From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from SA9PR02CU001.outbound.protection.outlook.com (mail-southcentralusazon11013061.outbound.protection.outlook.com [40.93.196.61]) (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 50891AD24; Mon, 2 Mar 2026 00:01:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.93.196.61 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772409706; cv=fail; b=faXALROwknizLAfEYY89NfCxU+l4znv1b5VP2m85t3iKTGreHPXVtqC3YY5xRTlsT8Iv4OmyXmeIepsAaHUDvOxhYYgPcBGjNc6WPHORIWkOoLhrt33FRtJxHSpBHSn8vQTdmiyAl0qhsqIpysZwdvJUiVHFUH5Z/Ivl9md3y1E= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772409706; c=relaxed/simple; bh=jdzxwSm7ai8ePebrDSsNmEaPLrqyXmoa2Vq6Avz5D1M=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: Content-Type:MIME-Version; b=kT4vKz1K56d/u36S+OfwhoyUbUiwqQy81x8pyPee8MyUQvr9c0YNLMahVLRFdhU7W7rZcHASy1gT770UgUYCLan5roe9ITb16iUcc5v1cicWnFco8VXi7R6rkTl6e0yhXAcvm14HhvsWWYoNfO9EAwX7dnA3Pu5qhyz0hFlB/+E= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com; spf=fail smtp.mailfrom=amd.com; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b=lGLY9ZHd; arc=fail smtp.client-ip=40.93.196.61 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amd.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=amd.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amd.com header.i=@amd.com header.b="lGLY9ZHd" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=ZDR12V9Q9/yMZCvS08OZHuXJ6SRMRdkUm5ey9FDHdssuxwHlFvXam4P0K/8jvQPffbvhbMoNBkM2COo4rvt7gFVzv7y8zW4qn4d/fjfl0kfmoFfybLVEaBbAbSyCsTW6tJ6GBXavT1zeCITb/h1p/XLNJTWWgl4bD8dVKPsIrWYor7h0ei02LRoYwny7wSIWeM3WxQ5jQxnI1UlpsOqmnFxmSthMxefbaTVnFHrOKMwYCj7TzJBjIJeoQB0SoZbajrQiywv4VQZAvH4LPswUCCbvBdl2eeD2r2nF/kbC3ZUWfCTCUPb7PWzVJGgGA00U5fst+q8mBrlxbmyScbRuWQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=e6G+K6cCwnv7M5AQHuUxt4whVOVF2uupdnefYegrI1I=; b=kAlD/mgHlzT3/sh4KDssWVXPdlW/VngVZOfKXjB3bostkLRef6slP+HL6R3LvwYnZ9ojc7V6wMFwKyi6hEJCCeahkG29pOZYtV0G5fB6//yAfwAl9Y0zdbhkGsye10cPimmRB2QOm4P1RHMlVebBlCdGit+xbXfsFEK4JCQudIdKi24afRke1nj/B3jB4vk2HNdkOxADkFB97kcjkLWKH0KwnJPr98Y/7SY/mdwdBFxMPAfeuM9auy84XXLy75+OH6Sn/+qbF9qY/PjPJ5APAJTRPbn+wL6XXlqaSAx1qYEQBGa9H/6V3cxZySjmOM2sLE2YdhGMKiB96EfFm9jpmg== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=amd.com; dmarc=pass action=none header.from=amd.com; dkim=pass header.d=amd.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amd.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=e6G+K6cCwnv7M5AQHuUxt4whVOVF2uupdnefYegrI1I=; b=lGLY9ZHdqe7pk/WCtJy3/82tUO4FMLo4kiWYojUxex7rtEuIUeueF7TzhSlQd3gURYeCLud0GVg+rcqwIpKrIkVMd5k2IB0R+GBdPtfX3TN0I14u631oCZBfNjJ2mmC99JUrBjtReozWn1gTV23geSce4IQMjpSvwAHJNrOhrSg= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from CH3PR12MB9194.namprd12.prod.outlook.com (2603:10b6:610:19f::7) by DS7PR12MB6048.namprd12.prod.outlook.com (2603:10b6:8:9f::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9654.18; Mon, 2 Mar 2026 00:01:41 +0000 Received: from CH3PR12MB9194.namprd12.prod.outlook.com ([fe80::1e6b:ca8b:7715:6fee]) by CH3PR12MB9194.namprd12.prod.outlook.com ([fe80::1e6b:ca8b:7715:6fee%4]) with mapi id 15.20.9654.015; Mon, 2 Mar 2026 00:01:41 +0000 Message-ID: <2a5b2d8c-7359-42bd-9e8e-2c3efacee747@amd.com> Date: Mon, 2 Mar 2026 11:01:24 +1100 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH kernel 6/9] x86/dma-direct: Stop changing encrypted page state for TDISP devices To: Jason Gunthorpe , Robin Murphy Cc: x86@kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-pci@vger.kernel.org, Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , "H. Peter Anvin" , Sean Christopherson , Paolo Bonzini , Andy Lutomirski , Peter Zijlstra , Bjorn Helgaas , Dan Williams , Marek Szyprowski , Andrew Morton , Catalin Marinas , Michael Ellerman , Mike Rapoport , Tom Lendacky , Ard Biesheuvel , Neeraj Upadhyay , Ashish Kalra , Stefano Garzarella , Melody Wang , Seongman Lee , Joerg Roedel , Nikunj A Dadhania , Michael Roth , Suravee Suthikulpanit , Andi Kleen , Kuppuswamy Sathyanarayanan , Tony Luck , David Woodhouse , Greg Kroah-Hartman , Denis Efremov , Geliang Tang , Piotr Gregor , "Michael S. Tsirkin" , Alex Williamson , Arnd Bergmann , Jesse Barnes , Jacob Pan , Yinghai Lu , Kevin Brodsky , Jonathan Cameron , "Aneesh Kumar K.V (Arm)" , Xu Yilun , Herbert Xu , Kim Phillips , Konrad Rzeszutek Wilk , Stefano Stabellini , Claire Chang , linux-coco@lists.linux.dev, iommu@lists.linux.dev, Jiri Pirko References: <20260225053806.3311234-1-aik@amd.com> <20260225053806.3311234-7-aik@amd.com> <20260228000630.GN44359@ziepe.ca> From: Alexey Kardashevskiy Content-Language: en-US In-Reply-To: <20260228000630.GN44359@ziepe.ca> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: SY5P282CA0151.AUSP282.PROD.OUTLOOK.COM (2603:10c6:10:24a::12) To CH3PR12MB9194.namprd12.prod.outlook.com (2603:10b6:610:19f::7) Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CH3PR12MB9194:EE_|DS7PR12MB6048:EE_ X-MS-Office365-Filtering-Correlation-Id: 76c66932-964c-47c9-8ff0-08de77eee1db X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|376014|7416014; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:CH3PR12MB9194.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(366016)(376014)(7416014);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?QlFSVytuQk5INmlhOUVzOS84YkZnUmMzVTUrNk5MY25yTXh3ZUxCUEFjMWxV?= =?utf-8?B?SFcvUXlUN25YdHNGMSs0NFlDdDZWL2w1K2c3RE1rYmJNM01saWdFd3ExWThS?= =?utf-8?B?TFUvdVcreWMrK0p0a09TakxhZzgvaEUwU1dCTFlpY2NOaEQ1dzhJcDZqSlkv?= =?utf-8?B?V3JqVlNTVjRNRmVicW8yMkErR1NYdjFLUVVXWjFpeHhQenlkWlBXWHJycGFG?