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load_helper only call cpu_loop_exit() when emulation is running 

The load_helper is sometimes called from register writes. When the load
fails check if emulation is running before jump out of the emulated code.
This commit is contained in:
Takacs, Philipp 2023-05-09 14:20:11 +02:00
parent 1d9c5c7653
commit 073c4b74ca
2 changed files with 35 additions and 15 deletions
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38
qemu/accel/tcg/cputlb.c
View File

@ -1520,21 +1520,25 @@ load_helper(CPUArchState *env, target_ulong addr, TCGMemOpIdx oi,
mr = find_memory_region(uc, paddr);
if (mr == NULL) {
uc->invalid_error = UC_ERR_MAP;
cpu_exit(uc->cpu);
// XXX(@lazymio): We have to exit early so that the target register won't be overwritten
// because qemu might generate tcg code like:
// qemu_ld_i64 x0,x1,leq,8 sync: 0 dead: 0 1
// where we don't have a change to recover x0 value
cpu_loop_exit(uc->cpu);
if (!uc->cpu->stopped) {
cpu_exit(uc->cpu);
// XXX(@lazymio): We have to exit early so that the target register won't be overwritten
// because qemu might generate tcg code like:
// qemu_ld_i64 x0,x1,leq,8 sync: 0 dead: 0 1
// where we don't have a change to recover x0 value
cpu_loop_exit(uc->cpu);
}
return 0;
}
} else {
uc->invalid_addr = paddr;
uc->invalid_error = error_code;
// printf("***** Invalid fetch (unmapped memory) at " TARGET_FMT_lx "\n", addr);
cpu_exit(uc->cpu);
// See comments above
cpu_loop_exit(uc->cpu);
if (!uc->cpu->stopped) {
cpu_exit(uc->cpu);
// See comments above
cpu_loop_exit(uc->cpu);
}
return 0;
}
}
@ -1588,9 +1592,11 @@ load_helper(CPUArchState *env, target_ulong addr, TCGMemOpIdx oi,
uc->invalid_addr = paddr;
uc->invalid_error = UC_ERR_READ_PROT;
// printf("***** Invalid memory read (non-readable) at " TARGET_FMT_lx "\n", addr);
cpu_exit(uc->cpu);
// See comments above
cpu_loop_exit(uc->cpu);
if (!uc->cpu->stopped) {
cpu_exit(uc->cpu);
// See comments above
cpu_loop_exit(uc->cpu);
}
return 0;
}
}
@ -1618,9 +1624,11 @@ load_helper(CPUArchState *env, target_ulong addr, TCGMemOpIdx oi,
uc->invalid_addr = paddr;
uc->invalid_error = UC_ERR_FETCH_PROT;
// printf("***** Invalid fetch (non-executable) at " TARGET_FMT_lx "\n", addr);
cpu_exit(uc->cpu);
// See comments above
cpu_loop_exit(uc->cpu);
if (!uc->cpu->stopped) {
cpu_exit(uc->cpu);
// See comments above
cpu_loop_exit(uc->cpu);
}
return 0;
}
}

12
tests/unit/test_x86.c
View File

@ -1415,6 +1415,17 @@ static void test_x86_vtlb(void)
OK(uc_close(uc));
}
static void test_x86_segmentation()
{
uc_engine *uc;
uint64_t fs = 0x53;
uc_x86_mmr gdtr = { 0, 0xfffff8076d962000, 0x57, 0 };
OK(uc_open(UC_ARCH_X86, UC_MODE_64, &uc));
OK(uc_reg_write(uc, UC_X86_REG_GDTR, &gdtr));
uc_assert_err(UC_ERR_EXCEPTION, uc_reg_write(uc, UC_X86_REG_FS, &fs));
}
TEST_LIST = {
{"test_x86_in", test_x86_in},
@ -1461,4 +1472,5 @@ TEST_LIST = {
{"test_x86_16_incorrect_ip", test_x86_16_incorrect_ip},
{"test_x86_mmu", test_x86_mmu},
{"test_x86_vtlb", test_x86_vtlb},
{"test_x86_segmentation", test_x86_segmentation},
{NULL, NULL}};