From e02cda008591317b1625707ff8e115a4841aa889 Mon Sep 17 00:00:00 2001
From: Timos Ampelikiotis <t.ampelikiotis@virtualopensystems.com>
Date: Tue, 10 Oct 2023 11:40:56 +0000
Subject: 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
---
disas/capstone.c | 326 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 326 insertions(+)
create mode 100644 disas/capstone.c
(limited to 'disas/capstone.c')
diff --git a/disas/capstone.c b/disas/capstone.c
new file mode 100644
index 000000000..20bc8f966
--- /dev/null
+++ b/disas/capstone.c
@@ -0,0 +1,326 @@
+/*
+ * Interface to the capstone disassembler.
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/bswap.h"
+#include "disas/dis-asm.h"
+#include "disas/capstone.h"
+
+
+/*
+ * Temporary storage for the capstone library. This will be alloced via
+ * malloc with a size private to the library; thus there's no reason not
+ * to share this across calls and across host vs target disassembly.
+ */
+static __thread cs_insn *cap_insn;
+
+/*
+ * The capstone library always skips 2 bytes for S390X.
+ * This is less than ideal, since we can tell from the first two bits
+ * the size of the insn and thus stay in sync with the insn stream.
+ */
+static size_t CAPSTONE_API
+cap_skipdata_s390x_cb(const uint8_t *code, size_t code_size,
+ size_t offset, void *user_data)
+{
+ size_t ilen;
+
+ /* See get_ilen() in target/s390x/internal.h. */
+ switch (code[offset] >> 6) {
+ case 0:
+ ilen = 2;
+ break;
+ case 1:
+ case 2:
+ ilen = 4;
+ break;
+ default:
+ ilen = 6;
+ break;
+ }
+
+ return ilen;
+}
+
+static const cs_opt_skipdata cap_skipdata_s390x = {
+ .mnemonic = ".byte",
+ .callback = cap_skipdata_s390x_cb
+};
+
+/*
+ * Initialize the Capstone library.
+ *
+ * ??? It would be nice to cache this. We would need one handle for the
+ * host and one for the target. For most targets we can reset specific
+ * parameters via cs_option(CS_OPT_MODE, new_mode), but we cannot change
+ * CS_ARCH_* in this way. Thus we would need to be able to close and
+ * re-open the target handle with a different arch for the target in order
+ * to handle AArch64 vs AArch32 mode switching.
+ */
+static cs_err cap_disas_start(disassemble_info *info, csh *handle)
+{
+ cs_mode cap_mode = info->cap_mode;
+ cs_err err;
+
+ cap_mode += (info->endian == BFD_ENDIAN_BIG ? CS_MODE_BIG_ENDIAN
+ : CS_MODE_LITTLE_ENDIAN);
+
+ err = cs_open(info->cap_arch, cap_mode, handle);
+ if (err != CS_ERR_OK) {
+ return err;
+ }
+
+ /* "Disassemble" unknown insns as ".byte W,X,Y,Z". */
+ cs_option(*handle, CS_OPT_SKIPDATA, CS_OPT_ON);
+
+ switch (info->cap_arch) {
+ case CS_ARCH_SYSZ:
+ cs_option(*handle, CS_OPT_SKIPDATA_SETUP,
+ (uintptr_t)&cap_skipdata_s390x);
+ break;
+
+ case CS_ARCH_X86:
+ /*
+ * We don't care about errors (if for some reason the library
+ * is compiled without AT&T syntax); the user will just have
+ * to deal with the Intel syntax.
+ */
+ cs_option(*handle, CS_OPT_SYNTAX, CS_OPT_SYNTAX_ATT);
+ break;
+ }
+
+ /* Allocate temp space for cs_disasm_iter. */
+ if (cap_insn == NULL) {
+ cap_insn = cs_malloc(*handle);
+ if (cap_insn == NULL) {
+ cs_close(handle);
+ return CS_ERR_MEM;
+ }
+ }
+ return CS_ERR_OK;
+}
+
+static void cap_dump_insn_units(disassemble_info *info, cs_insn *insn,
+ int i, int n)
+{
+ fprintf_function print = info->fprintf_func;
+ FILE *stream = info->stream;
+
+ switch (info->cap_insn_unit) {
+ case 4:
+ if (info->endian == BFD_ENDIAN_BIG) {
+ for (; i < n; i += 4) {
+ print(stream, " %08x", ldl_be_p(insn->bytes + i));
+
+ }
+ } else {
+ for (; i < n; i += 4) {
+ print(stream, " %08x", ldl_le_p(insn->bytes + i));
+ }
+ }
+ break;
+
+ case 2:
+ if (info->endian == BFD_ENDIAN_BIG) {
+ for (; i < n; i += 2) {
+ print(stream, " %04x", lduw_be_p(insn->bytes + i));
+ }
+ } else {
+ for (; i < n; i += 2) {
+ print(stream, " %04x", lduw_le_p(insn->bytes + i));
+ }
+ }
+ break;
+
+ default:
+ for (; i < n; i++) {
+ print(stream, " %02x", insn->bytes[i]);
+ }
+ break;
+ }
+}
+
+static void cap_dump_insn(disassemble_info *info, cs_insn *insn)
+{
+ fprintf_function print = info->fprintf_func;
+ FILE *stream = info->stream;
+ int i, n, split;
+
+ print(stream, "0x%08" PRIx64 ": ", insn->address);
+
+ n = insn->size;
+ split = info->cap_insn_split;
+
+ /* Dump the first SPLIT bytes of the instruction. */
