diff options
Diffstat (limited to 'accel/tcg/cputlb.c')
| -rw-r--r-- | accel/tcg/cputlb.c | 155 |
1 files changed, 84 insertions, 71 deletions
diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c index f6b388c961..c2a6190674 100644 --- a/accel/tcg/cputlb.c +++ b/accel/tcg/cputlb.c @@ -75,6 +75,9 @@ QEMU_BUILD_BUG_ON(NB_MMU_MODES > 16); void tlb_init(CPUState *cpu) { + CPUArchState *env = cpu->env_ptr; + + qemu_spin_init(&env->tlb_lock); } /* flush_all_helper: run fn across all cpus @@ -129,8 +132,17 @@ static void tlb_flush_nocheck(CPUState *cpu) atomic_set(&env->tlb_flush_count, env->tlb_flush_count + 1); tlb_debug("(count: %zu)\n", tlb_flush_count()); + /* + * tlb_table/tlb_v_table updates from any thread must hold tlb_lock. + * However, updates from the owner thread (as is the case here; see the + * above assert_cpu_is_self) do not need atomic_set because all reads + * that do not hold the lock are performed by the same owner thread. + */ + qemu_spin_lock(&env->tlb_lock); memset(env->tlb_table, -1, sizeof(env->tlb_table)); memset(env->tlb_v_table, -1, sizeof(env->tlb_v_table)); + qemu_spin_unlock(&env->tlb_lock); + cpu_tb_jmp_cache_clear(cpu); env->vtlb_index = 0; @@ -182,6 +194,7 @@ static void tlb_flush_by_mmuidx_async_work(CPUState *cpu, run_on_cpu_data data) tlb_debug("start: mmu_idx:0x%04lx\n", mmu_idx_bitmask); + qemu_spin_lock(&env->tlb_lock); for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) { if (test_bit(mmu_idx, &mmu_idx_bitmask)) { @@ -191,6 +204,7 @@ static void tlb_flush_by_mmuidx_async_work(CPUState *cpu, run_on_cpu_data data) memset(env->tlb_v_table[mmu_idx], -1, sizeof(env->tlb_v_table[0])); } } + qemu_spin_unlock(&env->tlb_lock); cpu_tb_jmp_cache_clear(cpu); @@ -247,19 +261,24 @@ static inline bool tlb_hit_page_anyprot(CPUTLBEntry *tlb_entry, tlb_hit_page(tlb_entry->addr_code, page); } -static inline void tlb_flush_entry(CPUTLBEntry *tlb_entry, target_ulong page) +/* Called with tlb_lock held */ +static inline void tlb_flush_entry_locked(CPUTLBEntry *tlb_entry, + target_ulong page) { if (tlb_hit_page_anyprot(tlb_entry, page)) { memset(tlb_entry, -1, sizeof(*tlb_entry)); } } -static inline void tlb_flush_vtlb_page(CPUArchState *env, int mmu_idx, - target_ulong page) +/* Called with tlb_lock held */ +static inline void tlb_flush_vtlb_page_locked(CPUArchState *env, int mmu_idx, + target_ulong page) { int k; + + assert_cpu_is_self(ENV_GET_CPU(env)); for (k = 0; k < CPU_VTLB_SIZE; k++) { - tlb_flush_entry(&env->tlb_v_table[mmu_idx][k], page); + tlb_flush_entry_locked(&env->tlb_v_table[mmu_idx][k], page); } } @@ -286,10 +305,12 @@ static void tlb_flush_page_async_work(CPUState *cpu, run_on_cpu_data data) addr &= TARGET_PAGE_MASK; i = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1); + qemu_spin_lock(&env->tlb_lock); for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) { - tlb_flush_entry(&env->tlb_table[mmu_idx][i], addr); - tlb_flush_vtlb_page(env, mmu_idx, addr); + tlb_flush_entry_locked(&env->tlb_table[mmu_idx][i], addr); + tlb_flush_vtlb_page_locked(env, mmu_idx, addr); } + qemu_spin_unlock(&env->tlb_lock); tb_flush_jmp_cache(cpu, addr); } @@ -326,12 +347,14 @@ static void tlb_flush_page_by_mmuidx_async_work(CPUState *cpu, tlb_debug("page:%d addr:"TARGET_FMT_lx" mmu_idx:0x%lx\n", page, addr, mmu_idx_bitmap); + qemu_spin_lock(&env->tlb_lock); for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) { if (test_bit(mmu_idx, &mmu_idx_bitmap)) { - tlb_flush_entry(&env->tlb_table[mmu_idx][page], addr); - tlb_flush_vtlb_page(env, mmu_idx, addr); + tlb_flush_entry_locked(&env->tlb_table[mmu_idx][page], addr); + tlb_flush_vtlb_page_locked(env, mmu_idx, addr); } } + qemu_spin_unlock(&env->tlb_lock); tb_flush_jmp_cache(cpu, addr); } @@ -454,72 +477,44 @@ void tlb_unprotect_code(ram_addr_t ram_addr) * most usual is detecting writes to code regions which may invalidate * generated code. * - * Because we want other vCPUs to respond to changes straight away we - * update the te->addr_write field atomically. If the TLB entry has - * been changed by the vCPU in the mean time we skip the update. + * Other vCPUs might be reading their TLBs during guest execution, so we update + * te->addr_write with atomic_set. We don't need to worry about this for + * oversized guests as MTTCG is disabled for them. * - * As this function uses atomic accesses we also need to ensure - * updates to tlb_entries follow the same access rules. We don't need - * to worry about this for oversized guests as MTTCG is disabled for - * them. + * Called with tlb_lock held. */ - -static void tlb_reset_dirty_range(CPUTLBEntry *tlb_entry, uintptr_t start, - uintptr_t length) +static void tlb_reset_dirty_range_locked(CPUTLBEntry *tlb_entry, + uintptr_t start, uintptr_t length) { -#if TCG_OVERSIZED_GUEST uintptr_t addr = tlb_entry->addr_write; if ((addr & (TLB_INVALID_MASK | TLB_MMIO | TLB_NOTDIRTY)) == 0) { addr &= TARGET_PAGE_MASK; addr += tlb_entry->addend; if ((addr - start) < length) { +#if TCG_OVERSIZED_GUEST tlb_entry->addr_write |= TLB_NOTDIRTY; - } - } #else - /* paired with atomic_mb_set in tlb_set_page_with_attrs */ - uintptr_t orig_addr = atomic_mb_read(&tlb_entry->addr_write); - uintptr_t addr = orig_addr; - - if ((addr & (TLB_INVALID_MASK | TLB_MMIO | TLB_NOTDIRTY)) == 0) { - addr &= TARGET_PAGE_MASK; - addr += atomic_read(&tlb_entry->addend); - if ((addr - start) < length) { - uintptr_t notdirty_addr = orig_addr | TLB_NOTDIRTY; - atomic_cmpxchg(&tlb_entry->addr_write, orig_addr, notdirty_addr); + atomic_set(&tlb_entry->addr_write, + tlb_entry->addr_write | TLB_NOTDIRTY); +#endif } } -#endif } -/* For atomic correctness when running MTTCG we need to use the right - * primitives when copying entries */ -static inline void copy_tlb_helper(CPUTLBEntry *d, CPUTLBEntry *s, - bool atomic_set) +/* + * Called with tlb_lock held. + * Called only from the vCPU context, i.e. the TLB's owner thread. + */ +static inline void copy_tlb_helper_locked(CPUTLBEntry *d, const CPUTLBEntry *s) { -#if TCG_OVERSIZED_GUEST *d = *s; -#else - if (atomic_set) { - d->addr_read = s->addr_read; - d->addr_code = s->addr_code; - atomic_set(&d->addend, atomic_read(&s->addend)); - /* Pairs with flag setting in tlb_reset_dirty_range */ - atomic_mb_set(&d->addr_write, atomic_read(&s->addr_write)); - } else { - d->addr_read = s->addr_read; - d->addr_write = atomic_read(&s->addr_write); - d->addr_code = s->addr_code; - d->addend = atomic_read(&s->addend); - } -#endif } /* This is a cross vCPU call (i.e. another vCPU resetting the flags of - * the target vCPU). As such care needs to be taken that we don't - * dangerously race with another vCPU update. The only thing actually - * updated is the target TLB entry ->addr_write flags. + * the target vCPU). + * We must take tlb_lock to avoid racing with another vCPU update. The only + * thing actually updated is the target TLB entry ->addr_write flags. */ void tlb_reset_dirty(CPUState *cpu, ram_addr_t start1, ram_addr_t length) { @@ -528,22 +523,26 @@ void tlb_reset_dirty(CPUState *cpu, ram_addr_t start1, ram_addr_t length) int mmu_idx; env = cpu->env_ptr; + qemu_spin_lock(&env->tlb_lock); for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) { unsigned int i; for (i = 0; i < CPU_TLB_SIZE; i++) { - tlb_reset_dirty_range(&env->tlb_table[mmu_idx][i], - start1, length); + tlb_reset_dirty_range_locked(&env->tlb_table[mmu_idx][i], start1, + length); } for (i = 0; i < CPU_VTLB_SIZE; i++) { - tlb_reset_dirty_range(&env->tlb_v_table[mmu_idx][i], - start1, length); + tlb_reset_dirty_range_locked(&env->tlb_v_table[mmu_idx][i], start1, + length); } } + qemu_spin_unlock(&env->tlb_lock); } -static