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, 280 insertions, 0 deletions

diff --git a/linux-user/sparc/cpu_loop.c b/linux-user/sparc/cpu_loop.c
new file mode 100644
index 000000000..0ba65e431
--- /dev/null
+++ b/linux-user/sparc/cpu_loop.c
@@ -0,0 +1,280 @@
+/*
+ *  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"
+
+#define SPARC64_STACK_BIAS 2047
+
+//#define DEBUG_WIN
+
+/* WARNING: dealing with register windows _is_ complicated. More info
+   can be found at http://www.sics.se/~psm/sparcstack.html */
+static inline int get_reg_index(CPUSPARCState *env, int cwp, int index)
+{
+    index = (index + cwp * 16) % (16 * env->nwindows);
+    /* wrap handling : if cwp is on the last window, then we use the
+       registers 'after' the end */
+    if (index < 8 && env->cwp == env->nwindows - 1)
+        index += 16 * env->nwindows;
+    return index;
+}
+
+/* save the register window 'cwp1' */
+static inline void save_window_offset(CPUSPARCState *env, int cwp1)
+{
+    unsigned int i;
+    abi_ulong sp_ptr;
+
+    sp_ptr = env->regbase[get_reg_index(env, cwp1, 6)];
+#ifdef TARGET_SPARC64
+    if (sp_ptr & 3)
+        sp_ptr += SPARC64_STACK_BIAS;
+#endif
+#if defined(DEBUG_WIN)
+    printf("win_overflow: sp_ptr=0x" TARGET_ABI_FMT_lx " save_cwp=%d\n",
+           sp_ptr, cwp1);
+#endif
+    for(i = 0; i < 16; i++) {
+        /* FIXME - what to do if put_user() fails? */
+        put_user_ual(env->regbase[get_reg_index(env, cwp1, 8 + i)], sp_ptr);
+        sp_ptr += sizeof(abi_ulong);
+    }
+}
+
+static void save_window(CPUSPARCState *env)
+{
+#ifndef TARGET_SPARC64
+    unsigned int new_wim;
+    new_wim = ((env->wim >> 1) | (env->wim << (env->nwindows - 1))) &
+        ((1LL << env->nwindows) - 1);
+    save_window_offset(env, cpu_cwp_dec(env, env->cwp - 2));
+    env->wim = new_wim;
+#else
+    /*
+     * cansave is zero if the spill trap handler is triggered by `save` and
+     * nonzero if triggered by a `flushw`
+     */
+    save_window_offset(env, cpu_cwp_dec(env, env->cwp - env->cansave - 2));
+    env->cansave++;
+    env->canrestore--;
+#endif
+}
+
+static void restore_window(CPUSPARCState *env)
+{
+#ifndef TARGET_SPARC64
+    unsigned int new_wim;
+#endif
+    unsigned int i, cwp1;
+    abi_ulong sp_ptr;
+
+#ifndef TARGET_SPARC64
+    new_wim = ((env->wim << 1) | (env->wim >> (env->nwindows - 1))) &
+        ((1LL << env->nwindows) - 1);
+#endif
+
+    /* restore the invalid window */
+    cwp1 = cpu_cwp_inc(env, env->cwp + 1);
+    sp_ptr = env->regbase[get_reg_index(env, cwp1, 6)];
+#ifdef TARGET_SPARC64
+    if (sp_ptr & 3)
+        sp_ptr += SPARC64_STACK_BIAS;
+#endif
+#if defined(DEBUG_WIN)
+    printf("win_underflow: sp_ptr=0x" TARGET_ABI_FMT_lx " load_cwp=%d\n",
+           sp_ptr, cwp1);
+#endif
+    for(i = 0; i < 16; i++) {
+        /* FIXME - what to do if get_user() fails? */
+        get_user_ual(env->regbase[get_reg_index(env, cwp1, 8 + i)], sp_ptr);
+        sp_ptr += sizeof(abi_ulong);
+    }
+#ifdef TARGET_SPARC64
+    env->canrestore++;
+    if (env->cleanwin < env->nwindows - 1)
+        env->cleanwin++;
+    env->cansave--;
+#else
+    env->wim = new_wim;
+#endif
+}
+
+static void flush_windows(CPUSPARCState *env)
+{
+    int offset, cwp1;
+
+    offset = 1;
+    for(;;) {
+        /* if restore would invoke restore_window(), then we can stop */
+        cwp1 = cpu_cwp_inc(env, env->cwp + offset);
+#ifndef TARGET_SPARC64
+        if (env->wim & (1 << cwp1))
+            break;
+#else
+        if (env->canrestore == 0)
+            break;
+        env->cansave++;
+        env->canrestore--;
+#endif
