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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,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 19E3BC433DB for ; Fri, 5 Mar 2021 15:59:09 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 9F95F64E6F for ; Fri, 5 Mar 2021 15:59:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9F95F64E6F Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:40434 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1lICr5-0008R6-PP for qemu-devel@archiver.kernel.org; Fri, 05 Mar 2021 10:59:07 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:40814) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1lICnp-00046i-Ay for qemu-devel@nongnu.org; Fri, 05 Mar 2021 10:55:45 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:46824) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.90_1) (envelope-from ) id 1lICnn-0003QX-M5 for qemu-devel@nongnu.org; Fri, 05 Mar 2021 10:55:45 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1614959742; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=PFzKoHqZVN58xXzW9REjb7dVMfQ+d82D122kA9U6f7Q=; b=Sp+UT/PWaNf6+9k4TkPzL6XMgssqBQcR8eBOTUtiKh5JRguXas5hK/jMoPftrAU570ItE2 EO6hFecpyyUqjIbIJ4sSqvKa/grFFl4bYg/EEGjr5wUZFu1O6jySxTd7tdP9qzHijetOUE yLQrudbQsrqaNJWCmtLOnOw1S+7Qvyc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-529-IMHxHxCWPJK4Qr_q3Yrmzw-1; Fri, 05 Mar 2021 10:55:40 -0500 X-MC-Unique: IMHxHxCWPJK4Qr_q3Yrmzw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3B0AF1005D45; Fri, 5 Mar 2021 15:55:39 +0000 (UTC) Received: from gondolin.redhat.com (ovpn-112-55.ams2.redhat.com [10.36.112.55]) by smtp.corp.redhat.com (Postfix) with ESMTP id DBE576B8DA; Fri, 5 Mar 2021 15:55:37 +0000 (UTC) From: Cornelia Huck To: Peter Maydell Subject: [PULL 7/8] vfio-ccw: Do not read region ret_code after write Date: Fri, 5 Mar 2021 16:55:16 +0100 Message-Id: <20210305155517.1604547-8-cohuck@redhat.com> In-Reply-To: <20210305155517.1604547-1-cohuck@redhat.com> References: <20210305155517.1604547-1-cohuck@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=cohuck@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII" Received-SPF: pass client-ip=216.205.24.124; envelope-from=cohuck@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Eric Farman , qemu-s390x@nongnu.org, Cornelia Huck , qemu-devel@nongnu.org, Matthew Rosato Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" From: Eric Farman A pwrite() call returns the number of bytes written (or -1 on error), and vfio-ccw compares this number with the size of the region to determine if an error had occurred or not. If they are not equal, this is a failure and the errno is used to determine exactly how things failed. An errno of zero is possible (though unlikely) in this situation and would be translated to a successful operation. If they ARE equal, the ret_code field is read from the region to determine how to proceed. While the kernel sets the ret_code field as necessary, the region and thus this field is not "written back" to the user. So the value can only be what it was initialized to, which is zero. So, let's convert an unexpected length with errno of zero to a return code of -EFAULT, and explicitly set an expected length to a return code of zero. This will be a little safer and clearer. Suggested-by: Matthew Rosato Signed-off-by: Eric Farman Message-Id: <20210303160739.2179378-1-farman@linux.ibm.com> Signed-off-by: Cornelia Huck --- hw/vfio/ccw.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/hw/vfio/ccw.c b/hw/vfio/ccw.c index bc78a0ad7638..b2df708e4b01 100644 --- a/hw/vfio/ccw.c +++ b/hw/vfio/ccw.c @@ -104,9 +104,9 @@ again: goto again; } error_report("vfio-ccw: write I/O region failed with errno=%d", errno); - ret = -errno; + ret = errno ? -errno : -EFAULT; } else { - ret = region->ret_code; + ret = 0; } switch (ret) { case 0: @@ -192,9 +192,9 @@ again: goto again; } error_report("vfio-ccw: write cmd region failed with errno=%d", errno); - ret = -errno; + ret = errno ? -errno : -EFAULT; } else { - ret = region->ret_code; + ret = 0; } switch (ret) { case 0: @@ -232,9 +232,9 @@ again: goto again; } error_report("vfio-ccw: write cmd region failed with errno=%d", errno); - ret = -errno; + ret = errno ? -errno : -EFAULT; } else { - ret = region->ret_code; + ret = 0; } switch (ret) { case 0: -- 2.26.2