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qemu/accel/tcg/plugin-gen.c
Emilio Cota 3fd62e73ad plugins: fix optimization in plugin_gen_disable_mem_helpers 
We were mistakenly checking tcg_ctx->plugin_insn as a canary to know
whether the TB had emitted helpers that might have accessed memory.

The problem is that tcg_ctx->plugin_insn gets updated on every
instruction in the TB, which results in us wrongly performing the
optimization (i.e. not clearing cpu->plugin_mem_cbs) way too often,
since it's not rare that the last instruction in the TB doesn't
use helpers.

Fix it by tracking a per-TB canary.

While at it, expand documentation.

Related: #1381

Signed-off-by: Emilio Cota <cota@braap.org>
Message-Id: <20230108164731.61469-2-cota@braap.org>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20230124180127.1881110-32-alex.bennee@linaro.org>
2023-02-02 11:48:20 +00:00

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/*
* plugin-gen.c - TCG-related bits of plugin infrastructure
*
* Copyright (C) 2018, Emilio G. Cota <cota@braap.org>
* License: GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*
* We support instrumentation at an instruction granularity. That is,
* if a plugin wants to instrument the memory accesses performed by a
* particular instruction, it can just do that instead of instrumenting
* all memory accesses. Thus, in order to do this we first have to
* translate a TB, so that plugins can decide what/where to instrument.
*
* Injecting the desired instrumentation could be done with a second
* translation pass that combined the instrumentation requests, but that
* would be ugly and inefficient since we would decode the guest code twice.
* Instead, during TB translation we add "empty" instrumentation calls for all
* possible instrumentation events, and then once we collect the instrumentation
* requests from plugins, we either "fill in" those empty events or remove them
* if they have no requests.
*
* When "filling in" an event we first copy the empty callback's TCG ops. This
* might seem unnecessary, but it is done to support an arbitrary number
* of callbacks per event. Take for example a regular instruction callback.
* We first generate a callback to an empty helper function. Then, if two
* plugins register one callback each for this instruction, we make two copies
* of the TCG ops generated for the empty callback, substituting the function
* pointer that points to the empty helper function with the plugins' desired
* callback functions. After that we remove the empty callback's ops.
*
* Note that the location in TCGOp.args[] of the pointer to a helper function
* varies across different guest and host architectures. Instead of duplicating
* the logic that figures this out, we rely on the fact that the empty
* callbacks point to empty functions that are unique pointers in the program.
* Thus, to find the right location we just have to look for a match in
* TCGOp.args[]. This is the main reason why we first copy an empty callback's
* TCG ops and then fill them in; regardless of whether we have one or many
* callbacks for that event, the logic to add all of them is the same.
*
* When generating more than one callback per event, we make a small
* optimization to avoid generating redundant operations. For instance, for the
* second and all subsequent callbacks of an event, we do not need to reload the
* CPU's index into a TCG temp, since the first callback did it already.
*/
#include "qemu/osdep.h"
#include "tcg/tcg.h"
#include "tcg/tcg-op.h"
#include "exec/exec-all.h"
#include "exec/plugin-gen.h"
#include "exec/translator.h"
#ifdef CONFIG_SOFTMMU
# define CONFIG_SOFTMMU_GATE 1
#else
# define CONFIG_SOFTMMU_GATE 0
#endif
/*
* plugin_cb_start TCG op args[]:
* 0: enum plugin_gen_from
* 1: enum plugin_gen_cb
* 2: set to 1 for mem callback that is a write, 0 otherwise.
*/
enum plugin_gen_from {
PLUGIN_GEN_FROM_TB,
PLUGIN_GEN_FROM_INSN,
PLUGIN_GEN_FROM_MEM,
PLUGIN_GEN_AFTER_INSN,
PLUGIN_GEN_N_FROMS,
};
enum plugin_gen_cb {
PLUGIN_GEN_CB_UDATA,
PLUGIN_GEN_CB_INLINE,
PLUGIN_GEN_CB_MEM,
PLUGIN_GEN_ENABLE_MEM_HELPER,
PLUGIN_GEN_DISABLE_MEM_HELPER,
PLUGIN_GEN_N_CBS,
};
/*
* These helpers are stubs that get dynamically switched out for calls
* direct to the plugin if they are subscribed to.
