jcs.org
qemu with hax to log dma reads & writes
jcs.org/2018/11/12/vfio
1#ifndef GEN_ICOUNT_H
2#define GEN_ICOUNT_H
3
4#include "qemu/timer.h"
5
6/* Helpers for instruction counting code generation. */
7
8static TCGOp *icount_start_insn;
9
10static inline void gen_io_start(void)
11{
12 TCGv_i32 tmp = tcg_const_i32(1);
13 tcg_gen_st_i32(tmp, cpu_env,
14 offsetof(ArchCPU, parent_obj.can_do_io) -
15 offsetof(ArchCPU, env));
16 tcg_temp_free_i32(tmp);
17}
18
19/*
20 * cpu->can_do_io is cleared automatically at the beginning of
21 * each translation block. The cost is minimal and only paid
22 * for -icount, plus it would be very easy to forget doing it
23 * in the translator. Therefore, backends only need to call
24 * gen_io_start.
25 */
26static inline void gen_io_end(void)
27{
28 TCGv_i32 tmp = tcg_const_i32(0);
29 tcg_gen_st_i32(tmp, cpu_env,
30 offsetof(ArchCPU, parent_obj.can_do_io) -
31 offsetof(ArchCPU, env));
32 tcg_temp_free_i32(tmp);
33}
34
35static inline void gen_tb_start(TranslationBlock *tb)
36{
37 TCGv_i32 count, imm;
38
39 tcg_ctx->exitreq_label = gen_new_label();
40 if (tb_cflags(tb) & CF_USE_ICOUNT) {
41 count = tcg_temp_local_new_i32();
42 } else {
43 count = tcg_temp_new_i32();
44 }
45
46 tcg_gen_ld_i32(count, cpu_env,
47 offsetof(ArchCPU, neg.icount_decr.u32) -
48 offsetof(ArchCPU, env));
49
50 if (tb_cflags(tb) & CF_USE_ICOUNT) {
51 imm = tcg_temp_new_i32();
52 /* We emit a movi with a dummy immediate argument. Keep the insn index
53 * of the movi so that we later (when we know the actual insn count)
54 * can update the immediate argument with the actual insn count. */
55 tcg_gen_movi_i32(imm, 0xdeadbeef);
56 icount_start_insn = tcg_last_op();
57
58 tcg_gen_sub_i32(count, count, imm);
59 tcg_temp_free_i32(imm);
60 }
61
62 tcg_gen_brcondi_i32(TCG_COND_LT, count, 0, tcg_ctx->exitreq_label);
63
64 if (tb_cflags(tb) & CF_USE_ICOUNT) {
65 tcg_gen_st16_i32(count, cpu_env,
66 offsetof(ArchCPU, neg.icount_decr.u16.low) -
67 offsetof(ArchCPU, env));
68 gen_io_end();
69 }
70
71 tcg_temp_free_i32(count);
72}
73
74static inline void gen_tb_end(TranslationBlock *tb, int num_insns)
75{
76 if (tb_cflags(tb) & CF_USE_ICOUNT) {
77 /* Update the num_insn immediate parameter now that we know
78 * the actual insn count. */
79 tcg_set_insn_param(icount_start_insn, 1, num_insns);
80 }
81
82 gen_set_label(tcg_ctx->exitreq_label);
83 tcg_gen_exit_tb(tb, TB_EXIT_REQUESTED);
84}
85
86#endif