= =?utf-8?B?VVpRNkJjUVRrdy9XY2ZFVW1PMmZKVXZrT0dwQ0QzR2Evb0Q2NHNBVWFOWDBk?= =?utf-8?B?SDFLZ1NHZEN5UTg5VG9VUk1sSWZZNjJyWnZQMkFKSmlPMjQ3YnczcXdJZzFs?= =?utf-8?B?NkNwbWRDU1pWeEdtLzFYSE1hNXRIMTlXcnpoVVhkNENiTTRnb2JJY1l1MGIx?= =?utf-8?B?Ymcvc0tJcGkvNThlcWhReS9MS1dhcVNObytmWXBRb3NtUGFxVUkvV3VjT1dN?= =?utf-8?B?SDRGZ3A3QlBKTHZJQ1h6NmFmTy90NTR6azhpRHdLbjJraExNOTJXWEhmTmNo?= =?utf-8?B?QnhsTURXRWxSTlRtREhZL0laK1QwYmdheG9ESTNWbEpkbG1DZ29Ia0FpU1lY?= =?utf-8?B?NWM4N2V4SytiL1NUcDFUeTAvTm5ldTFNRnNwaTJaSHdxcmh4S2FNTFl2YUFD?= =?utf-8?B?b0ZTa3VRRmMvQ3pCMHF2dHVCY256Yi9aa1lMVnFYWElZdGJMcVBpU0UyQy9W?= =?utf-8?B?SDV6NDRqNldmMFJPSmFGSVY1KzVhYk45WkF1VVQ0clBMQXZOLzlLeSs3K1pp?= =?utf-8?B?dmZtQnFMK2JKcjZ4UUwrdG9tcVRNaWhYRHNwV3NETnd2cDJuY0lndVo0SXNC?= =?utf-8?B?VFJiNXVUVzIvK0hQbWdtclJveXRlS2h1SVJibUo1UTVESnVpdVhEckwrczBK?= =?utf-8?B?bWZrL01uVk0va0lXdGZZcFlzbDQ0cmgxWUZWa2owemlhZHhSbVRMZDU0RFgz?= =?utf-8?B?VjBZZmJjdnc5U2lvR0xJcVV5bXB4S0V6UmtnQlpUQ052bWUrOUkrL3FkT1p6?= =?utf-8?B?V3lGNWZzbG9YT2F5bm9PUWhEY3o5KzFrYnpSTzhmYkltUlZiS2kzRytBZXQy?= =?utf-8?B?TkI5bTBWZldTblZkbXNHc2pkYnZCclZWdzZTalg4dW1adzBHVTZkMUxibjVN?= =?utf-8?B?eEVQZWVjRmt2ck9mcUVVdXpZeENCd3NVcGsxdldyRS9jWDBCeE0xNHoyTnpP?= =?utf-8?B?QWZpbDVObDd1QldEMkRoMEw3QmFIejE3SUEwSTVzS29GaTdHem9RYkJ6ci9F?= =?utf-8?B?bVJIZW8wKy9PTlNIM2cyV1g1bXdsajZuWjBqR3QzRFhWZEhZTVVIa2srcjl1?= =?utf-8?B?ZWVBUFlIbUxKYlNHNlE0RTdMbURGZjFhRWlxVHZTM0dsSk9YZm01a1FHOWk3?= =?utf-8?B?K0tDbzN6dmFmWWQyc3JxMWhhc0c2N0tCbSs4eG03WXk5NzQyTVd4ZHd2VWky?= =?utf-8?B?b2pSaFVSYWw1bXVCYU1ya2JXTjR4RGRlYnhsM1liZkpYZmZKSnB0YXNDZ2hT?= =?utf-8?B?ZDNybW50TVBJL2htUmxEWU0yUk5JRnV0QlVkR2lBdDZhU2lOZFY3ZTlkR3I5?= =?utf-8?B?d1pHTEZGU3RLTGp1VjhLQlA4dlVhY1NyaHJPTk1VYjB5MTFnSW1pclFmVXpZ?= =?utf-8?B?V3NxaXBiVDhodHVMbE1yU2wxVFNQTHdsd3NzYVBTaktpN2hqZzFDc3dRYlB2?= =?utf-8?B?UUpvdUdQcURmbktkWlFCOG03ZjRMVU1NeU9lMVNKNkhtZWJ3M3NBTjVBRGc3?= =?utf-8?B?Z3lNdWs2UzFTSUZnOEUzclB4OUJJb0ttWW9TUWxtQ2c1ME1QcWNRdFk4UHlz?= =?utf-8?B?Rml2Nm9aSjgzS29NTlliWDliM0JPenF0TS9oM3ZjZ3J5UW9qTWpnU0RoaTlN?= =?utf-8?B?eFhtYk1sN2lUbjd1QTUyb1JSOVNPeVM5VmNmR2ZtTVFlNHR0SUxEcm9EYlJi?= =?utf-8?B?Zk1iSG1oVGV4bE81eloxVDE5ZElLZXpmdTVxYWxlUC96WGFBR2pGNGcrNDJa?= =?utf-8?B?Q29sMFVMc3Z2SVJYMGxteHRhWEkxczNmOTYraGsrbjZBT3BJOG9IV3FVWlBW?= =?utf-8?B?VkQyL1NhZFJoQlk4UVRTdytqV1VNTTR0UnhZalBrZWJaS2l1enBLdHVWZXNp?= =?utf-8?B?dWZmR05LOHo5REZFUFArdnlyWnFlMG9PbDd1d0hHc3BnWnlHYlRCOWg5T0FW?= =?utf-8?B?aWFjL1VoZDYyQ01zWUlrdUdlNnQvZS9ncEZETW0wRHNyR2F3bjcwMTQ4RTg0?= =?utf-8?B?ZHZNWnFiTVRNaUZ5WnpyWHg4clluNWo5MW14Z1cvT3poZWp3d0dZN0oyUUpR?= =?utf-8?B?M0tRQmNzUi9uT0YxaFZUUlhEWlRXL29qMC9BbnJwWUdqU1BFQkNXdz09?= X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-Network-Message-Id: 76c66932-964c-47c9-8ff0-08de77eee1db X-MS-Exchange-CrossTenant-AuthSource: CH3PR12MB9194.