From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8E9F9C3279B for ; Wed, 4 Jul 2018 05:23:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4CD0A2457E for ; Wed, 4 Jul 2018 05:23:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4CD0A2457E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932706AbeGDFX2 (ORCPT ); Wed, 4 Jul 2018 01:23:28 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:33870 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1751826AbeGDFX1 (ORCPT ); Wed, 4 Jul 2018 01:23:27 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 5552840AC6DE; Wed, 4 Jul 2018 05:23:26 +0000 (UTC) Received: from [10.72.12.45] (ovpn-12-45.pek2.redhat.com [10.72.12.45]) by smtp.corp.redhat.com (Postfix) with ESMTPS id CB4562026D76; Wed, 4 Jul 2018 05:23:21 +0000 (UTC) Subject: Re: [PATCH net-next 8/8] vhost: event suppression for packed ring To: Wei Xu Cc: mst@redhat.com, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, tiwei.bie@intel.com, maxime.coquelin@redhat.com, jfreimann@redhat.com References: <1530596284-4101-1-git-send-email-jasowang@redhat.com> <1530596284-4101-9-git-send-email-jasowang@redhat.com> <20180704041352.GA9287@wei-ubt> From: Jason Wang Message-ID: <493c3a3e-e088-d6fb-1da4-cda8bfb34400@redhat.com> Date: Wed, 4 Jul 2018 13:23:18 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: <20180704041352.GA9287@wei-ubt> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.78 on 10.11.54.4 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Wed, 04 Jul 2018 05:23:26 +0000 (UTC) X-Greylist: inspected by milter-greylist-4.5.16 (mx1.redhat.com [10.11.55.7]); Wed, 04 Jul 2018 05:23:26 +0000 (UTC) for IP:'10.11.54.4' DOMAIN:'int-mx04.intmail.prod.int.rdu2.redhat.com' HELO:'smtp.corp.redhat.com' FROM:'jasowang@redhat.com' RCPT:'' Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018年07月04日 12:13, Wei Xu wrote: > On Tue, Jul 03, 2018 at 01:38:04PM +0800, Jason Wang wrote: >> This patch introduces support for event suppression. This is done by >> have a two areas: device area and driver area. One side could then try >> to disable or enable (delayed) notification from other side by using a >> boolean hint or event index interface in the areas. >> >> For more information, please refer Virtio spec. >> >> Signed-off-by: Jason Wang >> --- >> drivers/vhost/vhost.c | 191 ++++++++++++++++++++++++++++++++++++++++++++++---- >> drivers/vhost/vhost.h | 10 ++- >> 2 files changed, 185 insertions(+), 16 deletions(-) >> >> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c >> index 0f3f07c..cccbc82 100644 >> --- a/drivers/vhost/vhost.c >> +++ b/drivers/vhost/vhost.c >> @@ -1115,10 +1115,15 @@ static int vq_access_ok_packed(struct vhost_virtqueue *vq, unsigned int num, >> struct vring_used __user *used) >> { >> struct vring_desc_packed *packed = (struct vring_desc_packed *)desc; >> + struct vring_packed_desc_event *driver_event = >> + (struct vring_packed_desc_event *)avail; >> + struct vring_packed_desc_event *device_event = >> + (struct vring_packed_desc_event *)used; >> >> - /* TODO: check device area and driver area */ >> return access_ok(VERIFY_READ, packed, num * sizeof(*packed)) && >> - access_ok(VERIFY_WRITE, packed, num * sizeof(*packed)); >> + access_ok(VERIFY_WRITE, packed, num * sizeof(*packed)) && > R/W parameter doesn't make sense to most architectures and the comment in x86 > says WRITE is a superset of READ, is it possible to converge them here? > > /** > * access_ok: - Checks if a user space pointer is valid > * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE. Note that > * %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe > * to write to a block, it is always safe to read from it. > * @addr: User space pointer to start of block to check > * @size: Size of block to check > * > * Context: User context only. This function may sleep if pagefaults are > * enabled. > * > * Checks if a pointer to a block of memory in user space is valid. > * > * Returns true (nonzero) if the memory block may be valid, false (zero) > * if it is definitely invalid. > * > * Note that, depending on architecture, this function probably just > * checks that the pointer is in the user space range - after calling > * this function, memory access functions may still return -EFAULT. > */ > #define access_ok(type, addr, size) > ...... > > Thanks, > Wei > Well, this is a question that beyond the scope of this patch. My understanding is we should keep it unless type was meaningless on all archs. Thanks