From 7b0d792ce13c0e894ee32a94b321b329724c9a25 Mon Sep 17 00:00:00 2001 From: Richard Henderson Date: Thu, 19 Sep 2019 17:54:10 -0700 Subject: [PATCH] cputlb: Move ROM handling from I/O path to TLB path It does not require going through the whole I/O path in order to discard a write. Reviewed-by: David Hildenbrand Signed-off-by: Richard Henderson --- accel/tcg/cputlb.c | 36 +++++++++++++++++++++--------------- exec.c | 41 +---------------------------------------- include/exec/cpu-all.h | 5 ++++- include/exec/cpu-common.h | 1 - 4 files changed, 26 insertions(+), 57 deletions(-) diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c index 028eebcb44..404ec57a4e 100644 --- a/accel/tcg/cputlb.c +++ b/accel/tcg/cputlb.c @@ -577,7 +577,8 @@ static void tlb_reset_dirty_range_locked(CPUTLBEntry *tlb_entry, { uintptr_t addr = tlb_entry->addr_write; - if ((addr & (TLB_INVALID_MASK | TLB_MMIO | TLB_NOTDIRTY)) == 0) { + if ((addr & (TLB_INVALID_MASK | TLB_MMIO | + TLB_DISCARD_WRITE | TLB_NOTDIRTY)) == 0) { addr &= TARGET_PAGE_MASK; addr += tlb_entry->addend; if ((addr - start) < length) { @@ -745,7 +746,6 @@ void tlb_set_page_with_attrs(CPUState *cpu, target_ulong vaddr, address |= TLB_MMIO; addend = 0; } else { - /* TLB_MMIO for rom/romd handled below */ addend = (uintptr_t)memory_region_get_ram_ptr(section->mr) + xlat; } @@ -822,16 +822,17 @@ void tlb_set_page_with_attrs(CPUState *cpu, target_ulong vaddr, tn.addr_write = -1; if (prot & PAGE_WRITE) { - if ((memory_region_is_ram(section->mr) && section->readonly) - || memory_region_is_romd(section->mr)) { - /* Write access calls the I/O callback. */ - tn.addr_write = address | TLB_MMIO; - } else if (memory_region_is_ram(section->mr) - && cpu_physical_memory_is_clean( - memory_region_get_ram_addr(section->mr) + xlat)) { - tn.addr_write = address | TLB_NOTDIRTY; - } else { - tn.addr_write = address; + tn.addr_write = address; + if (memory_region_is_romd(section->mr)) { + /* Use the MMIO path so that the device can switch states. */ + tn.addr_write |= TLB_MMIO; + } else if (memory_region_is_ram(section->mr)) { + if (section->readonly) { + tn.addr_write |= TLB_DISCARD_WRITE; + } else if (cpu_physical_memory_is_clean( + memory_region_get_ram_addr(section->mr) + xlat)) { + tn.addr_write |= TLB_NOTDIRTY; + } } if (prot & PAGE_WRITE_INV) { tn.addr_write |= TLB_INVALID_MASK; @@ -904,7 +905,7 @@ static uint64_t io_readx(CPUArchState *env, CPUIOTLBEntry *iotlbentry, mr = section->mr; mr_offset = (iotlbentry->addr & TARGET_PAGE_MASK) + addr; cpu->mem_io_pc = retaddr; - if (mr != &io_mem_rom && mr != &io_mem_notdirty && !cpu->can_do_io) { + if (mr != &io_mem_notdirty && !cpu->can_do_io) { cpu_io_recompile(cpu, retaddr); } @@ -945,7 +946,7 @@ static void io_writex(CPUArchState *env, CPUIOTLBEntry *iotlbentry, section = iotlb_to_section(cpu, iotlbentry->addr, iotlbentry->attrs); mr = section->mr; mr_offset = (iotlbentry->addr & TARGET_PAGE_MASK) + addr; - if (mr != &io_mem_rom && mr != &io_mem_notdirty && !cpu->can_do_io) { + if (mr != &io_mem_notdirty && !cpu->can_do_io) { cpu_io_recompile(cpu, retaddr); } cpu->mem_io_vaddr = addr; @@ -1125,7 +1126,7 @@ void *probe_access(CPUArchState *env, target_ulong addr, int size, } /* Reject I/O access, or other required slow-path. */ - if (tlb_addr & (TLB_NOTDIRTY | TLB_MMIO | TLB_BSWAP)) { + if (tlb_addr & (TLB_NOTDIRTY | TLB_MMIO | TLB_BSWAP | TLB_DISCARD_WRITE)) { return NULL; } @@ -1617,6 +1618,11 @@ store_helper(CPUArchState *env, target_ulong addr, uint64_t val, return; } + /* Ignore writes to ROM. */ + if (unlikely(tlb_addr & TLB_DISCARD_WRITE)) { + return; + } + haddr = (void *)((uintptr_t)addr + entry->addend); /* diff --git