From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Date: Wed, 08 Jul 2009 08:06:46 +0000 Subject: Re: [PATCH 00/23] Add KVM support for PPC64 (970) hosts Message-Id: <4A545396.4020404@redhat.com> List-Id: References: <1246976262-4826-1-git-send-email-agraf@suse.de> In-Reply-To: <1246976262-4826-1-git-send-email-agraf@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: kvm-ppc@vger.kernel.org On 07/08/2009 09:22 AM, Benjamin Herrenschmidt wrote: > On Tue, 2009-07-07 at 19:08 +0300, Avi Kivity wrote: > >>> Or is using mmu_notifiers mandatory? :-). >>> >> It's highly recommended. >> > > Considering how "differnent" the ppc MMU is, I'm not sure mmu notifiers > is necessarily the right approach but we definitely should have a close > look. > I don't see how the mmu structure matters. All mmu notifiers does is tell you when Linux wants to drop a pte, it's completely up to you how to use this information. There are three ways of dealing with the problem: - ignore it (ia64, ppc) Easy to implement, but you can't swap or do any fancy stuff like page migration. If you have a large tlb/shadow, you pin a lot of pages. - use mmu notifiers (x86) Need reverse mapping to convert guest physical addresses to shadow/tlb addresses. Not difficult to implement but requires careful locking. - s390 (s390) You can s390 your problems away if you have s390 hardware. Can you explain your concerns? -- error compiling committee.c: too many arguments to function