From b2a8658ef5dc57ea9e7a45091724a719dd4bdcd3 Mon Sep 17 00:00:00 2001 From: Umesh Deshpande Date: Wed, 17 Aug 2011 00:01:33 -0700 Subject: protect the ramlist with a separate mutex Add the new mutex that protects shared state between ram_save_live and the iothread. If the iothread mutex has to be taken together with the ramlist mutex, the iothread shall always be _outside_. Signed-off-by: Paolo Bonzini Signed-off-by: Umesh Deshpande Signed-off-by: Juan Quintela Reviewed-by: Orit Wasserman --- arch_init.c | 9 ++++++++- exec.c | 29 +++++++++++++++++++++++++++-- include/exec/cpu-all.h | 9 +++++++++ 3 files changed, 44 insertions(+), 3 deletions(-) diff --git a/arch_init.c b/arch_init.c index 1f737dc1eb..fad1c4099a 100644 --- a/arch_init.c +++ b/arch_init.c @@ -528,7 +528,6 @@ static void ram_migration_cancel(void *opaque) migration_end(); } - static void reset_ram_globals(void) { last_block = NULL; @@ -547,6 +546,7 @@ static int ram_save_setup(QEMUFile *f, void *opaque) bitmap_set(migration_bitmap, 0, ram_pages); migration_dirty_pages = ram_pages; + qemu_mutex_lock_ramlist(); bytes_transferred = 0; reset_ram_globals(); @@ -574,6 +574,7 @@ static int ram_save_setup(QEMUFile *f, void *opaque) qemu_put_be64(f, block->length); } + qemu_mutex_unlock_ramlist(); qemu_put_be64(f, RAM_SAVE_FLAG_EOS); return 0; @@ -588,6 +589,8 @@ static int ram_save_iterate(QEMUFile *f, void *opaque) uint64_t expected_downtime; MigrationState *s = migrate_get_current(); + qemu_mutex_lock_ramlist(); + if (ram_list.version != last_version) { reset_ram_globals(); } @@ -636,6 +639,7 @@ static int ram_save_iterate(QEMUFile *f, void *opaque) bwidth = 0.000001; } + qemu_mutex_unlock_ramlist(); qemu_put_be64(f, RAM_SAVE_FLAG_EOS); expected_downtime = ram_save_remaining() * TARGET_PAGE_SIZE / bwidth; @@ -656,6 +660,8 @@ static int ram_save_complete(QEMUFile *f, void *opaque) { migration_bitmap_sync(); + qemu_mutex_lock_ramlist(); + /* try transferring iterative blocks of memory */ /* flush all remaining blocks regardless of rate limiting */ @@ -671,6 +677,7 @@ static int ram_save_complete(QEMUFile *f, void *opaque) } migration_end(); + qemu_mutex_unlock_ramlist(); qemu_put_be64(f, RAM_SAVE_FLAG_EOS); return 0; diff --git a/exec.c b/exec.c index 8478bef548..a6923addd4 100644 --- a/exec.c +++ b/exec.c @@ -213,6 +213,7 @@ bool memory_region_is_unassigned(MemoryRegion *mr) void cpu_exec_init_all(void) { #if !defined(CONFIG_USER_ONLY) + qemu_mutex_init(&ram_list.mutex); memory_map_init(); io_mem_init(); #endif @@ -801,6 +802,16 @@ void qemu_flush_coalesced_mmio_buffer(void) kvm_flush_coalesced_mmio_buffer(); } +void qemu_mutex_lock_ramlist(void) +{ + qemu_mutex_lock(&ram_list.mutex); +} + +void qemu_mutex_unlock_ramlist(void) +{ + qemu_mutex_unlock(&ram_list.mutex); +} + #if defined(__linux__) && !defined(TARGET_S390X) #include @@ -982,6 +993,8 @@ 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)) { fprintf(stderr, "RAMBlock \"%s\" already registered, abort!