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 90B35B6EF3 for ; Sun, 27 Jun 2010 18:16:46 +1000 (EST) Message-ID: <4C2708EB.9020500@redhat.com> Date: Sun, 27 Jun 2010 11:16:43 +0300 From: Avi Kivity MIME-Version: 1.0 To: Alexander Graf Subject: Re: [PATCH 02/26] KVM: PPC: Convert MSR to shared page References: <1277508314-915-1-git-send-email-agraf@suse.de> <1277508314-915-3-git-send-email-agraf@suse.de> In-Reply-To: <1277508314-915-3-git-send-email-agraf@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 06/26/2010 02:24 AM, Alexander Graf wrote: > One of the most obvious registers to share with the guest directly is the > MSR. The MSR contains the "interrupts enabled" flag which the guest has to > toggle in critical sections. > > So in order to bring the overhead of interrupt en- and disabling down, let's > put msr into the shared page. Keep in mind that even though you can fully read > its contents, writing to it doesn't always update all state. There are a few > safe fields that don't require hypervisor interaction. See the guest > implementation that follows later for reference. > You mean, see the documentation for reference. It should be possible to write the guest code looking only at the documentation. -- error compiling committee.c: too many arguments to function