From mboxrd@z Thu Jan 1 00:00:00 1970 From: Anthony Liguori Subject: Re: [PATCH] Handle vma regions with no backing page (v2) Date: Tue, 29 Apr 2008 17:51:46 -0500 Message-ID: <4817A682.3090308@us.ibm.com> References: <1209496160-20482-1-git-send-email-aliguori@us.ibm.com> <48179E8D.4070407@qumranet.com> <4817A06C.5000503@codemonkey.ws> <4817A44D.5080808@qumranet.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: Carsten Otte , Andrea Arcangeli , Hollis Blanchard , kvm-devel@lists.sourceforge.net, Ben-Ami Yassour , "Zhang, Xiantao" To: Avi Kivity Return-path: In-Reply-To: <4817A44D.5080808@qumranet.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: kvm-devel-bounces@lists.sourceforge.net Errors-To: kvm-devel-bounces@lists.sourceforge.net List-Id: kvm.vger.kernel.org Avi Kivity wrote: > It depends on what's going on? Does a page table point to mmio? Or > the glommerclock? > > Not sure there is a single answer. > >> Perhaps we should be replacing consumers of gfn_to_page() with >> copy_to_user() instead? > > Indeed we should. The problem is access in atomic contexts. It's > easy to detect failure, but not always easy to handle it. So I think we should replace it with a rate limited printk and returning bad_page. That way the guest can't exploit it and we'll still hopefully get printk()s to track down instances of things going bad. Regards, Anthony Liguori ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone