From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 08B7A322A2E; Fri, 2 Oct 2026 03:57:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790913441; cv=none; b=DVuFMUGOqkCR+RLks64mmTvtJLqIF5p3/p8gx5h0whJ1rF+7jHc/ejFSY7JSyrBcOTYLsX8nauMujRp0NKO9vs23D2LtzmpYrecSgpCp9JWbYyyVT7hWm1eU8zQDwHdh+wkS3dS2PlBFXlzyERhkTetp7gF+UfbdSf5k6yiZu34= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790913441; c=relaxed/simple; bh=ud0njTb+UTcmC7RfcGMaJx5fA1+AoT2gA/SldV45wKc=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=hSJC6dE2Nha+9GbX4P0lO5z7mLB5E4HxDcSAQoJ7osNkFu+m/Geg3dtwU6F62rB/Uh5kBigyWhxNPx3fkbUdb689d3bbGMrpq5OtTVUO0GhXHfUJqmADRGC2LGEmPOXW3a53ETpC7p6hrWEBIf18a4atylBbpN0wkdBp1qEgX/s= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=fiJkGWu5; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="fiJkGWu5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D0DED1F000FF; Fri, 2 Oct 2026 03:57:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790913439; bh=JGbxfjALTUQwxq1qJv01o3GgQpTAqeK9iKQm41v7RH0=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=fiJkGWu5LJxFkR3v6K0UnkZ3TKNnXEv4qWypJMDSvW9pkeN4RItLn2SBF7Ubej4VB xmU0yzbWQ12Xf4YDF4O15g4sX6iZyJFRFLedUWJREiGGU+Wj1V3Mz8n2f01OLYhyzf /KjbfSVPIWDd2SgNG2VrgelKFaIK+EPZ/hYD1HsKE1/iWsb4qj3bMQpZ/PepUuDqPC WmjdW0Dh2jfdQ2uCNRgr8cMfYE/5yyMqNYGPE4XiDZmI6Xm4UOlSA8xazXs8nvRQ7N eP4Tr3nd6sSTPpNViD1JuXoey7tLZx7cQj561YBho3gXAPvNle2TU5o0RMf7zuPGzJ ISREDXIhmnXwQ== Message-ID: Date: Thu, 1 Oct 2026 22:57:17 -0500 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4] iommu/amd: Make PerfOpt compulsory To: Vasant Hegde , Jason Gunthorpe Cc: Alex Deucher , Joerg Roedel , Suravee Suthikulpanit , "open list:RADEON and AMDGPU DRM DRIVERS" , open list , "open list:AMD IOMMU (AMD-VI)" References: <20261001182410.1525285-1-superm1@kernel.org> Content-Language: en-US From: Mario Limonciello In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 10/1/26 10:44 PM, Vasant Hegde wrote: > > > On 10/1/2026 11:54 PM, Mario Limonciello (AMD) wrote: >> PerfOpt is only a feature usable by integrated GPUs and only in identity >> mode. Instead of leaving a policy knob in amdgpu, just turn it on when >> an integrated GPU is in identity. >> >> PerfOpt locks the GPU into identity mode where the DTE is ignored, so mark >> it require_direct (blocks VFIO/iommufd claims) and disable PASID (no GCR3 >> table in the fast path). >> >> This drops quite a bit of compatibility glue. There was a refcounting >> system, exported symbols, and device attach/detach logic. By just setting >> it immediately it's a lot more straightforward. >> >> Suggested-by: Jason Gunthorpe >> Signed-off-by: Mario Limonciello (AMD) >> --- >> v4: >> * Disable PASID for PerfOpt devices >> * Don't allow attaching a blocked domain > > This will block attaching device to guest via vfio-pci. Is that fine? > > -Vasant > Right - The thing is from that experiment on v3, putting it in blocked domain does nothing while PerfOpt is enabled. I figured the user should be aware; so I was between blocking attaching a blocked domain or showing a warning.