From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: KVM: x86: Push potential exception error code on task switches Date: Wed, 14 Apr 2010 16:07:49 +0300 Message-ID: <4BC5BE25.8090800@redhat.com> References: <4BC5B0FB.8020700@siemens.com> <4BC5B38C.2040500@redhat.com> <4BC5B6FE.8060706@siemens.com> <4BC5BA84.8070507@redhat.com> <4BC5BBE1.5070706@siemens.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , kvm , Gleb Natapov To: Jan Kiszka Return-path: Received: from mx1.redhat.com ([209.132.183.28]:2735 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750939Ab0DNNHx (ORCPT ); Wed, 14 Apr 2010 09:07:53 -0400 In-Reply-To: <4BC5BBE1.5070706@siemens.com> Sender: kvm-owner@vger.kernel.org List-ID: On 04/14/2010 03:58 PM, Jan Kiszka wrote: > >> The TSS descriptor (gate doesn't have a size). But isn't it possible to >> have a 32-bit TSS with a 16-bit CS/SS? >> > Might be possible, but will cause troubles as the spec says: > > "The error code is pushed on the stack as a doubleword or word > (depending on the default interrupt, trap, or task gate size)." > My guess is that this is an error and that the 32-bitness of a TSS only refers to the format of the TSS, and has nothing to do with the code that actually runs. I'll ask Intel about it. Meanwhile this can be applied, if there's a problem with 16-bit exception handlers running through a 32-bit task referenced by a task gate in the IDT, it can be fixed later. -- error compiling committee.c: too many arguments to function