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 02 Mar 2026 00:01:41.0174 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: HlMfyNw9t2Kh4QJVurvjQDM7cgazvcB5e8k15Fv0UC6w3BnQ0KJyTG7ABR/pn/eKao6rZsu2Bc2Uev6liv4vIw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS7PR12MB6048 On 28/2/26 11:06, Jason Gunthorpe wrote: > On Wed, Feb 25, 2026 at 05:08:37PM +0000, Robin Murphy wrote: > >> I guess this comes back to the point I just raised on the previous patch - >> the current assumption is that devices cannot access private memory at all, >> and thus phys_to_dma() is implicitly only dealing with the mechanics of how >> the given device accesses shared memory. Once that no longer holds, I don't >> see how we can find the right answer without also consulting the relevant >> state of paddr itself, and that really *should* be able to be commonly >> abstracted across CoCo environments. > > Definately, I think building on this is a good place to start > > https://lore.kernel.org/all/20260223095136.225277-2-jiri@resnulli.us/ cool, thanks for the pointer. > Probably this series needs to take DMA_ATTR_CC_DECRYPTED and push it > down into the phys_to_dma() and make the swiotlb shared allocation > code force set it. > > But what value is stored in the phys_addr_t for shared pages on the > three arches? Does ARM and Intel set the high GPA/IPA bit in the > phys_addr or do they set it through the pgprot? What does AMD do? > ie can we test a bit in the phys_addr_t to reliably determine if it is > shared or private? Without secure vIOMMU, no Cbit in the S2 table (==host) for any VM. SDTE (==IOMMU) decides on shared/private for the device, i.e. (device_cc_accepted()?private:shared). With secure vIOMMU, PTEs in VM will or won't have the SME mask. >>> pci_device_add() enforces the FFFF_FFFF coherent DMA mask so >>> dma_alloc_coherent() fails when SME=on, this is how I ended up fixing >>> phys_to_dma() and not quite sure it is the right fix. > > Does AMD have the shared/private GPA split like ARM and Intel do? Ie > shared is always at a high GPA? What is the SME mask? sorry but I do not follow this entirely. In general, GPA != DMA handle. Cbit (bit51) is not an address bit in a GPA but it is a DMA handle so I mask it there. With one exception - 1) host 2) mem_encrypt=on 3) iommu=pt, but we default to IOMMU in the case of host+mem_encrypt=on and don't have Cbit in host's DMA handles. For CoCoVM, I could map everything again at the 1<<51 offset in the same S2 table to leak Cbit to the bus (useless though). There is vTOM in SDTE which is "every phys_addr_t above vTOM is no Cbit, below - with Cbit" (and there is the same thing for the CPU side in SEV) but this not it, right? AMD's SME mask for shared is 0, for private - 1<<51. Thanks, -- Alexey