diff options
| -rw-r--r-- | arch_init.c | 9 | ||||
| -rw-r--r-- | exec.c | 86 | ||||
| -rw-r--r-- | include/exec/cpu-all.h | 1 |
3 files changed, 62 insertions, 34 deletions
diff --git a/arch_init.c b/arch_init.c index 89c8fa4..71a539e 100644 --- a/arch_init.c +++ b/arch_init.c @@ -487,7 +487,6 @@ static void migration_bitmap_sync_range(ram_addr_t start, ram_addr_t length) } -/* Needs iothread lock! */ /* Fix me: there are too many global variables used in migration process. */ static int64_t start_time; static int64_t bytes_xfer_prev; @@ -500,6 +499,7 @@ static void migration_bitmap_sync_init(void) num_dirty_pages_period = 0; } +/* Called with iothread lock held, to protect ram_list.dirty_memory[] */ static void migration_bitmap_sync(void) { RAMBlock *block; @@ -688,9 +688,9 @@ static int ram_find_and_save_block(QEMUFile *f, bool last_stage) } } } + last_seen_block = block; last_offset = offset; - return bytes_sent; } @@ -816,6 +816,7 @@ static int ram_save_setup(QEMUFile *f, void *opaque) acct_clear(); } + /* iothread lock needed for ram_list.dirty_memory[] */ qemu_mutex_lock_iothread(); qemu_mutex_lock_ramlist(); bytes_transferred = 0; @@ -928,6 +929,7 @@ static int ram_save_iterate(QEMUFile *f, void *opaque) return total_sent; } +/* Called with iothread lock */ static int ram_save_complete(QEMUFile *f, void *opaque) { qemu_mutex_lock_ramlist(); @@ -1117,7 +1119,6 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) ret = -EINVAL; break; } - ch = qemu_get_byte(f); ram_handle_compressed(host, ch, TARGET_PAGE_SIZE); break; @@ -1128,7 +1129,6 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) ret = -EINVAL; break; } - qemu_get_buffer(f, host, TARGET_PAGE_SIZE); break; case RAM_SAVE_FLAG_XBZRLE: @@ -1138,7 +1138,6 @@ static int ram_load(QEMUFile *f, void *opaque, int version_id) ret = -EINVAL; break; } - if (load_xbzrle(f, addr, host) < 0) { error_report("Failed to decompress XBZRLE page at " RAM_ADDR_FMT, addr); @@ -1265,11 +1265,12 @@ static RAMBlock *find_ram_block(ram_addr_t addr) return NULL; } +/* Called with iothread lock held. */ void qemu_ram_set_idstr(ram_addr_t addr, const char *name, DeviceState *dev) { - RAMBlock *new_block = find_ram_block(addr); - RAMBlock *block; + RAMBlock *new_block, *block; + new_block = find_ram_block(addr); assert(new_block); assert(!new_block->idstr[0]); @@ -1282,7 +1283,6 @@ void qemu_ram_set_idstr(ram_addr_t addr, const char *name, DeviceState *dev) } pstrcat(new_block->idstr, sizeof(new_block->idstr), name); - /* This assumes the iothread lock is taken here too. */ qemu_mutex_lock_ramlist(); QTAILQ_FOREACH(block, &ram_list.blocks, next) { if (block != new_block && !strcmp(block->idstr, new_block->idstr)) { @@ -1294,10 +1294,17 @@ void qemu_ram_set_idstr(ram_addr_t addr, const char *name, DeviceState *dev) qemu_mutex_unlock_ramlist(); } +/* Called with iothread lock held. */ void qemu_ram_unset_idstr(ram_addr_t addr) { - RAMBlock *block = find_ram_block(addr); + RAMBlock *block; + /* FIXME: arch_init.c assumes that this is not called throughout + * migration. Ignore the problem since hot-unplug during migration + * does not work anyway. + */ + + block = find_ram_block(addr); if (block) { memset(block->idstr, 0, sizeof(block->idstr)); } @@ -1405,6 +1412,8 @@ static ram_addr_t ram_block_add(RAMBlock *new_block, Error **errp) if (new_ram_size > old_ram_size) { int i; + + /* ram_list.dirty_memory[] is protected by the iothread lock. */ for (i = 0; i < DIRTY_MEMORY_NUM; i++) { ram_list.dirty_memory[i] = bitmap_zero_extend(ram_list.dirty_memory[i], @@ -1583,7 +1592,6 @@ void qemu_ram_free(ram_addr_t addr) } } qemu_mutex_unlock_ramlist(); - } #ifndef _WIN32 @@ -1631,7 +1639,6 @@ void qemu_ram_remap(ram_addr_t addr, ram_addr_t length) memory_try_enable_merging(vaddr, length); qemu_ram_setup_dump(vaddr, length); } - return; } } } @@ -1639,49 +1646,60 @@ void qemu_ram_remap(ram_addr_t addr, ram_addr_t length) int qemu_get_ram_fd(ram_addr_t addr) { - RAMBlock *block = qemu_get_ram_block(addr); + RAMBlock *block; + int fd; - return block->fd; + block = qemu_get_ram_block(addr); + fd = block->fd; + return fd; } void *qemu_get_ram_block_host_ptr(ram_addr_t addr) { - RAMBlock *block = qemu_get_ram_block(addr); + RAMBlock *block; + void *ptr; - return ramblock_ptr(block, 0); + block = qemu_get_ram_block(addr); + ptr = ramblock_ptr(block, 0); + return ptr; } /* Return a host pointer to ram allocated with qemu_ram_alloc. - With the exception of the softmmu code in this file, this should - only be used for local memory (e.g. video ram) that the device owns, - and knows it isn't going to access beyond the end of the block. - - It should not be used for general purpose DMA. - Use cpu_physical_memory_map/cpu_physical_memory_rw instead. + * This should not be used for general purpose DMA. Use address_space_map + * or address_space_rw instead. For local memory (e.g. video ram) that the + * device owns, use memory_region_get_ram_ptr. */ void *qemu_get_ram_ptr(ram_addr_t addr) { - RAMBlock *block = qemu_get_ram_block(addr); + RAMBlock *block; + void *ptr; - if (xen_enabled()) { + block = qemu_get_ram_block(addr); + + if (xen_enabled() && block->host == NULL) { /* We need to check if the requested address is in the RAM * because we don't want to map the entire memory in QEMU. * In that case just map until the end of the page. */ if (block->offset == 0) { - return xen_map_cache(addr, 0, 0); - } else if (block->host == NULL) { - block->host = - xen_map_cache(block->offset, block->max_length, 1); + ptr = xen_map_cache(addr, 0, 0); + goto done; } + + block->host = xen_map_cache(block->offset, block->max_length, 1); } - return ramblock_ptr(block, addr - block->offset); + ptr = ramblock_ptr(block, addr - block->offset); + +done: + return ptr; } /* Return a host pointer to guest's ram. Similar to qemu_get_ram_ptr - * but takes a size argument */ + * but takes a size argument. + */ static void *qemu_ram_ptr_length(ram_addr_t addr, hwaddr *size) { + void *ptr; if (*size == 0) { return NULL; } @@ -1689,12 +1707,12 @@ static void *qemu_ram_ptr_length(ram_addr_t addr, hwaddr *size) return xen_map_cache(addr, *size, 1); } else { RAMBlock *block; - QTAILQ_FOREACH(block, &ram_list.blocks, next) { if (addr - block->offset < block->max_length) { if (addr - block->offset + *size > block->max_length) *size = block->max_length - addr + block->offset; - return ramblock_ptr(block, addr - block->offset); + ptr = ramblock_ptr(block, addr - block->offset); + return ptr; } } @@ -1704,15 +1722,24 @@ static void *qemu_ram_ptr_length(ram_addr_t addr, hwaddr *size) } /* Some of the softmmu routines need to translate from a host pointer - (typically a TLB entry) back to a ram offset. */ + * (typically a TLB entry) back to a ram offset. + * + * By the time this function returns, the returned pointer is not protected + * by RCU anymore. If the caller is not within an RCU critical section and + * does not hold the iothread lock, it must have other means of protecting the + * pointer, such as a reference to the region that includes the incoming + * ram_addr_t. + */ MemoryRegion *qemu_ram_addr_from_host(void *ptr, ram_addr_t *ram_addr) { RAMBlock *block; uint8_t *host = ptr; + MemoryRegion *mr; if (xen_enabled()) { *ram_addr = xen_ram_addr_from_mapcache(ptr); - return qemu_get_ram_block(*ram_addr)->mr; + mr = qemu_get_ram_block(*ram_addr)->mr; + return mr; } block = ram_list.mru_block; @@ -1734,7 +1761,8 @@ MemoryRegion *qemu_ram_addr_from_host(void *ptr, ram_addr_t *ram_addr) found: *ram_addr = block->offset + (host - block->host); - return block->mr; + mr = block->mr; + return mr; } static void notdirty_mem_write(void *opaque, hwaddr ram_addr, diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h index b8781d1..f7a3625 100644 --- a/include/exec/cpu-all.h +++ b/include/exec/cpu-all.h @@ -277,6 +277,7 @@ struct RAMBlock { ram_addr_t max_length; void (*resized)(const char*, uint64_t length, void *host); uint32_t flags; + /* Protected by iothread lock. */ char idstr[256]; /* Reads can take either the iothread or the ramlist lock. * Writes must take both locks. |