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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 537DCCAC5B8 for ; Tue, 30 Sep 2025 16:52:57 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B23AC8E0019; Tue, 30 Sep 2025 12:52:56 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id AFB128E0002; Tue, 30 Sep 2025 12:52:56 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A11A78E0019; Tue, 30 Sep 2025 12:52:56 -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 8EC898E0002 for ; Tue, 30 Sep 2025 12:52:56 -0400 (EDT) Received: from smtpin15.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id 307BC1A079B for ; Tue, 30 Sep 2025 16:52:56 +0000 (UTC) X-FDA: 83946511152.15.23FB1EA Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by imf08.hostedemail.com (Postfix) with ESMTP id D196016000C for ; Tue, 30 Sep 2025 16:52:53 +0000 (UTC) Authentication-Results: imf08.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="G02T/CxW"; spf=pass (imf08.hostedemail.com: domain of alex.williamson@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=alex.williamson@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1759251174; 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:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=JryoONnZtvrch8iWe5kQa/bp3US7CnLH1VFoC2oPQRw=; b=cwvhezlb6j5meHAPrpYwl7UJVoiUmvSHtbEO/9p5YjVfNIXH1aqtTAJIiEtYKxxJ7md95S pjWT/+hXUAS70pczLsb9dZRiVboJbvKUeRMc3fJUqLOs8eMN9+nDgW+Dl8hW9pAH/tmekG H8YWplkw7NypGSdpmtNx4f8QEGuCSG0= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1759251174; a=rsa-sha256; cv=none; b=w9W0hi/XMx1TcDy46RVISTu2xKTo2UbWlf2/oKG+lDDz7TJwB+qboTH3JbRJQAMK+JqMYk 0tRju+U3rpaQAcl2OBCuyB8xW9WsiuT0MRT95IQPlMO5mVfcKV/7Xv2Z8nM2CMBmL9HvvF bi22PM6K2UTkZoPbHk2lules9uGYd2c= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b="G02T/CxW"; spf=pass (imf08.hostedemail.com: domain of alex.williamson@redhat.com designates 170.10.129.124 as permitted sender) smtp.mailfrom=alex.williamson@redhat.com; dmarc=pass (policy=quarantine) header.from=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1759251173; h=from:from: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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=JryoONnZtvrch8iWe5kQa/bp3US7CnLH1VFoC2oPQRw=; b=G02T/CxWdFzdWNfhlIFwdrUzUnNBxZAHRXbim9H6o7KQF5KMS4DNUuK0/q0tS1t4VDHqf1 GOfXb5jTCrqx4i4h3f5VwHtoD6hlai8QA77ya8Sck7zGbs4bYIpeUgCs+aMFoPl2guGAKD IxWFGeHTQKPEyMC6jJaM17C6FhYIod4= Received: from mail-ot1-f72.google.com (mail-ot1-f72.google.com [209.85.210.72]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-637-B_rajAaDNZq8qI0B6VWGJw-1; Tue, 30 Sep 2025 12:52:51 -0400 X-MC-Unique: B_rajAaDNZq8qI0B6VWGJw-1 X-Mimecast-MFC-AGG-ID: B_rajAaDNZq8qI0B6VWGJw_1759251171 Received: by mail-ot1-f72.google.com with SMTP id 46e09a7af769-7aba0808204so1557668a34.3 for ; Tue, 30 Sep 2025 09:52:51 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1759251171; x=1759855971; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=JryoONnZtvrch8iWe5kQa/bp3US7CnLH1VFoC2oPQRw=; b=u+IRm4j12VWsxZiZ1h6B8unNnBYlaYc46jvQS+yqyGzT/9QbY8/cflQZxG1Wtntbmk kGe1hR7RRjO0jTwhdEWcyBhlDRI8miPM/dnM5uUF0OEGER4UhZ7Vewc4nuBZYSlzd4Sy q5JmtG3d69OGzcZDHDz4aCImowvOGcceoAu1lMZsXMgIqgWGGRouOjsSL+9YLTKTHlMh YyPTTLvP14ll0SZyXrVZ3DKrTqUS91FUAQ/Xsv/9TI6bOHVl6HntktH5kiqQUgcdmUm2 qQ5ygAle1Jbm5O8YXVuRa6/KOzhNCP72bIDJuagzm/J2tpfxpESphns5bs+HxDQbywmT 7DcQ== X-Forwarded-Encrypted: i=1; AJvYcCWHyh5Bsfj5pblnfv9wsCwOW8gnbWae2kq5vBIjFAfMBZEZHa2WJjwI0zRKrGdbrJg8NzgLJ852OA==@kvack.org X-Gm-Message-State: AOJu0Yws+lUP2rV1d47QKYvkzPQGwM1/LYZ2kHxua3s4iPHVHqhSbxDq PEMZfxve2jKkm7IeversRoUhR0YkTdda6XR4IIggCMavYbgdV6f+teVuGgwbLnXrKjokpR733sO xdOnrxDITQlalsE4WYuP4vkUoUAFEvmylKF+eh1m1yKy77Aa/vMfS X-Gm-Gg: ASbGnctJMYVh5IImdbTwHvYqKeL+Fl7K1u0oVImxbowqwWfZzVeqKwN53ST17on/JTW