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=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_2 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 23D88CA9EBB for ; Wed, 23 Oct 2019 21:07:33 +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 E94BF21A4A for ; Wed, 23 Oct 2019 21:07:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E94BF21A4A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com 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 D4BFCCDF; Wed, 23 Oct 2019 21:07:08 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id C319ACDD for ; Wed, 23 Oct 2019 21:07:07 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id B45E38A2 for ; Wed, 23 Oct 2019 21:07:06 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 23 Oct 2019 14:07:06 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.68,222,1569308400"; d="scan'208";a="191964696" Received: from jacob-builder.jf.intel.com (HELO jacob-builder) ([10.7.199.155]) by orsmga008.jf.intel.com with ESMTP; 23 Oct 2019 14:07:05 -0700 Date: Wed, 23 Oct 2019 14:11:26 -0700 From: Jacob Pan To: Lu Baolu Subject: Re: [PATCH v6 01/10] iommu/vt-d: Enlightened PASID allocation Message-ID: <20191023141126.38bc1644@jacob-builder> In-Reply-To: <20191023105523.75895d76@jacob-builder> References: <1571788403-42095-1-git-send-email-jacob.jun.pan@linux.intel.com> <1571788403-42095-2-git-send-email-jacob.jun.pan@linux.intel.com> <20191023004503.GB100970@otc-nc-03> <20191023105523.75895d76@jacob-builder> Organization: OTC X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.30; x86_64-pc-linux-gnu) MIME-Version: 1.0 Cc: "Tian, Kevin" , "Raj, Ashok" , Jean-Philippe Brucker , iommu@lists.linux-foundation.org, LKML , Alex Williamson , David Woodhouse , Jonathan Cameron 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, 23 Oct 2019 10:55:23 -0700 Jacob Pan wrote: > > > Do you have to check this everytime? every dmar_readq is going to > > > trap to the other side ... > > > > Yes. We don't need to check it every time. Check once and save the > > result during boot is enough. > > > > How about below incremental change? > > > Below is good but I was thinking to include vccap in struct > intel_iommu{} where cap and ecaps reside. i.e. > diff --git a/include/linux/intel-iommu.h b/include/linux/intel-iommu.h > index 14b87ae2916a..e2cf25c9c956 100644 > --- a/include/linux/intel-iommu.h > +++ b/include/linux/intel-iommu.h > @@ -528,6 +528,7 @@ struct intel_iommu { > u64 reg_size; /* size of hw register set */ > u64 cap; > u64 ecap; > + u64 vccap; > > Also, we can use a static branch here. > On a second thought, we cannot use static(branch) here in that we cannot assume there is only one vIOMMU all the time. Have to cache the vccap per iommu. > > diff --git a/drivers/iommu/intel-pasid.c > > b/drivers/iommu/intel-pasid.c index ff7e877b7a4d..c15d9d7e1e73 > > 100644 --- a/drivers/iommu/intel-pasid.c > > +++ b/drivers/iommu/intel-pasid.c > > @@ -29,22 +29,29 @@ u32 intel_pasid_max_id = PASID_MAX; > > [Jacob Pan] _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu