From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] Fix up vmx_set_segment for booting older guests. Date: Tue, 20 Oct 2009 22:20:26 +0900 Message-ID: <4ADDB91A.9040502@redhat.com> References: <1256025040-4941-1-git-send-email-clalance@redhat.com> <4ADD7081.8030409@redhat.com> <4ADD8A98.4010706@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, Paolo Bonzini To: Chris Lalancette Return-path: Received: from mx1.redhat.com ([209.132.183.28]:23519 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751845AbZJTNU0 (ORCPT ); Tue, 20 Oct 2009 09:20:26 -0400 Received: from int-mx05.intmail.prod.int.phx2.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.18]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id n9KDKULk029692 for ; Tue, 20 Oct 2009 09:20:31 -0400 In-Reply-To: <4ADD8A98.4010706@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 10/20/2009 07:02 PM, Chris Lalancette wrote: > get_desc_base() sign-extends because of some complicated u8 to unsigned rules > that I'm not completely sure of. The below patch fixes my original issue, but > I'm not at all sure that this is the right thing to do. I could also change > get_desc_base() itself to do the casting, which should do the right thing for > all callers, but I'm not sure if that's what all callers want. Anybody else > have an opinion? > get_desc_base() is broken and should be fixed. No caller could possibly want this sign extension (64-bit segment bases are only possible using MSR_FS_BASE/MSR_GS_BASE/MSR_KERNEL_GS_BASE). -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.