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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id 3983AC369D8 for ; Thu, 24 Apr 2025 02:58:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To: Content-Transfer-Encoding:Content-Type:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=L7oRP2YqJwVB6GeEu4BqvXzZqclhisHpp0fN6LY14JQ=; b=csLe4/FhdTIa0y4WpfyYaFXUQH cfMZH4xGyLAsrk0ZTcLXoQSW2bZaKX+LUyRUrlsrepMr9JKaxQx4DyDN6eqh5Fed/9xw0RsNdvPi1 vrzvEOSrWG6j8DyOihvOWVki/mjbWA50oi6xeSGCKGx3HZ2o9TqYxuYRMGJxND4POiM6V9i44flf4 efoOwYx6DgPv8dAg3V1AM5K3xNP5TeZAxbiL8rN+LaGB5s/sFxzhV8c+vHvXB8I93iqeLOGQeXPQK 3R4JCzQUQmswPZ835qO5ryrj4QHt3928fb+t/MffRkHs8K3usYOp61SO44bgq1z2MyJ367HMtLp+m Z3sJutmw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1u7mn2-0000000Cf9H-2klr; Thu, 24 Apr 2025 02:58:16 +0000 Received: from mail-qt1-x82c.google.com ([2607:f8b0:4864:20::82c]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1u7jb0-0000000CHP0-0HnW for linux-nvme@lists.infradead.org; Wed, 23 Apr 2025 23:33:40 +0000 Received: by mail-qt1-x82c.google.com with SMTP id d75a77b69052e-477282401b3so4518371cf.1 for ; Wed, 23 Apr 2025 16:33:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; t=1745451216; x=1746056016; darn=lists.infradead.org; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date:from:to :cc:subject:date:message-id:reply-to; bh=L7oRP2YqJwVB6GeEu4BqvXzZqclhisHpp0fN6LY14JQ=; b=kxmCpJrZaA51+J5Y8jFFaGEpik2cr2Qfxzn4v5ZHTIqYEkRjVf256PtxQNZsoCXCkz 2JiYHbbNeSVu0GDEYKwST5UymvGrMQFx372gTgqPfnL1fXBf3+hU6VDMlc/WtFjEfME9 UZXxv+56ta+5bCIsOD6x0hbu1H2ovmDSeKxepy4FVsFHLQSkuFh4GprIJuuOSzdXCflQ miVgAcyJr1TtrP2MmvClfLjMkJxAYQBLmjSSFzH5IwFeV4H4C1e/xHQXRZwdZLboSkTe ern9644BrrEsvFG3A5S1FyUomtMPh8INBTs7uS0YOCgJQ+fuyFmUk1SAIe/pf0vvgR4d ZXYw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1745451216; x=1746056016; h=in-reply-to:content-transfer-encoding:content-disposition :mime-version:references:message-id:subject:cc:to:from:date :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=L7oRP2YqJwVB6GeEu4BqvXzZqclhisHpp0fN6LY14JQ=; b=nh2Ubew7Zgnb1VI71kHLzPDBjRTsELRZwY/2bM3+UsAMW705Ttk4G1sXeHT+WE62+8 ur67A2Ce+U+RKGK1dX4G3fQUI//620fsbNfZju+32Mo7xMMvIjfX3ZZrVjH4JC27hIZv x8k0zQidGQw3nbcStYjqSYIiY3+hn5kI4SjvCfcz29Pk2KFHi8q7/Xh3Mvx2DeBFtO/D l0u2L6xi6p6clmFFzh4jGUN4H36gS92XUK50YPrjVH7MsXgMscnsMya5vYIo5jPIitFP zRH71LDgsIWtd+nsGqtpcxX1uGbT9Ue54jMYyN3fg72r/BRgb8v899cOxemPC3hiIbmp jWCw== X-Forwarded-Encrypted: i=1; AJvYcCXKwk2AEJ55B+h64ZhtOm8Gzqz7ihd39dC2hjU1dHvA0Ao8WMaHeEtqnGQHNRijiBuynDOsI4wCi+5Q@lists.infradead.org X-Gm-Message-State: AOJu0YxvsOyDkIBRs6pxp4xRfC8z7v0o/cwTS6vjcOZajpp87SudGYC4 psH4AabzCIb/uFPhmi+sb8o/YPHvH+s2z0FxxH9U0jhR7nLqqTuUZb5VTdAiv2A= X-Gm-Gg: ASbGncuax8vWa73duPn2zf/+iUy3GTn1xTV5kkAb1xJSjmCAvR+eKjnd2vtmCf2hPHo oZsfvjBpnsY38mIC71AVsLo7IXt8PlZjGBMb7j21F39bih7wzKhVvzN49mDoTxNigQTMSPZCsPc vaOI75O6OYE01EmUV/oMWoiYqBoFfRLwyb01wx1hHEUrjQP5hfLctAjYezl4nUf3pFZK7KGr28c CPEMmDuMK5quPkgpaSsVCIDwRKHlvzBXrOA3MGz/VEytn/yQanMwV3axGU4aU25KqBST1wmcJn2 zCZX4uhKG8STLj6eSlzJdSdU1YpO5N8RAM7Eg4YF4ebc2Zgg70lxCPKzgHM2vYZaSr/bWxgqZzF mnpIV34VoXMoZHm0QIKM= X-Google-Smtp-Source: AGHT+IHp4LWhqR/rJc6pqFU95w2BqdqjYtJ4SAe1Mvc/v+Ufccgyj7hWc7Mm96oBr3hzP4lBlnfnCQ== X-Received: by 2002:a05:622a:388:b0:476:b783:c94d with SMTP id d75a77b69052e-47eb4fbb928mr6490361cf.35.1745451216599; Wed, 23 Apr 2025 16:33:36 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-142-167-219-86.dhcp-dynamic.fibreop.ns.bellaliant.net. [142.167.219.86]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-47ea1ba154asm2538601cf.67.2025.04.23.16.33.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 23 Apr 2025 16:33:35 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1u7jax-00000007PKl-19Zx; Wed, 23 Apr 2025 20:33:35 -0300 Date: Wed, 23 Apr 2025 20:33:35 -0300 From: Jason Gunthorpe To: Mika =?utf-8?B?UGVudHRpbMOk?= Cc: Leon Romanovsky , Marek Szyprowski , Jens Axboe , Christoph Hellwig , Keith Busch , Leon Romanovsky , Jake Edge , Jonathan Corbet , Zhu Yanjun , Robin Murphy , Joerg Roedel , Will Deacon , Sagi Grimberg , Bjorn Helgaas , Logan Gunthorpe , Yishai Hadas , Shameer Kolothum , Kevin Tian , Alex Williamson , =?utf-8?B?SsOpcsO0bWU=?= Glisse , Andrew Morton , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-rdma@vger.kernel.org, iommu@lists.linux.dev, linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org, Niklas Schnelle , Chuck Lever , Luis Chamberlain , Matthew Wilcox , Dan Williams , Kanchan Joshi , Chaitanya Kulkarni Subject: Re: [PATCH v9 10/24] mm/hmm: let users to tag specific PFN with DMA mapped bit Message-ID: <20250423233335.GW1213339@ziepe.ca> References: <0a7c1e06269eee12ff8912fe0da4b7692081fcde.1745394536.git.leon@kernel.org> <7185c055-fc9e-4510-a9bf-6245673f2f92@redhat.com> <20250423181706.GT1213339@ziepe.ca> <36891b0e-d5fa-4cf8-a181-599a20af1da3@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <36891b0e-d5fa-4cf8-a181-599a20af1da3@redhat.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250423_163338_112192_ECD66272 X-CRM114-Status: GOOD ( 16.54 ) X-Mailman-Approved-At: Wed, 23 Apr 2025 19:58:12 -0700 X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Wed, Apr 23, 2025 at 09:37:24PM +0300, Mika Penttilä wrote: > > On 4/23/25 21:17, Jason Gunthorpe wrote: > > On Wed, Apr 23, 2025 at 08:54:05PM +0300, Mika Penttilä wrote: > >>> @@ -36,6 +38,13 @@ enum hmm_pfn_flags { > >>> HMM_PFN_VALID = 1UL << (BITS_PER_LONG - 1), > >>> HMM_PFN_WRITE = 1UL << (BITS_PER_LONG - 2), > >>> HMM_PFN_ERROR = 1UL << (BITS_PER_LONG - 3), > >>> + > >>> + /* > >>> + * Sticky flags, carried from input to output, > >>> + * don't forget to update HMM_PFN_INOUT_FLAGS > >>> + */ > >>> + HMM_PFN_DMA_MAPPED = 1UL << (BITS_PER_LONG - 7), > >>> + > >> How is this playing together with the mapped order usage? > > Order shift starts at bit 8, DMA_MAPPED is at bit 7 > > hmm bits are the high bits, and order is 5 bits starting from > (BITS_PER_LONG - 8) I see, so yes order occupies 5 bits [-4,-5,-6,-7,-8] and the DMA_MAPPED overlaps, it should be 9 not 7 because of the backwardness. Probably testing didn't hit this because the usual 2M order of 9 only sets bits -4 and -8 .. The way the order works it doesn't clear the 0 bits, which I wonder if is a little bug.. Jason