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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 74446C4740A for ; Mon, 9 Sep 2019 12:42:03 +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 49040218DE for ; Mon, 9 Sep 2019 12:42:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 49040218DE 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]:56136 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i7Iza-0006c7-0j for qemu-devel@archiver.kernel.org; Mon, 09 Sep 2019 08:42:02 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51354) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1i7Iyt-0006BA-W8 for qemu-devel@nongnu.org; Mon, 09 Sep 2019 08:41:20 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1i7Iys-0001jA-W4 for qemu-devel@nongnu.org; Mon, 09 Sep 2019 08:41:19 -0400 Received: from mx1.redhat.com ([209.132.183.28]:46646) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1i7Iys-0001ir-Ot for qemu-devel@nongnu.org; Mon, 09 Sep 2019 08:41:18 -0400 Received: from mail-qk1-f200.google.com (mail-qk1-f200.google.com [209.85.222.200]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 160212D0FCE for ; Mon, 9 Sep 2019 12:41:18 +0000 (UTC) Received: by mail-qk1-f200.google.com with SMTP id v143so16045181qka.21 for ; Mon, 09 Sep 2019 05:41:18 -0700 (PDT) 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=ZCuJG1Cac2wjmQE4JT82x3FrrbXbh6IGBXW9SAccfpE=; b=JtZ6xlwBcbQHQn0SHhA5YAiVUMhzLbnc/ef3UsMUESRCn8CIFHbVGjbXNkDbnoJCzd OUa2mNQDrNZiQJoRm/d4n98rycs3drRbem+7E8qccuyrvd7kOCTM6xYe3Zb28Rp9Y+j6 zLiw79J8tBx/L0H7sT3RRRd7/hqY/A5RMOS4zJDGT708HiVyCD9638tEBQj7QbmCPbh5 PY7UVxz0FlpBxrem7QH08rAfCb6k+GWF7TSo9+143Xtnde6XlMYsuSgb5f4FgQdS4Ggi tWeUCToKpkKtYUylO9AiG84sotr0Qb3dNqr2Ef7S/g+/ZcZvN59g9K8vBntVxyV7u6YW qjlQ== X-Gm-Message-State: APjAAAUx9RQ1YUYVQ7kSXoYEtWtb+q3Z8YFH+fI+v8roAOixnLN8g8nl LIXY2Z3yiCr4XDTVitbp9c5tuB60Ul1oIALGnHb2XGkmY/FqwXXU5Rzkn/orZGVOUYgIn2SCXrU GksnFgpRxLmW3Uh8= X-Received: by 2002:ad4:4524:: with SMTP id l4mr14493627qvu.69.1568032876899; Mon, 09 Sep 2019 05:41:16 -0700 (PDT) X-Google-Smtp-Source: APXvYqzQm+zO+c+xuiMd1s40AMx1xBvDmILqQZMX3Uck16iELOqg6iVXqxgkaLZV6y5+yoAgO7oO2Q== X-Received: by 2002:ad4:4524:: with SMTP id l4mr14493613qvu.69.1568032876657; Mon, 09 Sep 2019 05:41:16 -0700 (PDT) Received: from redhat.com ([80.74.107.118]) by smtp.gmail.com with ESMTPSA id a3sm6712872qta.68.2019.09.09.05.41.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Sep 2019 05:41:15 -0700 (PDT) Date: Mon, 9 Sep 2019 08:41:11 -0400 From: "Michael S. Tsirkin" To: Johannes Berg Message-ID: <20190909083902-mutt-send-email-mst@kernel.org> References: <20190902121233.13382-1-johannes@sipsolutions.net> <20190906121350.29202-1-johannes@sipsolutions.net> <20190906102217-mutt-send-email-mst@kernel.org> <20190906110340-mutt-send-email-mst@kernel.org> <20190908091207-mutt-send-email-mst@kernel.org> <8a9cf8a1726afce7fed8992a4f19fc808004ef88.camel@sipsolutions.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8a9cf8a1726afce7fed8992a4f19fc808004ef88.camel@sipsolutions.net> X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: Re: [Qemu-devel] [RFC] libvhost-user: implement VHOST_USER_PROTOCOL_F_KICK_CALL_MSGS 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: qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, Sep 09, 2019 at 01:35:19PM +0200, Johannes Berg wrote: > On Sun, 2019-09-08 at 09:13 -0400, Michael S. Tsirkin wrote: > > > > I think the only use for this extension would be for simulation > > > purposes, and even then only combined with the REPLY_ACK and SLAVE_REQ > > > extensions, i.e. you explicitly *want* your virtual machine to lock up / > > > wait for a response to the KICK command (and respectively, the device to > > > wait for a response to the CALL command). > > > > OK so when combined with these, it's OK I think. > > OK. > > > Do we want to force this restriction in code maybe then? > > Unlike in this patch, I was planning to not actually advertise > VHOST_USER_PROTOCOL_F_KICK_CALL_MSGS, and do that only if the user of > the library wants to advertise it, since devices used for simulation > also have to be careful about how they use this. > > However, if I understand correctly we cannot enforce that all of them > are used at the same time - we're the device side, so we only advertise > our features and the master actually sets the ones it wants to use, no? > > The only thing we could do is crash if it wants to use this feature > without the others, but would that really be helpful? We can return failure from SET_PROTOCOL_FEATURES. We can also fail all following messages. > I'm starting to actually get this working, so I'll post new patches in a > few days or so. > > johannes