From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with SMTP id 52E506B006A for ; Sun, 10 Oct 2010 08:48:05 -0400 (EDT) Message-ID: <4CB1B5EF.7040207@redhat.com> Date: Sun, 10 Oct 2010 14:47:43 +0200 From: Avi Kivity MIME-Version: 1.0 Subject: Re: [PATCH v6 06/12] Add PV MSR to enable asynchronous page faults delivery. References: <1286207794-16120-1-git-send-email-gleb@redhat.com> <1286207794-16120-7-git-send-email-gleb@redhat.com> <4CADC01E.3060409@redhat.com> <20101007175329.GF2397@redhat.com> In-Reply-To: <20101007175329.GF2397@redhat.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Gleb Natapov Cc: kvm@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, mingo@elte.hu, a.p.zijlstra@chello.nl, tglx@linutronix.de, hpa@zytor.com, riel@redhat.com, cl@linux-foundation.org, mtosatti@redhat.com List-ID: On 10/07/2010 07:53 PM, Gleb Natapov wrote: > On Thu, Oct 07, 2010 at 02:42:06PM +0200, Avi Kivity wrote: > > On 10/04/2010 05:56 PM, Gleb Natapov wrote: > > >Guest enables async PF vcpu functionality using this MSR. > > > > > > return NON_PRESENT; > > >+ > > >+MSR_KVM_ASYNC_PF_EN: 0x4b564d02 > > >+ data: Bits 63-6 hold 64-byte aligned physical address of a 32bit memory > > > > Given that it must be aligned anyway, we can require it to be a > > 64-byte region and also require that the guest zero it before > > writing the MSR. That will give us a little more flexibility in the > > future. > > > No code change needed, so OK. The guest needs to allocate a 64-byte per-cpu entry instead of a 4-byte entry. > > > > >+ return 0; > > >+ } > > >+ > > >+ if (kvm_gfn_to_hva_cache_init(vcpu->kvm,&vcpu->arch.apf.data, gpa)) > > >+ return 1; > > > > Note: we need to handle the memory being removed from underneath > > kvm_gfn_to_hve_cache(). Given that, we can just make > > kvm_gfn_to_hva_cache_init() return void. "success" means nothing > > when future changes can invalidate it. > > > I want to catch guest doing stupid things. If guest give us non-existent > address I want wrmsr to #GP. Ok. > > >+ > > >+ kvm_async_pf_wakeup_all(vcpu); > > > > Why is this needed? If all apfs are flushed at disable time, what > > do we need to wake up? > For migration. Destination will rewrite msr and all processes will be > waked up. Ok. What happens to apf completions that happen after all vcpus are stopped? > > > > Need to list the MSR for save/restore/reset. > > > > > This patch adds it to msrs_to_save, no? Yes, missed it somehow. -- error compiling committee.c: too many arguments to function -- 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