From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56614) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XUPre-0006Ub-Qv for qemu-devel@nongnu.org; Wed, 17 Sep 2014 20:46:32 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1XUPrX-0005xh-Fv for qemu-devel@nongnu.org; Wed, 17 Sep 2014 20:46:26 -0400 Received: from szxga01-in.huawei.com ([119.145.14.64]:10951) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1XUPrW-0005wr-Mj for qemu-devel@nongnu.org; Wed, 17 Sep 2014 20:46:19 -0400 Message-ID: <541A2B31.5000808@huawei.com> Date: Thu, 18 Sep 2014 08:45:37 +0800 From: Linhaifeng MIME-Version: 1.0 References: <20140917083815.GA10450@redhat.com> <541956B8.1070203@huawei.com> <20140917095638.GA11743@redhat.com> In-Reply-To: <20140917095638.GA11743@redhat.com> Content-Type: text/plain; charset="windows-1252" Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] vhost-user: VHOST_SET_MEM_TABLE, VHOST_SET_VRING_CALL need a reply? List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: "Michael S. Tsirkin" Cc: qemu-devel@nongnu.org, n.nikolaev@virtualopensystems.com, jerry.lilijun@huawei.com On 2014/9/17 17:56, Michael S. Tsirkin wrote: > On Wed, Sep 17, 2014 at 05:39:04PM +0800, Linhaifeng wrote: >> I think maybe is not need for the backend to wait for response. >> >> There is another way.vhost-user send "VHOST_GET_MEM_TABLE" to qemu then qemu send VHOST_SET_MEM_TABLE to update the regions of vhost-user.same as other command. >> If qemu could response the request of the vhost-user.the vhost-user could update date at anytime. > > The updates are initiated by QEMU, as a result of IOMMU, > memory hotplug or some other configuration change. How to deal with the vhost-user restart? when vhost-user restart it will lost the infomation which QEMU send. In the kernel mode vhost will restart with QEMU but in the user mode vhost will not. > >> I think it's very useful for Commercialization. >> >> On 2014/9/17 16:38, Michael S. Tsirkin wrote: >>> Reply-To: >>> >>> Thinking about the vhost-user protocol, VHOST_SET_MEM_TABLE >>> is used to update the memory mappings. >>> >>> So shouldn't we want for response? >>> Otherwise e.g. guest can start using the memory >>> that vhost-user can't access. >>> >>> Similarly, with an IOMMU vhost-user might access memory it shouldn't. >>> >>> VHOST_SET_VRING_CALL is used for MSI-X masking. >>> Again, after vector is masted by switching the call fd, >>> backend shouldn't assert the old one. >>> >>> Thoughts? >>> >>> > > . >