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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9DBC3C433EF for ; Mon, 27 Jun 2022 08:14:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233072AbiF0IOi (ORCPT ); Mon, 27 Jun 2022 04:14:38 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46600 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231282AbiF0IOh (ORCPT ); Mon, 27 Jun 2022 04:14:37 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 376D86270 for ; Mon, 27 Jun 2022 01:14:36 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1656317675; 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=pajM9hI9fI/87uBaTeYfHZ+TkaK2uNfPmDfKI6EwRtM=; b=EyZZHRmoVJ+rehBBd3oEfBipAtm9T5wlssvDIk1u1sv/gm/Rh1wOari7YQyZeRBvCseanR Qf1J3k5Lt2xsXd/89FTE13s9BMbu6ji049gm20KXV9n8sq95QA81MFDzSWpjd5snxK0aDV CJ6pZMNJ+1VjUNpo4iIpeANxM/bDA3E= Received: from mail-lf1-f70.google.com (mail-lf1-f70.google.com [209.85.167.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-76-tE7OOMN-PHKlEUKaOuEFDg-1; Mon, 27 Jun 2022 04:14:33 -0400 X-MC-Unique: tE7OOMN-PHKlEUKaOuEFDg-1 Received: by mail-lf1-f70.google.com with SMTP id i3-20020a056512318300b0047f86b47910so4342503lfe.14 for ; Mon, 27 Jun 2022 01:14:33 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=pajM9hI9fI/87uBaTeYfHZ+TkaK2uNfPmDfKI6EwRtM=; b=uMyM8+3JA4SXJheJgQWfprlZtk/QkfYqxweBn/7P9HxyTGdgTYlOgoHHhbQMpCIFkd AjqcYrwXLQFuxMCwmBQUkjtTWqdqMytuMavgSP3B52gnQboFrMan/REegnj8FkXA/ZDL TFM6yPO7+YwOPy3MtU6ixJmrdicBTFu6CLotCCVS3aZ8Qfo77GYxOfdwfI6LRdLsitNx oTo3saZLT/KQgrCCwqPKPTWSPpVN30IJj+w+GOzTI3yBlPQ9OmptcAGskmAmPpOJDFKK hArnRmwxCo6upCkMLH4BcZ4EFnOYSxAoLe+UY/nvXEytG2w+pF/WwtGywlg6Artp4M34 1SAQ== X-Gm-Message-State: AJIora+7Wutf2Ry1DkwrQvi0ZnwWW6EEeR1OfZT0Jt10yasOwQXgCchj vxaOjyaAPF9bOM7GwEfCvOwgEKMFD7tGSiqqYppsW2MUylOt9H/aRGu2b/vCQreuUYZAPPk3JML WBTpN5Hc9/2q0l78+hTxZz+Oxzxg35bHNWllaRCJsV/4a6w== X-Received: by 2002:a05:6512:3f0f:b0:47f:6f89:326 with SMTP id y15-20020a0565123f0f00b0047f6f890326mr7309007lfa.124.1656317672097; Mon, 27 Jun 2022 01:14:32 -0700 (PDT) X-Google-Smtp-Source: AGRyM1stSWl4OiPqPtvMuSHVstpPhV2ncpnK2QP/uZDvpStVqiSUc6+7r6HgRqJbkG0p8fApLKYURBWKalbv9dZOpEk= X-Received: by 2002:a05:6512:3f0f:b0:47f:6f89:326 with SMTP id y15-20020a0565123f0f00b0047f6f890326mr7309001lfa.124.1656317671894; Mon, 27 Jun 2022 01:14:31 -0700 (PDT) MIME-Version: 1.0 References: <20220624025621.128843-1-xuanzhuo@linux.alibaba.com> <20220624025621.128843-26-xuanzhuo@linux.alibaba.com> <20220624025817-mutt-send-email-mst@kernel.org> <20220627023841-mutt-send-email-mst@kernel.org> <20220627034733-mutt-send-email-mst@kernel.org> In-Reply-To: <20220627034733-mutt-send-email-mst@kernel.org> From: Jason Wang Date: Mon, 27 Jun 2022 16:14:20 +0800 Message-ID: Subject: Re: [PATCH v10 25/41] virtio_pci: struct virtio_pci_common_cfg add queue_notify_data To: "Michael S. Tsirkin" Cc: Xuan Zhuo , virtualization , Richard Weinberger , Anton Ivanov , Johannes Berg , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Hans de Goede , Mark Gross , Vadim Pasternak , Bjorn Andersson , Mathieu Poirier , Cornelia Huck , Halil Pasic , Eric Farman , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Vincent Whitchurch , linux-um@lists.infradead.org, netdev , platform-driver-x86@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, kvm , "open list:XDP (eXpress Data Path)" , kangjie.xu@linux.alibaba.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-remoteproc@vger.kernel.org On Mon, Jun 27, 2022 at 3:58 PM Michael S. Tsirkin wrote: > > On Mon, Jun 27, 2022 at 03:45:30PM +0800, Jason Wang wrote: > > On Mon, Jun 27, 2022 at 2:39 PM Michael S. Tsirkin wrote: > > > > > > On Mon, Jun 27, 2022 at 10:30:42AM +0800, Jason Wang wrote: > > > > On Fri, Jun 24, 2022 at 2:59 PM Michael S. Tsirkin wrote: > > > > > > > > > > On Fri, Jun 24, 2022 at 10:56:05AM +0800, Xuan Zhuo wrote: > > > > > > Add queue_notify_data in struct virtio_pci_common_cfg, which comes from > > > > > > here https://github.com/oasis-tcs/virtio-spec/issues/89 > > > > > > > > > > > > For not breaks uABI, add a new struct virtio_pci_common_cfg_notify. > > > > > > > > > > What exactly is meant by not breaking uABI? > > > > > Users are supposed to be prepared for struct size to change ... no? > > > > > > > > Not sure, any doc for this? > > > > > > > > Thanks > > > > > > > > > Well we have this: > > > > > > The drivers SHOULD only map part of configuration structure > > > large enough for device operation. The drivers MUST handle > > > an unexpectedly large \field{length}, but MAY check that \field{length} > > > is large enough for device operation. > > > > Yes, but that's the device/driver interface. What's done here is the > > userspace/kernel. > > > > Userspace may break if it uses e.g sizeof(struct virtio_pci_common_cfg)? > > > > Thanks > > Hmm I guess there's risk... but then how are we going to maintain this > going forward? Add a new struct on any change? This is the way we have used it for the past 5 or more years. I don't see why this must be handled in the vq reset feature. >Can we at least > prevent this going forward somehow? Like have some padding? Thanks > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Since I want to add queue_reset after queue_notify_data, I submitted > > > > > > this patch first. > > > > > > > > > > > > Signed-off-by: Xuan Zhuo > > > > > > Acked-by: Jason Wang > > > > > > --- > > > > > > include/uapi/linux/virtio_pci.h | 7 +++++++ > > > > > > 1 file changed, 7 insertions(+) > > > > > > > > > > > > diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h > > > > > > index 3a86f36d7e3d..22bec9bd0dfc 100644 > > > > > > --- a/include/uapi/linux/virtio_pci.h > > > > > > +++ b/include/uapi/linux/virtio_pci.h > > > > > > @@ -166,6 +166,13 @@ struct virtio_pci_common_cfg { > > > > > > __le32 queue_used_hi; /* read-write */ > > > > > > }; > > > > > > > > > > > > +struct virtio_pci_common_cfg_notify { > > > > > > + struct virtio_pci_common_cfg cfg; > > > > > > + > > > > > > + __le16 queue_notify_data; /* read-write */ > > > > > > + __le16 padding; > > > > > > +}; > > > > > > + > > > > > > /* Fields in VIRTIO_PCI_CAP_PCI_CFG: */ > > > > > > struct virtio_pci_cfg_cap { > > > > > > struct virtio_pci_cap cap; > > > > > > -- > > > > > > 2.31.0 > > > > > > > > > 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 Received: from smtp2.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 smtp.lore.kernel.org (Postfix) with ESMTPS id 7EC3EC43334 for ; Mon, 27 Jun 2022 08:14:41 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id 0FC24402D0; Mon, 27 Jun 2022 08:14:41 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org 0FC24402D0 Authentication-Results: smtp2.osuosl.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=EyZZHRmo X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id frNfh7XHOSku; Mon, 27 Jun 2022 08:14:40 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp2.osuosl.org (Postfix) with ESMTPS id 9261240BC7; Mon, 27 Jun 2022 08:14:39 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org 9261240BC7 Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 6F457C0032; Mon, 27 Jun 2022 08:14:39 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id A8201C002D for ; Mon, 27 Jun 2022 08:14:37 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id 8266440BC7 for ; Mon, 27 Jun 2022 