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Re: [Qemu-devel] [PATCH v14 08/34] tcg: Add generic translation framewor
From: |
Lluís Vilanova |
Subject: |
Re: [Qemu-devel] [PATCH v14 08/34] tcg: Add generic translation framework |
Date: |
Sat, 22 Jul 2017 01:49:58 +0300 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/25.2 (gnu/linux) |
Richard Henderson writes:
> From: Lluís Vilanova <address@hidden>
> Signed-off-by: Lluís Vilanova <address@hidden>
> Message-Id: <address@hidden>
> [rth: Moved max_insns adjustment from tb_start to init_disas_context.
> Removed pc_next return from translate_insn.
> Removed tcg_check_temp_count from generic loop.
> Moved gen_io_end to exactly match gen_io_start.
> Use qemu_log instead of error_report for temporary leaks.
> Moved TB size/icount assignments before disas_log.]
> Signed-off-by: Richard Henderson <address@hidden>
> ---
> include/exec/translator.h | 101 +++++++++++++++++++++++++++++++++++
> accel/tcg/translator.c | 133
> ++++++++++++++++++++++++++++++++++++++++++++++
> accel/tcg/Makefile.objs | 1 +
> 3 files changed, 235 insertions(+)
> create mode 100644 accel/tcg/translator.c
> diff --git a/include/exec/translator.h b/include/exec/translator.h
> index b51b8f8..aa84376 100644
> --- a/include/exec/translator.h
> +++ b/include/exec/translator.h
> @@ -10,6 +10,19 @@
> #ifndef EXEC__TRANSLATOR_H
> #define EXEC__TRANSLATOR_H
> +/*
> + * Include this header from a target-specific file, and add a
> + *
> + * DisasContextBase base;
> + *
> + * member in your target-specific DisasContext.
> + */
> +
> +
> +#include "exec/exec-all.h"
> +#include "tcg/tcg.h"
> +
> +
> /**
> * DisasJumpType:
> * @DISAS_NEXT: Next instruction in program order.
> @@ -37,4 +50,92 @@ typedef enum DisasJumpType {
> DISAS_TARGET_11,
> } DisasJumpType;
> +/**
> + * DisasContextBase:
> + * @tb: Translation block for this disassembly.
> + * @pc_first: Address of first guest instruction in this TB.
> + * @pc_next: Address of next guest instruction in this TB (current during
> + * disassembly).
> + * @is_jmp: What instruction to disassemble next.
> + * @num_insns: Number of translated instructions (including current).
> + * @singlestep_enabled: "Hardware" single stepping enabled.
> + *
> + * Architecture-agnostic disassembly context.
> + */
> +typedef struct DisasContextBase {
> + TranslationBlock *tb;
> + target_ulong pc_first;
> + target_ulong pc_next;
> + DisasJumpType is_jmp;
> + unsigned int num_insns;
> + bool singlestep_enabled;
> +} DisasContextBase;
> +
> +/**
> + * TranslatorOps:
> + * @init_disas_context:
> + * Initialize the target-specific portions of DisasContext struct.
> + * The generic DisasContextBase has already been initialized.
> + * Return max_insns, modified as necessary by db->tb->flags.
> + *
> + * @tb_start:
> + * Emit any code required before the start of the main loop,
> + * after the generic gen_tb_start().
> + *
> + * @insn_start:
> + * Emit the tcg_gen_insn_start opcode.
> + *
> + * @breakpoint_check:
> + * When called, the breakpoint has already been checked to match the PC,
> + * but the target may decide the breakpoint missed the address
> + * (e.g., due to conditions encoded in their flags). Return true to
> + * indicate that the breakpoint did hit, in which case no more
> breakpoints
> + * are checked. If the breakpoint did hit, emit any code required to
> + * signal the exception, and set db->is_jmp as necessary to terminate
> + * the main loop.
> + *
> + * @translate_insn:
> + * Disassemble one instruction and set db->pc_next for the start
> + * of the following instruction. Set db->is_jmp as necessary to
> + * terminate the main loop.
