diff options
| -rw-r--r-- | accel/tcg/cpu-exec.c | 20 | ||||
| -rw-r--r-- | accel/tcg/internal.h | 30 | ||||
| -rw-r--r-- | accel/tcg/tb-maint.c | 244 | ||||
| -rw-r--r-- | accel/tcg/translate-all.c | 43 | ||||
| -rw-r--r-- | accel/tcg/translator.c | 34 |
5 files changed, 237 insertions, 134 deletions
diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c index 31aa320..fdd6d3e 100644 --- a/accel/tcg/cpu-exec.c +++ b/accel/tcg/cpu-exec.c @@ -536,6 +536,26 @@ static void cpu_exec_longjmp_cleanup(CPUState *cpu) if (have_mmap_lock()) { mmap_unlock(); } +#else + /* + * For softmmu, a tlb_fill fault during translation will land here, + * and we need to release any page locks held. In system mode we + * have one tcg_ctx per thread, so we know it was this cpu doing + * the translation. + * + * Alternative 1: Install a cleanup to be called via an exception + * handling safe longjmp. It seems plausible that all our hosts + * support such a thing. We'd have to properly register unwind info + * for the JIT for EH, rather that just for GDB. + * + * Alternative 2: Set and restore cpu->jmp_env in tb_gen_code to + * capture the cpu_loop_exit longjmp, perform the cleanup, and + * jump again to arrive here. + */ + if (tcg_ctx->gen_tb) { + tb_unlock_pages(tcg_ctx->gen_tb); + tcg_ctx->gen_tb = NULL; + } #endif if (qemu_mutex_iothread_locked()) { qemu_mutex_unlock_iothread(); diff --git a/accel/tcg/internal.h b/accel/tcg/internal.h index 650c3ac..e8cbbde 100644 --- a/accel/tcg/internal.h +++ b/accel/tcg/internal.h @@ -10,6 +10,7 @@ #define ACCEL_TCG_INTERNAL_H #include "exec/exec-all.h" +#include "exec/translate-all.h" /* * Access to the various translations structures need to be serialised @@ -35,6 +36,32 @@ static inline void page_table_config_init(void) { } void page_table_config_init(void); #endif +#ifdef CONFIG_USER_ONLY +/* + * For user-only, page_protect sets the page read-only. + * Since most execution is already on read-only pages, and we'd need to + * account for other TBs on the same page, defer undoing any page protection + * until we receive the write fault. + */ +static inline void tb_lock_page0(tb_page_addr_t p0) +{ + page_protect(p0); +} + +static inline void tb_lock_page1(tb_page_addr_t p0, tb_page_addr_t p1) +{ + page_protect(p1); +} + +static inline void tb_unlock_page1(tb_page_addr_t p0, tb_page_addr_t p1) { } +static inline void tb_unlock_pages(TranslationBlock *tb) { } +#else +void tb_lock_page0(tb_page_addr_t); +void tb_lock_page1(tb_page_addr_t, tb_page_addr_t); +void tb_unlock_page1(tb_page_addr_t, tb_page_addr_t); +void tb_unlock_pages(TranslationBlock *); +#endif + #ifdef CONFIG_SOFTMMU void tb_invalidate_phys_range_fast(ram_addr_t ram_addr, unsigned size, @@ -48,8 +75,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu, vaddr pc, void page_init(void); void tb_htable_init(void); void tb_reset_jump(TranslationBlock *tb, int n); -TranslationBlock *tb_link_page(TranslationBlock *tb, tb_page_addr_t phys_pc, - tb_page_addr_t phys_page2); +TranslationBlock *tb_link_page(TranslationBlock *tb); bool tb_invalidate_phys_page_unwind(tb_page_addr_t addr, uintptr_t pc); void cpu_restore_state_from_tb(CPUState *cpu, TranslationBlock *tb, uintptr_t host_pc); diff --git a/accel/tcg/tb-maint.c b/accel/tcg/tb-maint.c index 9566224..c406b2f 100644 --- a/accel/tcg/tb-maint.c +++ b/accel/tcg/tb-maint.c @@ -70,17 +70,7 @@ typedef struct PageDesc PageDesc; */ #define assert_page_locked(pd) tcg_debug_assert(have_mmap_lock()) -static inline void page_lock_pair(PageDesc **ret_p1, tb_page_addr_t phys1, - PageDesc **ret_p2, tb_page_addr_t phys2, - bool alloc) -{ - *ret_p1 = NULL; - *ret_p2 = NULL; -} - -static inline void page_unlock(PageDesc *pd) { } -static inline void page_lock_tb(const TranslationBlock *tb) { } -static inline void page_unlock_tb(const TranslationBlock *tb) { } +static inline void tb_lock_pages(const TranslationBlock *tb) { } /* * For user-only, since we are protecting all of memory with a single lock, @@ -96,7 +86,7 @@ static void tb_remove_all(void) } /* Call with mmap_lock held. */ -static void tb_record(TranslationBlock *tb, PageDesc *p1, PageDesc *p2) +static void tb_record(TranslationBlock *tb) { vaddr addr; int flags; @@ -391,12 +381,108 @@ static void page_lock(PageDesc *pd) qemu_spin_lock(&pd->lock); } +/* Like qemu_spin_trylock, returns false on success */ +static bool page_trylock(PageDesc *pd) +{ + bool busy = qemu_spin_trylock(&pd->lock); + if (!busy) { + page_lock__debug(pd); + } + return busy; +} + static void page_unlock(PageDesc *pd) { qemu_spin_unlock(&pd->lock); page_unlock__debug(pd); } +void tb_lock_page0(tb_page_addr_t paddr) +{ + page_lock(page_find_alloc(paddr >> TARGET_PAGE_BITS, true)); +} + +void tb_lock_page1(tb_page_addr_t paddr0, tb_page_addr_t paddr1) +{ + tb_page_addr_t pindex0 = paddr0 >> TARGET_PAGE_BITS; + tb_page_addr_t pindex1 = paddr1 >> TARGET_PAGE_BITS; + PageDesc *pd0, *pd1; + + if (pindex0 == pindex1) { + /* Identical pages, and the first page is already locked. */ + return; + } + + pd1 = page_find_alloc(pindex1, true); + if (pindex0 < pindex1) { + /* Correct locking order, we may block. */ + page_lock(pd1); + return; + } + + /* Incorrect locking order, we cannot block lest we deadlock. */ + if (!page_trylock(pd1)) { + return; + } + + /* + * Drop the lock on page0 and get both page locks in the right order. + * Restart translation via longjmp. + */ + pd0 = page_find_alloc(pindex0, false); + page_unlock(pd0); + page_lock(pd1); + page_lock(pd0); + siglongjmp(tcg_ctx->jmp_trans, -3); +} + +void tb_unlock_page1(tb_page_addr_t paddr0, tb_page_addr_t paddr1) +{ + tb_page_addr_t pindex0 = paddr0 >> TARGET_PAGE_BITS; + tb_page_addr_t pindex1 = paddr1 >> TARGET_PAGE_BITS; + + if (pindex0 != pindex1) { + page_unlock(page_find_alloc(pindex1, false)); + } +} + +static void tb_lock_pages(TranslationBlock *tb) +{ + tb_page_addr_t paddr0 = tb_page_addr0(tb); + tb_page_addr_t paddr1 = tb_page_addr1(tb); + tb_page_addr_t pindex0 = paddr0 >> TARGET_PAGE_BITS; + tb_page_addr_t pindex1 = paddr1 >> TARGET_PAGE_BITS; + + if (unlikely(paddr0 == -1)) { + return; + } + if (unlikely(paddr1 != -1) && pindex0 != pindex1) { + if (pindex0 < pindex1) { + page_lock(page_find_alloc(pindex0, true)); + page_lock(page_find_alloc(pindex1, true)); + return; + } + page_lock(page_find_alloc(pindex1, true)); + } + page_lock(page_find_alloc(pindex0, true)); +} + +void tb_unlock_pages(TranslationBlock *tb) +{ + tb_page_addr_t paddr0 = tb_page_addr0(tb); + tb_page_addr_t paddr1 = tb_page_addr1(tb); + tb_page_addr_t pindex0 = paddr0 >> TARGET_PAGE_BITS; + tb_page_addr_t pindex1 = paddr1 >> TARGET_PAGE_BITS; + + if (unlikely(paddr0 == -1)) { + return; + } + if (unlikely(paddr1 != -1) && pindex0 != pindex1) { + page_unlock(page_find_alloc(pindex1, false)); + } + page_unlock(page_find_alloc(pindex0, false)); +} + static inline struct page_entry * page_entry_new(PageDesc *pd, tb_page_addr_t index) { @@ -420,13 +506,10 @@ static void page_entry_destroy(gpointer p) /* returns false on success */ static bool page_entry_trylock(struct page_entry *pe) { - bool busy; - - busy = qemu_spin_trylock(&pe->pd->lock); + bool busy = page_trylock(pe->pd); if (!busy) { g_assert(!pe->locked); pe->locked = true; - page_lock__debug(pe->pd); } return busy; } @@ -604,8 +687,7 @@ static void tb_remove_all(void) * Add the tb in the target page and protect it if necessary. * Called with @p->lock held. */ -static inline void tb_page_add(PageDesc *p, TranslationBlock *tb, - unsigned int n) +static void tb_page_add(PageDesc *p, TranslationBlock *tb, unsigned int n) { bool page_already_protected; @@ -625,15 +707,21 @@ static inline void tb_page_add(PageDesc *p, TranslationBlock *tb, } } -static void tb_record(TranslationBlock *tb, PageDesc *p1, PageDesc *p2) +static void tb_record(TranslationBlock *tb) { - tb_page_add(p1, tb, 0); - if (unlikely(p2)) { - tb_page_add(p2, tb, 1); + tb_page_addr_t paddr0 = tb_page_addr0(tb); + tb_page_addr_t paddr1 = tb_page_addr1(tb); + tb_page_addr_t pindex0 = paddr0 >> TARGET_PAGE_BITS; + tb_page_addr_t pindex1 = paddr0 >> TARGET_PAGE_BITS; + + assert(paddr0 != -1); + if (unlikely(paddr1 != -1) && pindex0 != pindex1) { + tb_page_add(page_find_alloc(pindex1, false), tb, 1); } + tb_page_add(page_find_alloc(pindex0, false), tb, 0); } -static inline void tb_page_remove(PageDesc *pd, TranslationBlock *tb) +static void tb_page_remove(PageDesc *pd, TranslationBlock *tb) { TranslationBlock *tb1; uintptr_t *pprev; @@ -653,74 +741,16 @@ static inline void tb_page_remove(PageDesc *pd, TranslationBlock *tb) static void tb_remove(TranslationBlock *tb) { - PageDesc *pd; - - pd = page_find(tb->page_addr[0] >> TARGET_PAGE_BITS); - tb_page_remove(pd, tb); - if (unlikely(tb->page_addr[1] != -1)) { - pd = page_find(tb->page_addr[1] >> TARGET_PAGE_BITS); - tb_page_remove(pd, tb); - } -} - -static void page_lock_pair(PageDesc **ret_p1, tb_page_addr_t phys1, - PageDesc **ret_p2, tb_page_addr_t phys2, bool alloc) -{ - PageDesc *p1, *p2; - tb_page_addr_t page1; - tb_page_addr_t page2; - - assert_memory_lock(); - g_assert(phys1 != -1); - - page1 = phys1 >> TARGET_PAGE_BITS; - page2 = phys2 >> TARGET_PAGE_BITS; - - p1 = page_find_alloc(page1, alloc); - if (ret_p1) { - *ret_p1 = p1; - } - if (likely(phys2 == -1)) { - page_lock(p1); - return; - } else if (page1 == page2) { - page_lock(p1); - if (ret_p2) { - *ret_p2 = p1; - } - return; - } - p2 = page_find_alloc(page2, alloc); - if (ret_p2) { - *ret_p2 = p2; - } - if (page1 < page2) { - page_lock(p1); - page_lock(p2); - } else { - page_lock(p2); - page_lock(p1); - } -} - -/* lock the page(s) of a TB in the correct acquisition order */ -static void page_lock_tb(const TranslationBlock *tb) -{ - page_lock_pair(NULL, tb_page_addr0(tb), NULL, tb_page_addr1(tb), false); -} - -static void page_unlock_tb(const TranslationBlock *tb) -{ - PageDesc *p1 = page_find(tb_page_addr0(tb) >> TARGET_PAGE_BITS); - - page_unlock(p1); - if (unlikely(tb_page_addr1(tb) != -1)) { - PageDesc *p2 = page_find(tb_page_addr1(tb) >> TARGET_PAGE_BITS); - - if (p2 != p1) { - page_unlock(p2); - } + tb_page_addr_t paddr0 = tb_page_addr0(tb); + tb_page_addr_t paddr1 = tb_page_addr1(tb); + tb_page_addr_t pindex0 = paddr0 >> TARGET_PAGE_BITS; + tb_page_addr_t pindex1 = paddr0 >> TARGET_PAGE_BITS; + + assert(paddr0 != -1); + if (unlikely(paddr1 != -1) && pindex0 != pindex1) { + tb_page_remove(page_find_alloc(pindex1, false), tb); } + tb_page_remove(page_find_alloc(pindex0, false), tb); } #endif /* CONFIG_USER_ONLY */ @@ -925,18 +955,16 @@ static void tb_phys_invalidate__locked(TranslationBlock *tb) void tb_phys_invalidate(TranslationBlock *tb, tb_page_addr_t page_addr) { if (page_addr == -1 && tb_page_addr0(tb) != -1) { - page_lock_tb(tb); + tb_lock_pages(tb); do_tb_phys_invalidate(tb, true); - page_unlock_tb(tb); + tb_unlock_pages(tb); } else { do_tb_phys_invalidate(tb, false); } } /* - * Add a new TB and link it to the physical page tables. phys_page2 is - * (-1) to indicate that only one page contains the TB. - * + * Add a new TB and link it to the physical page tables. * Called with mmap_lock held for user-mode emulation. * * Returns a pointer @tb, or a pointer to an existing TB that matches @tb. @@ -944,43 +972,29 @@ void tb_phys_invalidate(TranslationBlock *tb, tb_page_addr_t page_addr) * for the same block of guest code that @tb corresponds to. In that case, * the caller should discard the original @tb, and use instead the returned TB. */ -TranslationBlock *tb_link_page(TranslationBlock *tb, tb_page_addr_t phys_pc, - tb_page_addr_t phys_page2) +TranslationBlock *tb_link_page(TranslationBlock *tb) { - PageDesc *p; - PageDesc *p2 = NULL; void *existing_tb = NULL; uint32_t h; assert_memory_lock(); tcg_debug_assert(!(tb->cflags & CF_INVALID)); - /* - * Add the TB to the page list, acquiring first the pages's locks. - * We keep the locks held until after inserting the TB in the hash table, - * so that if the insertion fails we know for sure that the TBs are still - * in the page descriptors. - * Note that inserting into the hash table first isn't an option, since - * we can only insert TBs that are fully initialized. - */ - page_lock_pair(&p, phys_pc, &p2, phys_page2, true); - tb_record(tb, p, p2); + tb_record(tb); /* add in the hash table */ - h = tb_hash_func(phys_pc, (tb->cflags & CF_PCREL ? 0 : tb->pc), + h = tb_hash_func(tb_page_addr0(tb), (tb->cflags & CF_PCREL ? 0 : tb->pc), tb->flags, tb->cs_base, tb->cflags); qht_insert(&tb_ctx.htable, tb, h, &existing_tb); /* remove TB from the page(s) if we couldn't insert it */ if (unlikely(existing_tb)) { tb_remove(tb); - tb = existing_tb; + tb_unlock_pages(tb); + return existing_tb; } - if (p2 && p2 != p) { - page_unlock(p2); - } - page_unlock(p); + tb_unlock_pages(tb); return tb; } diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c index d3d4fbc..4c17474 100644 --- a/accel/tcg/translate-all.c +++ b/accel/tcg/translate-all.c @@ -290,7 +290,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu, { CPUArchState *env = cpu->env_ptr; TranslationBlock *tb, *existing_tb; - tb_page_addr_t phys_pc; + tb_page_addr_t phys_pc, phys_p2; tcg_insn_unit *gen_code_buf; int gen_code_size, search_size, max_insns; int64_t ti; @@ -313,6 +313,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu, QEMU_BUILD_BUG_ON(CF_COUNT_MASK + 1 != TCG_MAX_INSNS); buffer_overflow: + assert_no_pages_locked(); tb = tcg_tb_alloc(tcg_ctx); if (unlikely(!tb)) { /* flush must be done */ @@ -333,6 +334,10 @@ TranslationBlock *tb_gen_code(CPUState *cpu, tb->cflags = cflags; tb_set_page_addr0(tb, phys_pc); tb_set_page_addr1(tb, -1); + if (phys_pc != -1) { + tb_lock_page0(phys_pc); + } + tcg_ctx->gen_tb = tb; tcg_ctx->addr_type = TARGET_LONG_BITS == 32 ? TCG_TYPE_I32 : TCG_TYPE_I64; #ifdef CONFIG_SOFTMMU @@ -349,8 +354,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu, tcg_ctx->guest_mo = TCG_MO_ALL; #endif - tb_overflow: - + restart_translate: trace_translate_block(tb, pc, tb->tc.ptr); gen_code_size = setjmp_gen_code(env, tb, pc, host_pc, &max_insns, &ti); @@ -369,6 +373,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu, qemu_log_mask(CPU_LOG_TB_OP | CPU_LOG_TB_OP_OPT, "Restarting code generation for " "code_gen_buffer overflow\n"); + tb_unlock_pages(tb); goto buffer_overflow; case -2: @@ -387,14 +392,39 @@ TranslationBlock *tb_gen_code(CPUState *cpu, "Restarting code generation with " "smaller translation block (max %d insns)\n", max_insns); - goto