From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36898) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bFayh-000292-KA for qemu-devel@nongnu.org; Wed, 22 Jun 2016 01:45:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bFayd-00011p-HD for qemu-devel@nongnu.org; Wed, 22 Jun 2016 01:45:30 -0400 Received: from [59.151.112.132] (port=48331 helo=heian.cn.fujitsu.com) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bFayc-00011B-TP for qemu-devel@nongnu.org; Wed, 22 Jun 2016 01:45:27 -0400 References: <1464315131-25834-1-git-send-email-zhoujie2011@cn.fujitsu.com> <20160527100655.60db8206@t450s.home> <30d1cd95-7f67-29cf-c55e-0565364d89ff@cn.fujitsu.com> <41b0c187-ade0-182e-46b5-afd3e99f1e36@cn.fujitsu.com> <20160620103226.0ff61b21@ul30vt.home> <20160620211306.66a6b249@t450s.home> <576935FC.1080503@easystack.cn> <20160621084443.330f932d@t450s.home> <20160621215626.71c99582@t450s.home> From: Zhou Jie Message-ID: <113474d2-8408-db49-e7ef-8c6b736af866@cn.fujitsu.com> Date: Wed, 22 Jun 2016 13:45:10 +0800 MIME-Version: 1.0 In-Reply-To: <20160621215626.71c99582@t450s.home> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v8 11/12] vfio: register aer resume notification handler for aer resume List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Alex Williamson Cc: Chen Fan , Chen Fan , izumi.taku@jp.fujitsu.com, caoj.fnst@cn.fujitsu.com, qemu-devel@nongnu.org, mst@redhat.com Hi Alex, >> >> In vfio I have some questions. >> 1. How can I disable the access by mmap? >> We can disable all access to vfio fd by returning a EAGAIN error >> if user try to access it during the reset period until the host >> reset finished. >> But about the bar region which is maped by vfio_pci_mmap. >> How can I disable it in vfio driver? >> Even there is a way to do it, >> how about the complexity to recovery the mmap? > > That's exactly the "sticky point" I refer to above, you'd need to > solve that problem. MST would probably still argue that we don't need > to disable all those interfaces, a userspace driver can already do > things like disable mmio space and then attempt to read from the mmio > space of the device. You said we should not depend on user to protect the device be accessed during the reset period. > So maybe the problem can be simplified to > non-device specific interfaces, like config space access plus ioctls. I don't understand what's your mean. Sincerely Zhoujie