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=-0.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 4A9E4C43613 for ; Fri, 21 Jun 2019 15:34:51 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (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 285852075E for ; Fri, 21 Jun 2019 15:34:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 285852075E Authentication-Results: mail.kernel.org; dmarc=none (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 mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id B91E8D8D; Fri, 21 Jun 2019 15:34:50 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 08EFBCC6 for ; Fri, 21 Jun 2019 15:34:49 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from Galois.linutronix.de (Galois.linutronix.de [146.0.238.70]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 928E5831 for ; Fri, 21 Jun 2019 15:34:48 +0000 (UTC) Received: from p5b06daab.dip0.t-ipconnect.de ([91.6.218.171] helo=nanos) by Galois.linutronix.de with esmtpsa (TLS1.2:DHE_RSA_AES_256_CBC_SHA256:256) (Exim 4.80) (envelope-from ) id 1heLXd-00065k-Gq; Fri, 21 Jun 2019 17:33:29 +0200 Date: Fri, 21 Jun 2019 17:33:28 +0200 (CEST) From: Thomas Gleixner To: Jacob Pan Subject: Re: [RFC PATCH v4 20/21] iommu/vt-d: hpet: Reserve an interrupt remampping table entry for watchdog In-Reply-To: <20190619084316.71ce5477@jacob-builder> Message-ID: References: <1558660583-28561-1-git-send-email-ricardo.neri-calderon@linux.intel.com> <1558660583-28561-21-git-send-email-ricardo.neri-calderon@linux.intel.com> <20190619084316.71ce5477@jacob-builder> User-Agent: Alpine 2.21 (DEB 202 2017-01-01) MIME-Version: 1.0 X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1, SHORTCIRCUIT=-0.0001 Cc: Kate Stewart , "Ravi V. Shankar" , Tony Luck , Ashok Raj , Peter Zijlstra , Jan Kiszka , x86 , Ricardo Neri , Stephane Eranian , LKML , Juergen Gross , Bjorn Helgaas , iommu@lists.linux-foundation.org, Philippe Ombredanne , Randy Dunlap , "Eric W. Biederman" , Ricardo Neri , Andi Kleen , Borislav Petkov , Ingo Molnar , Wincy Van X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 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 Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org On Wed, 19 Jun 2019, Jacob Pan wrote: > On Tue, 18 Jun 2019 01:08:06 +0200 (CEST) > Thomas Gleixner wrote: > > > > Unless this problem is not solved and I doubt it can be solved after > > talking to IOMMU people and studying manuals, > > I agree. modify irte might be done with cmpxchg_double() but the queued > invalidation interface for IRTE cache flush is shared with DMA and > requires holding a spinlock for enque descriptors, QI tail update etc. > > Also, reserving & manipulating IRTE slot for hpet via backdoor might not > be needed if the HPET PCI BDF (found in ACPI) can be utilized. But it > might need more work to add a fake PCI device for HPET. What would PCI/BDF solve? Thanks, tglx _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu