From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [RFC PATCH] emulator: Fix task switch into/out of VM86 Date: Tue, 10 Jan 2012 11:01:22 +0200 Message-ID: <20120110090122.GI2167@redhat.com> References: <1326139810-5448-1-git-send-email-kwolf@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org To: Kevin Wolf Return-path: Received: from mx1.redhat.com ([209.132.183.28]:43604 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754201Ab2AJJBZ (ORCPT ); Tue, 10 Jan 2012 04:01:25 -0500 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q0A91ODR014622 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 10 Jan 2012 04:01:25 -0500 Content-Disposition: inline In-Reply-To: <1326139810-5448-1-git-send-email-kwolf@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: 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? For vm86 we can change: else reason = TASK_SWITCH_CALL; to else if (vcpu in vm86 mode) reason = TASK_SWITCH_GATE; else reason = TASK_SWITCH_CALL; IIRC you can't change tasks by call in vm86 mode. -- Gleb.