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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id F3C4DCA0EE4 for ; Thu, 14 Aug 2025 13:31:15 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 92AA9900165; Thu, 14 Aug 2025 09:31:15 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 9029C900023; Thu, 14 Aug 2025 09:31:15 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 818BF900165; Thu, 14 Aug 2025 09:31:15 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 6F457900023 for ; Thu, 14 Aug 2025 09:31:15 -0400 (EDT) Received: from smtpin16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id F36661385F5 for ; Thu, 14 Aug 2025 13:31:14 +0000 (UTC) X-FDA: 83775449268.16.11A839A Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf14.hostedemail.com (Postfix) with ESMTP id 57F05100009 for ; Thu, 14 Aug 2025 13:31:13 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=XqHxW8YW; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf14.hostedemail.com: domain of leon@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=leon@kernel.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1755178273; a=rsa-sha256; cv=none; b=GyUJQyx5af99twcGWbjXZGgw92r1rxmqmbeT0b5QUGqbs7wezJeVGmf9F4ZmstZn11lABl X1YMTZYC8D+a0fnN+VIjdrJLreJ5w44N6c75ee26thgu/YP1uDyR3AB2M95GS3f+o9MeE9 yP3hTsbBdWhffeF4sBfpiUauOsBy2xU= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=XqHxW8YW; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf14.hostedemail.com: domain of leon@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=leon@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1755178273; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=/aVLEAIiIUq96sEpteKq4xn0CYp2Pr/HhvYRjdNe/U0=; b=LkQRoGv0HdXvdsSI+OQ0KAAJcE/Gtkzg+SVurudQ4pO3mn/TUG5gVSsDdcXx6ZUnnf3wZ3 yb/fe1f8KQzBzT/XMf/vd74h9/lgeqt9EXqVHm+UkJX0EJuS0B4XXE6UgGY/klZ/i60qzU 3G3or2vhl9LOA4uqLMPFiCago78dkYY= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 766E96111F; Thu, 14 Aug 2025 13:31:12 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 02E81C4CEF1; Thu, 14 Aug 2025 13:31:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1755178272; bh=WW0xB1u8XI1L1gGsXl6wpt3WDXrr4yCiJlHi7BUNlCY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XqHxW8YW58Ln/tIjnGi73wY9qD5/Iqkzwyv6qop3T0s5v319Ftg/c1ujK3/+Pmp3O 3SJY9d+x4hq26C9R4ldz3ap27JZ3CK6dbddTXlBk+z2z09uVrOYjtUFTpeGlFvgNjV L1huyBWZL3RmFzTXcCZe8HHfxLc3AApxz5Ss7QLL+ussS/TR5qi1rfohz3kzvuYQXA z9fOR+m/fazEworlcK45UcqDrJLI+rHyeuLbz0YS0ZizqgTQFWAKE1JSOTRnlpXZlF 3y7wTMxm2dgJYYjVCyrbQbIxiWn20GP+y7nUAEOT4RU14M4Kgk2W8/qCK/ckcjXpyq NVGeZpIDI1XVQ== Date: Thu, 14 Aug 2025 16:31:06 +0300 From: Leon Romanovsky To: Jason Gunthorpe Cc: Marek Szyprowski , Abdiel Janulgue , Alexander Potapenko , Alex Gaynor , Andrew Morton , Christoph Hellwig , Danilo Krummrich , iommu@lists.linux.dev, Jason Wang , Jens Axboe , Joerg Roedel , Jonathan Corbet , Juergen Gross , kasan-dev@googlegroups.com, Keith Busch , linux-block@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-nvme@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, linux-trace-kernel@vger.kernel.org, Madhavan Srinivasan , Masami Hiramatsu , Michael Ellerman , "Michael S. Tsirkin" , Miguel Ojeda , Robin Murphy , rust-for-linux@vger.kernel.org, Sagi Grimberg , Stefano Stabellini , Steven Rostedt , virtualization@lists.linux.dev, Will Deacon , xen-devel@lists.xenproject.org Subject: Re: [PATCH v1 08/16] kmsan: convert kmsan_handle_dma to use physical