a/exec.c b/exec.c index 5f2587b621..ea8c0b18ac 100644 --- a/exec.c +++ b/exec.c @@ -88,7 +88,7 @@ static MemoryRegion *system_io; AddressSpace address_space_io; AddressSpace address_space_memory; -MemoryRegion io_mem_rom, io_mem_notdirty; +MemoryRegion io_mem_notdirty; static MemoryRegion io_mem_unassigned; #endif @@ -192,7 +192,6 @@ typedef struct subpage_t { #define PHYS_SECTION_UNASSIGNED 0 #define PHYS_SECTION_NOTDIRTY 1 -#define PHYS_SECTION_ROM 2 static void io_mem_init(void); static void memory_map_init(void); @@ -1475,8 +1474,6 @@ hwaddr memory_region_section_get_iotlb(CPUState *cpu, iotlb = memory_region_get_ram_addr(section->mr) + xlat; if (!section->readonly) { iotlb |= PHYS_SECTION_NOTDIRTY; - } else { - iotlb |= PHYS_SECTION_ROM; } } else { AddressSpaceDispatch *d; @@ -3002,38 +2999,6 @@ static uint16_t dummy_section(PhysPageMap *map, FlatView *fv, MemoryRegion *mr) return phys_section_add(map, §ion); } -static void readonly_mem_write(void *opaque, hwaddr addr, - uint64_t val, unsigned size) -{ - /* Ignore any write to ROM. */ -} - -static bool readonly_mem_accepts(void *opaque, hwaddr addr, - unsigned size, bool is_write, - MemTxAttrs attrs) -{ - return is_write; -} - -/* This will only be used for writes, because reads are special cased - * to directly access the underlying host ram. - */ -static const MemoryRegionOps readonly_mem_ops = { - .write = readonly_mem_write, - .valid.accepts = readonly_mem_accepts, - .endianness = DEVICE_NATIVE_ENDIAN, - .valid = { - .min_access_size = 1, - .max_access_size = 8, - .unaligned = false, - }, - .impl = { - .min_access_size = 1, - .max_access_size = 8, - .unaligned = false, - }, -}; - MemoryRegionSection *iotlb_to_section(CPUState *cpu, hwaddr index, MemTxAttrs attrs) { @@ -3047,8 +3012,6 @@ MemoryRegionSection *iotlb_to_section(CPUState *cpu, static void io_mem_init(void) { - memory_region_init_io(&io_mem_rom, NULL, &readonly_mem_ops, - NULL, NULL, UINT64_MAX); memory_region_init_io(&io_mem_unassigned, NULL, &unassigned_mem_ops, NULL, NULL, UINT64_MAX); @@ -3069,8 +3032,6 @@ AddressSpaceDispatch *address_space_dispatch_new(FlatView *fv) assert(n == PHYS_SECTION_UNASSIGNED); n = dummy_section(&d->map, fv, &io_mem_notdirty); assert(n == PHYS_SECTION_NOTDIRTY); - n = dummy_section(&d->map, fv, &io_mem_rom); - assert(n == PHYS_SECTION_ROM); d->phys_map = (PhysPageEntry) { .ptr = PHYS_MAP_NODE_NIL, .skip = 1 }; diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h index d148bded35..ad9ab85eb3 100644 --- a/include/exec/cpu-all.h +++ b/include/exec/cpu-all.h @@ -337,12 +337,15 @@ CPUArchState *cpu_copy(CPUArchState *env); #define TLB_WATCHPOINT (1 << (TARGET_PAGE_BITS_MIN - 4)) /* Set if TLB entry requires byte swap. */ #define TLB_BSWAP (1 << (TARGET_PAGE_BITS_MIN - 5)) +/* Set if TLB entry writes ignored. */ +#define TLB_DISCARD_WRITE (1 << (TARGET_PAGE_BITS_MIN - 6)) /* Use this mask to check interception with an alignment mask * in a TCG backend. */ #define TLB_FLAGS_MASK \ - (TLB_INVALID_MASK | TLB_NOTDIRTY | TLB_MMIO | TLB_WATCHPOINT | TLB_BSWAP) + (TLB_INVALID_MASK | TLB_NOTDIRTY | TLB_MMIO \ + | TLB_WATCHPOINT | TLB_BSWAP | TLB_DISCARD_WRITE) /** * tlb_hit_page: return true if page aligned @addr is a hit against the diff --git a/include/exec/cpu-common.h b/include/exec/cpu-common.h index f7dbe75fbc..1c0e03ddc2 100644 --- a/include/exec/cpu-common.h +++ b/include/exec/cpu-common.h @@ -100,7 +100,6 @@ void qemu_flush_coalesced_mmio_buffer(void); void cpu_flush_icache_range(hwaddr start, hwaddr len); -extern struct MemoryRegion io_mem_rom; extern struct MemoryRegion io_mem_notdirty; typedef int (RAMBlockIterFunc)(RAMBlock *rb, void *opaque); -- 2.11.0