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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 08188C433E1 for ; Sun, 23 Aug 2020 08:03:20 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (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 C26F920767 for ; Sun, 23 Aug 2020 08:03:19 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="OSUGo4PT"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="tMc6ZKpq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C26F920767 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linutronix.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id 6211920371; Sun, 23 Aug 2020 08:03:18 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id UsFp91EK9mUD; Sun, 23 Aug 2020 08:03:14 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by silver.osuosl.org (Postfix) with ESMTP id 290CA2014A; Sun, 23 Aug 2020 08:03:14 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 0FBD8C016F; Sun, 23 Aug 2020 08:03:14 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 50198C0051 for ; Sun, 23 Aug 2020 08:03:12 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id 481C585F55 for ; Sun, 23 Aug 2020 08:03:12 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 3CjOHmizLQ07 for ; Sun, 23 Aug 2020 08:03:11 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by fraxinus.osuosl.org (Postfix) with ESMTPS id AA3E785F53 for ; Sun, 23 Aug 2020 08:03:11 +0000 (UTC) From: Thomas Gleixner DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1598169788; 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=1r81LXAzLVDLyLks6MQQbnmtJ0OK+dyyaovYHtczdF8=; b=OSUGo4PT4Ot+VGZW7JgEcWsC8MLwYCCnwHNCt3TYiEzvYBVXe45Rvl3FX/Y0isC1ShdQQ3 RIh/bv3QSwwzvd8iYJBo7gkkwrPBgPqWBWG0qyIj42/W8ULqyGPqdtcmY9SWXIe6qo1A1Q G8rQ4XqyV5X9tf+kKzjK0R1QN5bjpdFSWtGLnHuCi+FXplbjlm/gIBBAoZuWJKD4qsyf1+ E4sJhAD2xn/VQyYp3NoK60i70Z16VK3CVNEGe2YhdqoIM5dCPu+czaZXI3Of9hT7hNOiiq KycdvEqCmdiPmuLVuylio+jeqSn+LdOfVq0686G5ly9H6MwoSrM+c5IPwwJFcQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1598169788; 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=1r81LXAzLVDLyLks6MQQbnmtJ0OK+dyyaovYHtczdF8=; b=tMc6ZKpqYdgSdwXa7ZmkDUuCxCEpdWuXt4VgP89zL1RSX0c8gVXVItieBv1Rh/DCd8vqw0 Q7nUMe69k9VLtDAQ== To: Jason Gunthorpe Subject: Re: [patch RFC 38/38] irqchip: Add IMS array driver - NOT FOR MERGING In-Reply-To: <20200822230511.GD1152540@nvidia.com> References: <20200821002424.119492231@linutronix.de> <20200821002949.049867339@linutronix.de> <20200821124547.GY1152540@nvidia.com> <874kovsrvk.fsf@nanos.tec.linutronix.de> <20200821201705.GA2811871@nvidia.com> <87pn7jr27z.fsf@nanos.tec.linutronix.de> <20200822005125.GB1152540@nvidia.com> <874kovqx8q.fsf@nanos.tec.linutronix.de> <20200822230511.GD1152540@nvidia.com> Date: Sun, 23 Aug 2020 10:03:07 +0200 Message-ID: <875z99ssas.fsf@nanos.tec.linutronix.de> MIME-Version: 1.0 Cc: Dimitri Sivanich , linux-hyperv@vger.kernel.org, Steve Wahl , linux-pci@vger.kernel.org, "K. Y. Srinivasan" , Boris Ostrovsky , Wei Liu , Dave Jiang , Baolu Lu , Marc Zyngier , x86@kernel.org, Megha Dey , xen-devel@lists.xenproject.org, Kevin Tian , Konrad Rzeszutek Wilk , Haiyang Zhang , Alex Williamson , Stefano Stabellini , Bjorn Helgaas , Stephen Hemminger , Dan Williams , Jon Derrick , Juergen Gross , Russ Anderson , Greg Kroah-Hartman , LKML , iommu@lists.linux-foundation.org, Jacob Pan , "Rafael J. Wysocki" X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Sat, Aug 22 2020 at 20:05, Jason Gunthorpe wrote: > On Sat, Aug 22, 2020 at 03:34:45AM +0200, Thomas Gleixner wrote: > As a silicon design it might work, but it means existing devices can't > be used with this dev_msi. It is also the sort of thing that would > need a standard document to have any hope of multiple vendors fitting > into it. Eg at PCI-SIG or something. Fair enough. >> If you don't do that then you simply can't write to that space from the >> CPU and you have to transport this kind information always via command >> queues. > > Yes, exactly. This is part of the architectural design of the device, > has been for a long time. Has positives and negatives. As always and it clearly follows the general HW design rule "we can fix that in software". >> > I suppose the core code could provide this as a service? Sort of a >> > varient of the other lazy things above? >> >> Kinda. That needs a lot of thought for the affinity setting stuff >> because it can be called from contexts which do not allow that. It's >> solvable though, but I clearly need to stare at the corner cases for a >> while. > > If possible, this would be ideal, as we could use the dev_msi on a big > installed base of existing HW. I'll have a look, but I'm surely not going to like the outcome. Thanks, tglx _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu