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, 108 insertions, 0 deletions

diff --git a/linux-user/openrisc/cpu_loop.c b/linux-user/openrisc/cpu_loop.c
new file mode 100644
index 000000000..3cfdbbf03
--- /dev/null
+++ b/linux-user/openrisc/cpu_loop.c
@@ -0,0 +1,108 @@
+/*
+ *  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(CPUOpenRISCState *env)
+{
+    CPUState *cs = env_cpu(env);
+    int trapnr;
+    abi_long ret;
+    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_SYSCALL:
+            env->pc += 4;   /* 0xc00; */
+            ret = do_syscall(env,
+                             cpu_get_gpr(env, 11), /* return value       */
+                             cpu_get_gpr(env, 3),  /* r3 - r7 are params */
+                             cpu_get_gpr(env, 4),
+                             cpu_get_gpr(env, 5),
+                             cpu_get_gpr(env, 6),
+                             cpu_get_gpr(env, 7),
+                             cpu_get_gpr(env, 8), 0, 0);
+            if (ret == -TARGET_ERESTARTSYS) {
+                env->pc -= 4;
+            } else if (ret != -TARGET_QEMU_ESIGRETURN) {
+                cpu_set_gpr(env, 11, ret);
+            }
+            break;
+        case EXCP_ALIGN:
+            info.si_signo = TARGET_SIGBUS;
+            info.si_errno = 0;
+            info.si_code = TARGET_BUS_ADRALN;
+            info._sifields._sigfault._addr = env->pc;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
+            break;
+        case EXCP_ILLEGAL:
+            info.si_signo = TARGET_SIGILL;
+            info.si_errno = 0;
+            info.si_code = TARGET_ILL_ILLOPC;
+            info._sifields._sigfault._addr = env->pc;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
+            break;
+        case EXCP_INTERRUPT:
+            /* We processed the pending cpu work above.  */
+            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;
+        case EXCP_RANGE:
+            /* Requires SR.OVE set, which linux-user won't do. */
+            cpu_abort(cs, "Unexpected RANGE exception");
+        case EXCP_FPE:
+            /*
+             * Requires FPSCR.FPEE set.  Writes to FPSCR from usermode not
+             * yet enabled in kernel ABI, so linux-user does not either.
+             */
+            cpu_abort(cs, "Unexpected FPE exception");
+        default:
+            g_assert_not_reached();
+        }
+        process_pending_signals(env);
+    }
+}
+
+void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
+{
+    int i;
+
+    for (i = 0; i < 32; i++) {
+        cpu_set_gpr(env, i, regs->gpr[i]);
+    }
+    env->pc = regs->pc;
+    cpu_set_sr(env, regs->sr);
+}