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=-15.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 9A6D5C4743C for ; Mon, 21 Jun 2021 15:47:33 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 5678161042 for ; Mon, 21 Jun 2021 15:47:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5678161042 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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:MIME-Version:Date:Message-ID:From: References:Cc:To:Subject:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=3+GIhVEoXoRyy51UDgN2yN4HqxpGpvnC5S9t1WqzSMA=; b=5Gim4oY8X5ci9Z4EV8SIdTqx06 SpjhblmyJbRpBOJHlGb/BI9+zuS4e20JK7Nl2oOtxqGty6wAUnn2TNU8RjGB6hq1qUzoy6RPDMzod kZPR/eJmOKWMAyy9Kzc+LVt/Z7XuQclliG2/Iq7XGdpv3OMwn3Pm1l7FQ+/hRLeNNQBpOjYXDlHmZ ayapJVyOYSGCtmhB73CW2gRahPwL+WK4bXazXKi6oSOi5N1BNNMhwrQbXx9ZSR7UX88ILLOqU232I XGMdtht6j+et+Xcdd+UoxTE3SNLA7JpbT7qi5cM7iIYUOIrId+zP63IDb67p/srxib9dJamvuvT0w MIh4Vasw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1lvM7g-003yYg-W0; Mon, 21 Jun 2021 15:46:05 +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 1lvM7d-003yXz-CP for linux-arm-kernel@lists.infradead.org; Mon, 21 Jun 2021 15:46:02 +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 A4C051042; Mon, 21 Jun 2021 08:45:57 -0700 (PDT) Received: from [10.57.9.136] (unknown [10.57.9.136]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 44A4D3F694; Mon, 21 Jun 2021 08:45:56 -0700 (PDT) Subject: Re: [PATCHv2 1/3] iommu/io-pgtable: Add a quirk to use tlb_flush_all() for partial walk flush To: Sai Prakash Ranjan , Will Deacon , Joerg Roedel Cc: Thierry Reding , linux-arm-msm@vger.kernel.org, Douglas Anderson , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, linux-arm-kernel@lists.infradead.org References: From: Robin Murphy Message-ID: <904f283c-f8b1-ba84-d010-eacc87bb53c5@arm.com> Date: Mon, 21 Jun 2021 16:45:50 +0100 User-Agent: Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 MIME-Version: 1.0 In-Reply-To: Content-Language: en-GB X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210621_084601_572908_E58ABE6D X-CRM114-Status: GOOD ( 24.49 ) 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 2021-06-18 03:51, Sai Prakash Ranjan wrote: > Add a quirk IO_PGTABLE_QUIRK_TLB_INV_ALL to invalidate entire context > with tlb_flush_all() callback in partial walk flush to improve unmap > performance on select few platforms where the cost of over-invalidation > is less than the unmap latency. I still think this doesn't belong anywhere near io-pgtable at all. It's a driver-internal decision how exactly it implements a non-leaf invalidation, and that may be more complex than a predetermined boolean decision. For example, I've just realised for SMMUv3 we can't invalidate multiple levels of table at once with a range command, since if we assume the whole thing is mapped at worst-case page granularity we may fail to invalidate any parts which are mapped as intermediate-level blocks. If invalidating a 1GB region (with 4KB granule) means having to fall back to 256K non-range commands, we may not want to invalidate by VA then, even though doing so for a 2MB region is still optimal. It's also quite feasible that drivers might want to do this for leaf invalidations too - if you don't like issuing 512 commands to invalidate 2MB, do you like issuing 511 commands to invalidate 2044KB? - and at that point the logic really has to be in the driver anyway. Robin. > Signed-off-by: Sai Prakash Ranjan > --- > drivers/iommu/io-pgtable-arm.c | 3 ++- > include/linux/io-pgtable.h | 5 +++++ > 2 files changed, 7 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c > index 87def58e79b5..5d362f2214bd 100644 > --- a/drivers/iommu/io-pgtable-arm.c > +++ b/drivers/iommu/io-pgtable-arm.c > @@ -768,7 +768,8 @@ arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie) > if (cfg->quirks & ~(IO_PGTABLE_QUIRK_ARM_NS | > IO_PGTABLE_QUIRK_NON_STRICT | > IO_PGTABLE_QUIRK_ARM_TTBR1 | > - IO_PGTABLE_QUIRK_ARM_OUTER_WBWA)) > + IO_PGTABLE_QUIRK_ARM_OUTER_WBWA | > + IO_PGTABLE_QUIRK_TLB_INV_ALL)) > return NULL; > > data = arm_lpae_alloc_pgtable(cfg); > diff --git a/include/linux/io-pgtable.h b/include/linux/io-pgtable.h > index 4d40dfa75b55..45441592a0e6 100644 > --- a/include/linux/io-pgtable.h > +++ b/include/linux/io-pgtable.h > @@ -82,6 +82,10 @@ struct io_pgtable_cfg { > * > * IO_PGTABLE_QUIRK_ARM_OUTER_WBWA: Override the outer-cacheability > * attributes set in the TCR for a non-coherent page-table walker. > + * > + * IO_PGTABLE_QUIRK_TLB_INV_ALL: Use TLBIALL/TLBIASID to invalidate > + * entire context for partial walk flush to increase unmap > + * performance on select few platforms. > */ > #define IO_PGTABLE_QUIRK_ARM_NS BIT(0) > #define IO_PGTABLE_QUIRK_NO_PERMS BIT(1) > @@ -89,6 +93,7 @@ struct io_pgtable_cfg { > #define IO_PGTABLE_QUIRK_NON_STRICT BIT(4) > #define IO_PGTABLE_QUIRK_ARM_TTBR1 BIT(5) > #define IO_PGTABLE_QUIRK_ARM_OUTER_WBWA BIT(6) > + #define IO_PGTABLE_QUIRK_TLB_INV_ALL BIT(7) > unsigned long quirks; > unsigned long pgsize_bitmap; > unsigned int ias; > _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel