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, 209 insertions, 0 deletions

diff --git a/linux-user/alpha/cpu_loop.c b/linux-user/alpha/cpu_loop.c
new file mode 100644
index 000000000..4029849d5
--- /dev/null
+++ b/linux-user/alpha/cpu_loop.c
@@ -0,0 +1,209 @@
+/*
+ *  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(CPUAlphaState *env)
+{
+    CPUState *cs = env_cpu(env);
+    int trapnr;
+    target_siginfo_t info;
+    abi_long sysret;
+
+    while (1) {
+        bool arch_interrupt = true;
+
+        cpu_exec_start(cs);
+        trapnr = cpu_exec(cs);
+        cpu_exec_end(cs);
+        process_queued_cpu_work(cs);
+
+        switch (trapnr) {
+        case EXCP_RESET:
+            fprintf(stderr, "Reset requested. Exit\n");
+            exit(EXIT_FAILURE);
+            break;
+        case EXCP_MCHK:
+            fprintf(stderr, "Machine check exception. Exit\n");
+            exit(EXIT_FAILURE);
+            break;
+        case EXCP_SMP_INTERRUPT:
+        case EXCP_CLK_INTERRUPT:
+        case EXCP_DEV_INTERRUPT:
+            fprintf(stderr, "External interrupt. Exit\n");
+            exit(EXIT_FAILURE);
+            break;
+        case EXCP_OPCDEC:
+        do_sigill:
+            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_ARITH:
+            info.si_signo = TARGET_SIGFPE;
+            info.si_errno = 0;
+            info.si_code = TARGET_FPE_FLTINV;
+            info._sifields._sigfault._addr = env->pc;
+            queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
+            break;
+        case EXCP_FEN:
+            /* No-op.  Linux simply re-enables the FPU.  */
+            break;
+        case EXCP_CALL_PAL:
+            switch (env->error_code) {
+            case 0x80:
+                /* BPT */
+                info.si_signo = TARGET_SIGTRAP;
+                info.si_errno = 0;
+                info.si_code = TARGET_TRAP_BRKPT;
+                info._sifields._sigfault._addr = env->pc;
+                queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
+                break;
+            case 0x81:
+                /* BUGCHK */
+                info.si_signo = TARGET_SIGTRAP;
+                info.si_errno = 0;
+                info.si_code = 0;
+                info._sifields._sigfault._addr = env->pc;
+                queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
+                break;
+            case 0x83:
+                /* CALLSYS */
+                trapnr = env->ir[IR_V0];
+                sysret = do_syscall(env, trapnr,
+                                    env->ir[IR_A0], env->ir[IR_A1],
+                                    env->ir[IR_A2], env->ir[IR_A3],
+                                    env->ir[IR_A4], env->ir[IR_A5],
+                                    0, 0);
+                if (sysret == -TARGET_ERESTARTSYS) {
+                    env->pc -= 4;
+                    break;
+                }
+                if (sysret == -TARGET_QEMU_ESIGRETURN) {
+                    break;
+                }
+                /* Syscall writes 0 to V0 to bypass error check, similar
+                   to how this is handled internal to Linux kernel.
+                   (Ab)use trapnr temporarily as boolean indicating error.  */
+                trapnr = (env->ir[IR_V0] != 0 && sysret < 0);
+                env->ir[IR_V0] = (trapnr ? -sysret : sysret);
+                env->ir[IR_A3] = trapnr;
+                break;
+            case 0x86:
+                /* IMB */
+                /* ??? We can probably elide the code using page_unprotect
+                   that is checking for self-modifying code.  Instead we
+                   could simply call tb_flush here.  Until we work out the
+                   changes required to turn off the extra write protection,
+                   this can be a no-op.  */
+                break;
+            case 0x9E:
+                /* RDUNIQUE */
+                /* Handled in the translator for usermode.  */
+                abort();
+            case 0x9F:
+                /* WRUNIQUE */
+                /* Handled in the translator for usermode.  */
+                abort();
+            case 0xAA:
+                /* GENTRAP */
+                info.si_signo = TARGET_SIGFPE;
+                switch (env->ir[IR_A0]) {
+                case TARGET_GEN_INTOVF:
+                    info.si_code = TARGET_FPE_INTOVF;
+                    break;
+                case TARGET_GEN_INTDIV:
+                    info.si_code = TARGET_FPE_INTDIV;
+                    break;
+                case TARGET_GEN_FLTOVF:
+                    info.si_code = TARGET_FPE_FLTOVF;
+                    break;
+                case TARGET_GEN_FLTUND:
+                    info.si_code = TARGET_FPE_FLTUND;
+                    break;
+                case TARGET_GEN_FLTINV:
+                    info.si_code = TARGET_FPE_FLTINV;
+                    break;
+                case TARGET_GEN_FLTINE:
+                    info.si_code = TARGET_FPE_FLTRES;
+                    break;
+                case TARGET_GEN_ROPRAND:
+                    info.si_code = 0;
+                    break;
+                default:
+                    info.si_signo = TARGET_SIGTRAP;
+                    info.si_code = 0;
+                    break;
+                }
+                info.si_errno = 0;
+                info._sifields._sigfault._addr = env->pc;
+                queue_signal(env, info.si_signo, QEMU_SI_FAULT, &info);
+                break;
+            default:
+                goto do_sigill;
+            }
+            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_INTERRUPT:
+            /* Just indicate that signals should be handled asap.  */
+            break;
+        case EXCP_ATOMIC:
+            cpu_exec_step_atomic(cs);
+            arch_interrupt = false;
+            break;
+        default:
+            fprintf(stderr, "Unhandled trap: 0x%x\n", trapnr);
+            cpu_dump_state(cs, stderr, 0);
+            exit(EXIT_FAILURE);
+        }
+        process_pending_signals (env);
+
+        /* Most of the traps imply a transition through PALcode, which
+           implies an REI instruction has been executed.  Which means
+           that RX and LOCK_ADDR should be cleared.  But there are a
+           few exceptions for traps internal to QEMU.  */
+        if (arch_interrupt) {
+            env->flags &= ~ENV_FLAG_RX_FLAG;
+            env->lock_addr = -1;
+        }
+    }
+}
+
+void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
+{
+    int i;
+
+    for(i = 0; i < 28; i++) {
+        env->ir[i] = ((abi_ulong *)regs)[i];
+    }
+    env->ir[IR_SP] = regs->usp;
+    env->pc = regs->pc;
+}