\n", @@ -989,6 +1002,7 @@ void qemu_ram_set_idstr(ram_addr_t addr, const char *name, DeviceState *dev) abort(); } } + qemu_mutex_unlock_ramlist(); } static int memory_try_enable_merging(void *addr, size_t len) @@ -1012,6 +1026,8 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host, size = TARGET_PAGE_ALIGN(size); new_block = g_malloc0(sizeof(*new_block)); + /* This assumes the iothread lock is taken here too. */ + qemu_mutex_lock_ramlist(); new_block->mr = mr; new_block->offset = find_ram_offset(size); if (host) { @@ -1057,6 +1073,7 @@ ram_addr_t qemu_ram_alloc_from_ptr(ram_addr_t size, void *host, ram_list.mru_block = NULL; ram_list.version++; + qemu_mutex_unlock_ramlist(); ram_list.phys_dirty = g_realloc(ram_list.phys_dirty, last_ram_offset() >> TARGET_PAGE_BITS); @@ -1082,21 +1099,26 @@ void qemu_ram_free_from_ptr(ram_addr_t addr) { RAMBlock *block; + /* This assumes the iothread lock is taken here too. */ + qemu_mutex_lock_ramlist(); QTAILQ_FOREACH(block, &ram_list.blocks, next) { if (addr == block->offset) { QTAILQ_REMOVE(&ram_list.blocks, block, next); ram_list.mru_block = NULL; ram_list.version++; g_free(block); - return; + break; } } + qemu_mutex_unlock_ramlist(); } void qemu_ram_free(ram_addr_t addr) { RAMBlock *block; + /* This assumes the iothread lock is taken here too. */ + qemu_mutex_lock_ramlist(); QTAILQ_FOREACH(block, &ram_list.blocks, next) { if (addr == block->offset) { QTAILQ_REMOVE(&ram_list.blocks, block, next); @@ -1127,9 +1149,10 @@ void qemu_ram_free(ram_addr_t addr) #endif } g_free(block); - return; + break; } } + qemu_mutex_unlock_ramlist(); } @@ -1207,6 +1230,7 @@ void *qemu_get_ram_ptr(ram_addr_t addr) { RAMBlock *block; + /* The list is protected by the iothread lock here. */ block = ram_list.mru_block; if (block && addr - block->offset < block->length) { goto found; @@ -1246,6 +1270,7 @@ static void *qemu_safe_ram_ptr(ram_addr_t addr) { RAMBlock *block; + /* The list is protected by the iothread lock here. */ QTAILQ_FOREACH(block, &ram_list.blocks, next) { if (addr - block->offset < block->length) { if (xen_enabled()) { diff --git a/include/exec/cpu-all.h b/include/exec/cpu-all.h index f052b38974..439e88deb4 100644 --- a/include/exec/cpu-all.h +++ b/include/exec/cpu-all.h @@ -22,6 +22,7 @@ #include "qemu-common.h" #include "qemu/tls.h" #include "exec/cpu-common.h" +#include "qemu/thread.h" /* some important defines: * @@ -487,6 +488,9 @@ typedef struct RAMBlock { ram_addr_t length; uint32_t flags; char idstr[256]; + /* Reads can take either the iothread or the ramlist lock. + * Writes must take both locks. + */ QTAILQ_ENTRY(RAMBlock) next; #if defined(__linux__) && !defined(TARGET_S390X) int fd; @@ -494,8 +498,11 @@ typedef struct RAMBlock { } RAMBlock; typedef struct RAMList { + QemuMutex mutex; + /* Protected by the iothread lock. */ uint8_t *phys_dirty; RAMBlock *mru_block; + /* Protected by the ramlist lock. */ QTAILQ_HEAD(, RAMBlock) blocks; uint32_t version; } RAMList; @@ -516,6 +523,8 @@ extern int mem_prealloc; void dump_exec_info(FILE *f, fprintf_function cpu_fprintf); ram_addr_t last_ram_offset(void); +void qemu_mutex_lock_ramlist(void); +void qemu_mutex_unlock_ramlist(void); #endif /* !CONFIG_USER_ONLY */ int cpu_memory_rw_debug(CPUArchState *env, target_ulong addr, -- cgit v1.2.1