From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qt1-f169.google.com (mail-qt1-f169.google.com [209.85.160.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id BDCB2223DC0 for ; Wed, 23 Apr 2025 23:33:37 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.169 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745451219; cv=none; b=JdCwOpKAfmNNWSr1lqf/5uwK8PNmPFNwAeme4CBDyBr/yI6+4R6eBRjYSGhBPFebECLImfjRmMQXGI9aJaDKHjBNFWB768wJAlWu2CP0MHJaIg5kZzt4VwMC/Lzhbi4qJDyNWN5olFXWVtiGJz+eyw5JJOVDX+YnbIvvTrjHDLw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745451219; c=relaxed/simple; bh=El3tntKet6XFP5tu5jRccRiIHcbcsNXplDjGS1RgqqY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=PHg28Z0gQdRgUfsZj78uaevs7a+SQ3SrmMRmDUD9VLH3X0zMuTjzu0oXX3l9ErUFJ0edlcH+WAEs8K5mSwUBZicTMNBHre26m4qudb8tF/8BVSIazgmq/muj749+4HXeCepGVK67a+9PzmlY7l1K/YGnF0FnveFFLv2os1Azyu8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca; spf=pass smtp.mailfrom=ziepe.ca; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b=lI//r8XI; arc=none smtp.client-ip=209.85.160.169 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=ziepe.ca Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ziepe.ca Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=ziepe.ca header.i=@ziepe.ca header.b="lI//r8XI" Received: by mail-qt1-f169.google.com with SMTP id d75a77b69052e-47688ae873fso4464951cf.0 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.linux.dev; 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=lI//r8XIk5Id32jnqr131a0knxutJbYtRsV3gvW7Qf1Gm4cykmeOlfE8ltR6f/dYPR 1vy03Vtrjvcruc1rc3ybNqmvK8Xc0k+Ghl5HJ7xy8RVYVe2t5hTwW9DwEZSMFU6b79zb RgKR/He5DGoVAAxV9Kv5XS90H/Wdv6ykdJGwgm/HXRKnJ/Q+vkcLqW/zu2r31MojNcHF vVF9wft1N/8Lu6VCDfh9q8s+WenEpnqXgMVut/98JeRFVDIMh8Bg+VtunYtNnvzIgesb MSU38b21LU1dzyCAdZScFiUrKjoAd9qK4Ipu/RDfFzvE9M2+F/pmazvnWQ19555rpin2 bAbQ== 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=FTgSNkORs2WPqv3O/U/Rfmp2Yj1LTHWLfnRl4AVvQzqSQf1GPIoA/2FXGSaLm17V8X fm15SDlQ0er+oqACNiUHyt5EMVUKu5NjiQi/nP77swvhtOebYvsBUe6yvyT5EtH/8d/t 6Dziw8QGWhhUbdYZCmA6NfWkAvh6RnuBqsgWmav3Bvo9bCa0u9YFgeHGq90A7NkjfBjG Q+EBDjJu8HoTg3PGiS/tgWA30CVMRBJirNBp46e5Snyb7JeZQO7f+nzcfFGK8qgfY3+R a3m818pkSi4xKUexY2D9YMBCeEMsyp0uiBrnfOyhlF/6iQg/ZV/tGdPkiLDWqloAqdLo DTIg== X-Forwarded-Encrypted: i=1; AJvYcCW/8u6eYZZjnh8z0UrWcN0w/dXM3EH6MHijjRx8WMNgmsyH0zhnSxAOlq0Gf2MovWaI4TNfLw==@lists.linux.dev X-Gm-Message-State: AOJu0Ywvoa5lBIrGqrw4URdOxcIlzU4t/rvw9uoBd6nxVIgT8So5UJ7q l8CgyyjBuISiN4E6284R3525/Kx+f+PtijmlCfzeqfHy0a3boL1T+8bvtkj9lh8= X-Gm-Gg: ASbGncuAtwzWRVgftEIEgJTPHggv0xU3Ki1sYeQzvAezToLZSN3hjp6R8+RkpMu0pSm fWCWQOppBCZ+bdCbeNAt5+j8+067Nk89dJxeFne2Bc4rvP4C5PKF/i4JOoeAoc2tbK6lboAHiXf 2HPox6bFmNdEPnzsfBN1rO4Dudg6S4C4nwrUVV1h8IY7q30Hi5mBVJYGP9u1f0BMFsfZDoUbQAI qdF4WUI39UYx5ao38zbtDm+SrPO08op8NF0MBZinc7Cli1qdfB8QywNn0MtCBNO03w8rX56G7Zj 815nPWNuCuouYLOU0CHHMI8wpywTIV3q0G7+d8Ma24q9s0G54RXqHVNFA60lzJK7togHYehUTT0 U71ksU6w07I26Z/D312g= 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> Precedence: bulk X-Mailing-List: iommu@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: 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> 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