H/DqUGC2TBNot04P/6KggYAhObzqEbGdiuJ9tk5h0Q9hqyP5F+0KJlHFi7YqB79R41XndfEYD5x sFTV4VtQtaaZKVv7IiAH5c9KcP0jrJbq5ej5bgNKJdQ3iTyYgvAHAzd2idA2OCyH4N0fyJF7tn6 PgfTAJGE1ptn+vDFYHbBlR+U9pDw4qz3cg61BqmDDjOnQOTRvQvf/3NMUu3+ORyxJV2Oh0/TvEt +t0W1yhRWkHCVwIw6JzhY1rLZuYSu0u92ARkaHQ3UcGyo3nd X-Received: by 2002:a05:6808:f86:b0:438:33fd:317c with SMTP id 5614622812f47-43fa41bd61fmr82484b6e.3.1759251171064; Tue, 30 Sep 2025 09:52:51 -0700 (PDT) X-Google-Smtp-Source: AGHT+IEwZ3/lKZz7Fdu2TvHNlTbKRk5qveSl6rvSejYaxAMAP02EZ6HQb/uugFp+9XcOcN4obhcZxg== X-Received: by 2002:a05:6808:f86:b0:438:33fd:317c with SMTP id 5614622812f47-43fa41bd61fmr82463b6e.3.1759251170626; Tue, 30 Sep 2025 09:52:50 -0700 (PDT) Received: from redhat.com ([38.15.36.11]) by smtp.gmail.com with ESMTPSA id 5614622812f47-43f51238c63sm2746753b6e.22.2025.09.30.09.52.48 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Sep 2025 09:52:49 -0700 (PDT) Date: Tue, 30 Sep 2025 10:52:47 -0600 From: Alex Williamson To: Jason Gunthorpe Cc: Shameer Kolothum , Leon Romanovsky , Andrew Morton , Bjorn Helgaas , Christian =?UTF-8?B?S8O2bmln?= , "dri-devel@lists.freedesktop.org" , "iommu@lists.linux.dev" , Jens Axboe , Joerg Roedel , "kvm@vger.kernel.org" , "linaro-mm-sig@lists.linaro.org" , "linux-block@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "linux-media@vger.kernel.org" , "linux-mm@kvack.org" , "linux-pci@vger.kernel.org" , Logan Gunthorpe , Marek Szyprowski , Robin Murphy , Sumit Semwal , Vivek Kasireddy , Will Deacon Subject: Re: [PATCH v4 10/10] vfio/pci: Add dma-buf export support for MMIO regions Message-ID: <20250930105247.1935b553.alex.williamson@redhat.com> In-Reply-To: <20250930143408.GI2942991@nvidia.com> References: <53f3ea1947919a5e657b4f83e74ca53aa45814d4.1759070796.git.leon@kernel.org> <20250929151749.2007b192.alex.williamson@redhat.com> <20250930090048.GG324804@unreal> <20250930143408.GI2942991@nvidia.com> X-Mailer: Claws Mail 4.3.1 (GTK 3.24.43; x86_64-redhat-linux-gnu) MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: zU8Q8TMwkaQiM-s0hXnViFPdL1mjm62-2H8gncSt33A_1759251171 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: D196016000C X-Stat-Signature: b1yx5d7nfju9h5bs3w4jhds9j3qrdxby X-Rspam-User: X-HE-Tag: 1759251173-586781 X-HE-Meta: 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 t0oPoxzR 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 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 Tue, 30 Sep 2025 11:34:08 -0300 Jason Gunthorpe wrote: > On Tue, Sep 30, 2025 at 12:50:47PM +0000, Shameer Kolothum wrote: > > > This is where hisi_acc reports a different BAR size as it tries to hide > > the migration control region from Guest access. > > I think for now we should disable DMABUF for any PCI driver that > implements a VFIO_DEVICE_GET_REGION_INFO > > For a while I've wanted to further reduce the use of the ioctl > multiplexer, so maybe this series: > > https://github.com/jgunthorpe/linux/commits/vfio_get_region_info_op/ > > And then the dmabuf code can check if the ops are set to the generic > or not and disable itself automatically. > > Otherwise perhaps route the dmabuf through an op and deliberately omit > it (with a comment!) from hisi, virtio, nvgrace. > > We need to route it through an op anyhow as those three drivers will > probably eventually want to implement their own version. Can't we basically achieve the same by testing the ioctl is vfio_pci_core_ioctl? Your proposal would have better granularity, but we'd probably want an ops callback that we can use without a userspace buffer to get the advertised region size if we ever want to support a device that both modifies the size of the region relative to the BAR and supports p2p. Thanks, Alex