addresses Message-ID: <20250814133106.GE310013@unreal> References: <5b40377b621e49ff4107fa10646c828ccc94e53e.1754292567.git.leon@kernel.org> <20250807122115.GH184255@nvidia.com> <20250813150718.GB310013@unreal> <20250814121316.GC699432@nvidia.com> <20250814123506.GD310013@unreal> <20250814124448.GE699432@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250814124448.GE699432@nvidia.com> X-Rspamd-Queue-Id: 57F05100009 X-Stat-Signature: a88fqbn3beeauqn69xcofeyn5iyanqe5 X-Rspam-User: X-Rspamd-Server: rspam06 X-HE-Tag: 1755178273-7488 X-HE-Meta: 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 a4Z5j6+G IuZwZ3wVraUmOymPo2/HkKRP6+eFRpNjY9G3xpeNKs7oK1tcZj8IB3pswv1Q08SozifPf6LOZkzUJRyS6miRioHvdkVmN3UwTOvKhAkTjd8eld73cze+/iDyzNTjE6eNKDuzGMNBy1g1SiH67zJMzNs1l8JW8TvcKcSot9pMXyiuu+1I++pO6uz1eJaFGGsdC9woOAQ2G0409fByHCSDhStKyw2mqh01uXmQjlqLlL2MDkBt0d1LoHy4lKDpUWa/RR/Yf9OrI4j1HMbiJ9rtbWV6CHf90I+9XcJHwNw9X31SXAdEYX1v0USBTgN/X1PQ/fvtL1t6h20DE7JGncWaA39+br41oykDv+w14YBzOAXs2p0LXgdlhXyQSxQ== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Thu, Aug 14, 2025 at 09:44:48AM -0300, Jason Gunthorpe wrote: > On Thu, Aug 14, 2025 at 03:35:06PM +0300, Leon Romanovsky wrote: > > > Then check attrs here, not pfn_valid. > > > > attrs are not available in kmsan_handle_dma(). I can add it if you prefer. > > That makes more sense to the overall design. The comments I gave > before were driving at a promise to never try to touch a struct page > for ATTR_MMIO and think this should be comphrensive to never touching > a struct page even if pfnvalid. > > > > > So let's keep this patch as is. > > > > > > Still need to fix the remarks you clipped, do not check PageHighMem > > > just call kmap_local_pfn(). All thie PageHighMem stuff is new to this > > > patch and should not be here, it is the wrong way to use highmem. > > > > Sure, thanks > > I am wondering if there is some reason it was written like this in the > first place. Maybe we can't even do kmap here.. So perhaps if there is > not a strong reason to change it just continue to check pagehighmem > and fail. > > if (!(attrs & ATTR_MMIO) && PageHighMem(phys_to_page(phys))) > return; Does this version good enough? There is no need to call to kmap_local_pfn() if we prevent PageHighMem pages. diff --git a/mm/kmsan/hooks.c b/mm/kmsan/hooks.c index eab7912a3bf0..d9cf70f4159c 100644 --- a/mm/kmsan/hooks.c +++ b/mm/kmsan/hooks.c @@ -337,13 +337,13 @@ static void kmsan_handle_dma_page(const void *addr, size_t size, /* Helper function to handle DMA data transfers. */ void kmsan_handle_dma(phys_addr_t phys, size_t size, - enum dma_data_direction dir) + enum dma_data_direction dir, unsigned long attrs) { u64 page_offset, to_go, addr; struct page *page; void *kaddr; - if (!pfn_valid(PHYS_PFN(phys))) + if ((attrs & ATTR_MMIO) || PageHighMem(phys_to_page(phys))) return; page = phys_to_page(phys); @@ -357,19 +357,12 @@ void kmsan_handle_dma(phys_addr_t phys, size_t size, while (size > 0) { to_go = min(PAGE_SIZE - page_offset, (u64)size); - if (PageHighMem(page)) - /* Handle highmem pages using kmap */ - kaddr = kmap_local_page(page); - else - /* Lowmem pages can be accessed directly */ - kaddr = page_address(page); + /* Lowmem pages can be accessed directly */ + kaddr = page_address(page); addr = (u64)kaddr + page_offset; kmsan_handle_dma_page((void *)addr, to_go, dir); - if (PageHighMem(page)) - kunmap_local(page); - phys += to_go; size -= to_go; (END) > > Jason >