+        save_window_offset(env, cwp1);
+        offset++;
+    }
+    cwp1 = cpu_cwp_inc(env, env->cwp + 1);
+#ifndef TARGET_SPARC64
+    /* set wim so that restore will reload the registers */
+    env->wim = 1 << cwp1;
+#endif
+#if defined(DEBUG_WIN)
+    printf("flush_windows: nb=%d\n", offset - 1);
+#endif
+}
+
+void cpu_loop (CPUSPARCState *env)
+{
+    CPUState *cs = env_cpu(env);
+    int trapnr;
+    abi_long ret;
+    target_siginfo_t info;
+
+    while (1) {
+        cpu_exec_start(cs);
+        trapnr = cpu_exec(cs);
+        cpu_exec_end(cs);
+        process_queued_cpu_work(cs);
+
+        /* Compute PSR before exposing state.  */
+        if (env->cc_op != CC_OP_FLAGS) {
+            cpu_get_psr(env);
+        }
+
+        switch (trapnr) {
+#ifndef TARGET_SPARC64
+        case 0x88:
+        case 0x90:
+#else
+        case 0x110:
+        case 0x16d:
+#endif
+            ret = do_syscall (env, env->gregs[1],
+                              env->regwptr[0], env->regwptr[1],
+                              env->regwptr[2], env->regwptr[3],
+                              env->regwptr[4], env->regwptr[5],
+                              0, 0);
+            if (ret == -TARGET_ERESTARTSYS || ret == -TARGET_QEMU_ESIGRETURN) {
+                break;
+            }
+            if ((abi_ulong)ret >= (abi_ulong)(-515)) {
+#if defined(TARGET_SPARC64) && !defined(TARGET_ABI32)
+                env->xcc |= PSR_CARRY;
+#else
+                env->psr |= PSR_CARRY;
+#endif
+                ret = -ret;
+            } else {
+#if defined(TARGET_SPARC64) && !defined(TARGET_ABI32)
+                env->xcc &= ~PSR_CARRY;
+#else
+                env->psr &= ~PSR_CARRY;
+#endif
+            }
+            env->regwptr[0] = ret;
+            /* next instruction */
+            env->pc = env->npc;
+            env->npc = env->npc + 4;
+            break;
+        case 0x83: /* flush windows */
+#ifdef TARGET_ABI32
+        case 0x103:
+#endif
+            flush_windows(env);
+            /* next instruction */
+            env->pc = env->npc;
+            env->npc = env->npc + 4;
+            break;
+#ifndef TARGET_SPARC64
+        case TT_WIN_OVF: /* window overflow */
+            save_window(env);
+            break;
+        case TT_WIN_UNF: /* window underflow */
+            restore_window(env);
+            break;
+#else
+        case TT_SPILL: /* window overflow */
+            save_window(env);
+            break;
+        case TT_FILL: /* window underflow */
+            restore_window(env);
+            break;
+#ifndef TARGET_ABI32
+        case 0x16e:
+            flush_windows(env);
+            sparc64_get_context(env);
+            break;
+        case 0x16f:
+            flush_windows(env);
+            sparc64_set_context(env);
+            break;
+#endif
+#endif
+        case EXCP_INTERRUPT:
+            /* just indicate that signals should be handled asap */
+            break;
+        case TT_ILL_INSN:
+            {
+                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_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:
+            fprintf(stderr, "Unhandled trap: 0x%x\n", trapnr);
+            cpu_dump_state(cs, stderr, 0);
+            exit(EXIT_FAILURE);
+        }
+        process_pending_signals (env);
+    }
+}
+
+void target_cpu_copy_regs(CPUArchState *env, struct target_pt_regs *regs)
+{
+    int i;
+    env->pc = regs->pc;
+    env->npc = regs->npc;
+    env->y = regs->y;
+    for(i = 0; i < 8; i++)
+        env->gregs[i] = regs->u_regs[i];
+    for(i = 0; i < 8; i++)
+        env->regwptr[i] = regs->u_regs[i + 8];
+}