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 lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (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 247BDC2BA4C for ; Wed, 26 Jan 2022 15:54:48 +0000 (UTC) Received: from list by lists.xenproject.org with outflank-mailman.260993.451417 (Exim 4.92) (envelope-from ) id 1nCkd0-0006K4-AE; Wed, 26 Jan 2022 15:54:34 +0000 X-Outflank-Mailman: Message body and most headers restored to incoming version Received: by outflank-mailman (output) from mailman id 260993.451417; Wed, 26 Jan 2022 15:54:34 +0000 Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1nCkd0-0006Jx-6d; Wed, 26 Jan 2022 15:54:34 +0000 Received: by outflank-mailman (input) for mailman id 260993; Wed, 26 Jan 2022 15:54:33 +0000 Received: from se1-gles-flk1-in.inumbo.com ([94.247.172.50] helo=se1-gles-flk1.inumbo.com) by lists.xenproject.org with esmtp (Exim 4.92) (envelope-from ) id 1nCkcz-0006Jr-1R for xen-devel@lists.xenproject.org; Wed, 26 Jan 2022 15:54:33 +0000 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by se1-gles-flk1.inumbo.com (Halon) with ESMTP id 4027121b-7ec0-11ec-8f75-fffcc8bd4f1a; Wed, 26 Jan 2022 16:54:32 +0100 (CET) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 37572D6E; Wed, 26 Jan 2022 07:54:31 -0800 (PST) Received: from [10.57.68.47] (unknown [10.57.68.47]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F387C3F766; Wed, 26 Jan 2022 07:54:29 -0800 (PST) X-BeenThere: xen-devel@lists.xenproject.org List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Errors-To: xen-devel-bounces@lists.xenproject.org Precedence: list Sender: "Xen-devel" X-Inumbo-ID: 4027121b-7ec0-11ec-8f75-fffcc8bd4f1a Message-ID: <447f89ca-86c0-dc35-e7ac-e6639a573670@arm.com> Date: Wed, 26 Jan 2022 15:54:25 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:91.0) Gecko/20100101 Thunderbird/91.5.1 Subject: Re: [PATCH v3 1/2] dt-bindings: arm: xen: document Xen iommu device Content-Language: en-GB To: Sergiy Kibrik Cc: Stefano Stabellini , Julien Grall , Oleksandr Tyshchenko , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "xen-devel@lists.xenproject.org" References: <20220117123251.140867-1-Sergiy_Kibrik@epam.com> <20220117123251.140867-2-Sergiy_Kibrik@epam.com> From: Robin Murphy In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2022-01-26 15:09, Sergiy Kibrik wrote: > Hi Robin, > >> >> This could break Linux guests, since depending on the deferred probe >> timeout setting it could lead to drivers never probing because the "IOMMU" >> never becomes available. >> > > I've noticed no deferred probe timeouts when booting with this patch. Could you please explain more on how this would break guests? Right now I think it would actually require command-line intervention, e.g. "fw_devlink=on" or "deferred_probe_timeout=3600" (with modules enabled for the latter to take full effect), but I'm wary of the potential for future config options to control those behaviours by default. Robin. > Thank you! > > -- Sergiy 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 1B41EC2BA4C for ; Wed, 26 Jan 2022 17:07:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: Content-Transfer-Encoding:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:From:References:Cc:To:Subject: MIME-Version:Date:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=BB+ViOa9yQYjxohvn0F5joF4C8gcyQl/c8qHg0gZ+1w=; b=F1YPdBmtI304rs SttLA+ZahVEOaG+dMVhzUCg2cBf5PvEMQSn9txX6h/eGr0kA+9wK0/6AN81VvJ8wNA+4VGLxroFOy Q9U5bgZw7UGIWfSCAzrN86PZmQHEOWUGKLaE1PcTlpk0HHZVamR7gAhkStzxIH+7r+5ZX9C7dNwyV WR0PyFMx94e47x1ibYn7D6AxreuzTIAKnmtwwAuMnrwXp8r/hzpmd9xh08aGrRPSgf99RoU3QUdvV zoPCK2CEKfDPbJoSiKJ9c4rVczOa2LdbfYgMYVAmj48I31IiX4DODWSxpEPS7tBb0o0WKEHdstsyi YU96wiXS4IAMuoPEK5+Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nClk0-00Crfr-GN; Wed, 26 Jan 2022 17:05:52 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nCkcy-00CRVD-F8 for linux-arm-kernel@lists.infradead.org; Wed, 26 Jan 2022 15:54:33 +0000 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 37572D6E; Wed, 26 Jan 2022 07:54:31 -0800 (PST) Received: from [10.57.68.47] (unknown [10.57.68.47]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id F387C3F766; Wed, 26 Jan 2022 07:54:29 -0800 (PST) Message-ID: <447f89ca-86c0-dc35-e7ac-e6639a573670@arm.com> Date: Wed, 26 Jan 2022 15:54:25 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:91.0) Gecko/20100101 Thunderbird/91.5.1 Subject: Re: [PATCH v3 1/2] dt-bindings: arm: xen: document Xen iommu device Content-Language: en-GB To: Sergiy Kibrik Cc: Stefano Stabellini , Julien Grall , Oleksandr Tyshchenko , "devicetree@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "xen-devel@lists.xenproject.org" References: <20220117123251.140867-1-Sergiy_Kibrik@epam.com> <20220117123251.140867-2-Sergiy_Kibrik@epam.com> From: Robin Murphy In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220126_075432_606125_56B121DA X-CRM114-Status: UNSURE ( 8.42 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On 2022-01-26 15:09, Sergiy Kibrik wrote: > Hi Robin, > >> >> This could break Linux guests, since depending on the deferred probe >> timeout setting it could lead to drivers never probing because the "IOMMU" >> never becomes available. >> > > I've noticed no deferred probe timeouts when booting with this patch. Could you please explain more on how this would break guests? Right now I think it would actually require command-line intervention, e.g. "fw_devlink=on" or "deferred_probe_timeout=3600" (with modules enabled for the latter to take full effect), but I'm wary of the potential for future config options to control those behaviours by default. Robin. > Thank you! > > -- Sergiy _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel