diff options
| author | Ilya Leoshkevich <iii@linux.ibm.com> | 2021-08-05 22:48:35 +0200 |
|---|---|---|
| committer | Richard Henderson <richard.henderson@linaro.org> | 2021-09-14 12:00:20 -0700 |
| commit | f025692c992c1ed6cc54ac2802cff14e9052c0d3 (patch) | |
| tree | 01931a3394d5f38e9f237de94ac0b82fcce8ff22 /include | |
| parent | 4e116893c6079b51efdc9e226be3f1a530f47f5e (diff) | |
accel/tcg: Clear PAGE_WRITE before translation
translate_insn() implementations fetch instruction bytes piecemeal,
which can cause qemu-user to generate inconsistent translations if
another thread modifies them concurrently [1].
Fix by making pages containing translated instruction non-writable
right before loading instruction bytes from them.
[1] https://lists.nongnu.org/archive/html/qemu-devel/2021-08/msg00644.html
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <20210805204835.158918-1-iii@linux.ibm.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/exec/translate-all.h | 1 | ||||
| -rw-r--r-- | include/exec/translator.h | 39 |
2 files changed, 24 insertions, 16 deletions
diff --git a/include/exec/translate-all.h b/include/exec/translate-all.h index a557b4e2bb..9f646389af 100644 --- a/include/exec/translate-all.h +++ b/include/exec/translate-all.h @@ -33,6 +33,7 @@ void tb_invalidate_phys_page_range(tb_page_addr_t start, tb_page_addr_t end); void tb_check_watchpoint(CPUState *cpu, uintptr_t retaddr); #ifdef CONFIG_USER_ONLY +void page_protect(tb_page_addr_t page_addr); int page_unprotect(target_ulong address, uintptr_t pc); #endif diff --git a/include/exec/translator.h b/include/exec/translator.h index 6c054e8d05..9bc46eda59 100644 --- a/include/exec/translator.h +++ b/include/exec/translator.h @@ -23,6 +23,7 @@ #include "exec/exec-all.h" #include "exec/cpu_ldst.h" #include "exec/plugin-gen.h" +#include "exec/translate-all.h" #include "tcg/tcg.h" @@ -74,6 +75,17 @@ typedef struct DisasContextBase { int num_insns; int max_insns; bool singlestep_enabled; +#ifdef CONFIG_USER_ONLY + /* + * Guest address of the last byte of the last protected page. + * + * Pages containing the translated instructions are made non-writable in + * order to achieve consistency in case another thread is modifying the + * code while translate_insn() fetches the instruction bytes piecemeal. + * Such writer threads are blocked on mmap_lock() in page_unprotect(). + */ + target_ulong page_protect_end; +#endif } DisasContextBase; /** @@ -156,28 +168,23 @@ bool translator_use_goto_tb(DisasContextBase *db, target_ulong dest); */ #define GEN_TRANSLATOR_LD(fullname, type, load_fn, swap_fn) \ - static inline type \ - fullname ## _swap(CPUArchState *env, DisasContextBase *dcbase, \ - abi_ptr pc, bool do_swap) \ - { \ - type ret = load_fn(env, pc); \ - if (do_swap) { \ - ret = swap_fn(ret); \ - } \ - plugin_insn_append(&ret, sizeof(ret)); \ - return ret; \ - } \ + type fullname ## _swap(CPUArchState *env, DisasContextBase *dcbase, \ + abi_ptr pc, bool do_swap); \ static inline type fullname(CPUArchState *env, \ DisasContextBase *dcbase, abi_ptr pc) \ { \ return fullname ## _swap(env, dcbase, pc, false); \ } -GEN_TRANSLATOR_LD(translator_ldub, uint8_t, cpu_ldub_code, /* no swap */) -GEN_TRANSLATOR_LD(translator_ldsw, int16_t, cpu_ldsw_code, bswap16) -GEN_TRANSLATOR_LD(translator_lduw, uint16_t, cpu_lduw_code, bswap16) -GEN_TRANSLATOR_LD(translator_ldl, uint32_t, cpu_ldl_code, bswap32) -GEN_TRANSLATOR_LD(translator_ldq, uint64_t, cpu_ldq_code, bswap64) +#define FOR_EACH_TRANSLATOR_LD(F) \ + F(translator_ldub, uint8_t, cpu_ldub_code, /* no swap */) \ + F(translator_ldsw, int16_t, cpu_ldsw_code, bswap16) \ + F(translator_lduw, uint16_t, cpu_lduw_code, bswap16) \ + F(translator_ldl, uint32_t, cpu_ldl_code, bswap32) \ + F(translator_ldq, uint64_t, cpu_ldq_code, bswap64) + +FOR_EACH_TRANSLATOR_LD(GEN_TRANSLATOR_LD) + #undef GEN_TRANSLATOR_LD #endif /* EXEC__TRANSLATOR_H */ |