From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 996F8199FAB; Wed, 15 Apr 2026 18:24:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776277444; cv=none; b=uPKV1DLeH93bde+3ESA+ZM0LOoYeje9EURdt/ZQNESrJ4/BiKm92EpGTpfQuwdhG0S3n0ufIDT6TN8RYwZszNrR5A+VD53hnjKqj+L6CwvX7fTgkS6XZN0JLA3W9e96x6vOagB5S5VwewHSujheGLjNtWSBaoT9s8ufgf01nIKk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776277444; c=relaxed/simple; bh=toz3JdrFqywdQ1N1YW6RdFzMCnDjkLzxlrNd6YI/f4Q=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=UHMw5BAap2d7WkXQrCVNFLYbJW7cl3osYQVcZjfSNB/lMAct0UQhaQWlJf7nMmb07PGl3Kwjv1bTFy41Kf11GCewaABeuwlEfEDsSM3NemH7EdHhTK2GEPulWTTLLMAorxbednSmJSo+ZV7XaYCxNLmmqIU4ABsrsBGgz8RhoGg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OZjDMZmG; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="OZjDMZmG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C2499C19424; Wed, 15 Apr 2026 18:24:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1776277444; bh=toz3JdrFqywdQ1N1YW6RdFzMCnDjkLzxlrNd6YI/f4Q=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=OZjDMZmG9Tv5XNzNODl/4eBvz0K87GeLOCUOjAKBNFkdQGaCxlglToNBr/O3nRt1U kW8gHJJFo4bY5eLtHljzoJiB/h5q7XP3m4glZo2yyysUrLtl2xBleCDhqLw10iiPqM 7O0PyjAFzxvofjdsGZg9FmvoyMztV+21HT9s8dAzR5rbAYh3Cqp7x7Zlr/hyg9ly/+ nQHgtcBxltryV/JH3XgwVCbrOCWQY/aSDCzskrmoLvP2id/8RKp/ytOaveGsQdtOT7 Ic7SColmb7LIviu/UDMkv+ynO0gZIlS1XLgXwET8bOqYR3OBt3VqCutHNEItd578CV VZwe+h9e5hK9Q== Date: Wed, 15 Apr 2026 21:23:59 +0300 From: Leon Romanovsky To: Matt Evans Cc: Alex Williamson , Jason Gunthorpe , Kevin Tian , Vivek Kasireddy , Ankit Agrawal , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] vfio/pci: Don't export DMABUFs for unmappable BARs Message-ID: <20260415182359.GC361495@unreal> References: <20260415181623.1021090-1-mattev@meta.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260415181623.1021090-1-mattev@meta.com> On Wed, Apr 15, 2026 at 11:16:23AM -0700, Matt Evans wrote: > Although vfio_pci_core_feature_dma_buf() validates that both requested > DMABUF ranges and the PCI resources being referenced are page-aligned, > there may be reasons other than alignment that cause a BAR to be > unmappable. > > Add a check for vdev->bar_mmap_supported[index], similar to the VFIO > mmap path. > > Fixes: 5d74781ebc86c ("vfio/pci: Add dma-buf export support for MMIO regions") > Signed-off-by: Matt Evans > --- > drivers/vfio/pci/vfio_pci_dmabuf.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/vfio/pci/vfio_pci_dmabuf.c b/drivers/vfio/pci/vfio_pci_dmabuf.c > index f87fd32e4a01..4ccaf3531e02 100644 > --- a/drivers/vfio/pci/vfio_pci_dmabuf.c > +++ b/drivers/vfio/pci/vfio_pci_dmabuf.c > @@ -249,6 +249,9 @@ int vfio_pci_core_feature_dma_buf(struct vfio_pci_core_device *vdev, u32 flags, > if (get_dma_buf.region_index >= VFIO_PCI_ROM_REGION_INDEX) > return -ENODEV; > > + if (!vdev->bar_mmap_supported[get_dma_buf.region_index]) > + return -EINVAL; I noticed this check in vfio_pci_core_mmap(). Isn't that sufficient? Thanks > + > dma_ranges = memdup_array_user(&arg->dma_ranges, get_dma_buf.nr_ranges, > sizeof(*dma_ranges)); > if (IS_ERR(dma_ranges)) > -- > 2.47.3 >