08:14:37 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org 8266440BC7 X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id hUeXy_AoNjx0 for ; Mon, 27 Jun 2022 08:14:36 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp2.osuosl.org 601DF402D0 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by smtp2.osuosl.org (Postfix) with ESMTPS id 601DF402D0 for ; Mon, 27 Jun 2022 08:14:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1656317675; 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=pajM9hI9fI/87uBaTeYfHZ+TkaK2uNfPmDfKI6EwRtM=; b=EyZZHRmoVJ+rehBBd3oEfBipAtm9T5wlssvDIk1u1sv/gm/Rh1wOari7YQyZeRBvCseanR Qf1J3k5Lt2xsXd/89FTE13s9BMbu6ji049gm20KXV9n8sq95QA81MFDzSWpjd5snxK0aDV CJ6pZMNJ+1VjUNpo4iIpeANxM/bDA3E= Received: from mail-lf1-f69.google.com (mail-lf1-f69.google.com [209.85.167.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-434-dkgkYoicOWCcCYZpM7osog-1; Mon, 27 Jun 2022 04:14:33 -0400 X-MC-Unique: dkgkYoicOWCcCYZpM7osog-1 Received: by mail-lf1-f69.google.com with SMTP id b2-20020a0565120b8200b00477a4532448so4370740lfv.22 for ; Mon, 27 Jun 2022 01:14:33 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=pajM9hI9fI/87uBaTeYfHZ+TkaK2uNfPmDfKI6EwRtM=; b=T3glCOcGvbLH+pgFae0icDXJ2krCa3mDkH5t0SSk53knBp3VRrJotSp7hSMrDyivVK QbB+pPW6YF4+hzzod8BnOa3p7D8+3Zf2ItIm0qCJgrm4+K/BufmXkhUKNoZ19EiLYsEV /uzqh+BT4c9PI6I8J6J1kcxuSPaylrflCbasmZ01o4QGlAOcCAsEK0lH4GeHcfo71Qk5 MGWzIncESwBZS3dgYNrjGrxJKMY/klRFDRVyGJ0+KybYiUnrwf6Jx+ObfA7545zfqcZR 2Ui3EPAZLj2eaRU5I12Zo/l59ALcZBmoIGeNI43KzFHm7UdLTkHsc2BJR1/2ZKIqeQz/ cdGA== X-Gm-Message-State: AJIora/+NTeqKTKJhykmrl7nLILiEAjckQFIhP25lFbkOmv+ogbCHiVQ t0uygeDoOv9N3RCCKisxyhlEoJ3RJ1XCpbkRVvdAZtB1Fl8ZiMbsq+yVXGmHBav03vNzrP56alq xGT2j8EZI88O7jDJ583gpwd4LLB0NmRF5i7McFm2u7CkhrBnZeKlFQai3LQ== X-Received: by 2002:a05:6512:3f0f:b0:47f:6f89:326 with SMTP id y15-20020a0565123f0f00b0047f6f890326mr7309019lfa.124.1656317672102; Mon, 27 Jun 2022 01:14:32 -0700 (PDT) X-Google-Smtp-Source: AGRyM1stSWl4OiPqPtvMuSHVstpPhV2ncpnK2QP/uZDvpStVqiSUc6+7r6HgRqJbkG0p8fApLKYURBWKalbv9dZOpEk= X-Received: by 2002:a05:6512:3f0f:b0:47f:6f89:326 with SMTP id y15-20020a0565123f0f00b0047f6f890326mr7309001lfa.124.1656317671894; Mon, 27 Jun 2022 01:14:31 -0700 (PDT) MIME-Version: 1.0 References: <20220624025621.128843-1-xuanzhuo@linux.alibaba.com> <20220624025621.128843-26-xuanzhuo@linux.alibaba.com> <20220624025817-mutt-send-email-mst@kernel.org> <20220627023841-mutt-send-email-mst@kernel.org> <20220627034733-mutt-send-email-mst@kernel.org> In-Reply-To: <20220627034733-mutt-send-email-mst@kernel.org> From: Jason Wang Date: Mon, 27 Jun 2022 16:14:20 +0800 Message-ID: Subject: Re: [PATCH v10 25/41] virtio_pci: struct virtio_pci_common_cfg add queue_notify_data To: "Michael S. Tsirkin" Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=jasowang@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Cc: Vadim Pasternak , linux-remoteproc@vger.kernel.org, Alexei Starovoitov , virtualization , Eric Dumazet , Alexander Gordeev , kangjie.xu@linux.alibaba.com, Anton Ivanov , kvm , Daniel Borkmann , Richard Weinberger , Vincent Whitchurch , John Fastabend , Halil Pasic , Jakub Kicinski , platform-driver-x86@vger.kernel.org, Eric Farman , Jesper Dangaard Brouer , Vasily Gorbik , linux-s390@vger.kernel.org, Heiko Carstens , linux-um@lists.infradead.org, Mark Gross , Hans de Goede , Bjorn Andersson , "open list:XDP \(eXpress Data Path\)" , Paolo Abeni , Mathieu Poirier , netdev , Cornelia Huck , Sven Schnelle , Johannes Berg , "David S. Miller" 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-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" On Mon, Jun 27, 2022 at 3:58 PM Michael