From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-qk1-f176.google.com (mail-qk1-f176.google.com [209.85.222.176]) (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 488B52F5A23 for ; Wed, 29 Oct 2025 20:44:14 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.222.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761770656; cv=none; b=TNvVDUXTwlnV9Yshs1mgLzuxTc3XS9ayzmcn2Jq81GKgvVl6ehtGwNUOjnWGEDAI0+gCFirkDqPWBITllteXzeWPVOakS8AhZLhPGVpRpZ3bs3bZ69bzQmW40NlXn+2vAuzmW4A6aRIDkg/aTrp1avzt3yfoOl5TaDCHHpn3KH4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761770656; c=relaxed/simple; bh=PpaAnelvP90qNut+ZwW7vK2RK0H4rH7vlQYQGs2uXZI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=OqJhnoBu9c3mxMs9mrXgu19Cw1Vaae66AiA0PbcmsbLxFZaVEMqfPtde5DUs5lkgO2iTHmjPZMOMjqWX1YGoSQbBveOdMNvAwU83X6AnrnDvDTBPEHbWhQDzauXYwIRLngFZVW77JqOZ8ZDMC4WiIGj1O7Fv6EdbRMRpVKrIGm0= 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=NdZ6LFnT; arc=none smtp.client-ip=209.85.222.176 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="NdZ6LFnT" Received: by mail-qk1-f176.google.com with SMTP id af79cd13be357-88f8f346c2cso26276885a.0 for ; Wed, 29 Oct 2025 13:44:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ziepe.ca; s=google; t=1761770653; x=1762375453; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=RXmwII94RIU4hvYvWVxvISL3Cf6KBQEXeyuNCmaeDUA=; b=NdZ6LFnTI6zrhukv2ioDeAyjWqg6+j1Uuru17kHskflsn1LWBlkItFGc7c7FM3RljP yNnibcKgqCu4WjAaGG6c4isZ79B+uilkmI9YEZJa5qx+ybSZK9nMRJzxRxRCeRNIhWuA fTXGFnp5F91EUwy76Gnlay+5vEK4F2az4C8WttulzlsB+VDrq0c2hnsoL6VsfwMR+Y+p PhVmLtEGWeulzW9Db67U4hK+aj3aJ1qGkROJRfSu1jJQJU4aqAgfMG41/l8kdySPdb4L QZM08T8laY4cKBaz+Szz9g5zNkE5YbReJwaZ1Ni1yy/UtV3JwhBwR2m6yfNwWiNQ3pJp LU5g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1761770653; x=1762375453; h=in-reply-to: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=RXmwII94RIU4hvYvWVxvISL3Cf6KBQEXeyuNCmaeDUA=; b=aq7SaRsOsB8V2yhWUl9AhFRNTlQAEdbRLBtXEfXD+d6YDnkbryNxUzJYoHXnbe5JOm 9nqQYcZfSnqHKH2a6/CLIJBxkfkhpBkYrJqzopmf422fihl6b6tMNrGsinHCTRHbbxLQ 2tqCFHD22D243H9VEdPwmsy41XCIEAzc+LyYI1iTpWwf8W9pl+cZ7efKizzrsPYG4yKj wHpCkvJRPKHyPsrjNHtN1iiuDfSttmhJEENo9ggKsqszFrHy6xAG0uxAuQW5ly+9nWhF jXzs7oNc25ej4i8lUlFn6IqY5frrLF/vg+suRXFyULzkbbIpWl98qofleSRucKApo5EF iglA== X-Forwarded-Encrypted: i=1; AJvYcCXfsMQ1/J0NyEVpVf2kY+7xaPmw1GMf93H3W5u31yfvoBYZ+WPD5WaKvJyPkHQHyKOtlDymkRoWJXnOc8I=@vger.kernel.org X-Gm-Message-State: AOJu0YyiQciNfuwHd0CgftwWr+GfDdpfsB4CzKebLub8e9p5wMS8r2sk mlZYdFIVYjsoFL9X1RwMnB74NpapnbmgpTGTsjTsCueoS9BEEWaJPyU0rUbliexbO2I= X-Gm-Gg: ASbGncv6OeAqodUuyH4/Um9b2yh1/Dyo/gMlVjSU37CZSt7UzTxz0uilrtQzn5j9aab ZSOf0eqJ53X09U6l9VLEEIuTukDhqGfp+PZTZw2t7BZZ6DgtR9lPjNhOboOGQJDTt/XnGGfmgnE gPUmNvg1S/nJAP7DxIeOHhygd5GjZsx3KNzX8aowDpTzcziv5n9I0z2z6OWdav3CzhkCSQGoV9U RjLvi/OSv9pV0vX5Sr2tUOD1YV2w98SIRGN2TtpBDm8w5/WuCN8hWDWXpf5ehik7Af/9Nc7gFF7 dFjgWFn05InDgK9gpxSouEvAcKCDshigxdpTZNXGZzpbsRbUDPA1l1XgK050fJaiF9nfnK4RO2r 9ahPAxURZ0kngexZN/5qTOmXRTc05PssV58+k/i4rSt4FFTYRNlGbkbGvgUJ0fhhlxVkqB6a9k6 Ma7omXXOKdHqkg3IxK4RDa3FQlSSCPO402y9TpaCZfyQU7rg== X-Google-Smtp-Source: AGHT+IGATc8r8DQBwuLiAP3r8TNXYtoAaZC4C/pNuGjsCGGzvT3LRAi9w0bLz5mbYMTI7xxUZ0KOWQ== X-Received: by 2002:a05:620a:4496:b0:892:9838:b17a with SMTP id af79cd13be357-8a8e407c6d6mr467678485a.3.1761770653172; Wed, 29 Oct 2025 13:44:13 -0700 (PDT) Received: from ziepe.ca (hlfxns017vw-47-55-120-4.dhcp-dynamic.fibreop.ns.bellaliant.net. [47.55.120.4]) by smtp.gmail.com with ESMTPSA id af79cd13be357-89f24ecbc11sm1141931785a.24.2025.10.29.13.44.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 29 Oct 2025 13:44:12 -0700 (PDT) Received: from jgg by wakko with local (Exim 4.97) (envelope-from ) id 1vED1g-000000053O5-0MFV; Wed, 29 Oct 2025 17:44:12 -0300 Date: Wed, 29 Oct 2025 17:44:12 -0300 From: Jason Gunthorpe To: Mukesh R Cc: alex.williamson@redhat.com, joe@perches.com, kvm@vger.kernel.org, "linux-kernel@vger.kernel.org" , "linux-hyperv@vger.kernel.org" , "wei.liu@kernel.org" Subject: Re: [RFC] Making vma_to_pfn() public (due to vm_pgoff change) Message-ID: <20251029204412.GU760669@ziepe.ca> References: 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: On Mon, Oct 27, 2025 at 02:21:56PM -0700, Mukesh R wrote: > Hi Alex, > > This regards vfio passthru support on hyperv running linux as dom0 aka > root. At a high level, cloud hypervisor uses vfio for set up as usual, > then maps the mmio ranges via the hyperv linux driver ioctls. > > Over a year ago, when working on this I had used vm_pgoff to get the pfn > for the mmio, that was 5.15 and early 6.x kernels. Now that I am porting > to 6.18 for upstreaming, I noticed: > > commit aac6db75a9fc > Author: Alex Williamson > vfio/pci: Use unmap_mapping_range() > > changed the behavior and vm_pgoff is no longer holding the pfn. In light > of that, I wondered if the following minor change, making vma_to_pfn() > public (after renaming it), would be acceptable to you. No way, no driver should be looking into VMAs like this - it is already a known security problem. Is this "hyperv linux driver ioctls" upstream? You should probably be looking to use the coming DMABUF stuff instead. Jason