From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail143.messagelabs.com (mail143.messagelabs.com [216.82.254.35]) by kanga.kvack.org (Postfix) with ESMTP id C27766B0047 for ; Sun, 17 Jan 2010 10:09:35 -0500 (EST) Subject: Re: [PATCH v3 04/12] Add "handle page fault" PV helper. From: Peter Zijlstra In-Reply-To: <20100117144411.GI31692@redhat.com> References: <1262700774-1808-1-git-send-email-gleb@redhat.com> <1262700774-1808-5-git-send-email-gleb@redhat.com> <1263490267.4244.340.camel@laptop> <20100117144411.GI31692@redhat.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Date: Sun, 17 Jan 2010 16:09:40 +0100 Message-ID: <1263740980.557.20980.camel@twins> Mime-Version: 1.0 Sender: owner-linux-mm@kvack.org To: Gleb Natapov Cc: kvm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, avi@redhat.com, mingo@elte.hu, tglx@linutronix.de, hpa@zytor.com, riel@redhat.com, cl@linux-foundation.org List-ID: On Sun, 2010-01-17 at 16:44 +0200, Gleb Natapov wrote: > On Thu, Jan 14, 2010 at 06:31:07PM +0100, Peter Zijlstra wrote: > > On Tue, 2010-01-05 at 16:12 +0200, Gleb Natapov wrote: > > > Allow paravirtualized guest to do special handling for some page faul= ts. > > >=20 > > > The patch adds one 'if' to do_page_fault() function. The call is patc= hed > > > out when running on physical HW. I ran kernbech on the kernel with an= d > > > without that additional 'if' and result were rawly the same: > >=20 > > So why not program a different handler address for the #PF/#GP faults > > and avoid the if all together? > I would gladly use fault vector reserved by x86 architecture, but I am > not sure Intel will be happy about it. Whatever are we doing to end up in do_page_fault() as it stands? Surely we can tell the CPU to go elsewhere to handle faults? Isn't that as simple as calling set_intr_gate(14, my_page_fault) somewhere on the cpuinit instead of the regular page_fault handler? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org