From mboxrd@z Thu Jan 1 00:00:00 1970 From: Steven Rostedt Subject: Re: [Patch] Fix for x86_64 boot failures due to bad segment setup for protected mode. Date: Thu, 09 Nov 2006 09:28:35 -0500 Message-ID: <45533B13.6030904@redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Keir Fraser Cc: Wilfred Yu , Xiaohui Xin , "xen-devel@lists.xensource.com" , Susie Li , "Li, Xin B" , Herbert Xu List-Id: xen-devel@lists.xenproject.org Keir Fraser wrote: > On 9/11/06 12:56, "Steven Rostedt" wrote: > >> The old approach would just update all the selectors if they fit inside >> the GDT table, whether or not they were changed or loaded. So when Linux >> had a bad (extremely large) GDT limit, we loaded all the selectors into >> the shadow selector, even though they were bogus. > > A smaller patch might have been to implement those VMENTER sanity checks > inside load_seg(). I'm sure they're quite simple. However, this new approach > is arguably saner than the old, and it's worked on a few images I've tested > it with, so I checked it in and we'll see how it holds up under wider > testing. > I believed Stephen looked at the sanity check approach, and determined that the code to simulate the sanity checks would be quite complex and error prone. But Stephen can correct me if I'm wrong. -- Steve