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=-18.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 B513EC15509 for ; Fri, 5 Mar 2021 12:40:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9EB3264F44 for ; Fri, 5 Mar 2021 12:40:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233361AbhCEMkF (ORCPT ); Fri, 5 Mar 2021 07:40:05 -0500 Received: from mail.kernel.org ([198.145.29.99]:54152 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232733AbhCEMji (ORCPT ); Fri, 5 Mar 2021 07:39:38 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 7AECF6501C; Fri, 5 Mar 2021 12:39:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1614947978; bh=El/3BVmJ2zxGNUIp70E+TrLyWejOQG194Ghg3d9EY7A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Pxb2s4VeX3LX+l8KRqWWV2PjMnwfKuVrNa9JLHupq3USasrgW5uTvrU8PkDarFMZu xM5JOBmAuFWd5FnnOK6D+36p17QPQJOjrseii+OV4C7SSiwHoH4bOxMJ2ELTPYwPbX JaJIHuvm+kWpYhOQEILyG3rsCWfngSqee0annJFc= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Halil Pasic , Cornelia Huck , Vasily Gorbik Subject: [PATCH 4.14 06/39] virtio/s390: implement virtio-ccw revision 2 correctly Date: Fri, 5 Mar 2021 13:22:05 +0100 Message-Id: <20210305120852.074408683@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210305120851.751937389@linuxfoundation.org> References: <20210305120851.751937389@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Cornelia Huck commit 182f709c5cff683e6732d04c78e328de0532284f upstream. CCW_CMD_READ_STATUS was introduced with revision 2 of virtio-ccw, and drivers should only rely on it being implemented when they negotiated at least that revision with the device. However, virtio_ccw_get_status() issued READ_STATUS for any device operating at least at revision 1. If the device accepts READ_STATUS regardless of the negotiated revision (which some implementations like QEMU do, even though the spec currently does not allow it), everything works as intended. While a device rejecting the command should also be handled gracefully, we will not be able to see any changes the device makes to the status, such as setting NEEDS_RESET or setting the status to zero after a completed reset. We negotiated the revision to at most 1, as we never bumped the maximum revision; let's do that now and properly send READ_STATUS only if we are operating at least at revision 2. Cc: stable@vger.kernel.org Fixes: 7d3ce5ab9430 ("virtio/s390: support READ_STATUS command for virtio-ccw") Reviewed-by: Halil Pasic Signed-off-by: Cornelia Huck Signed-off-by: Vasily Gorbik Link: https://lore.kernel.org/r/20210216110645.1087321-1-cohuck@redhat.com Signed-off-by: Vasily Gorbik Signed-off-by: Greg Kroah-Hartman --- drivers/s390/virtio/virtio_ccw.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) --- a/drivers/s390/virtio/virtio_ccw.c +++ b/drivers/s390/virtio/virtio_ccw.c @@ -106,7 +106,7 @@ struct virtio_rev_info { }; /* the highest virtio-ccw revision we support */ -#define VIRTIO_CCW_REV_MAX 1 +#define VIRTIO_CCW_REV_MAX 2 struct virtio_ccw_vq_info { struct virtqueue *vq; @@ -911,7 +911,7 @@ static u8 virtio_ccw_get_status(struct v u8 old_status = *vcdev->status; struct ccw1 *ccw; - if (vcdev->revision < 1) + if (vcdev->revision < 2) return *vcdev->status; ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL);