From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCHv1 dont apply] RFC: kvm eoi PV using shared memory Date: Tue, 17 Apr 2012 12:24:41 +0300 Message-ID: <4F8D36D9.9080708@redhat.com> References: <20120410132756.GA14101@redhat.com> <20120415161857.GA8710@redhat.com> <20120416100807.GO11918@redhat.com> <20120416110919.GA11605@redhat.com> <20120416112446.GQ11918@redhat.com> <20120416121824.GD11605@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: Gleb Natapov , kvm@vger.kernel.org To: "Michael S. Tsirkin" Return-path: Received: from mx1.redhat.com ([209.132.183.28]:35073 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755484Ab2DQJYn (ORCPT ); Tue, 17 Apr 2012 05:24:43 -0400 Received: from int-mx09.intmail.prod.int.phx2.redhat.com (int-mx09.intmail.prod.int.phx2.redhat.com [10.5.11.22]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q3H9OhDb012139 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 17 Apr 2012 05:24:43 -0400 In-Reply-To: <20120416121824.GD11605@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 04/16/2012 03:18 PM, Michael S. Tsirkin wrote: > On Mon, Apr 16, 2012 at 02:24:46PM +0300, Gleb Natapov wrote: > > On Mon, Apr 16, 2012 at 02:09:20PM +0300, Michael S. Tsirkin wrote: > > > Thanks very much for the review. I'll address the comments. > > > Some questions on your comments below. > > > > > > On Mon, Apr 16, 2012 at 01:08:07PM +0300, Gleb Natapov wrote: > > > > > @@ -37,6 +38,8 @@ > > > > > #define MSR_KVM_SYSTEM_TIME_NEW 0x4b564d01 > > > > > #define MSR_KVM_ASYNC_PF_EN 0x4b564d02 > > > > > #define MSR_KVM_STEAL_TIME 0x4b564d03 > > > > > +#define MSR_KVM_EOI_EN 0x4b564d04 > > > > > +#define MSR_KVM_EOI_DISABLED 0x0L > > > > This is valid gpa. Follow others MSR example i.e align the address to, > > > > lets say dword, and use lsb as enable bit. > > > > > > We only need a single byte, since this is per-CPU - > > > it's better to save the memory, so no alignment is required. > > > An explicit disable msr would also address this, right? > > > > > We do not have shortage of memory. > > Better make all MSRs works the same > > way. > > I agree it's nice to have EOI and ASYNC_PF look similar > but wasting memory is also bad. I'll ponder this some more. Wasting three bytes? > > BTW have you added new MSR to msrs_to_save array? I forgot to > > checked. > > I didn't yet. Trying to understand how will that affect > cross-version migration - any input? It will just work. -- error compiling committee.c: too many arguments to function