Pierrick Bouvier <pierrick.bouv...@linaro.org> writes:
> Instead of working on a fixed memory location, allow to address it based
> on cpu_index, an element size and a given offset.
> Result address: ptr + offset + cpu_index * element_size.
>
> With this, we can target a member in a struct array from a base pointer.
>
> Current semantic is not modified, thus inline operation still targets
> always the same memory location.
>
> Signed-off-by: Pierrick Bouvier <pierrick.bouv...@linaro.org>
> ---
> accel/tcg/plugin-gen.c | 67 +++++++++++++++++++++++++++++++++++-------
> include/qemu/plugin.h | 3 ++
> plugins/api.c | 7 +++--
> plugins/core.c | 18 +++++++++---
> plugins/plugin.h | 6 ++--
> 5 files changed, 81 insertions(+), 20 deletions(-)
>
> diff --git a/accel/tcg/plugin-gen.c b/accel/tcg/plugin-gen.c
> index b37ce7683e6..1a2375d7779 100644
> --- a/accel/tcg/plugin-gen.c
> +++ b/accel/tcg/plugin-gen.c
> @@ -132,16 +132,28 @@ static void gen_empty_udata_cb_no_rwg(void)
> */
> static void gen_empty_inline_cb(void)
> {
> + TCGv_i32 cpu_index = tcg_temp_ebb_new_i32();
> + TCGv_ptr cpu_index_as_ptr = tcg_temp_ebb_new_ptr();
> TCGv_i64 val = tcg_temp_ebb_new_i64();
> TCGv_ptr ptr = tcg_temp_ebb_new_ptr();
>
> + tcg_gen_ld_i32(cpu_index, tcg_env,
> + -offsetof(ArchCPU, env) + offsetof(CPUState, cpu_index));
> + /* pass an immediate != 0 so that it doesn't get optimized away */
> + tcg_gen_muli_i32(cpu_index, cpu_index, 0xdeadbeef);
> + tcg_gen_ext_i32_ptr(cpu_index_as_ptr, cpu_index);
> +
> tcg_gen_movi_ptr(ptr, 0);
> + tcg_gen_add_ptr(ptr, ptr, cpu_index_as_ptr);
> 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);
> + tcg_temp_free_ptr(cpu_index_as_ptr);
> + tcg_temp_free_i32(cpu_index);
> }
>
<snip>
> if (UINTPTR_MAX == UINT32_MAX) {
> @@ -395,18 +439,19 @@ 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 */
> + char *ptr = cb->userp;
> + if (!cb->inline_direct_ptr) {
> + /* dereference userp once to get access to memory location */
> + ptr = *(char **)cb->userp;
> + }
I'm confused here, probably because inline_direct_ptr gets removed later
on?
> + op = copy_ld_i32(&begin_op, op);
> + op = copy_mul_i32(&begin_op, op, cb->inline_element_size);
> + op = copy_ext_i32_ptr(&begin_op, op);
> + op = copy_const_ptr(&begin_op, op, ptr + cb->inline_offset);
> + op = copy_add_ptr(&begin_op, op);
> 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;
> }
>
> diff --git a/include/qemu/plugin.h b/include/qemu/plugin.h
> index b0c5ac68293..9346249145d 100644
> --- a/include/qemu/plugin.h
> +++ b/include/qemu/plugin.h
> @@ -86,6 +86,9 @@ enum plugin_dyn_cb_subtype {
> struct qemu_plugin_dyn_cb {
> union qemu_plugin_cb_sig f;
> void *userp;
> + size_t inline_offset;
> + size_t inline_element_size;
> + bool inline_direct_ptr;
Ahh here it is.
(I seem to recall there is a setting for git to order headers first that
helps with this).
We could do with some documentation here. I can guess the offset and
element size values but what inline_direct_ptr means is not clear.
> enum plugin_dyn_cb_subtype type;
> /* @rw applies to mem callbacks only (both regular and inline) */
> enum qemu_plugin_mem_rw rw;
> diff --git a/plugins/api.c b/plugins/api.c
> index 8d5cca53295..e777eb4e9fc 100644
> --- a/plugins/api.c
> +++ b/plugins/api.c
> @@ -106,7 +106,8 @@ void qemu_plugin_register_vcpu_tb_exec_inline(struct
> qemu_plugin_tb *tb,
> void *ptr, uint64_t imm)
> {
> if (!tb->mem_only) {
> - plugin_register_inline_op(&tb->cbs[PLUGIN_CB_INLINE], 0, op, ptr,
> imm);
> + plugin_register_inline_op(&tb->cbs[PLUGIN_CB_INLINE],
> + 0, op, ptr, 0, sizeof(uint64_t), true,
> imm);
> }
> }
>
> @@ -131,7 +132,7 @@ void qemu_plugin_register_vcpu_insn_exec_inline(struct
> qemu_plugin_insn *insn,
> {
> if (!insn->mem_only) {
>
> plugin_register_inline_op(&insn->cbs[PLUGIN_CB_INSN][PLUGIN_CB_INLINE],
> - 0, op, ptr, imm);
> + 0, op, ptr, 0, sizeof(uint64_t), true,
> imm);
> }
> }
>
> @@ -156,7 +157,7 @@ void qemu_plugin_register_vcpu_mem_inline(struct
> qemu_plugin_insn *insn,
> uint64_t imm)
> {
> plugin_register_inline_op(&insn->cbs[PLUGIN_CB_MEM][PLUGIN_CB_INLINE],
> - rw, op, ptr, imm);
> + rw, op, ptr, 0, sizeof(uint64_t), true, imm);
> }
>
> void qemu_plugin_register_vcpu_tb_trans_cb(qemu_plugin_id_t id,
> diff --git a/plugins/core.c b/plugins/core.c
> index 49588285dd0..e07b9cdf229 100644
> --- a/plugins/core.c
> +++ b/plugins/core.c
> @@ -280,13 +280,18 @@ static struct qemu_plugin_dyn_cb
> *plugin_get_dyn_cb(GArray **arr)
>
> void plugin_register_inline_op(GArray **arr,
> enum qemu_plugin_mem_rw rw,
> - enum qemu_plugin_op op, void *ptr,
> + enum qemu_plugin_op op,
> + void *ptr, size_t offset, size_t element_size,
> + bool direct_ptr,
> uint64_t imm)
> {
> struct qemu_plugin_dyn_cb *dyn_cb;
>
> dyn_cb = plugin_get_dyn_cb(arr);
> dyn_cb->userp = ptr;
> + dyn_cb->inline_element_size = element_size;
> + dyn_cb->inline_offset = offset;
> + dyn_cb->inline_direct_ptr = direct_ptr;
> dyn_cb->type = PLUGIN_CB_INLINE;
> dyn_cb->rw = rw;
> dyn_cb->inline_insn.op = op;
> @@ -431,9 +436,14 @@ void qemu_plugin_flush_cb(void)
> plugin_cb__simple(QEMU_PLUGIN_EV_FLUSH);
> }
>
> -void exec_inline_op(struct qemu_plugin_dyn_cb *cb)
> +void exec_inline_op(struct qemu_plugin_dyn_cb *cb, int cpu_index)
> {
> - uint64_t *val = cb->userp;
> + char *ptr = cb->userp;
> + if (!cb->inline_direct_ptr) {
> + ptr = *(char **) cb->userp;
> + }
> + ptr += cb->inline_offset;
> + uint64_t *val = (uint64_t *)(ptr + cpu_index * cb->inline_element_size);
>
> switch (cb->inline_insn.op) {
> case QEMU_PLUGIN_INLINE_ADD_U64:
> @@ -466,7 +476,7 @@ void qemu_plugin_vcpu_mem_cb(CPUState *cpu, uint64_t
> vaddr,
> vaddr, cb->userp);
> break;
> case PLUGIN_CB_INLINE:
> - exec_inline_op(cb);
> + exec_inline_op(cb, cpu->cpu_index);
> break;
> default:
> g_assert_not_reached();
> diff --git a/plugins/plugin.h b/plugins/plugin.h
> index 5eb2fdbc85e..2c278379b70 100644
> --- a/plugins/plugin.h
> +++ b/plugins/plugin.h
> @@ -66,7 +66,9 @@ struct qemu_plugin_ctx
> *plugin_id_to_ctx_locked(qemu_plugin_id_t id);
>
> void plugin_register_inline_op(GArray **arr,
> enum qemu_plugin_mem_rw rw,
> - enum qemu_plugin_op op, void *ptr,
> + enum qemu_plugin_op op,
> + void *ptr, size_t offset, size_t element_size,
> + bool direct_ptr,
> uint64_t imm);
>
> void plugin_reset_uninstall(qemu_plugin_id_t id,
> @@ -95,6 +97,6 @@ void plugin_register_vcpu_mem_cb(GArray **arr,
> enum qemu_plugin_mem_rw rw,
> void *udata);
>
> -void exec_inline_op(struct qemu_plugin_dyn_cb *cb);
> +void exec_inline_op(struct qemu_plugin_dyn_cb *cb, int cpu_index);
>
> #endif /* PLUGIN_H */
--
Alex Bennée
Virtualisation Tech Lead @ Linaro