+ cap_dump_insn_units(info, insn, 0, MIN(n, split));
+
+ /* Add padding up to SPLIT so that mnemonics line up. */
+ if (n < split) {
+ int width = (split - n) / info->cap_insn_unit;
+ width *= (2 * info->cap_insn_unit + 1);
+ print(stream, "%*s", width, "");
+ }
+
+ /* Print the actual instruction. */
+ print(stream, " %-8s %s\n", insn->mnemonic, insn->op_str);
+
+ /* Dump any remaining part of the insn on subsequent lines. */
+ for (i = split; i < n; i += split) {
+ print(stream, "0x%08" PRIx64 ": ", insn->address + i);
+ cap_dump_insn_units(info, insn, i, MIN(n, i + split));
+ print(stream, "\n");
+ }
+}
+
+/* Disassemble SIZE bytes at PC for the target. */
+bool cap_disas_target(disassemble_info *info, uint64_t pc, size_t size)
+{
+ uint8_t cap_buf[1024];
+ csh handle;
+ cs_insn *insn;
+ size_t csize = 0;
+
+ if (cap_disas_start(info, &handle) != CS_ERR_OK) {
+ return false;
+ }
+ insn = cap_insn;
+
+ while (1) {
+ size_t tsize = MIN(sizeof(cap_buf) - csize, size);
+ const uint8_t *cbuf = cap_buf;
+
+ info->read_memory_func(pc + csize, cap_buf + csize, tsize, info);
+ csize += tsize;
+ size -= tsize;
+
+ while (cs_disasm_iter(handle, &cbuf, &csize, &pc, insn)) {
+ cap_dump_insn(info, insn);
+ }
+
+ /* If the target memory is not consumed, go back for more... */
+ if (size != 0) {
+ /*
+ * ... taking care to move any remaining fractional insn
+ * to the beginning of the buffer.
+ */
+ if (csize != 0) {
+ memmove(cap_buf, cbuf, csize);
+ }
+ continue;
+ }
+
+ /*
+ * Since the target memory is consumed, we should not have
+ * a remaining fractional insn.
+ */
+ if (csize != 0) {
+ info->fprintf_func(info->stream,
+ "Disassembler disagrees with translator "
+ "over instruction decoding\n"
+ "Please report this to qemu-devel@nongnu.org\n");
+ }
+ break;
+ }
+
+ cs_close(&handle);
+ return true;
+}
+
+/* Disassemble SIZE bytes at CODE for the host. */
+bool cap_disas_host(disassemble_info *info, const void *code, size_t size)
+{
+ csh handle;
+ const uint8_t *cbuf;
+ cs_insn *insn;
+ uint64_t pc;
+
+ if (cap_disas_start(info, &handle) != CS_ERR_OK) {
+ return false;
+ }
+ insn = cap_insn;
+
+ cbuf = code;
+ pc = (uintptr_t)code;
+
+ while (cs_disasm_iter(handle, &cbuf, &size, &pc, insn)) {
+ cap_dump_insn(info, insn);
+ }
+ if (size != 0) {
+ info->fprintf_func(info->stream,
+ "Disassembler disagrees with TCG over instruction encoding\n"
+ "Please report this to qemu-devel@nongnu.org\n");
+ }
+
+ cs_close(&handle);
+ return true;
+}
+
+/* Disassemble COUNT insns at PC for the target. */
+bool cap_disas_monitor(disassemble_info *info, uint64_t pc, int count)
+{
+ uint8_t cap_buf[32];
+ csh handle;
+ cs_insn *insn;
+ size_t csize = 0;
+
+ if (cap_disas_start(info, &handle) != CS_ERR_OK) {
+ return false;
+ }
+ insn = cap_insn;
+
+ while (1) {
+ /*
+ * We want to read memory for one insn, but generically we do not
+ * know how much memory that is. We have a small buffer which is
+ * known to be sufficient for all supported targets. Try to not
+ * read beyond the page, Just In Case. For even more simplicity,
+ * ignore the actual target page size and use a 1k boundary. If
+ * that turns out to be insufficient, we'll come back around the
+ * loop and read more.
+ */
+ uint64_t epc = QEMU_ALIGN_UP(pc + csize + 1, 1024);
+ size_t tsize = MIN(sizeof(cap_buf) - csize, epc - pc);
+ const uint8_t *cbuf = cap_buf;
+
+ /* Make certain that we can make progress. */
+ assert(tsize != 0);
+ info->read_memory_func(pc + csize, cap_buf + csize, tsize, info);
+ csize += tsize;
+
+ if (cs_disasm_iter(handle, &cbuf, &csize, &pc, insn)) {
+ cap_dump_insn(info, insn);
+ if (--count <= 0) {
+ break;
+ }
+ }
+ memmove(cap_buf, cbuf, csize);
+ }
+
+ cs_close(&handle);
+ return true;
+}
+
+/* Disassemble a single instruction directly into plugin output */
+bool cap_disas_plugin(disassemble_info *info, uint64_t pc, size_t size)
+{
+ uint8_t cap_buf[32];
+ const uint8_t *cbuf = cap_buf;
+ csh handle;
+
+ if (cap_disas_start(info, &handle) != CS_ERR_OK) {
+ return false;
+ }
+
+ assert(size < sizeof(cap_buf));
+ info->read_memory_func(pc, cap_buf, size, info);
+
+ if (cs_disasm_iter(handle, &cbuf, &size, &pc, cap_insn)) {
+ info->fprintf_func(info->stream, "%s %s",
+ cap_insn->mnemonic, cap_insn->op_str);
+ }
+
+ cs_close(&handle);
+ return true;
+}
--
cgit