From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jerone Young Subject: x86-64 32bit applications support discussion Date: Mon, 14 Mar 2005 11:02:27 -0600 Message-ID: <1110819748.5379.60.camel@thinkpad> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Sender: xen-devel-admin@lists.sourceforge.net Errors-To: xen-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , List-Archive: To: xen-devel List-Id: xen-devel@lists.xenproject.org This thread is intended for discussion of 32bit application support under x86-64 virtual domains. To all reading this is for development purposes (x86-64 support is not done yet). I've been actively looking into 32bit application support for the x86-64 Virutal Domains. I do have a question that I wanted to bring to the list to start the discussion. Since the virtual domain & applications are all running in ring 3. Does the hypervisor need to know how to tell the CPU when and when not to go into compatibility mode to run running 32bit applications properly under virtual domains? As you may know while under Long mode you have two sub modes: 64-bit mode & compatibility (for 32bit stuff). The problem I see is that since we are in Long Mode the virutal domain needs to tell CPU to go into the sub mode compatibility mode for it's 32 applications but does not have the access to do so. I'm not sure the best way of going about this (new hypercall?) ? -- Jerone Young IBM Linux Technology Center jyoung5@us.ibm.com 512-838-1157 (T/L: 678-1157) ------------------------------------------------------- SF email is sponsored by - The IT Product Guide Read honest & candid reviews on hundreds of IT Products from real users. Discover which products truly live up to the hype. Start reading now. http://ads.osdn.com/?ad_id=6595&alloc_id=14396&op=click