From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Daney Subject: Re: [PATCH 10/18] KVM/MIPS32-VZ: Add API for VZ-ASE Capability Date: Thu, 30 May 2013 11:35:40 -0700 Message-ID: <51A79BFC.6060204@gmail.com> References: <1368942460-15577-1-git-send-email-sanjayl@kymasys.com> <1368942460-15577-11-git-send-email-sanjayl@kymasys.com> <51A4DC99.7040706@redhat.com> <51A7875F.4080606@gmail.com> <51A79193.6080908@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Sanjay Lal , kvm@vger.kernel.org, linux-mips@linux-mips.org, Ralf Baechle , Gleb Natapov , Marcelo Tosatti To: Paolo Bonzini Return-path: Received: from mail-pb0-f51.google.com ([209.85.160.51]:39023 "EHLO mail-pb0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752874Ab3E3Sfn (ORCPT ); Thu, 30 May 2013 14:35:43 -0400 Received: by mail-pb0-f51.google.com with SMTP id jt11so825374pbb.38 for ; Thu, 30 May 2013 11:35:43 -0700 (PDT) In-Reply-To: <51A79193.6080908@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 05/30/2013 10:51 AM, Paolo Bonzini wrote: > Il 30/05/2013 19:07, David Daney ha scritto: >> On 05/28/2013 09:34 AM, Paolo Bonzini wrote: >>> Il 19/05/2013 07:47, Sanjay Lal ha scritto: >>>> - Add API to allow clients (QEMU etc.) to check whether the H/W >>>> supports the MIPS VZ-ASE. >>> >>> Why does this matter to userspace? Do the userspace have some way to >>> detect if the kernel is unmodified or minimally-modified? >>> >> >> There are (will be) two types of VM presented by MIPS KVM: >> >> 1) That provided by the initial patch where a faux-MIPS is emulated and >> all kernel code must be in the USEG address space. >> >> 2) Real MIPS, addressing works as per the architecture specification. >> >> Presumably the user-space client would like to know which of these are >> supported, as well as be able to select the desired model. > > Understood. It's really two different machine types. > >> I don't know the best way to do this, but I agree that >> KVM_CAP_MIPS_VZ_ASE is probably not the best name for it. >> >> My idea was to have the arg of the KVM_CREATE_VM ioctl specify the >> desired style > > Ok. How complex is it? Do you plan to do this when the patches are > "really ready" for Linus' tree? I am currently working on preparing a patch set that implements MIPS-VZ in a slightly different manner than Sanjay's patches. So there will likely be some back and forth getting everything properly integrated into a sane implementation So I don't know exactly how to answer this question other than to say, that I don't think things should go into Linus's tree until they are "really ready", which would include resolving this issue. David Daney