inline void tlb_set_dirty1(CPUTLBEntry *tlb_entry, target_ulong vaddr) +/* Called with tlb_lock held */ +static inline void tlb_set_dirty1_locked(CPUTLBEntry *tlb_entry, + target_ulong vaddr) { if (tlb_entry->addr_write == (vaddr | TLB_NOTDIRTY)) { tlb_entry->addr_write = vaddr; @@ -562,16 +561,18 @@ void tlb_set_dirty(CPUState *cpu, target_ulong vaddr) vaddr &= TARGET_PAGE_MASK; i = (vaddr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1); + qemu_spin_lock(&env->tlb_lock); for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) { - tlb_set_dirty1(&env->tlb_table[mmu_idx][i], vaddr); + tlb_set_dirty1_locked(&env->tlb_table[mmu_idx][i], vaddr); } for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) { int k; for (k = 0; k < CPU_VTLB_SIZE; k++) { - tlb_set_dirty1(&env->tlb_v_table[mmu_idx][k], vaddr); + tlb_set_dirty1_locked(&env->tlb_v_table[mmu_idx][k], vaddr); } } + qemu_spin_unlock(&env->tlb_lock); } /* Our TLB does not support large pages, so remember the area covered by @@ -658,9 +659,6 @@ void tlb_set_page_with_attrs(CPUState *cpu, target_ulong vaddr, addend = (uintptr_t)memory_region_get_ram_ptr(section->mr) + xlat; } - /* Make sure there's no cached translation for the new page. */ - tlb_flush_vtlb_page(env, mmu_idx, vaddr_page); - code_address = address; iotlb = memory_region_section_get_iotlb(cpu, section, vaddr_page, paddr_page, xlat, prot, &address); @@ -669,6 +667,18 @@ void tlb_set_page_with_attrs(CPUState *cpu, target_ulong vaddr, te = &env->tlb_table[mmu_idx][index]; /* + * Hold the TLB lock for the rest of the function. We could acquire/release + * the lock several times in the function, but it is faster to amortize the + * acquisition cost by acquiring it just once. Note that this leads to + * a longer critical section, but this is not a concern since the TLB lock + * is unlikely to be contended. + */ + qemu_spin_lock(&env->tlb_lock); + + /* Make sure there's no cached translation for the new page. */ + tlb_flush_vtlb_page_locked(env, mmu_idx, vaddr_page); + + /* * Only evict the old entry to the victim tlb if it's for a * different page; otherwise just overwrite the stale data. */ @@ -677,7 +687,7 @@ void tlb_set_page_with_attrs(CPUState *cpu, target_ulong vaddr, CPUTLBEntry *tv = &env->tlb_v_table[mmu_idx][vidx]; /* Evict the old entry into the victim tlb. */ - copy_tlb_helper(tv, te, true); + copy_tlb_helper_locked(tv, te); env->iotlb_v[mmu_idx][vidx] = env->iotlb[mmu_idx][index]; } @@ -729,9 +739,8 @@ void tlb_set_page_with_attrs(CPUState *cpu, target_ulong vaddr, } } - /* Pairs with flag setting in tlb_reset_dirty_range */ - copy_tlb_helper(te, &tn, true); - /* atomic_mb_set(&te->addr_write, write_address); */ + copy_tlb_helper_locked(te, &tn); + qemu_spin_unlock(&env->tlb_lock); } /* Add a new TLB entry, but without specifying the memory @@ -895,6 +904,8 @@ static bool victim_tlb_hit(CPUArchState *env, size_t mmu_idx, size_t index, size_t elt_ofs, target_ulong page) { size_t vidx; + + assert_cpu_is_self(ENV_GET_CPU(env)); for (vidx = 0; vidx < CPU_VTLB_SIZE; ++vidx) { CPUTLBEntry *vtlb = &env->tlb_v_table[mmu_idx][vidx]; target_ulong cmp = *(target_ulong *)((uintptr_t)vtlb + elt_ofs); @@ -903,9 +914,11 @@ static bool victim_tlb_hit(CPUArchState *env, size_t mmu_idx, size_t index, /* Found entry in victim tlb, swap tlb and iotlb. */ CPUTLBEntry tmptlb, *tlb = &env->tlb_table[mmu_idx][index]; - copy_tlb_helper(&tmptlb, tlb, false); - copy_tlb_helper(tlb, vtlb, true); - copy_tlb_helper(vtlb, &tmptlb, true); + qemu_spin_lock(&env->tlb_lock); + copy_tlb_helper_locked(&tmptlb, tlb); + copy_tlb_helper_locked(tlb, vtlb); + copy_tlb_helper_locked(vtlb, &tmptlb); + qemu_spin_unlock(&env->tlb_lock); CPUIOTLBEntry tmpio, *io = &env->iotlb[mmu_idx][index]; CPUIOTLBEntry *vio = &env->iotlb_v[mmu_idx][vidx]; |