From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: Re: [patch 08/18] x86: pvclock: generic pvclock vsyscall initialization Date: Mon, 29 Oct 2012 12:54:19 -0200 Message-ID: <20121029145419.GB13104@amt.cnet> References: <20121024131340.742340256@redhat.com> <20121024131621.658249278@redhat.com> <508E902C.4080402@parallels.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org, johnstul@us.ibm.com, jeremy@goop.org, zamsden@gmail.com, gleb@redhat.com, avi@redhat.com, pbonzini@redhat.com To: Glauber Costa Return-path: Received: from mx1.redhat.com ([209.132.183.28]:27310 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757222Ab2J2PZl (ORCPT ); Mon, 29 Oct 2012 11:25:41 -0400 Content-Disposition: inline In-Reply-To: <508E902C.4080402@parallels.com> Sender: kvm-owner@vger.kernel.org List-ID: On Mon, Oct 29, 2012 at 06:18:20PM +0400, Glauber Costa wrote: > On 10/24/2012 05:13 PM, Marcelo Tosatti wrote: > > Index: vsyscall/arch/x86/Kconfig > > =================================================================== > > --- vsyscall.orig/arch/x86/Kconfig > > +++ vsyscall/arch/x86/Kconfig > > @@ -632,6 +632,13 @@ config PARAVIRT_SPINLOCKS > > > > config PARAVIRT_CLOCK > > bool > > +config PARAVIRT_CLOCK_VSYSCALL > > + bool "Paravirt clock vsyscall support" > > + depends on PARAVIRT_CLOCK && GENERIC_TIME_VSYSCALL > > + ---help--- > > + Enable performance critical clock related system calls to > > + be executed in userspace, provided that the hypervisor > > + supports it. > > > > endif > > Besides debugging, what is the point in having this as an > extra-selectable? Is there any case in which a virtual machine has code > for this, but may decide to run without it ? Don't think so (its pretty small anyway, the code). > I believe all this code in vsyscall should be wrapped in PARAVIRT_CLOCK > only. Unless Jeremy has a reason, i'm fine with that.