From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kevin Wolf Subject: Re: [RFC PATCH] emulator: Fix task switch into/out of VM86 Date: Tue, 10 Jan 2012 12:25:18 +0100 Message-ID: <4F0C201E.3040206@redhat.com> References: <1326139810-5448-1-git-send-email-kwolf@redhat.com> <20120110090122.GI2167@redhat.com> <4F0C04A6.1080705@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Gleb Natapov Return-path: Received: from mx1.redhat.com ([209.132.183.28]:1838 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752853Ab2AJLV4 (ORCPT ); Tue, 10 Jan 2012 06:21:56 -0500 Received: from int-mx02.intmail.prod.int.phx2.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q0ABLtHZ016691 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 10 Jan 2012 06:21:55 -0500 In-Reply-To: <4F0C04A6.1080705@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Am 10.01.2012 10:28, schrieb Kevin Wolf: > Am 10.01.2012 10:01, schrieb Gleb Natapov: >> On Mon, Jan 09, 2012 at 09:10:10PM +0100, Kevin Wolf wrote: >>> * This works with VMX, but with SVM I have an additional problem: When >>> trying to exit VM86 (usually by an exception) through a task gate in >>> the IDT, the code runs into the reason = TASK_SWITCH_CALL path. I >>> searched a bit in the documentation, but didn't find any obvious way >>> to fix this. >>> >> Hmm, so exit_int_info is invalid during task switch exit even though >> task switch was caused by an exception. I wonder is this the case when >> vcpu is not in vm86 mode too? > > No idea, I would have to try it out. Did that now, and it looks like exit_int_info is always 0 during the task switch intercept for a task gate in the IDT. So special-casing VM86 won't help, I'm afraid. Kevin