From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752302AbcGFGF1 (ORCPT ); Wed, 6 Jul 2016 02:05:27 -0400 Received: from mail-wm0-f68.google.com ([74.125.82.68]:35602 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750832AbcGFGFZ (ORCPT ); Wed, 6 Jul 2016 02:05:25 -0400 Subject: Re: [PATCH 0/2] KVM: MMU: support VMAs that got remap_pfn_range-ed To: Xiao Guangrong , Neo Jia References: <1467291711-3230-1-git-send-email-pbonzini@redhat.com> <20160705054147.GA27138@nvidia.com> <577C664E.3080802@linux.intel.com> Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org, Kirti Wankhede , Andrea Arcangeli , =?UTF-8?B?UmFkaW0gS3LEjW3DocWZ?= From: Paolo Bonzini Message-ID: <4eb9131a-d2cb-9142-1db3-d7138bf03309@redhat.com> Date: Wed, 6 Jul 2016 08:05:15 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: <577C664E.3080802@linux.intel.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/07/2016 04:00, Xiao Guangrong wrote: > > > On 07/05/2016 08:18 PM, Paolo Bonzini wrote: >> >> >> On 05/07/2016 07:41, Neo Jia wrote: >>> On Thu, Jun 30, 2016 at 03:01:49PM +0200, Paolo Bonzini wrote: >>>> The vGPU folks would like to trap the first access to a BAR by setting >>>> vm_ops on the VMAs produced by mmap-ing a VFIO device. The fault >>>> handler >>>> then can use remap_pfn_range to place some non-reserved pages in the >>>> VMA. >>>> >>>> KVM lacks support for this kind of non-linear VM_PFNMAP mapping, and >>>> these >>>> patches should fix this. >>> >>> Hi Paolo, >>> >>> I have tested your patches with the mediated passthru patchset that >>> is being >>> reviewed in KVM and QEMU mailing list. >>> >>> The fault handler gets called successfully and the previously mapped >>> memory gets >>> unmmaped correctly via unmap_mapping_range. >> >> Great, then I'll include them in 4.8. > > Code is okay, but i still suspect if this implementation, fetch mmio > pages in fault handler, is needed. We'd better include these patches > after the design of vfio framework is decided. I think that this fixes a bug anyway, the previous handling of VM_PFNMAP is too simplistic. Paolo