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 483E7EB64DC for ; Mon, 3 Jul 2023 08:23:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229504AbjGCIXC (ORCPT ); Mon, 3 Jul 2023 04:23:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33472 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231470AbjGCIWy (ORCPT ); Mon, 3 Jul 2023 04:22:54 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CFD03E49 for ; Mon, 3 Jul 2023 01:21:59 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1688372518; 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=KDniCynZ7+HhXvQAOCX57oK500g52Olq9GhoAqPPWUs=; b=cgTPl2Ehw3ms3uzU+vOtVVXlZfNkNTwHs10ipklox4g5GIgTamEMioYbOeQWl2Uva6scMo bnqcYJnzPFn/BbLvtBMUQW6LKGOG3FgFuVbjAa8OCt8Mjmk+VrFLP1JuTYcEA3flgIeXyu cwSOemSNozAcTNA+TkUz9TZokxWi97k= Received: from mail-yb1-f198.google.com (mail-yb1-f198.google.com [209.85.219.198]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-33-Lin_dUMlONaXPDElQHAbYA-1; Mon, 03 Jul 2023 04:21:57 -0400 X-MC-Unique: Lin_dUMlONaXPDElQHAbYA-1 Received: by mail-yb1-f198.google.com with SMTP id 3f1490d57ef6-c0bf91d259fso4491595276.1 for ; Mon, 03 Jul 2023 01:21:57 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1688372517; x=1690964517; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=KDniCynZ7+HhXvQAOCX57oK500g52Olq9GhoAqPPWUs=; b=af8Y91Nu0PFkwRIqDXJLKhsAN9CSbbi3u5r/eE6U2ZiBCf/W8CU+nsKsjmP1Xg0U/I qJ80ccVPx5yUrZ0vta1ifakCJZXmxU9V/2GiaxnHsFDd1/YgS05I8BnOtpzwoVC1l9Qs u61NrUpjdSBN0H9Y83OgteKkMBLFA2WcYR/Kg3hJjT0Axy27OcOevpDnLrOhMGSi6r/d 8Pomqy1nzWQW2r9W3gC7MfuCMwrRdbsa/SEK/Ngwx9sRoIBR+KZHIcPNVevLNLd40kil xSTYh7Ruw8xmhWmLJboCHjmtd4UM8D2y1e6YSs9YW2nYhlCRQnu1XV/VIqf+cpwXm33O zEVw== X-Gm-Message-State: ABy/qLaDWW7MG4uLW/OtVSSUkMVno0+/GsrLC3atTrzHvukf63ul3K7U pDqUrI9BKfS4L/APFLwa8T4vxevmZqdE+XnYSLEj3tK/V5i26MQiy80LCCy+gensWbNbJWZRrgo DX7cq/f15X9SZttUNqhAJiFVLFF306buh2PDyZdln X-Received: by 2002:a25:21d5:0:b0:c39:e0f5:8616 with SMTP id h204-20020a2521d5000000b00c39e0f58616mr8210959ybh.46.1688372517230; Mon, 03 Jul 2023 01:21:57 -0700 (PDT) X-Google-Smtp-Source: APBJJlHDI1TQ4yNBXhXRy2Ls9tZMeCzZCw/5NxW05oDphDYt6dbi8koo6BBkhcCkUZtgb7JdeBJbNiY37ga/25hmyqw= X-Received: by 2002:a25:21d5:0:b0:c39:e0f5:8616 with SMTP id h204-20020a2521d5000000b00c39e0f58616mr8210946ybh.46.1688372516994; Mon, 03 Jul 2023 01:21:56 -0700 (PDT) MIME-Version: 1.0 References: <20230609092127.170673-1-eperezma@redhat.com> <20230609092127.170673-3-eperezma@redhat.com> <20230609121244-mutt-send-email-mst@kernel.org> In-Reply-To: <20230609121244-mutt-send-email-mst@kernel.org> From: Eugenio Perez Martin Date: Mon, 3 Jul 2023 10:21:20 +0200 Message-ID: Subject: Re: [PATCH v2 2/4] vdpa: accept VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK backend feature To: "Michael S. Tsirkin" Cc: Jason Wang , Zhu Lingshan , virtualization@lists.linux-foundation.org, "Gonglei (Arei)" , longpeng2@huawei.com, Lei Yang , Parav Pandit , Gautam Dawar , Dragos Tatulea , Laurent Vivier , linux-api@vger.kernel.org, Liuxiangdong , linux-kernel@vger.kernel.org, alvaro.karsz@solid-run.com, Shannon Nelson , Stefano Garzarella , Cindy Lu , si-wei.liu@oracle.com, Harpreet Singh Anand Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 9, 2023 at 6:13=E2=80=AFPM Michael S. Tsirkin = wrote: > > On Fri, Jun 09, 2023 at 11:21:25AM +0200, Eugenio P=C3=A9rez wrote: > > Accepting VHOST_BACKEND_F_ENABLE_AFTER_DRIVER_OK backend feature if > > userland sets it. > > > > Signed-off-by: Eugenio P=C3=A9rez > > Acked-by: Shannon Nelson > > I don't get it, so all vdpa devices accept this automatically? > Should this not be up to the parent? > At the moment I don't see a reason why if a parent offers this feature, it could reject it afterwards. However I think we can add a fail if userland acks the backend feature but the parent does not offer it however. Would it work to add such fail in vdpa frontend and move it to the backend if and when any parent driver needs it in the future? Thanks! > > --- > > drivers/vhost/vdpa.c | 3 ++- > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c > > index bf77924d5b60..a3204406b73d 100644 > > --- a/drivers/vhost/vdpa.c > > +++ b/drivers/vhost/vdpa.c > > @@ -680,7 +680,8 @@ static long vhost_vdpa_unlocked_ioctl(struct file *= filep, > > return -EFAULT; > > if (features & ~(VHOST_VDPA_BACKEND_FEATURES | > > BIT_ULL(VHOST_BACKEND_F_SUSPEND) | > > - BIT_ULL(VHOST_BACKEND_F_RESUME))) > > + BIT_ULL(VHOST_BACKEND_F_RESUME) | > > + BIT_ULL(VHOST_BACKEND_F_ENABLE_AFTER_DRI= VER_OK))) > > return -EOPNOTSUPP; > > if ((features & BIT_ULL(VHOST_BACKEND_F_SUSPEND)) && > > !vhost_vdpa_can_suspend(v)) > > -- > > 2.31.1 >