From 68fea038553039e53d425c6399202d13f1e5cfb8 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Fri, 29 Jun 2018 13:07:08 -0700 Subject: accel/tcg: Avoid caching overwritten tlb entries When installing a TLB entry, remove any cached version of the same page in the VTLB. If the existing TLB entry matches, do not copy into the VTLB, but overwrite it. Reviewed-by: Peter Maydell Signed-off-by: Richard Henderson --- accel/tcg/cputlb.c | 61 +++++++++++++++++++++++++++++++----------------------- 1 file changed, 35 insertions(+), 26 deletions(-) (limited to 'accel') diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c index cc90a5fe92..20c147d655 100644 --- a/accel/tcg/cputlb.c +++ b/accel/tcg/cputlb.c @@ -235,17 +235,30 @@ void tlb_flush_by_mmuidx_all_cpus_synced(CPUState *src_cpu, async_safe_run_on_cpu(src_cpu, fn, RUN_ON_CPU_HOST_INT(idxmap)); } +static inline bool tlb_hit_page_anyprot(CPUTLBEntry *tlb_entry, + target_ulong page) +{ + return tlb_hit_page(tlb_entry->addr_read, page) || + tlb_hit_page(tlb_entry->addr_write, page) || + tlb_hit_page(tlb_entry->addr_code, page); +} - -static inline void tlb_flush_entry(CPUTLBEntry *tlb_entry, target_ulong addr) +static inline void tlb_flush_entry(CPUTLBEntry *tlb_entry, target_ulong page) { - if (tlb_hit_page(tlb_entry->addr_read, addr) || - tlb_hit_page(tlb_entry->addr_write, addr) || - tlb_hit_page(tlb_entry->addr_code, addr)) { + 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) +{ + int k; + for (k = 0; k < CPU_VTLB_SIZE; k++) { + tlb_flush_entry(&env->tlb_v_table[mmu_idx][k], page); + } +} + static void tlb_flush_page_async_work(CPUState *cpu, run_on_cpu_data data) { CPUArchState *env = cpu->env_ptr; @@ -271,14 +284,7 @@ static void tlb_flush_page_async_work(CPUState *cpu, run_on_cpu_data data) i = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1); for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) { tlb_flush_entry(&env->tlb_table[mmu_idx][i], addr); - } - - /* check whether there are entries that need to be flushed in the vtlb */ - for (mmu_idx = 0; mmu_idx < NB_MMU_MODES; mmu_idx++) { - int k; - for (k = 0; k < CPU_VTLB_SIZE; k++) { - tlb_flush_entry(&env->tlb_v_table[mmu_idx][k], addr); - } + tlb_flush_vtlb_page(env, mmu_idx, addr); } tb_flush_jmp_cache(cpu, addr); @@ -310,7 +316,6 @@ static void tlb_flush_page_by_mmuidx_async_work(CPUState *cpu, unsigned long mmu_idx_bitmap = addr_and_mmuidx & ALL_MMUIDX_BITS; int page = (addr >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1); int mmu_idx; - int i; assert_cpu_is_self(cpu); @@ -320,11 +325,7 @@ static void tlb_flush_page_by_mmuidx_async_work(CPUState *cpu, 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); - - /* check whether there are vltb entries that need to be flushed */ - for (i = 0; i < CPU_VTLB_SIZE; i++) { - tlb_flush_entry(&env->tlb_v_table[mmu_idx][i], addr); - } + tlb_flush_vtlb_page(env, mmu_idx, addr); } } @@ -609,10 +610,9 @@ void tlb_set_page_with_attrs(CPUState *cpu, target_ulong vaddr, target_ulong address; target_ulong code_address; uintptr_t addend; - CPUTLBEntry *te, *tv, tn; + CPUTLBEntry *te, tn; hwaddr iotlb, xlat, sz, paddr_page; target_ulong vaddr_page; - unsigned vidx = env->vtlb_index++ % CPU_VTLB_SIZE; int asidx = cpu_asidx_from_attrs(cpu, attrs); assert_cpu_is_self(cpu); @@ -654,19 +654,28 @@ 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); index = (vaddr_page >> TARGET_PAGE_BITS) & (CPU_TLB_SIZE - 1); te = &env->tlb_table[mmu_idx][index]; - /* do not discard the translation in te, evict it into a victim tlb */ - tv = &env->tlb_v_table[mmu_idx][vidx]; - /* addr_write can race with tlb_reset_dirty_range */ - copy_tlb_helper(tv, te, true); + /* + * Only evict the old entry to the victim tlb if it's for a + * different page; otherwise just overwrite the stale data. + */ + if (!tlb_hit_page_anyprot(te, vaddr_page)) { + unsigned vidx = env->vtlb_index++ % CPU_VTLB_SIZE; + CPUTLBEntry *tv = &env->tlb_v_table[mmu_idx][vidx]; - env->iotlb_v[mmu_idx][vidx] = env->iotlb[mmu_idx][index]; + /* Evict the old entry into the victim tlb. */ + copy_tlb_helper(tv, te, true); + env->iotlb_v[mmu_idx][vidx] = env->iotlb[mmu_idx][index]; + } /* refill the tlb */ /* -- cgit v1.2.3