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=-2.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 F1A31C4CEC5 for ; Thu, 12 Sep 2019 14:03:07 +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 BAEED20CC7 for ; Thu, 12 Sep 2019 14:03:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="zZWoHe9q" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BAEED20CC7 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org 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 F2EE0E1C; Thu, 12 Sep 2019 14:03:05 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id F0BD5DDC for ; Thu, 12 Sep 2019 14:03:03 +0000 (UTC) Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id AF56782B for ; Thu, 12 Sep 2019 14:03:03 +0000 (UTC) Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id BBFBA20856; Thu, 12 Sep 2019 14:02:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1568296983; bh=W/mFNJBuhBpmbDbmK2QLeeqrvyKptqabZ5ypFqgATbU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=zZWoHe9qke0fWfFJOlp7u5U6VNJ/lxOM6p5vMkZZFDleEdE1MM1auzRRZd1JCYzZN nCbzbEtEpYAkC86lEARz1IW1i5vUYhqPWk9cRUWCg/5A3JAdcXl5MG4tPAjfsJj/+m puXi1FKE2G+rPXBGADanJd04R0aDp5LpwZKXyxes= Date: Thu, 12 Sep 2019 15:02:56 +0100 From: Will Deacon To: Guo Ren Subject: Re: [PATCH RFC 11/14] arm64: Move the ASID allocator code in a separate file Message-ID: <20190912140256.fwbutgmadpjbjnab@willie-the-truck> References: <20190321163623.20219-12-julien.grall@arm.com> <0dfe120b-066a-2ac8-13bc-3f5a29e2caa3@arm.com> <20190619091219.GB7767@fuggles.cambridge.arm.com> <20190619123939.GF7767@fuggles.cambridge.arm.com> <20190624104006.lvm32nahemaqklxc@willie-the-truck> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20170113 (1.7.2) Cc: julien.thierry@arm.com, Catalin Marinas , Palmer Dabbelt , Will Deacon , christoffer.dall@arm.com, Atish Patra , Julien Grall , gary@garyguo.net, linux-riscv@lists.infradead.org, kvmarm@lists.cs.columbia.edu, Mike Rapoport , aou@eecs.berkeley.edu, Arnd Bergmann , suzuki.poulose@arm.com, Marc Zyngier , Paul Walmsley , linux-arm-kernel@lists.infradead.org, Anup Patel , Linux Kernel Mailing List , iommu@lists.linux-foundation.org, james.morse@arm.com 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 Sun, Sep 08, 2019 at 07:52:55AM +0800, Guo Ren wrote: > On Mon, Jun 24, 2019 at 6:40 PM Will Deacon wrote: > > > I'll keep my system use the same ASID for SMP + IOMMU :P > > > > You will want a separate allocator for that: > > > > https://lkml.kernel.org/r/20190610184714.6786-2-jean-philippe.brucker@arm.com > > Yes, it is hard to maintain ASID between IOMMU and CPUMMU or different > system, because it's difficult to synchronize the IO_ASID when the CPU > ASID is rollover. > But we could still use hardware broadcast TLB invalidation instruction > to uniformly manage the ASID and IO_ASID, or OTHER_ASID in our IOMMU. That's probably a bad idea, because you'll likely stall execution on the CPU until the IOTLB has completed invalidation. In the case of ATS, I think an endpoint ATC is permitted to take over a minute to respond. In reality, I suspect the worst you'll ever see would be in the msec range, but that's still an unacceptable period of time to hold a CPU. > Welcome to join our disscusion: > "Introduce an implementation of IOMMU in linux-riscv" > 9 Sep 2019, 10:45 Jade-room-I&II (Corinthia Hotel Lisbon) RISC-V MC I attended this session, but it unfortunately raised many more questions than it answered. Will _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu