From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 0/6] Add rudimentary Hyper-V guest support Date: Mon, 18 May 2009 18:20:07 +0300 Message-ID: <4A117CA7.5010503@redhat.com> References: <1242375740-31222-1-git-send-email-agraf@suse.de> <0EF5ED01-F027-470C-B766-3DB8EF616AE8@suse.de> <4A107CE1.2030707@redhat.com> <4A1162CD.4060900@redhat.com> <059C7BD2-8EA4-4A56-AD63-D84DCF700000@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: KVM list , Joerg Roedel To: Alexander Graf Return-path: Received: from mx2.redhat.com ([66.187.237.31]:42257 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754451AbZERPUy (ORCPT ); Mon, 18 May 2009 11:20:54 -0400 In-Reply-To: <059C7BD2-8EA4-4A56-AD63-D84DCF700000@suse.de> Sender: kvm-owner@vger.kernel.org List-ID: Alexander Graf wrote: > > On 18.05.2009, at 15:29, Avi Kivity wrote: > >> Alexander Graf wrote: >>>> >>>> There's only a limited potential here (a factor of three, reducing >>>> 6 exits to 2, less the emulation overhead). There's a lot more to >>>> be gained from nested npt, since you'll avoid most of the original >>>> exits in the first place. >>> >>> I think the reversed is the case. Look at those numbers (w2k8 bootup): >>> >>> http://pastebin.ca/1423596 >>> >>> The only thing nested NPT would achieve is a reduction of #NPF >>> exits. But they are absolutely in the minority today already. Normal >>> #PF's do get directly passed to the guest already. >> >> #NPF exits are caused when guest/host mappings change, which they >> don't, or by mmio (which happens both for guest and nguest). >> >> I don't understand how you can pass #PFs directly to the guest. >> Surely the guest has enabled pagefault interception, and you need to >> set up its vmcb? > > I guess you're right: http://pastebin.ca/1426458 Any idea where the ioio exits come from? If it's IDE, we can eliminate them by using virtio. -- error compiling committee.c: too many arguments to function