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 B367EC28D13 for ; Tue, 2 Mar 2021 04:09:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8CF8264DDD for ; Tue, 2 Mar 2021 04:09:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1443115AbhCBCSm (ORCPT ); Mon, 1 Mar 2021 21:18:42 -0500 Received: from mail.kernel.org ([198.145.29.99]:55166 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235973AbhCATor (ORCPT ); Mon, 1 Mar 2021 14:44:47 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 750A0650FD; Mon, 1 Mar 2021 17:02:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1614618125; bh=mDNce7JorKvDfVda5uTF6y2n3mrETWCjGAl4Rk/5v2w=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dANfAeBGM8OHtDRmzRsYoFUEd+osdDX6VjVq4zl5IvMoyrS2as95d1zd0vjG7dnzA TtB6KPv9cjS/xu2e53Mds9/0JDRraaGVh8kzoKEDREpQxBxXfCaLgLLX7JmS367BJl oI8CaGIMEsLJPEEnu6NftqrsPrPpz4MsJ1a2Z3BY= 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 5.4 315/340] virtio/s390: implement virtio-ccw revision 2 correctly Date: Mon, 1 Mar 2021 17:14:19 +0100 Message-Id: <20210301161103.793008004@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210301161048.294656001@linuxfoundation.org> References: <20210301161048.294656001@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 @@ -117,7 +117,7 @@ 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; @@ -952,7 +952,7 @@ static u8 virtio_ccw_get_status(struct v u8 old_status = vcdev->dma_area->status; struct ccw1 *ccw; - if (vcdev->revision < 1) + if (vcdev->revision < 2) return vcdev->dma_area->status; ccw = ccw_device_dma_zalloc(vcdev->cdev, sizeof(*ccw));