From mboxrd@z Thu Jan 1 00:00:00 1970 From: Gleb Natapov Subject: Re: [PATCH] KVM: x86: Avoid zapping mmio sptes twice for generation wraparound Date: Wed, 3 Jul 2013 12:10:57 +0300 Message-ID: <20130703091057.GG18508@redhat.com> References: <20130703171804.89d6cc2c.yoshikawa_takuya_b1@lab.ntt.co.jp> <51D3E093.3020408@redhat.com> <51D3E33D.1090704@linux.vnet.ibm.com> <51D3E5DC.5020902@linux.vnet.ibm.com> <51D3E69F.2050104@redhat.com> <20130703180500.4b78ecdf.yoshikawa_takuya_b1@lab.ntt.co.jp> <20130703090535.GF18508@redhat.com> <51D3EA02.2010008@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Takuya Yoshikawa , Xiao Guangrong , kvm@vger.kernel.org To: Paolo Bonzini Return-path: Received: from mx1.redhat.com ([209.132.183.28]:46188 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753038Ab3GCJLC (ORCPT ); Wed, 3 Jul 2013 05:11:02 -0400 Content-Disposition: inline In-Reply-To: <51D3EA02.2010008@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Wed, Jul 03, 2013 at 11:08:18AM +0200, Paolo Bonzini wrote: > Il 03/07/2013 11:05, Gleb Natapov ha scritto: > >>> Yes, the actual operation would be the same as this patch. You can > >>> rename kvm_mmu_invalidate_mmio_sptes to kvm_arch_memslots_installed, or > >>> something like that. But it would have to touch all architectures. > >> > >> I tried to avoid introducing x86-centric code into the generic one. > >> > >> If another arch can gain something by such function, I'm willing to > >> touch all arch code. > >> > > Please do. X86 is the most optimized one so it does things other arches > > do not yet. Slot generation update hook sounds generic enough. > > Yes, makes sense. However, this patch is still an improvement because > the current code is too easily mistaken for an off-by-one bug. > > Any improvements to the API can go on top. > If Takuya will send the proper fix shortly I do not see any reason to apply this one. It does not fix any bug. -- Gleb.