From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by ozlabs.org (Postfix) with ESMTP id 113BDB6F0C for ; Sun, 27 Jun 2010 19:53:16 +1000 (EST) Message-ID: <4C271F8A.5090903@redhat.com> Date: Sun, 27 Jun 2010 12:53:14 +0300 From: Avi Kivity MIME-Version: 1.0 To: Alexander Graf Subject: Re: [PATCH 09/26] KVM: PPC: Add PV guest scratch registers References: <1277508314-915-1-git-send-email-agraf@suse.de> <1277508314-915-10-git-send-email-agraf@suse.de> <4C270A34.4020706@redhat.com> <27BB673F-F34E-4CC6-A22D-02CF95E7529F@suse.de> In-Reply-To: <27BB673F-F34E-4CC6-A22D-02CF95E7529F@suse.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Cc: linuxppc-dev , KVM list , "kvm-ppc@vger.kernel.org" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 06/27/2010 12:41 PM, Alexander Graf wrote: > > Am 27.06.2010 um 10:22 schrieb Avi Kivity : > >> On 06/26/2010 02:24 AM, Alexander Graf wrote: >>> While running in hooked code we need to store register contents out >>> because >>> we must not clobber any registers. >>> >>> So let's add some fields to the shared page we can just happily >>> write to. >>> >>> >> >> How are these protected during interrupts? > > By the 'critical section' bit. When in a critical section (read: using > scratch registers), we don't issue interrupts. Ok. I thought you needed scratch registers to set up the critical section, but you don't. Neat stuff. -- error compiling committee.c: too many arguments to function