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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?YqzgIfB0VUyv0s8dhrMye2C0rnaBvWsHLBCPrT+L+yzKPIPTQdbKCcpgs9pv?= =?us-ascii?Q?VbFSxB+WitZI5tgRtNIAkms0bNweQnww8dFuY+4lIAzWNzVJeB40AwjlRI3R?= =?us-ascii?Q?M62fvs2Y+YbnhBvxbAJyqt2PFhqK5HqpoNHdtcE1lj/Okarw6kY6rHRRIpGF?= =?us-ascii?Q?KxveQ0dKdZBZgZlEZtqImj/b+Lkrwugv1reVkHQEpkMQ2auPQS1txDKU80fH?= =?us-ascii?Q?NDBL/OHZC3LsbkbihcOlAKXM5gA8i2K1R4t/K+c5Vv0RdZG/msmSXQxC1ZK8?= =?us-ascii?Q?OZvC/8WVjlZMi4GI2Rwg8kJLlvb9WzAE0DMP0ePRzTT4T/Uip9pUqVRyj1rV?= =?us-ascii?Q?0fbjrGKSruUtjLxnjnLgSAricty/5B4GLdIm9M9lzLY3s/SvChx2qI9hh9Aw?= =?us-ascii?Q?oz1EKQYvqhwwd4lIxjYdxXA/ZIPXn83ZMMOh/89iVTn9bRh24cA58t4WdBJj?= =?us-ascii?Q?vqp01MsNywbJx6Gpd7+ELzWmEZjrMb5QUzKyw+/tM9b2bN4NId12szFuoeu6?= =?us-ascii?Q?wrfv6Z/vNG2UgR+p+OHHsRrD5F0jz/HXVGMECWEsEOcGyrimg8sjP0re7ytd?= =?us-ascii?Q?x/VtQ5jLr9kytROe/w9ousPBJneXVHs+GZvdl5Y7d0CIfq2NkSNhSlgFPPph?= =?us-ascii?Q?/Fra8gSiiJVJfMsWCSFhIR3aRaM6ZXq0GlFsm6MdTRX5ZuAp1dgWe4C14Z7Q?= =?us-ascii?Q?l1JjTt1fsvOlNKVjE6R1Zgo4s3ESP0Uw2+40xFWU0mTp3jhD/mUBiF+CyLyu?= =?us-ascii?Q?tDPhhTxjMXUiOTQYS8xVrvoXC9U1ZW/dQ3T5e8aX8ybPDAqc/EFhDgjU1TZc?= =?us-ascii?Q?4nRpy0gxyhnJ138dS9mcglBAo+y5950Z6su/KzEDF70LeVLgMqq7cQTUuk17?= =?us-ascii?Q?Z8N1rMOi98vno/LLh7/9iPtwuWj2HH9LhJ7QHB2KDApc8CqpwiKCk3ug3H8u?= =?us-ascii?Q?mAtjH8ZUhnqw5PhRsuSl78YsD5wx8sz2iB/m5ko5D8EFWnA27T7G40i1t3+m?= =?us-ascii?Q?92tYOJuLN1HN9r0OBuQ56kIyQp549XESXJib09yl14Vdi8oxmA9G0v9PaDKi?= =?us-ascii?Q?m+xdO5xUvLR6xDbKZWYpxgQGu41TUL0/2c5/jgvjWRdsUiVpdCdv6F7o+SeJ?= =?us-ascii?Q?Jq4CSGoHteUCpXxrbE/zldPl4ZNS7D3g8NdWZyZVqgPqVSSZ1/g2rV3BcG1K?= =?us-ascii?Q?53zwZacGIs8bQMG9QSV80SWxLVJUw1Rgeyq1WYnWbdVCsz+MOdltM6zoh3c7?= =?us-ascii?Q?uFsHsa5/2fO5FXhzdM0xrvWffLkNDJ/6qv+jWr90gDcqaJHq50//X1eXQ33i?= =?us-ascii?Q?OCauoUMA3CdebH0UcuFEQxCx/5BMYMC4HyLhZhoF35t0H2wqHoB5DNgnomSc?= =?us-ascii?Q?vQ0SSyJpXCN4TRxIAaZICslTNrjppYXkDFQXG8jli1o9ceyqcnjt5iSDGo2r?= =?us-ascii?Q?R7wT9I7D7BHj3j+0ze94kxtYiezHQualjKYxIwVjfk6qOrw0FQqGPNfgI79A?= =?us-ascii?Q?CPyUqdl33+PCdYiw/C1WstPiq9qmWn09xGOFlGVMI7JRHpJjTqWmb5v8z6wS?= =?us-ascii?Q?F4SI7gBcZOziTgRWlCSdyDmR6crjpNjfbw2S1cDr549yVhXUoh1HoLTMsbDF?= =?us-ascii?Q?jA=3D=3D?= X-MS-Exchange-CrossTenant-Network-Message-Id: 74c1dbd5-c08a-46a5-922c-08da7eb9cca3 X-MS-Exchange-CrossTenant-AuthSource: SJ1PR11MB6201.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Aug 2022 12:29:29.5230 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: fJJOcIzoU0V+iWkkVydfYbtHvNVjlY22SqfHqSspyEB/WjM51wVGdAIFl4nPRLEqN7rK2DouakrbkWmOtL0lew== X-MS-Exchange-Transport-CrossTenantHeadersStamped: MW3PR11MB4587 X-OriginatorOrg: intel.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Aug 15, 2022 at 09:43:00AM +0200, Peter Zijlstra wrote: > On Sat, Aug 13, 2022 at 10:38:23PM +0000, Ashok Raj wrote: > > > The proposal here is an even simpler option. The criteria for a microcode to > > be a viable late-load candidate is that no CPUID or OS visible MSR features > > are removed with respect to an earlier version of the microcode. > > > > Pseudocode for late-load is as follows: > > > > if header.min_required_id == 0 > > This is old format microcode, block late-load > > else if current_ucode_version < header.min_required_id > > Current version is too old, block late-load of this microcode. > > else > > OK to proceed with late-load. > > What about ucode that adds CPUID bits? Since the kernel will not re-init > it will not pick up on those. But userspace might. > > Should we at all time enable CPUID intercept to ensure user visible > CPUID doesn't change? The protection is to make sure any existing users won't experience a feature pulled under their feet. Using new features aren't dangerous though, and should be permitted.