tb_overflow; + + /* + * The half-sized TB may not cross pages. + * TODO: Fix all targets that cross pages except with + * the first insn, at which point this can't be reached. + */ + phys_p2 = tb_page_addr1(tb); + if (unlikely(phys_p2 != -1)) { + tb_unlock_page1(phys_pc, phys_p2); + tb_set_page_addr1(tb, -1); + } + goto restart_translate; + + case -3: + /* + * We had a page lock ordering problem. In order to avoid + * deadlock we had to drop the lock on page0, which means + * that everything we translated so far is compromised. + * Restart with locks held on both pages. + */ + qemu_log_mask(CPU_LOG_TB_OP | CPU_LOG_TB_OP_OPT, + "Restarting code generation with re-locked pages"); + goto restart_translate; default: g_assert_not_reached(); } } + tcg_ctx->gen_tb = NULL; + search_size = encode_search(tb, (void *)gen_code_buf + gen_code_size); if (unlikely(search_size < 0)) { + tb_unlock_pages(tb); goto buffer_overflow; } tb->tc.size = gen_code_size; @@ -504,6 +534,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu, * before attempting to link to other TBs or add to the lookup table. */ if (tb_page_addr0(tb) == -1) { + assert_no_pages_locked(); return tb; } @@ -518,7 +549,9 @@ TranslationBlock *tb_gen_code(CPUState *cpu, * No explicit memory barrier is required -- tb_link_page() makes the * TB visible in a consistent state. */ - existing_tb = tb_link_page(tb, tb_page_addr0(tb), tb_page_addr1(tb)); + existing_tb = tb_link_page(tb); + assert_no_pages_locked(); + /* if the TB already exists, discard what we just translated */ if (unlikely(existing_tb != tb)) { uintptr_t orig_aligned = (uintptr_t)gen_code_buf; diff --git a/accel/tcg/translator.c b/accel/tcg/translator.c index 0fd9efc..1a6a544 100644 --- a/accel/tcg/translator.c +++ b/accel/tcg/translator.c @@ -12,9 +12,9 @@ #include "qemu/error-report.h" #include "exec/exec-all.h" #include "exec/translator.h" -#include "exec/translate-all.h" #include "exec/plugin-gen.h" #include "tcg/tcg-op-common.h" +#include "internal.h" static void gen_io_start(void) { @@ -147,10 +147,6 @@ void translator_loop(CPUState *cpu, TranslationBlock *tb, int *max_insns, db->host_addr[0] = host_pc; db->host_addr[1] = NULL; -#ifdef CONFIG_USER_ONLY - page_protect(pc); -#endif - ops->init_disas_context(db, cpu); tcg_debug_assert(db->is_jmp == DISAS_NEXT); /* no early exit */ @@ -256,22 +252,36 @@ static void *translator_access(CPUArchState *env, DisasContextBase *db, host = db->host_addr[1]; base = TARGET_PAGE_ALIGN(db->pc_first); if (host == NULL) { - tb_page_addr_t phys_page = - get_page_addr_code_hostp(env, base, &db->host_addr[1]); + tb_page_addr_t page0, old_page1, new_page1; + + new_page1 = get_page_addr_code_hostp(env, base, &db->host_addr[1]); /* * If the second page is MMIO, treat as if the first page * was MMIO as well, so that we do not cache the TB. */ - if (unlikely(phys_page == -1)) { + if (unlikely(new_page1 == -1)) { + tb_unlock_pages(tb); tb_set_page_addr0(tb, -1); return NULL; } - tb_set_page_addr1(tb, phys_page); -#ifdef CONFIG_USER_ONLY - page_protect(end); -#endif + /* + * If this is not the first time around, and page1 matches, + * then we already have the page locked. Alternately, we're + * not doing anything to prevent the PTE from changing, so + * we might wind up with a different page, requiring us to + * re-do the locking. + */ + old_page1 = tb_page_addr1(tb); + if (likely(new_page1 != old_page1)) { + page0 = tb_page_addr0(tb); + if (unlikely(old_page1 != -1)) { + tb_unlock_page1(page0, old_page1); + } + tb_set_page_addr1(tb, new_page1); + tb_lock_page1(page0, new_page1); + } host = db->host_addr[1]; } |