 env->dregs[5],
+                                 env->aregs[0],
+                                 0, 0);
+                if (ret == -TARGET_ERESTARTSYS) {
+                    env->pc -= 2;
+                } else if (ret != -TARGET_QEMU_ESIGRETURN) {
+                    env->dregs[0] = ret;
+                }
+            }
+            break;
+        case EXCP_INTERRUPT:
+            /* just indicate that signals should be handled asap */
+            break;
+        case EXCP_DEBUG:
+            info.si_signo = TARGET_SIGTRAP;
+            info.si_errno = 0;
+            info.si_code = TARGET_TRAP_BRKPT;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
+            break;
+        case EXCP_ATOMIC:
+            cpu_exec_step_atomic(cs);
+            break;
+        default:
+            EXCP_DUMP(env, "qemu: unhandled CPU exception 0x%x - aborting\n", trapnr);
+            abort();
+        }
+        process_pending_signals(env);
+    }
+}
+
+void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
+{
+    CPUState *cpu = env_cpu(env);
+    TaskState *ts = cpu->opaque;
+    struct image_info *info = ts->info;
+
+    env->pc = regs->pc;
+    env->dregs[0] = regs->d0;
+    env->dregs[1] = regs->d1;
+    env->dregs[2] = regs->d2;
+    env->dregs[3] = regs->d3;
+    env->dregs[4] = regs->d4;
+    env->dregs[5] = regs->d5;
+    env->dregs[6] = regs->d6;
+    env->dregs[7] = regs->d7;
+    env->aregs[0] = regs->a0;
+    env->aregs[1] = regs->a1;
+    env->aregs[2] = regs->a2;
+    env->aregs[3] = regs->a3;
+    env->aregs[4] = regs->a4;
+    env->aregs[5] = regs->a5;
+    env->aregs[6] = regs->a6;
+    env->aregs[7] = regs->usp;
+    env->sr = regs->sr;
+
+    ts->stack_base = info->start_stack;
+    ts->heap_base = info->brk;
+    /* This will be filled in on the first SYS_HEAPINFO call.  */
+    ts->heap_limit = 0;
+}