From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:56281) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1SuAPe-0003FM-GB for qemu-devel@nongnu.org; Wed, 25 Jul 2012 18:50:43 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1SuAPa-00023h-70 for qemu-devel@nongnu.org; Wed, 25 Jul 2012 18:50:38 -0400 From: Tyler Hall Date: Wed, 25 Jul 2012 18:45:04 -0400 Message-Id: <1343256304-32029-2-git-send-email-tylerwhall@gmail.com> In-Reply-To: <1343256304-32029-1-git-send-email-tylerwhall@gmail.com> References: <1343256304-32029-1-git-send-email-tylerwhall@gmail.com> Subject: [Qemu-devel] [PATCH 2/2] exec.c: Use subpages for large unaligned mappings List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: qemu-trivial@nongnu.org, Tyler Hall Registering a multi-page memory region that is non-page-aligned results in a subpage from the start to the page boundary, some number of full pages, and possibly another subpage from the last page boundary to the end. The full pages will have a value for offset_within_region that is not a multiple of TARGET_PAGE_SIZE. Accesses through softmmu are unable to handle this and will segfault. Handling full pages through subpages is not optimal, but only non-page-aligned mappings take the penalty. Signed-off-by: Tyler Hall --- exec.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/exec.c b/exec.c index 27b100c..e6ac3e7 100644 --- a/exec.c +++ b/exec.c @@ -2305,10 +2305,15 @@ void cpu_register_physical_memory_log(MemoryRegionSection *section, remain.offset_within_address_space += now.size; remain.offset_within_region += now.size; } - now = remain; - now.size &= TARGET_PAGE_MASK; - if (now.size) { - register_multipage(&now); + while (remain.size >= TARGET_PAGE_SIZE) { + now = remain; + if (remain.offset_within_region & ~TARGET_PAGE_MASK) { + now.size = TARGET_PAGE_SIZE; + register_subpage(&now); + } else { + now.size &= TARGET_PAGE_MASK; + register_multipage(&now); + } remain.size -= now.size; remain.offset_within_address_space += now.size; remain.offset_within_region += now.size; -- 1.7.11