From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [patch 07/11] [PATCH] kvm-s390-ucontrol: interface to inject faults on a vcpu page table Date: Wed, 04 Jan 2012 16:52:46 +0200 Message-ID: <4F0467BE.8010908@redhat.com> References: <20120104092519.060746143@de.ibm.com> <20120104093602.530415566@de.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Marcelo Tossati , Christian Borntraeger , Heiko Carstens , Martin Schwidefsky , Cornelia Huck , KVM , Joachim von Buttlar , Jens Freimann , agraf@suse.de To: Carsten Otte Return-path: Received: from mx1.redhat.com ([209.132.183.28]:18690 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755783Ab2ADOw5 (ORCPT ); Wed, 4 Jan 2012 09:52:57 -0500 In-Reply-To: <20120104093602.530415566@de.ibm.com> Sender: kvm-owner@vger.kernel.org List-ID: On 01/04/2012 11:25 AM, Carsten Otte wrote: > This patch allows the user to fault in pages on a virtual cpus > address space for user controlled virtual machines. Typically this > is superfluous because userspace can just create a mapping and > let the kernel's page fault logic take are of it. There is one > exception: SIE won't start if the lowcore is not present. Normally > the kernel takes care of this [handle_validity() in > arch/s390/kvm/intercept.c] but since the kernel does not handle > intercepts for user controlled virtual machines, userspace needs to > be able to handle this condition. There is an alternative, if you can recognize this condition exactly from the hardware fault, you can fault the lowcore yourself and retry. This eliminates a user interface. Is this workable? -- error compiling committee.c: too many arguments to function