From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:38096) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Tgfoa-0002R7-9c for qemu-devel@nongnu.org; Thu, 06 Dec 2012 13:04:53 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TgfoZ-00045w-5a for qemu-devel@nongnu.org; Thu, 06 Dec 2012 13:04:52 -0500 Received: from ducie-dc1.codethink.co.uk ([37.128.190.40]:51833) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TgfoZ-00045j-09 for qemu-devel@nongnu.org; Thu, 06 Dec 2012 13:04:51 -0500 Received: from [192.168.24.102] (snark.dyn.ducie.codethink.co.uk [192.168.24.102]) by ducie-dc1.codethink.co.uk (Postfix) with ESMTPSA id 0A02D46BE14 for ; Thu, 6 Dec 2012 18:04:48 +0000 (GMT) Message-ID: <50C0DE3B.8060008@codethink.co.uk> Date: Thu, 06 Dec 2012 18:04:43 +0000 From: Ian Molton MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Understanding KVM List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Hi, Im trying to figure out how (on, say, x86), qemu (1.3, git) knows when the guest has accessed a page - in particular, on a framebuffer. It looks like its done via dirty page logs, which are maintained by the host kernel, so probably this is a kernel question, more than a qemu one. Is this the case? if so, where do the bits in the dirty bitmap get set? I cant find anything in the kernel that seems to do much with it, other than to copy the bitmap to userspace. -Ian