From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:37951) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1VtZAm-0000Y8-CH for qemu-devel@nongnu.org; Thu, 19 Dec 2013 03:41:41 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1VtZAg-0000cM-Uu for qemu-devel@nongnu.org; Thu, 19 Dec 2013 03:41:36 -0500 Date: Thu, 19 Dec 2013 19:41:22 +1100 From: Paul Mackerras Message-ID: <20131219084122.GA6244@iris.ozlabs.ibm.com> References: <1383834662-12473-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <1383834662-12473-3-git-send-email-aneesh.kumar@linux.vnet.ibm.com> <472FFF53-4DE5-4138-A5D0-6466B884F358@suse.de> <87eh599vnm.fsf@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87eh599vnm.fsf@linux.vnet.ibm.com> Subject: Re: [Qemu-devel] [PATCH -V7 3/3] target-ppc: Fix page table lookup with kvm enabled List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Aneesh Kumar K.V" Cc: "qemu-ppc@nongnu.org list:PowerPC" , Alexander Graf , QEMU Developers On Thu, Dec 19, 2013 at 12:25:57PM +0530, Aneesh Kumar K.V wrote: > Alexander Graf writes: > > > This breaks if you run a 64-bit guest on a 32-bit host trying to > > access memory beyond 4GB. In that case htab_base is hwaddr (64bit) > > while uint8_t is only 32bit wide. > > Wow!! didn't know that is possible. I don't believe it is. All of the 64-bit instructions would trap and we don't have code to emulate them (and even if we did, it would be painfully slow given that there would be a lot of them). Paul.