Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1764332AbXJOLQT (ORCPT ); Mon, 15 Oct 2007 07:16:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1755745AbXJOLQI (ORCPT ); Mon, 15 Oct 2007 07:16:08 -0400 Received: from il.qumranet.com ([82.166.9.18]:35037 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757707AbXJOLQH (ORCPT ); Mon, 15 Oct 2007 07:16:07 -0400 Message-ID: <47134BCE.1080306@qumranet.com> Date: Mon, 15 Oct 2007 13:15:26 +0200 From: Avi Kivity User-Agent: Thunderbird 2.0.0.0 (X11/20070419) MIME-Version: 1.0 To: Laurent Vivier CC: Ingo Molnar , linux-kernel Subject: Re: [RESEND 2][PATCH 4/4] Modify KVM to update guest time accounting. References: <46E550EF.5080209@bull.net> <20071015093800.GA22818@elte.hu> <47133732.2090809@qumranet.com> <20071015095125.GB28367@elte.hu> <47133ABD.8050608@qumranet.com> <471346B0.8050102@bull.net> In-Reply-To: <471346B0.8050102@bull.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1451 Lines: 58 Laurent Vivier wrote: > Avi Kivity wrote: > >> Ingo Molnar wrote: >> >>> * Avi Kivity wrote: >>> >>> >>> >>>> This bit can go; for the external module I can add it back in >>>> external-module-compat.h. No need to pollute mainline with backward >>>> compatibility stuff. >>>> >>>> >>> hm: >>> >>> static inline void kvm_guest_enter(void) >>> { >>> current->flags |= PF_VCPU; >>> } >>> >>> static inline void kvm_guest_exit(void) >>> { >>> } >>> >>> shouldnt PF_VCPU be cleared in kvm_guest_exit()? >>> >>> >> IIRC the accounting code clears it, but yes, it may not have been called >> at all, so clearing it here is needed. >> >> > > No, It must not be cleared here because we can't enter in the accounting code > between kvm_guest_enter(void) and kvm_guest_exit(void). > > Right. > This is why the accounting code clears it. > But if we didn't get an interrupt in that time? We can clear it a bit later, after local_irq_enable() in __vcpu_run(). However we need a nop instruction first because "sti" keeps interrupts disabled for one more instruction. -- error compiling committee.c: too many arguments to function - 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/