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=-8.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 91837C63697 for ; Wed, 18 Nov 2020 11:39:42 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) (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 D9AA921D7A for ; Wed, 18 Nov 2020 11:39:41 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="X4cajgCd" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D9AA921D7A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=virtualization-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id 588E887220; Wed, 18 Nov 2020 11:39:41 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Iy38TSyDhtfP; Wed, 18 Nov 2020 11:39:40 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by hemlock.osuosl.org (Postfix) with ESMTP id A8F2987183; Wed, 18 Nov 2020 11:39:40 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 9030EC0891; Wed, 18 Nov 2020 11:39:40 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id 4E628C07FF for ; Wed, 18 Nov 2020 11:39:39 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id 35B1E871BE for ; Wed, 18 Nov 2020 11:39:39 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id w4CWTlAUyU2R for ; Wed, 18 Nov 2020 11:39:38 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [216.205.24.124]) by hemlock.osuosl.org (Postfix) with ESMTPS id 76A4187183 for ; Wed, 18 Nov 2020 11:39:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1605699577; 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: in-reply-to:in-reply-to:references:references; bh=6R/6pwwpmuxG0MDZ4yvt0MqGRHPil6xB7qtVxel0gLg=; b=X4cajgCdFap8AddpVm6mBcxKBnfPrT98XeIuByHs3q1rc4gNAcxNEbnJpgXPtBWgqWp3cN HEVWFh2GRUXOImllN1pKov7lmIVTXtkc8Z+TfBPDecVbnXkjQUKoJSsk+7Eu/6tVSeiTTf 9tFbH0c/TsMNWJzylMSN3YCizThmf94= Received: from mail-wm1-f71.google.com (mail-wm1-f71.google.com [209.85.128.71]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-435-1UNIpVJ-Pq-rSGyCJabA-w-1; Wed, 18 Nov 2020 06:39:35 -0500 X-MC-Unique: 1UNIpVJ-Pq-rSGyCJabA-w-1 Received: by mail-wm1-f71.google.com with SMTP id a134so739968wmd.8 for ; Wed, 18 Nov 2020 03:39:35 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=6R/6pwwpmuxG0MDZ4yvt0MqGRHPil6xB7qtVxel0gLg=; b=Ets9jaTgRHnFgGKyNP8ePvh0sA5DYbgMS0Cf6Y4mdsAUyAjZfcQSvLE41hase9evsB NnHp1O7RzETKDsCgrwFJUvq7LsX9yNUE5JALH2hxsCdTCn6gBwJ3Otoz540tnfMCCLDf 2T1RDrHLIC+5nXnRWckStuTWDeZKIfrfEcw6ZqQi1npkZ5EGR/mbH3mVRKgh/OUCoea+ Z4ffOdKFYL6J4TF6R+vt0iv967yghKgl0Ui+10o2oV9ToIIiBlMj0+pvmUYwvJ40yoJs 1T/aOHX17E1xiQa+IpqFBUc+tIX0Zq3WEwxiKvyKhQ86tJEuoUXFcI/onz+s7Wig/YjG Tj8Q== X-Gm-Message-State: AOAM532sYHN8kOAMPKMhUz/zX+8M0bka5rAG4FgyggwbcN5quoPdIKI4 3DU/k7YJIfc/AKsIGV+9NCSvSA4fFqfX/NTE2N/1DooxDSQhwRFmRWXqfiDYmXiKLnWfSnr3Epa JkcZhWuoyyoaTgYC+QCR8WcKQ1Wr51hrDZvsxxYys0w== X-Received: by 2002:a7b:c1ce:: with SMTP id a14mr4098637wmj.126.1605699574083; Wed, 18 Nov 2020 03:39:34 -0800 (PST) X-Google-Smtp-Source: ABdhPJzrPLqC5uRTn2T9zd6p9hbLUkX2tNzGSzrjqO2hEeUwzwzrRTmKFuYoh+KPvYKlSgz9RTE61A== X-Received: by 2002:a7b:c1ce:: with SMTP id a14mr4098620wmj.126.1605699573741; Wed, 18 Nov 2020 03:39:33 -0800 (PST) Received: from steredhat (host-79-17-248-175.retail.telecomitalia.it. [79.17.248.175]) by smtp.gmail.com with ESMTPSA id y16sm31384125wrt.25.2020.11.18.03.39.32 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 18 Nov 2020 03:39:33 -0800 (PST) Date: Wed, 18 Nov 2020 12:39:30 +0100 From: Stefano Garzarella To: Stefan Hajnoczi Subject: Re: [PATCH RFC 04/12] vdpa: add vdpa simulator for block device Message-ID: <20201118113930.p7uigootcb42wqix@steredhat> References: <20201113134712.69744-1-sgarzare@redhat.com> <20201113134712.69744-5-sgarzare@redhat.com> <20201117111121.GD131917@stefanha-x1.localdomain> <20201117141620.ytium7r6xpxi4and@steredhat> <20201117164342.GT131917@stefanha-x1.localdomain> <20201117173811.lw4nwicoykhnn3tt@steredhat> <20201118112355.GE182763@stefanha-x1.localdomain> MIME-Version: 1.0 In-Reply-To: <20201118112355.GE182763@stefanha-x1.localdomain> Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=sgarzare@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Disposition: inline Cc: Laurent Vivier , Max Gurtovoy , "Michael S. Tsirkin" , linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, Eli Cohen X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" On Wed, Nov 18, 2020 at 11:23:55AM +0000, Stefan Hajnoczi wrote: >On Tue, Nov 17, 2020 at 06:38:11PM +0100, Stefano Garzarella wrote: >> On Tue, Nov 17, 2020 at 04:43:42PM +0000, Stefan Hajnoczi wrote: >> > On Tue, Nov 17, 2020 at 03:16:20PM +0100, Stefano Garzarella wrote: >> > > On Tue, Nov 17, 2020 at 11:11:21AM +0000, Stefan Hajnoczi wrote: >> > > > On Fri, Nov 13, 2020 at 02:47:04PM +0100, Stefano Garzarella wrote: >> > > > > +static void vdpasim_blk_work(struct work_struct *work) >> > > > > +{ >> > > > > + struct vdpasim *vdpasim = container_of(work, struct vdpasim, work); >> > > > > + u8 status = VIRTIO_BLK_S_OK; >> > > > > + int i; >> > > > > + >> > > > > + spin_lock(&vdpasim->lock); >> > > > > + >> > > > > + if (!(vdpasim->status & VIRTIO_CONFIG_S_DRIVER_OK)) >> > > > > + goto out; >> > > > > + >> > > > > + for (i = 0; i < VDPASIM_BLK_VQ_NUM; i++) { >> > > > > + struct vdpasim_virtqueue *vq = &vdpasim->vqs[i]; >> > > > > + >> > > > > + if (!vq->ready) >> > > > > + continue; >> > > > > + >> > > > > + while (vringh_getdesc_iotlb(&vq->vring, &vq->iov, &vq->iov, >> > > > > + &vq->head, GFP_ATOMIC) > 0) { >> > > > > + >> > > > > + int write; >> > > > > + >> > > > > + vq->iov.i = vq->iov.used - 1; >> > > > > + write = vringh_iov_push_iotlb(&vq->vring, &vq->iov, &status, 1); >> > > > > + if (write <= 0) >> > > > > + break; >> > > > >> > > > We're lucky the guest driver doesn't crash after VIRTIO_BLK_T_GET_ID? :) >> > > >> > > The crash could happen if the simulator doesn't put the string terminator, >> > > but in virtio_blk.c, the serial_show() initialize the buffer putting the >> > > string terminator in the VIRTIO_BLK_ID_BYTES element: >> > > >> > > buf[VIRTIO_BLK_ID_BYTES] = '\0'; >> > > err = virtblk_get_id(disk, buf); >> > > >> > > This should prevent the issue, right? >> > > >> > > However in the last patch of this series I implemented VIRTIO_BLK_T_GET_ID >> > > support :-) >> > >> > Windows, BSD, macOS, etc guest drivers aren't necessarily going to >> > terminate or initialize the serial string buffer. >> >> Unfortunately I discovered that VIRTIO_BLK_T_GET_ID is not in the VIRTIO >> specs, so, just for curiosity, I checked the QEMU code and I found this: >> >> case VIRTIO_BLK_T_GET_ID: >> { >> /* >> * NB: per existing s/n string convention the string is >> * terminated by '\0' only when shorter than buffer. >> */ >> const char *serial = s->conf.serial ? s->conf.serial : ""; >> size_t size = MIN(strlen(serial) + 1, >> MIN(iov_size(in_iov, in_num), >> VIRTIO_BLK_ID_BYTES)); >> iov_from_buf(in_iov, in_num, 0, serial, size); >> virtio_blk_req_complete(req, VIRTIO_BLK_S_OK); >> virtio_blk_free_request(req); >> break; >> } >> >> It seems that the device emulation in QEMU expects that the driver >> terminates the serial string buffer. >> >> Do you know why VIRTIO_BLK_T_GET_ID is not in the specs? >> Should we add it? > >It's about to be merged into the VIRTIO spec: >https://github.com/oasis-tcs/virtio-spec/issues/63 > Great! Thanks for the link! Stefano _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization