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 Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 24F2AC433FE for ; Wed, 9 Nov 2022 14:17:18 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 34F6310E04A; Wed, 9 Nov 2022 14:17:17 +0000 (UTC) Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by gabe.freedesktop.org (Postfix) with ESMTP id 2ADB210E04A for ; Wed, 9 Nov 2022 14:17:14 +0000 (UTC) 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 EC8EC1FB; Wed, 9 Nov 2022 06:17:19 -0800 (PST) Received: from [10.57.1.94] (unknown [10.57.1.94]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1DF323F73D; Wed, 9 Nov 2022 06:17:10 -0800 (PST) Message-ID: Date: Wed, 9 Nov 2022 14:17:07 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.2.2 Subject: Re: [PATCH] drm/panfrost: Split io-pgtable requests properly To: Robin Murphy , robh@kernel.org, tomeu.vizoso@collabora.com References: <49e54bb4019cd06e01549b106d7ac37c3d182cd3.1667927179.git.robin.murphy@arm.com> Content-Language: en-GB From: Steven Price In-Reply-To: <49e54bb4019cd06e01549b106d7ac37c3d182cd3.1667927179.git.robin.murphy@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: linux-arm-kernel@lists.infradead.org, Dmitry Osipenko , alyssa.rosenzweig@collabora.com, dri-devel@lists.freedesktop.org Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" On 08/11/2022 17:06, Robin Murphy wrote: > Although we don't use 1GB block mappings, we still need to split > map/unmap requests at 1GB boundaries to match what io-pgtable expects. > Fix that, and add some explanation to make sense of it all. > > Fixes: 3740b081795a ("drm/panfrost: Update io-pgtable API") > Reported-by: Dmitry Osipenko > Signed-off-by: Robin Murphy Reviewed-by: Steven Price I'll push to drm-misc-fixes. Thanks, Steve > --- > The previous diff turned out to be not quite right, so I've not > included Dmitry's Tested-by given for that. > --- > drivers/gpu/drm/panfrost/panfrost_mmu.c | 11 ++++++++++- > 1 file changed, 10 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/panfrost/panfrost_mmu.c b/drivers/gpu/drm/panfrost/panfrost_mmu.c > index e246d914e7f6..4e83a1891f3e 100644 > --- a/drivers/gpu/drm/panfrost/panfrost_mmu.c > +++ b/drivers/gpu/drm/panfrost/panfrost_mmu.c > @@ -250,13 +250,22 @@ void panfrost_mmu_reset(struct panfrost_device *pfdev) > > static size_t get_pgsize(u64 addr, size_t size, size_t *count) > { > + /* > + * io-pgtable only operates on multiple pages within a single table > + * entry, so we need to split at boundaries of the table size, i.e. > + * the next block size up. The distance from address A to the next > + * boundary of block size B is logically B - A % B, but in unsigned > + * two's complement where B is a power of two we get the equivalence > + * B - A % B == (B - A) % B == (n * B - A) % B, and choose n = 0 :) > + */ > size_t blk_offset = -addr % SZ_2M; > > if (blk_offset || size < SZ_2M) { > *count = min_not_zero(blk_offset, size) / SZ_4K; > return SZ_4K; > } > - *count = size / SZ_2M; > + blk_offset = -addr % SZ_1G ?: SZ_1G; > + *count = min(blk_offset, size) / SZ_2M; > return SZ_2M; > } >