*/
void HELPER(plugin_vcpu_udata_cb)(uint32_t cpu_index, void *udata)
{ }
void HELPER(plugin_vcpu_mem_cb)(unsigned int vcpu_index,
qemu_plugin_meminfo_t info, uint64_t vaddr,
void *userdata)
{ }
static void do_gen_mem_cb(TCGv vaddr, uint32_t info)
{
TCGv_i32 cpu_index = tcg_temp_new_i32();
TCGv_i32 meminfo = tcg_const_i32(info);
TCGv_i64 vaddr64 = tcg_temp_new_i64();
TCGv_ptr udata = tcg_const_ptr(NULL);
tcg_gen_ld_i32(cpu_index, cpu_env,
-offsetof(ArchCPU, env) + offsetof(CPUState, cpu_index));
tcg_gen_extu_tl_i64(vaddr64, vaddr);
gen_helper_plugin_vcpu_mem_cb(cpu_index, meminfo, vaddr64, udata);
tcg_temp_free_ptr(udata);
tcg_temp_free_i64(vaddr64);
tcg_temp_free_i32(meminfo);
tcg_temp_free_i32(cpu_index);
}
static void gen_empty_udata_cb(void)
{
TCGv_i32 cpu_index = tcg_temp_new_i32();
TCGv_ptr udata = tcg_const_ptr(NULL); /* will be overwritten later */
tcg_gen_ld_i32(cpu_index, cpu_env,
-offsetof(ArchCPU, env) + offsetof(CPUState, cpu_index));
gen_helper_plugin_vcpu_udata_cb(cpu_index, udata);
tcg_temp_free_ptr(udata);
tcg_temp_free_i32(cpu_index);
}
/*
* For now we only support addi_i64.
* When we support more ops, we can generate one empty inline cb for each.
*/
static void gen_empty_inline_cb(void)
{
TCGv_i64 val = tcg_temp_new_i64();
TCGv_ptr ptr = tcg_const_ptr(NULL); /* overwritten later */
tcg_gen_ld_i64(val, ptr, 0);
/* pass an immediate != 0 so that it doesn't get optimized away */
tcg_gen_addi_i64(val, val, 0xdeadface);
tcg_gen_st_i64(val, ptr, 0);
tcg_temp_free_ptr(ptr);
tcg_temp_free_i64(val);
}
static void gen_empty_mem_cb(TCGv addr, uint32_t info)
{
do_gen_mem_cb(addr, info);
}
/*
* Share the same function for enable/disable. When enabling, the NULL
* pointer will be overwritten later.
*/
static void gen_empty_mem_helper(void)
{
TCGv_ptr ptr;
ptr = tcg_const_ptr(NULL);
tcg_gen_st_ptr(ptr, cpu_env, offsetof(CPUState, plugin_mem_cbs) -
offsetof(ArchCPU, env));
tcg_temp_free_ptr(ptr);
}
static void gen_plugin_cb_start(enum plugin_gen_from from,
enum plugin_gen_cb type, unsigned wr)
{
tcg_gen_plugin_cb_start(from, type, wr);
}
static void gen_wrapped(enum plugin_gen_from from,
enum plugin_gen_cb type, void (*func)(void))
{
gen_plugin_cb_start(from, type, 0);
func();
tcg_gen_plugin_cb_end();
}
static void plugin_gen_empty_callback(enum plugin_gen_from from)
{
switch (from) {
case PLUGIN_GEN_AFTER_INSN:
gen_wrapped(from, PLUGIN_GEN_DISABLE_MEM_HELPER,
gen_empty_mem_helper);
break;
case PLUGIN_GEN_FROM_INSN:
/*
* Note: plugin_gen_inject() relies on ENABLE_MEM_HELPER being
* the first callback of an instruction
*/
gen_wrapped(from, PLUGIN_GEN_ENABLE_MEM_HELPER,
gen_empty_mem_helper);
/* fall through */
case PLUGIN_GEN_FROM_TB:
gen_wrapped(from, PLUGIN_GEN_CB_UDATA, gen_empty_udata_cb);
gen_wrapped(from, PLUGIN_GEN_CB_INLINE, gen_empty_inline_cb);
break;
default:
g_assert_not_reached();
}
}
union mem_gen_fn {
void (*mem_fn)(TCGv, uint32_t);
void (*inline_fn)(void);
};
static void gen_mem_wrapped(enum plugin_gen_cb type,
const union mem_gen_fn *f, TCGv addr,
uint32_t info, bool is_mem)
{
enum qemu_plugin_mem_rw rw = get_plugin_meminfo_rw(info);
gen_plugin_cb_start(PLUGIN_GEN_FROM_MEM, type, rw);
if (is_mem) {
f->mem_fn(addr, info);
} else {
f->inline_fn();
}
tcg_gen_plugin_cb_end();
}
void plugin_gen_empty_mem_callback(TCGv addr, uint32_t info)
{
union mem_gen_fn fn;
fn.mem_fn = gen_empty_mem_cb;
gen_mem_wrapped(PLUGIN_GEN_CB_MEM, &fn, addr, info, true);
fn.inline_fn = gen_empty_inline_cb;
gen_mem_wrapped(PLUGIN_GEN_CB_INLINE, &fn, 0, info, false);
}
static TCGOp *find_op(TCGOp *op, TCGOpcode opc)
{
while (op) {
if (op->opc == opc) {
return op;
}
op = QTAILQ_NEXT(op, link);
}
return NULL;
}
static TCGOp *rm_ops_range(TCGOp *begin, TCGOp *end)
{
TCGOp *ret = QTAILQ_NEXT(end, link);
QTAILQ_REMOVE_SEVERAL(&tcg_ctx->ops, begin, end, link);
return ret;
}
/* remove all ops until (and including) plugin_cb_end */
static TCGOp *rm_ops(TCGOp *op)
{
TCGOp *end_op = find_op(op, INDEX_op_plugin_cb_end);
tcg_debug_assert(end_op);
return rm_ops_range(op, end_op);
}
static TCGOp *copy_op_nocheck(TCGOp **begin_op, TCGOp *op)
{
TCGOp *old_op = QTAILQ_NEXT(*begin_op, link);
unsigned nargs = old_op->nargs;
*begin_op = old_op;
op = tcg_op_insert_after(tcg_ctx, op, old_op->opc, nargs);
memcpy(op->args, old_op->args, sizeof(op->args[0]) * nargs);
return op;
}
static TCGOp *copy_op(TCGOp **begin_op, TCGOp *op, TCGOpcode opc)
{
op = copy_op_nocheck(begin_op, op);
tcg_debug_assert((*begin_op)->opc == opc);
return op;
}
static TCGOp *copy_extu_i32_i64(TCGOp **begin_op, TCGOp *op)
{
if (TCG_TARGET_REG_BITS == 32) {
/* mov_i32 */
op = copy_op(begin_op, op, INDEX_op_mov_i32);
/* mov_i32 w/ $0 */
op = copy_op(begin_op, op, INDEX_op_mov_i32);
} else {
/* extu_i32_i64 */
op = copy_op(begin_op, op, INDEX_op_extu_i32_i64);
}
return op;
}
static TCGOp *copy_mov_i64(TCGOp **begin_op, TCGOp *op)
{
if (TCG_TARGET_REG_BITS == 32) {
/* 2x mov_i32 */
op = copy_op(begin_op, op, INDEX_op_mov_i32);
op = copy_op(begin_op, op, INDEX_op_mov_i32);
} else {
/* mov_i64 */
op = copy_op(begin_op, op, INDEX_op_mov_i64);
}
return op;
}
static TCGOp *copy_const_ptr(TCGOp **begin_op, TCGOp *op, void *ptr)
{
if (UINTPTR_MAX == UINT32_MAX) {
/* mov_i32 */
op = copy_op(begin_op, op, INDEX_op_mov_i32);
op->args[1] = tcgv_i32_arg(tcg_constant_i32((uintptr_t)ptr));
} else {
/* mov_i64 */
op = copy_op(begin_op, op, INDEX_op_mov_i64);
op->args[1] = tcgv_i64_arg(tcg_constant_i64((uintptr_t)ptr));
}
return op;
}
static TCGOp *copy_extu_tl_i64(TCGOp **begin_op, TCGOp *op)
{
if (TARGET_LONG_BITS == 32) {
/* extu_i32_i64 */
op = copy_extu_i32_i64(begin_op, op);
} else {
/* mov_i64 */
op = copy_mov_i64(begin_op, op);
}
return op;
}
static TCGOp *copy_ld_i64(TCGOp **begin_op, TCGOp *op)
{
if (TCG_TARGET_REG_BITS == 32) {
/* 2x ld_i32 */
op = copy_op(begin_op, op, INDEX_op_ld_i32);
op = copy_op(begin_op, op, INDEX_op_ld_i32);
} else {
/* ld_i64 */
op = copy_op(begin_op, op, INDEX_op_ld_i64);
}
return op;
}
static TCGOp *copy_st_i64(TCGOp **begin_op, TCGOp *op)
{
if (TCG_TARGET_REG_BITS == 32) {
/* 2x st_i32 */
op = copy_op(begin_op, op, INDEX_op_st_i32);
op = copy_op(begin_op, op, INDEX_op_st_i32);
} else {
/* st_i64 */
op = copy_op(begin_op, op, INDEX_op_st_i64);
}
return op;
}
static TCGOp *copy_add_i64(TCGOp **begin_op, TCGOp *op, uint64_t v)
{
if (TCG_TARGET_REG_BITS == 32) {
/* all 32-bit backends must implement add2_i32 */
g_assert(TCG_TARGET_HAS_add2_i32);
op = copy_op(begin_op, op, INDEX_op_add2_i32);
op->args[4] = tcgv_i32_arg(tcg_constant_i32(v));
op->args[5] = tcgv_i32_arg(tcg_constant_i32(v >> 32));
} else {
op = copy_op(begin_op, op, INDEX_op_add_i64);
op->args[2] = tcgv_i64_arg(tcg_constant_i64(v));
}
return op;
}
static TCGOp *copy_st_ptr(TCGOp **begin_op, TCGOp *op)
{
if (UINTPTR_MAX == UINT32_MAX) {
/* st_i32 */
op = copy_op(begin_op, op, INDEX_op_st_i32);
} else {
/* st_i64 */
op = copy_st_i64(begin_op, op);
}
return op;
}
static TCGOp *copy_call(TCGOp **begin_op, TCGOp *op, void *empty_func,
void *func, int *cb_idx)
{
TCGOp *old_op;
int func_idx;
/* copy all ops until the call */
do {
op = copy_op_nocheck(begin_op, op);
} while (op->opc != INDEX_op_call);
/* fill in the op call */
old_op = *begin_op;
TCGOP_CALLI(op) = TCGOP_CALLI(old_op);
TCGOP_CALLO(op) = TCGOP_CALLO(old_op);
tcg_debug_assert(op->life == 0);
func_idx = TCGOP_CALLO(op) + TCGOP_CALLI(op);
*cb_idx = func_idx;
op->args[func_idx] = (uintptr_t)func;
return op;
}
/*
* When we append/replace ops here we are sensitive to changing patterns of
* TCGOps generated by the tcg_gen_FOO calls when we generated the
* empty callbacks. This will assert very quickly in a debug build as
* we assert the ops we are replacing are the correct ones.
*/
static TCGOp *append_udata_cb(const struct qemu_plugin_dyn_cb *cb,
TCGOp *begin_op, TCGOp *op, int *cb_idx)
{
/* const_ptr */
op = copy_const_ptr(&begin_op, op, cb->userp);
/* copy the ld_i32, but note that we only have to copy it once */
if (*cb_idx == -1) {
op = copy_op(&begin_op, op, INDEX_op_ld_i32);
} else {
begin_op = QTAILQ_NEXT(begin_op, link);
tcg_debug_assert(begin_op && begin_op->opc == INDEX_op_ld_i32);
}
/* call */
op = copy_call(&begin_op, op, HELPER(plugin_vcpu_udata_cb),
cb->f.vcpu_udata, cb_idx);
return op;
}
static TCGOp *append_inline_cb(const struct qemu_plugin_dyn_cb *cb,
TCGOp *begin_op, TCGOp *op,
int *unused)
{
/* const_ptr */
op = copy_const_ptr(&begin_op, op, cb->userp);
/* ld_i64 */
op = copy_ld_i64(&begin_op, op);
/* add_i64 */
op = copy_add_i64(&begin_op, op, cb->inline_insn.imm);
/* st_i64 */
op = copy_st_i64(&begin_op, op);
return op;
}
static TCGOp *append_mem_cb(const struct qemu_plugin_dyn_cb *cb,
TCGOp *begin_op, TCGOp *op, int *cb_idx)
{
enum plugin_gen_cb type = begin_op->args[1];
tcg_debug_assert(type == PLUGIN_GEN_CB_MEM);
/* const_i32 == mov_i32 ("info", so it remains as is) */
op = copy_op(&begin_op, op, INDEX_op_mov_i32);
/* const_ptr */
op = copy_const_ptr(&begin_op, op, cb->userp);
/* copy the ld_i32, but note that we only have to copy it once */
if (*cb_idx == -1) {
op = copy_op(&begin_op, op, INDEX_op_ld_i32);
} else {
begin_op = QTAILQ_NEXT(begin_op, link);
tcg_debug_assert(begin_op && begin_op->opc == INDEX_op_ld_i32);
}
/* extu_tl_i64 */
op = copy_extu_tl_i64(&begin_op, op);
if (type == PLUGIN_GEN_CB_MEM) {
/* call */
op = copy_call(&begin_op, op, HELPER(plugin_vcpu_mem_cb),
cb->f.vcpu_udata, cb_idx);
}
return op;
}
typedef TCGOp *(*inject_fn)(const struct qemu_plugin_dyn_cb *cb,
TCGOp *begin_op, TCGOp *op, int *intp);
typedef bool (*op_ok_fn)(const TCGOp *op, const struct qemu_plugin_dyn_cb *cb);
static bool op_ok(const TCGOp *op, const struct qemu_plugin_dyn_cb *cb)
{
return true;
}
static bool op_rw(const TCGOp *op, const struct qemu_plugin_dyn_cb *cb)
{
int w;
w = op->args[2];
return !!(cb->rw & (w + 1));
}
static void inject_cb_type(const GArray *cbs, TCGOp *begin_op,
inject_fn inject, op_ok_fn ok)
{
TCGOp *end_op;
TCGOp *op;
int cb_idx = -1;
int i;
if (!cbs || cbs->len == 0) {
rm_ops(begin_op);
return;
}
end_op = find_op(begin_op, INDEX_op_plugin_cb_end);
tcg_debug_assert(end_op);
op = end_op;
for (i = 0; i < cbs->len; i++) {
struct qemu_plugin_dyn_cb *cb =
&g_array_index(cbs, struct qemu_plugin_dyn_cb, i);
if (!ok(begin_op, cb)) {
continue;
}
op = inject(cb, begin_op, op, &cb_idx);
}
rm_ops_range(begin_op, end_op);
}
static void
inject_udata_cb(const GArray *cbs, TCGOp *begin_op)
{
inject_cb_type(cbs, begin_op, append_udata_cb, op_ok);
}
static void
inject_inline_cb(const GArray *cbs, TCGOp *begin_op, op_ok_fn ok)
{
inject_cb_type(cbs, begin_op, append_inline_cb, ok);
}
static void
inject_mem_cb(const GArray *cbs, TCGOp *begin_op)
{
inject_cb_type(cbs, begin_op, append_mem_cb, op_rw);
}
/* we could change the ops in place, but we can reuse more code by copying */
static void inject_mem_helper(TCGOp *begin_op, GArray *arr)
{
TCGOp *orig_op = begin_op;
TCGOp *end_op;
TCGOp *op;
end_op = find_op(begin_op, INDEX_op_plugin_cb_end);
tcg_debug_assert(end_op);
/* const ptr */
op = copy_const_ptr(&begin_op, end_op, arr);
/* st_ptr */
op = copy_st_ptr(&begin_op, op);
rm_ops_range(orig_op, end_op);
}
/*
* Tracking memory accesses performed from helpers requires extra work.
* If an instruction is emulated with helpers, we do two things:
* (1) copy the CB descriptors, and keep track of it so that they can be
* freed later on, and (2) point CPUState.plugin_mem_cbs to the descriptors, so
* that we can read them at run-time (i.e. when the helper executes).
* This run-time access is performed from qemu_plugin_vcpu_mem_cb.
*
* Note that plugin_gen_disable_mem_helpers undoes (2). Since it
* is possible that the code we generate after the instruction is
* dead, we also add checks before generating tb_exit etc.
*/
static void inject_mem_enable_helper(struct qemu_plugin_tb *ptb,
struct qemu_plugin_insn *plugin_insn,
TCGOp *begin_op)
{
GArray *cbs[2];
GArray *arr;
size_t n_cbs, i;
cbs[0] = plugin_insn->cbs[PLUGIN_CB_MEM][PLUGIN_CB_REGULAR];
cbs[1] = plugin_insn->cbs[PLUGIN_CB_MEM][PLUGIN_CB_INLINE];
n_cbs = 0;
for (i = 0; i < ARRAY_SIZE(cbs); i++) {
n_cbs += cbs[i]->len;
}
plugin_insn->mem_helper = plugin_insn->calls_helpers && n_cbs;
if (likely(!plugin_insn->mem_helper)) {
rm_ops(begin_op);
return;
}
ptb->mem_helper = true;
arr = g_array_sized_new(false, false,
sizeof(struct qemu_plugin_dyn_cb), n_cbs);
for (i = 0; i < ARRAY_SIZE(cbs); i++) {
g_array_append_vals(arr, cbs[i]->data, cbs[i]->len);
}
qemu_plugin_add_dyn_cb_arr(arr);
inject_mem_helper(begin_op, arr);
}
static void inject_mem_disable_helper(struct qemu_plugin_insn *plugin_insn,
TCGOp *begin_op)
{
if (likely(!plugin_insn->mem_helper)) {
rm_ops(begin_op);
return;
}
inject_mem_helper(begin_op, NULL);
}
/* called before finishing a TB with exit_tb, goto_tb or goto_ptr */
void plugin_gen_disable_mem_helpers(void)
{
TCGv_ptr ptr;
/*
* We could emit the clearing unconditionally and be done. However, this can
* be wasteful if for instance plugins don't track memory accesses, or if
* most TBs don't use helpers. Instead, emit the clearing iff the TB calls
* helpers that might access guest memory.
*
* Note: we do not reset plugin_tb->mem_helper here; a TB might have several
* exit points, and we want to emit the clearing from all of them.
*/
if (!tcg_ctx->plugin_tb->mem_helper) {
return;
}
ptr = tcg_const_ptr(NULL);
tcg_gen_st_ptr(ptr, cpu_env, offsetof(CPUState, plugin_mem_cbs) -
offsetof(ArchCPU, env));
tcg_temp_free_ptr(ptr);
}
static void plugin_gen_tb_udata(const struct qemu_plugin_tb *ptb,
TCGOp *begin_op)
{
inject_udata_cb(ptb->cbs[PLUGIN_CB_REGULAR], begin_op);
}
static void plugin_gen_tb_inline(const struct qemu_plugin_tb *ptb,
TCGOp *begin_op)
{
inject_inline_cb(ptb->cbs[PLUGIN_CB_INLINE], begin_op, op_ok);
}
static void plugin_gen_insn_udata(const struct qemu_plugin_tb *ptb,
TCGOp *begin_op, int insn_idx)
{
struct qemu_plugin_insn *insn = g_ptr_array_index(ptb->insns, insn_idx);
inject_udata_cb(insn->cbs[PLUGIN_CB_INSN][PLUGIN_CB_REGULAR], begin_op);
}
static void plugin_gen_insn_inline(const struct qemu_plugin_tb *ptb,
TCGOp *begin_op, int insn_idx)
{
struct qemu_plugin_insn *insn = g_ptr_array_index(ptb->insns, insn_idx);
inject_inline_cb(insn->cbs[PLUGIN_CB_INSN][PLUGIN_CB_INLINE],
begin_op, op_ok);
}
static void plugin_gen_mem_regular(const struct qemu_plugin_tb *ptb,
TCGOp *begin_op, int insn_idx)
{
struct qemu_plugin_insn *insn = g_ptr_array_index(ptb->insns, insn_idx);
inject_mem_cb(insn->cbs[PLUGIN_CB_MEM][PLUGIN_CB_REGULAR], begin_op);
}
static void plugin_gen_mem_inline(const struct qemu_plugin_tb *ptb,
TCGOp *begin_op, int insn_idx)
{
const GArray *cbs;
struct qemu_plugin_insn *insn = g_ptr_array_index(ptb->insns, insn_idx);
cbs = insn->cbs[PLUGIN_CB_MEM][PLUGIN_CB_INLINE];
inject_inline_cb(cbs, begin_op, op_rw);
}
static void plugin_gen_enable_mem_helper(struct qemu_plugin_tb *ptb,
TCGOp *begin_op, int insn_idx)
{
struct qemu_plugin_insn *insn = g_ptr_array_index(ptb->insns, insn_idx);
inject_mem_enable_helper(ptb, insn, begin_op);
}
static void plugin_gen_disable_mem_helper(struct qemu_plugin_tb *ptb,
TCGOp *begin_op, int insn_idx)
{
struct qemu_plugin_insn *insn = g_ptr_array_index(ptb->insns, insn_idx);
inject_mem_disable_helper(insn, begin_op);
}
/* #define DEBUG_PLUGIN_GEN_OPS */
static void pr_ops(void)
{
#ifdef DEBUG_PLUGIN_GEN_OPS
TCGOp *op;
int i = 0;
QTAILQ_FOREACH(op, &tcg_ctx->ops, link) {
const char *name = "";
const char *type = "";
if (op->opc == INDEX_op_plugin_cb_start) {
switch (op->args[0]) {
case PLUGIN_GEN_FROM_TB:
name = "tb";
break;
case PLUGIN_GEN_FROM_INSN:
name = "insn";
break;
case PLUGIN_GEN_FROM_MEM:
name = "mem";
break;
case PLUGIN_GEN_AFTER_INSN:
name = "after insn";
break;
default:
break;
}
switch (op->args[1]) {
case PLUGIN_GEN_CB_UDATA:
type = "udata";
break;
case PLUGIN_GEN_CB_INLINE:
type = "inline";
break;
case PLUGIN_GEN_CB_MEM:
type = "mem";
break;
case PLUGIN_GEN_ENABLE_MEM_HELPER:
type = "enable mem helper";
break;
case PLUGIN_GEN_DISABLE_MEM_HELPER:
type = "disable mem helper";
break;
default:
break;
}
}
printf("op[%2i]: %s %s %s\n", i, tcg_op_defs[op->opc].name, name, type);
i++;
}
#endif
}
static void plugin_gen_inject(struct qemu_plugin_tb *plugin_tb)
{
TCGOp *op;
int insn_idx = -1;
pr_ops();
QTAILQ_FOREACH(op, &tcg_ctx->ops, link) {
switch (op->opc) {
case INDEX_op_insn_start:
insn_idx++;
break;
case INDEX_op_plugin_cb_start:
{
enum plugin_gen_from from = op->args[0];
enum plugin_gen_cb type = op->args[1];
switch (from) {
case PLUGIN_GEN_FROM_TB:
{
g_assert(insn_idx == -1);
switch (type) {
case PLUGIN_GEN_CB_UDATA:
plugin_gen_tb_udata(plugin_tb, op);
break;
case PLUGIN_GEN_CB_INLINE:
plugin_gen_tb_inline(plugin_tb, op);
break;
default:
g_assert_not_reached();
}
break;
}
case PLUGIN_GEN_FROM_INSN:
{
g_assert(insn_idx >= 0);
switch (type) {
case PLUGIN_GEN_CB_UDATA:
plugin_gen_insn_udata(plugin_tb, op, insn_idx);
break;
case PLUGIN_GEN_CB_INLINE:
