Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754637AbaGUVaY (ORCPT ); Mon, 21 Jul 2014 17:30:24 -0400 Received: from mail-wg0-f43.google.com ([74.125.82.43]:58126 "EHLO mail-wg0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753368AbaGUVaW (ORCPT ); Mon, 21 Jul 2014 17:30:22 -0400 Message-ID: <53CD866A.9020704@gmail.com> Date: Tue, 22 Jul 2014 00:30:18 +0300 From: Nadav Amit User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Paolo Bonzini , Nadav Amit CC: tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, gleb@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 2/7] KVM: x86: Function for determining exception type References: <1405942650-22589-1-git-send-email-namit@cs.technion.ac.il> <1405942650-22589-3-git-send-email-namit@cs.technion.ac.il> <53CD0514.8040308@redhat.com> In-Reply-To: <53CD0514.8040308@redhat.com> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Few comments to see we are on the same page: On 7/21/14, 3:18 PM, Paolo Bonzini wrote: > Il 21/07/2014 13:37, Nadav Amit ha scritto: >> +int kvm_exception_type(unsigned int nr) > > The manual calls this the exception class. Yes, but it also calls it exception "type" (see table 6-1 "Protected-Mode Exceptions and Interrupts" on the SDM). I called it exception type, since there is a function exception_class that is used to handle nested exceptions. >> + case VE_VECTOR: >> + return EXCPT_FAULT; >> + case DB_VECTOR: >> + return EXCPT_FAULT_OR_TRAP; > > It is only a fault for instruction fetch breakpoints. You can modify > kvm_vcpu_check_breakpoint to set RF, add a comment here that fault > handling is done elsewhere, and return EXCPT_TRAP. Unless I am mistaken, kvm_vcpu_check_breakpoint checks only for instruction breakpoint. Since instruction breakpoint should not cause RF to be set, this function should not be changed. Anyhow, I would return EXCPT_TRAP on DB_VECTOR. Nadav -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/