From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:59406) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aTVUn-00071g-Qf for qemu-devel@nongnu.org; Wed, 10 Feb 2016 09:11:55 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aTVUk-0002IS-CO for qemu-devel@nongnu.org; Wed, 10 Feb 2016 09:11:53 -0500 Received: from mx1.redhat.com ([209.132.183.28]:48510) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aTVUk-0002IL-4l for qemu-devel@nongnu.org; Wed, 10 Feb 2016 09:11:50 -0500 From: Paolo Bonzini Date: Wed, 10 Feb 2016 15:11:45 +0100 Message-Id: <1455113505-11237-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PATCH] memory: fix usage of find_next_bit and find_next_zero_bit List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: peter.maydell@linaro.org, stefanha@redhat.com The last two arguments to these functions are the last and first bit to check relative to the base. The code was using incorrectly the first bit and the number of bits. Fix this in cpu_physical_memory_get_dirty and cpu_physical_memory_all_dirty. This requires a few changes in the iteration; change the code in cpu_physical_memory_set_dirty_range to match. Fixes: 5b82b70 Cc: Stefan Hajnoczi Signed-off-by: Paolo Bonzini --- include/exec/ram_addr.h | 55 ++++++++++++++++++++++++++++++++----------------- 1 file changed, 36 insertions(+), 19 deletions(-) diff --git a/include/exec/ram_addr.h b/include/exec/ram_addr.h index b1413a1..5d33def 100644 --- a/include/exec/ram_addr.h +++ b/include/exec/ram_addr.h @@ -121,6 +121,7 @@ static inline bool cpu_physical_memory_get_dirty(ram_addr_t start, { DirtyMemoryBlocks *blocks; unsigned long end, page; + unsigned long idx, offset, base; bool dirty = false; assert(client < DIRTY_MEMORY_NUM); @@ -132,17 +133,22 @@ static inline bool cpu_physical_memory_get_dirty(ram_addr_t start, blocks = atomic_rcu_read(&ram_list.dirty_memory[client]); + idx = page / DIRTY_MEMORY_BLOCK_SIZE; + offset = page % DIRTY_MEMORY_BLOCK_SIZE; + base = page - offset; while (page < end) { - unsigned long idx = page / DIRTY_MEMORY_BLOCK_SIZE; - unsigned long offset = page % DIRTY_MEMORY_BLOCK_SIZE; - unsigned long num = MIN(end - page, DIRTY_MEMORY_BLOCK_SIZE - offset); - - if (find_next_bit(blocks->blocks[idx], offset, num) < num) { + unsigned long next = MIN(end, base + DIRTY_MEMORY_BLOCK_SIZE); + unsigned long num = next - base; + unsigned long found = find_next_bit(blocks->blocks[idx], num, offset); + if (found < num) { dirty = true; break; } - page += num; + page = next; + idx++; + offset = 0; + base += DIRTY_MEMORY_BLOCK_SIZE; } rcu_read_unlock(); @@ -156,6 +162,7 @@ static inline bool cpu_physical_memory_all_dirty(ram_addr_t start, { DirtyMemoryBlocks *blocks; unsigned long end, page; + unsigned long idx, offset, base; bool dirty = true; assert(client < DIRTY_MEMORY_NUM); @@ -167,17 +174,22 @@ static inline bool cpu_physical_memory_all_dirty(ram_addr_t start, blocks = atomic_rcu_read(&ram_list.dirty_memory[client]); + idx = page / DIRTY_MEMORY_BLOCK_SIZE; + offset = page % DIRTY_MEMORY_BLOCK_SIZE; + base = page - offset; while (page < end) { - unsigned long idx = page / DIRTY_MEMORY_BLOCK_SIZE; - unsigned long offset = page % DIRTY_MEMORY_BLOCK_SIZE; - unsigned long num = MIN(end - page, DIRTY_MEMORY_BLOCK_SIZE - offset); - - if (find_next_zero_bit(blocks->blocks[idx], offset, num) < num) { + unsigned long next = MIN(end, base + DIRTY_MEMORY_BLOCK_SIZE); + unsigned long num = next - base; + unsigned long found = find_next_zero_bit(blocks->blocks[idx], num, offset); + if (found < num) { dirty = false; break; } - page += num; + page = next; + idx++; + offset = 0; + base += DIRTY_MEMORY_BLOCK_SIZE; } rcu_read_unlock(); @@ -248,6 +260,7 @@ static inline void cpu_physical_memory_set_dirty_range(ram_addr_t start, { DirtyMemoryBlocks *blocks[DIRTY_MEMORY_NUM]; unsigned long end, page; + unsigned long idx, offset, base; int i; if (!mask && !xen_enabled()) { @@ -263,25 +276,29 @@ static inline void cpu_physical_memory_set_dirty_range(ram_addr_t start, blocks[i] = atomic_rcu_read(&ram_list.dirty_memory[i]); } + idx = page / DIRTY_MEMORY_BLOCK_SIZE; + offset = page % DIRTY_MEMORY_BLOCK_SIZE; + base = page - offset; while (page < end) { - unsigned long idx = page / DIRTY_MEMORY_BLOCK_SIZE; - unsigned long offset = page % DIRTY_MEMORY_BLOCK_SIZE; - unsigned long num = MIN(end - page, DIRTY_MEMORY_BLOCK_SIZE - offset); + unsigned long next = MIN(end, base + DIRTY_MEMORY_BLOCK_SIZE); if (likely(mask & (1 << DIRTY_MEMORY_MIGRATION))) { bitmap_set_atomic(blocks[DIRTY_MEMORY_MIGRATION]->blocks[idx], - offset, num); + offset, next - page); } if (unlikely(mask & (1 << DIRTY_MEMORY_VGA))) { bitmap_set_atomic(blocks[DIRTY_MEMORY_VGA]->blocks[idx], - offset, num); + offset, next - page); } if (unlikely(mask & (1 << DIRTY_MEMORY_CODE))) { bitmap_set_atomic(blocks[DIRTY_MEMORY_CODE]->blocks[idx], - offset, num); + offset, next - page); } - page += num; + page = next; + idx++; + offset = 0; + base += DIRTY_MEMORY_BLOCK_SIZE; } rcu_read_unlock(); -- 2.5.0