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, 178 insertions, 0 deletions

diff --git a/accel/tcg/translator.c b/accel/tcg/translator.c
new file mode 100644
index 000000000..f06c31426
--- /dev/null
+++ b/accel/tcg/translator.c
@@ -0,0 +1,178 @@
+/*
+ * Generic intermediate code generation.
+ *
+ * Copyright (C) 2016-2017 Lluís Vilanova <vilanova@ac.upc.edu>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/error-report.h"
+#include "tcg/tcg.h"
+#include "tcg/tcg-op.h"
+#include "exec/exec-all.h"
+#include "exec/gen-icount.h"
+#include "exec/log.h"
+#include "exec/translator.h"
+#include "exec/plugin-gen.h"
+#include "sysemu/replay.h"
+
+/* Pairs with tcg_clear_temp_count.
+   To be called by #TranslatorOps.{translate_insn,tb_stop} if
+   (1) the target is sufficiently clean to support reporting,
+   (2) as and when all temporaries are known to be consumed.
+   For most targets, (2) is at the end of translate_insn.  */
+void translator_loop_temp_check(DisasContextBase *db)
+{
+    if (tcg_check_temp_count()) {
+        qemu_log("warning: TCG temporary leaks before "
+                 TARGET_FMT_lx "\n", db->pc_next);
+    }
+}
+
+bool translator_use_goto_tb(DisasContextBase *db, target_ulong dest)
+{
+    /* Suppress goto_tb if requested. */
+    if (tb_cflags(db->tb) & CF_NO_GOTO_TB) {
+        return false;
+    }
+
+    /* Check for the dest on the same page as the start of the TB.  */
+    return ((db->pc_first ^ dest) & TARGET_PAGE_MASK) == 0;
+}
+
+static inline void translator_page_protect(DisasContextBase *dcbase,
+                                           target_ulong pc)
+{
+#ifdef CONFIG_USER_ONLY
+    dcbase->page_protect_end = pc | ~TARGET_PAGE_MASK;
+    page_protect(pc);
+#endif
+}
+
+void translator_loop(const TranslatorOps *ops, DisasContextBase *db,
+                     CPUState *cpu, TranslationBlock *tb, int max_insns)
+{
+    uint32_t cflags = tb_cflags(tb);
+    bool plugin_enabled;
+
+    /* Initialize DisasContext */
+    db->tb = tb;
+    db->pc_first = tb->pc;
+    db->pc_next = db->pc_first;
+    db->is_jmp = DISAS_NEXT;
+    db->num_insns = 0;
+    db->max_insns = max_insns;
+    db->singlestep_enabled = cflags & CF_SINGLE_STEP;
+    translator_page_protect(db, db->pc_next);
+
+    ops->init_disas_context(db, cpu);
+    tcg_debug_assert(db->is_jmp == DISAS_NEXT);  /* no early exit */
+
+    /* Reset the temp count so that we can identify leaks */
+    tcg_clear_temp_count();
+
+    /* Start translating.  */
+    gen_tb_start(db->tb);
+    ops->tb_start(db, cpu);
+    tcg_debug_assert(db->is_jmp == DISAS_NEXT);  /* no early exit */
+
+    plugin_enabled = plugin_gen_tb_start(cpu, tb, cflags & CF_MEMI_ONLY);
+
+    while (true) {
+        db->num_insns++;
+        ops->insn_start(db, cpu);
+        tcg_debug_assert(db->is_jmp == DISAS_NEXT);  /* no early exit */
+
+        if (plugin_enabled) {
+            plugin_gen_insn_start(cpu, db);
+        }
+
+        /* Disassemble one instruction.  The translate_insn hook should
+           update db->pc_next and db->is_jmp to indicate what should be
+           done next -- either exiting this loop or locate the start of
+           the next instruction.  */
+        if (db->num_insns == db->max_insns && (cflags & CF_LAST_IO)) {
+            /* Accept I/O on the last instruction.  */
+            gen_io_start();
+            ops->translate_insn(db, cpu);
+        } else {
+            /* we should only see CF_MEMI_ONLY for io_recompile */
+            tcg_debug_assert(!(cflags & CF_MEMI_ONLY));
+            ops->translate_insn(db, cpu);
+        }
+
+        /* Stop translation if translate_insn so indicated.  */
+        if (db->is_jmp != DISAS_NEXT) {
+            break;
+        }
+
+        /*
+         * We can't instrument after instructions that change control
+         * flow although this only really affects post-load operations.
+         */
+        if (plugin_enabled) {
+            plugin_gen_insn_end();
+        }
+
+        /* Stop translation if the output buffer is full,
+           or we have executed all of the allowed instructions.  */
+        if (tcg_op_buf_full() || db->num_insns >= db->max_insns) {
+            db->is_jmp = DISAS_TOO_MANY;
+            break;
+        }
+    }
+
+    /* Emit code to exit the TB, as indicated by db->is_jmp.  */
+    ops->tb_stop(db, cpu);
+    gen_tb_end(db->tb, db->num_insns);
+
+    if (plugin_enabled) {
+        plugin_gen_tb_end(cpu);
+    }
+
+    /* The disas_log hook may use these values rather than recompute.  */
+    tb->size = db->pc_next - db->pc_first;
+    tb->icount = db->num_insns;
+
+#ifdef DEBUG_DISAS
+    if (qemu_loglevel_mask(CPU_LOG_TB_IN_ASM)
+        && qemu_log_in_addr_range(db->pc_first)) {
+        FILE *logfile = qemu_log_lock();
+        qemu_log("----------------\n");
+        ops->disas_log(db, cpu);
+        qemu_log("\n");
+        qemu_log_unlock(logfile);
+    }
+#endif
+}
+
+static inline void translator_maybe_page_protect(DisasContextBase *dcbase,
+                                                 target_ulong pc, size_t len)
+{
+#ifdef CONFIG_USER_ONLY
+    target_ulong end = pc + len - 1;
+
+    if (end > dcbase->page_protect_end) {
+        translator_page_protect(dcbase, end);
+    }
+#endif
+}
+
+#define GEN_TRANSLATOR_LD(fullname, type, load_fn, swap_fn)             \
+    type fullname ## _swap(CPUArchState *env, DisasContextBase *dcbase, \
+                           abi_ptr pc, bool do_swap)                    \
+    {                                                                   \
+        translator_maybe_page_protect(dcbase, pc, sizeof(type));        \
+        type ret = load_fn(env, pc);                                    \
+        if (do_swap) {                                                  \
+            ret = swap_fn(ret);                                         \
+        }                                                               \
+        plugin_insn_append(pc, &ret, sizeof(ret));                      \
+        return ret;                                                     \
+    }
+
+FOR_EACH_TRANSLATOR_LD(GEN_TRANSLATOR_LD)
+
+#undef GEN_TRANSLATOR_LD