From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753269AbeDSSKu (ORCPT ); Thu, 19 Apr 2018 14:10:50 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:46496 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753176AbeDSSKs (ORCPT ); Thu, 19 Apr 2018 14:10:48 -0400 Date: Thu, 19 Apr 2018 21:10:47 +0300 From: "Michael S. Tsirkin" To: Paolo Bonzini Cc: linux-kernel@vger.kernel.org, Ohad Ben-Cohen , Bjorn Andersson , linux-remoteproc@vger.kernel.org, Jason Wang , virtualization@lists.linux-foundation.org Subject: Re: [PATCH] virtio_ring: switch to dma_XX barriers for rpmsg Message-ID: <20180419210843-mutt-send-email-mst@kernel.org> References: <1524159181-351878-1-git-send-email-mst@redhat.com> <5047d08c-9f9e-2902-d425-1fac849ce5b4@redhat.com> <20180419204017-mutt-send-email-mst@kernel.org> <524fb400-2325-f60b-7e03-15be01888afc@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <524fb400-2325-f60b-7e03-15be01888afc@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 19, 2018 at 07:48:24PM +0200, Paolo Bonzini wrote: > On 19/04/2018 19:46, Michael S. Tsirkin wrote: > >> This should be okay, but I wonder if there should be a virtio_wmb(...) > >> or an "if (weak_barriers) wmb()" before the "writel" in vm_notify > >> (drivers/virtio/virtio_mmio.c). > >> > >> Thanks, > >> > >> Paolo > > That one uses weak barriers AFAIK. > > > > IIUC you mean rproc_virtio_notify. > > > > I suspect it works because specific kick callbacks have a barrier internally. > > Yes, that one. At least keystone_rproc_kick doesn't seem to have a barrier. > > Paolo Maybe it's wrong or not used with virtio then. This patch won't change anything with respect to that though. -- MST