> + *
> + * @tb_stop:
> + * Emit any opcodes required to exit the TB, based on db->is_jmp.
> + *
> + * @disas_log:
> + * Print instruction disassembly to log.
> + */
> +typedef struct TranslatorOps {
> + int (*init_disas_context)(DisasContextBase *db, CPUState *cpu,
> + int max_insns);
> + void (*tb_start)(DisasContextBase *db, CPUState *cpu);
> + void (*insn_start)(DisasContextBase *db, CPUState *cpu);
> + bool (*breakpoint_check)(DisasContextBase *db, CPUState *cpu,
> + const CPUBreakpoint *bp);
> + void (*translate_insn)(DisasContextBase *db, CPUState *cpu);
> + void (*tb_stop)(DisasContextBase *db, CPUState *cpu);
> + void (*disas_log)(const DisasContextBase *db, CPUState *cpu);
> +} TranslatorOps;
> +
> +/**
> + * translator_loop:
> + * @ops: Target-specific operations.
> + * @db: Disassembly context.
> + * @cpu: Target vCPU.
> + * @tb: Translation block.
> + *
> + * Generic translator loop.
> + *
> + * Translation will stop in the following cases (in order):
> + * - When et by #TranslatorOps::insn_start.
Seems untrue; there's a tcg_debug_assert, so this should now probably be
breakpoint_check() instead.
> + * - When set by #TranslatorOps::translate_insn.
> + * - When the TCG operation buffer is full.
> + * - When single-stepping is enabled (system-wide or on the current vCPU).
> + * - When too many instructions have been translated.
> + */
> +void translator_loop(const TranslatorOps *ops, DisasContextBase *db,
> + CPUState *cpu, TranslationBlock *tb);
For the "When set by #TranslatorOps:..." I'd also talk about setting is_jmp for
that, and describe the type of stop that different is_jmp values produce
(TOO_MANY is "delayed" and NORETURN is "immediate" when set in
breakpoint_check; all values are "immediate" when set in translate_insn()).
Thanks,
Lluis
- [Qemu-devel] [PATCH v14 04/34] target/arm: Use DISAS_NORETURN, (continued)
- [Qemu-devel] [PATCH v14 04/34] target/arm: Use DISAS_NORETURN, Richard Henderson, 2017/07/15
- [Qemu-devel] [PATCH v14 06/34] target/arm: Delay check for magic kernel page, Richard Henderson, 2017/07/15
- [Qemu-devel] [PATCH v14 07/34] target/arm: Set is_jmp properly after single-stepping, Richard Henderson, 2017/07/15
- [Qemu-devel] [PATCH v14 05/34] target: [tcg] Use a generic enum for DISAS_ values, Richard Henderson, 2017/07/15
- [Qemu-devel] [PATCH v14 08/34] tcg: Add generic translation framework, Richard Henderson, 2017/07/15
- [Qemu-devel] [PATCH v14 10/34] target/i386: [tcg] Port to init_disas_context, Richard Henderson, 2017/07/15
- [Qemu-devel] [PATCH v14 09/34] target/i386: [tcg] Port to DisasContextBase, Richard Henderson, 2017/07/15
- [Qemu-devel] [PATCH v14 12/34] target/i386: [tcg] Port to breakpoint_check, Richard Henderson, 2017/07/15
- [Qemu-devel] [PATCH v14 11/34] target/i386: [tcg] Port to insn_start, Richard Henderson, 2017/07/15
- [Qemu-devel] [PATCH v14 13/34] target/i386: [tcg] Port to translate_insn, Richard Henderson, 2017/07/15
- [Qemu-devel] [PATCH v14 14/34] target/i386: [tcg] Port to tb_stop, Richard Henderson, 2017/07/15
- [Qemu-devel] [PATCH v14 16/34] target/i386: [tcg] Port to generic translation framework, Richard Henderson, 2017/07/15
- [Qemu-devel] [PATCH v14 15/34] target/i386: [tcg] Port to disas_log, Richard Henderson, 2017/07/15