S. Tsirkin wrote: > > On Mon, Jun 27, 2022 at 03:45:30PM +0800, Jason Wang wrote: > > On Mon, Jun 27, 2022 at 2:39 PM Michael S. Tsirkin wrote: > > > > > > On Mon, Jun 27, 2022 at 10:30:42AM +0800, Jason Wang wrote: > > > > On Fri, Jun 24, 2022 at 2:59 PM Michael S. Tsirkin wrote: > > > > > > > > > > On Fri, Jun 24, 2022 at 10:56:05AM +0800, Xuan Zhuo wrote: > > > > > > Add queue_notify_data in struct virtio_pci_common_cfg, which comes from > > > > > > here https://github.com/oasis-tcs/virtio-spec/issues/89 > > > > > > > > > > > > For not breaks uABI, add a new struct virtio_pci_common_cfg_notify. > > > > > > > > > > What exactly is meant by not breaking uABI? > > > > > Users are supposed to be prepared for struct size to change ... no? > > > > > > > > Not sure, any doc for this? > > > > > > > > Thanks > > > > > > > > > Well we have this: > > > > > > The drivers SHOULD only map part of configuration structure > > > large enough for device operation. The drivers MUST handle > > > an unexpectedly large \field{length}, but MAY check that \field{length} > > > is large enough for device operation. > > > > Yes, but that's the device/driver interface. What's done here is the > > userspace/kernel. > > > > Userspace may break if it uses e.g sizeof(struct virtio_pci_common_cfg)? > > > > Thanks > > Hmm I guess there's risk... but then how are we going to maintain this > going forward? Add a new struct on any change? This is the way we have used it for the past 5 or more years. I don't see why this must be handled in the vq reset feature. >Can we at least > prevent this going forward somehow? Like have some padding? Thanks > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Since I want to add queue_reset after queue_notify_data, I submitted > > > > > > this patch first. > > > > > > > > > > > > Signed-off-by: Xuan Zhuo > > > > > > Acked-by: Jason Wang > > > > > > --- > > > > > > include/uapi/linux/virtio_pci.h | 7 +++++++ > > > > > > 1 file changed, 7 insertions(+) > > > > > > > > > > > > diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h > > > > > > index 3a86f36d7e3d..22bec9bd0dfc 100644 > > > > > > --- a/include/uapi/linux/virtio_pci.h > > > > > > +++ b/include/uapi/linux/virtio_pci.h > > > > > > @@ -166,6 +166,13 @@ struct virtio_pci_common_cfg { > > > > > > __le32 queue_used_hi; /* read-write */ > > > > > > }; > > > > > > > > > > > > +struct virtio_pci_common_cfg_notify { > > > > > > + struct virtio_pci_common_cfg cfg; > > > > > > + > > > > > > + __le16 queue_notify_data; /* read-write */ > > > > > > + __le16 padding; > > > > > > +}; > > > > > > + > > > > > > /* Fields in VIRTIO_PCI_CAP_PCI_CFG: */ > > > > > > struct virtio_pci_cfg_cap { > > > > > > struct virtio_pci_cap cap; > > > > > > -- > > > > > > 2.31.0 > > > > > > > > > _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1o5jtF-00Giyr-1G for linux-um@lists.infradead.org; Mon, 27 Jun 2022 08:14:38 +0000 Received: by mail-lf1-f72.google.com with SMTP id v5-20020a05651203a500b0047faf076d1dso4319047lfp.8 for ; Mon, 27 Jun 2022 01:14:33 -0700 (PDT) MIME-Version: 1.0 References: <20220624025621.128843-1-xuanzhuo@linux.alibaba.com> <20220624025621.128843-26-xuanzhuo@linux.alibaba.com> <20220624025817-mutt-send-email-mst@kernel.org> <20220627023841-mutt-send-email-mst@kernel.org> <20220627034733-mutt-send-email-mst@kernel.org> In-Reply-To: <20220627034733-mutt-send-email-mst@kernel.org> From: Jason Wang Date: Mon, 27 Jun 2022 16:14:20 +0800 Message-ID: Subject: Re: [PATCH v10 25/41] virtio_pci: struct virtio_pci_common_cfg add queue_notify_data List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-um" Errors-To: linux-um-bounces+geert=linux-m68k.org@lists.infradead.org To: "Michael S. Tsirkin" Cc: Xuan Zhuo , virtualization , Richard Weinberger , Anton Ivanov , Johannes Berg , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Hans de Goede , Mark Gross , Vadim Pasternak , Bjorn Andersson , Mathieu Poirier , Cornelia Huck , Halil Pasic , Eric Farman , Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Christian Borntraeger , Sven Schnelle , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Vincent Whitchurch , linux-um@lists.infradead.org, netdev , platform-driver-x86@vger.kernel.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, kvm , "open list:XDP (eXpress Data Path)" , kangjie.xu@linux.alibaba.com On Mon, Jun 27, 2022 at 3:58 PM Michael S. Tsirkin wrote: > > On Mon, Jun 27, 2022 at 03:45:30PM +0800, Jason Wang wrote: > > On Mon, Jun 27, 2022 at 2:39 PM Michael S. Tsirkin wrote: > > > > > > On Mon, Jun 27, 2022 at 10:30:42AM +0800, Jason Wang wrote: > > > > On Fri, Jun 24, 2022 at 2:59 PM Michael S. Tsirkin wrote: > > > > > > > > > > On Fri, Jun 24, 2022 at 10:56:05AM +0800, Xuan Zhuo wrote: > > > > > > Add queue_notify_data in struct virtio_pci_common_cfg, which comes from > > > > > > here https://github.com/oasis-tcs/virtio-spec/issues/89 > > > > > > > > > > > > For not breaks uABI, add a new struct virtio_pci_common_cfg_notify. > > > > > > > > > > What exactly is meant by not breaking uABI? > > > > > Users are supposed to be prepared for struct size to change ... no? > > > > > > > > Not sure, any doc for this? > > > > > > > > Thanks > > > > > > > > > Well we have this: > > > > > > The drivers SHOULD only map part of configuration structure > > > large enough for device operation. The drivers MUST handle > > > an unexpectedly large \field{length}, but MAY check that \field{length} > > > is large enough for device operation. > > > > Yes, but that's the device/driver interface. What's done here is the > > userspace/kernel. > > > > Userspace may break if it uses e.g sizeof(struct virtio_pci_common_cfg)? > > > > Thanks > > Hmm I guess there's risk... but then how are we going to maintain this > going forward? Add a new struct on any change? This is the way we have used it for the past 5 or more years. I don't see why this must be handled in the vq reset feature. >Can we at least > prevent this going forward somehow? Like have some padding? Thanks > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > Since I want to add queue_reset after queue_notify_data, I submitted > > > > > > this patch first. > > > > > > > > > > > > Signed-off-by: Xuan Zhuo > > > > > > Acked-by: Jason Wang > > > > > > --- > > > > > > include/uapi/linux/virtio_pci.h | 7 +++++++ > > > > > > 1 file changed, 7 insertions(+) > > > > > > > > > > > > diff --git a/include/uapi/linux/virtio_pci.h b/include/uapi/linux/virtio_pci.h > > > > > > index 3a86f36d7e3d..22bec9bd0dfc 100644 > > > > > > --- a/include/uapi/linux/virtio_pci.h > > > > > > +++ b/include/uapi/linux/virtio_pci.h > > > > > > @@ -166,6 +166,13 @@ struct virtio_pci_common_cfg { > > > > > > __le32 queue_used_hi; /* read-write */ > > > > > > }; > > > > > > > > > > > > +struct virtio_pci_common_cfg_notify { > > > > > > + struct virtio_pci_common_cfg cfg; > > > > > > + > > > > > > + __le16 queue_notify_data; /* read-write */ > > > > > > + __le16 padding; > > > > > > +}; > > > > > > + > > > > > > /* Fields in VIRTIO_PCI_CAP_PCI_CFG: */ > > > > > > struct virtio_pci_cfg_cap { > > > > > > struct virtio_pci_cap cap; > > > > > > -- > > > > > > 2.31.0 > > > > > > > > > _______________________________________________ linux-um mailing list linux-um@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-um