On 4/24/24 16:02, Richard Henderson wrote:
> Introduce a new plugin_cb op and migrate one operation.
> By using emit_before_op, we do not need to emit opcodes
> early and modify them later -- we can simply emit the
> final set of opcodes once.
>
> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
> ---
> include/tcg/tcg-op-common.h | 1 +
> include/tcg/tcg-opc.h | 1 +
> accel/tcg/plugin-gen.c | 74 +++++++++++++++++++++----------------
> tcg/tcg-op.c | 5 +++
> 4 files changed, 50 insertions(+), 31 deletions(-)
>
> diff --git a/include/tcg/tcg-op-common.h b/include/tcg/tcg-op-common.h
> index 2d932a515e..9de5a7f280 100644
> --- a/include/tcg/tcg-op-common.h
> +++ b/include/tcg/tcg-op-common.h
> @@ -74,6 +74,7 @@ void tcg_gen_goto_tb(unsigned idx);
> */
> void tcg_gen_lookup_and_goto_ptr(void);
>
> +void tcg_gen_plugin_cb(unsigned from);
> void tcg_gen_plugin_cb_start(unsigned from, unsigned type, unsigned wr);
> void tcg_gen_plugin_cb_end(void);
>
> diff --git a/include/tcg/tcg-opc.h b/include/tcg/tcg-opc.h
> index b80227fa1c..3b7cb2bce1 100644
> --- a/include/tcg/tcg-opc.h
> +++ b/include/tcg/tcg-opc.h
> @@ -197,6 +197,7 @@ DEF(exit_tb, 0, 0, 1, TCG_OPF_BB_EXIT | TCG_OPF_BB_END)
> DEF(goto_tb, 0, 0, 1, TCG_OPF_BB_EXIT | TCG_OPF_BB_END)
> DEF(goto_ptr, 0, 1, 0, TCG_OPF_BB_EXIT | TCG_OPF_BB_END)
>
> +DEF(plugin_cb, 0, 0, 1, TCG_OPF_NOT_PRESENT)
> DEF(plugin_cb_start, 0, 0, 3, TCG_OPF_NOT_PRESENT)
> DEF(plugin_cb_end, 0, 0, 0, TCG_OPF_NOT_PRESENT)
>
> diff --git a/accel/tcg/plugin-gen.c b/accel/tcg/plugin-gen.c
> index 4b488943ff..4b02c0bfbf 100644
> --- a/accel/tcg/plugin-gen.c
> +++ b/accel/tcg/plugin-gen.c
> @@ -201,8 +201,7 @@ 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);
> + tcg_gen_plugin_cb(from);
> break;
> case PLUGIN_GEN_FROM_INSN:
> /*
> @@ -608,16 +607,6 @@ static void inject_mem_enable_helper(struct qemu_plugin_tb *ptb,
> 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)
> {
> @@ -703,11 +692,14 @@ static void plugin_gen_enable_mem_helper(struct qemu_plugin_tb *ptb,
> 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)
> +static void gen_disable_mem_helper(struct qemu_plugin_tb *ptb,
> + struct qemu_plugin_insn *insn)
> {
> - struct qemu_plugin_insn *insn = g_ptr_array_index(ptb->insns, insn_idx);
> - inject_mem_disable_helper(insn, begin_op);
> + if (insn->mem_helper) {
> + tcg_gen_st_ptr(tcg_constant_ptr(0), tcg_env,
> + offsetof(CPUState, plugin_mem_cbs) -
> + offsetof(ArchCPU, env));
> + }
> }
>
> /* #define DEBUG_PLUGIN_GEN_OPS */
> @@ -766,16 +758,49 @@ static void pr_ops(void)
>
> static void plugin_gen_inject(struct qemu_plugin_tb *plugin_tb)
> {
> - TCGOp *op;
> + TCGOp *op, *next;
> int insn_idx = -1;
>
> pr_ops();
>
> - QTAILQ_FOREACH(op, &tcg_ctx->ops, link) {
> + /*
> + * While injecting code, we cannot afford to reuse any ebb temps
> + * that might be live within the existing opcode stream.
> + * The simplest solution is to release them all and create new.
> + */
> + memset(tcg_ctx->free_temps, 0, sizeof(tcg_ctx->free_temps));
> +
> + QTAILQ_FOREACH_SAFE(op, &tcg_ctx->ops, link, next) {
> switch (op->opc) {
> case INDEX_op_insn_start:
> insn_idx++;
> break;
> +
> + case INDEX_op_plugin_cb:
> + {
> + enum plugin_gen_from from = op->args[0];
> + struct qemu_plugin_insn *insn = NULL;
> +
> + if (insn_idx >= 0) {
> + insn = g_ptr_array_index(plugin_tb->insns, insn_idx);
> + }
> +
> + tcg_ctx->emit_before_op = op;
> +
> + switch (from) {
> + case PLUGIN_GEN_AFTER_INSN:
> + assert(insn != NULL);
> + gen_disable_mem_helper(plugin_tb, insn);
> + break;
> + default:
> + g_assert_not_reached();
> + }
> +
> + tcg_ctx->emit_before_op = NULL;
> + tcg_op_remove(tcg_ctx, op);
> + break;
> + }
> +
> case INDEX_op_plugin_cb_start:
> {
> enum plugin_gen_from from = op->args[0];
> @@ -840,19 +865,6 @@ static void plugin_gen_inject(struct qemu_plugin_tb *plugin_tb)
>
> 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();
> }
> diff --git a/tcg/tcg-op.c b/tcg/tcg-op.c
> index aa6bc6f57d..0f2026c91c 100644
> --- a/tcg/tcg-op.c
> +++ b/tcg/tcg-op.c
> @@ -312,6 +312,11 @@ void tcg_gen_mb(TCGBar mb_type)
> }
> }
>
> +void tcg_gen_plugin_cb(unsigned from)
> +{
> + tcg_gen_op1(INDEX_op_plugin_cb, from);
> +}
> +
> void tcg_gen_plugin_cb_start(unsigned from, unsigned type, unsigned wr)
> {
> tcg_gen_op3(INDEX_op_plugin_cb_start, from, type, wr);
Reviewed-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>