plugin_gen_insn_inline(plugin_tb, op, insn_idx);
break;
case PLUGIN_GEN_ENABLE_MEM_HELPER:
plugin_gen_enable_mem_helper(plugin_tb, op, insn_idx);
break;
default:
g_assert_not_reached();
}
break;
}
case PLUGIN_GEN_FROM_MEM:
{
g_assert(insn_idx >= 0);
switch (type) {
case PLUGIN_GEN_CB_MEM:
plugin_gen_mem_regular(plugin_tb, op, insn_idx);
break;
case PLUGIN_GEN_CB_INLINE:
plugin_gen_mem_inline(plugin_tb, op, insn_idx);
break;
default:
g_assert_not_reached();
}
break;
}
case PLUGIN_GEN_AFTER_INSN:
{
g_assert(insn_idx >= 0);
switch (type) {
case PLUGIN_GEN_DISABLE_MEM_HELPER:
plugin_gen_disable_mem_helper(plugin_tb, op, insn_idx);
break;
default:
g_assert_not_reached();
}
break;
}
default:
g_assert_not_reached();
}
break;
}
default:
/* plugins don't care about any other ops */
break;
}
}
pr_ops();
}
bool plugin_gen_tb_start(CPUState *cpu, const DisasContextBase *db,
bool mem_only)
{
bool ret = false;
if (test_bit(QEMU_PLUGIN_EV_VCPU_TB_TRANS, cpu->plugin_mask)) {
struct qemu_plugin_tb *ptb = tcg_ctx->plugin_tb;
int i;
/* reset callbacks */
for (i = 0; i < PLUGIN_N_CB_SUBTYPES; i++) {
if (ptb->cbs[i]) {
g_array_set_size(ptb->cbs[i], 0);
}
}
ptb->n = 0;
ret = true;
ptb->vaddr = db->pc_first;
ptb->vaddr2 = -1;
ptb->haddr1 = db->host_addr[0];
ptb->haddr2 = NULL;
ptb->mem_only = mem_only;
ptb->mem_helper = false;
plugin_gen_empty_callback(PLUGIN_GEN_FROM_TB);
}
tcg_ctx->plugin_insn = NULL;
return ret;
}
void plugin_gen_insn_start(CPUState *cpu, const DisasContextBase *db)
{
struct qemu_plugin_tb *ptb = tcg_ctx->plugin_tb;
struct qemu_plugin_insn *pinsn;
pinsn = qemu_plugin_tb_insn_get(ptb, db->pc_next);
tcg_ctx->plugin_insn = pinsn;
plugin_gen_empty_callback(PLUGIN_GEN_FROM_INSN);
/*
* Detect page crossing to get the new host address.
* Note that we skip this when haddr1 == NULL, e.g. when we're
* fetching instructions from a region not backed by RAM.
*/
if (ptb->haddr1 == NULL) {
pinsn->haddr = NULL;
} else if (is_same_page(db, db->pc_next)) {
pinsn->haddr = ptb->haddr1 + pinsn->vaddr - ptb->vaddr;
} else {
if (ptb->vaddr2 == -1) {
ptb->vaddr2 = TARGET_PAGE_ALIGN(db->pc_first);
get_page_addr_code_hostp(cpu->env_ptr, ptb->vaddr2, &ptb->haddr2);
}
pinsn->haddr = ptb->haddr2 + pinsn->vaddr - ptb->vaddr2;
}
}
void plugin_gen_insn_end(void)
{
plugin_gen_empty_callback(PLUGIN_GEN_AFTER_INSN);
}
/*
* There are cases where we never get to finalise a translation - for
* example a page fault during translation. As a result we shouldn't
* do any clean-up here and make sure things are reset in
* plugin_gen_tb_start.
*/
void plugin_gen_tb_end(CPUState *cpu)
{
struct qemu_plugin_tb *ptb = tcg_ctx->plugin_tb;
/* collect instrumentation requests */
qemu_plugin_tb_trans_cb(cpu, ptb);
/* inject the instrumentation at the appropriate places */
plugin_gen_inject(ptb);
}
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