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X-MS-Exchange-AntiSpam-MessageData: =?utf-8?B?d2s3NExEbmgrbnpEYjV1OVFiak9ZS091L1hGOU5Nc0dPbzJNeTd3U1ZLdzR5?= =?utf-8?B?aFJZZyt3Qk9kd3JLbVJTdU1Wa3ViUzIzUE1aYTJWaXh4b09qSU1QT0IwU0cx?= =?utf-8?B?K0VJTmxzSU1IRzdSb1lPR3JoNVFtanFSVlZTZGNXd2NRMWpySzNFMkdxaEJi?= =?utf-8?B?ZU8vOWNJZ0RwY3R4S1FudG9GdW1kVW5NVEUzRVpHaFo5NTFLNURWMU01akhQ?= =?utf-8?B?Y3YzeUIyUXhTUXFIa1NZSFYrcEY0K1daN2hvMmM4c3lQNzkzTUFUVzZFMWxP?= =?utf-8?B?eks0LzIzRlM3SFpOOXBTTEZvVXc2Njc3TGxoVlpsV09LWmZ2KzNkR2xUd0Nr?= =?utf-8?B?Y3pUNHJ5dHFFM1Mwc0dLV0FaU292UUU2T2R3bklYMWg3R2dzU0NYTTMxUjRG?= =?utf-8?B?dHI0bkFvNVRJYVRPQWJHMS9KanZZcEplemh1NzVoMGd4UngyZTk3c0lPcld5?= =?utf-8?B?M1IzMHNiUGlXcFRLbks1eXZpM3IvaHdpbEJ3c0ZhM1BsaTFiWG9xMXpXQjQ0?= =?utf-8?B?WFFycjVtYUlWa1liTGRZQjhvRmF3NmhkOXZkdTdJdml3T0hES3RBR1BMay9B?= =?utf-8?B?SUpRYXEzelJaL1pLUC82OUU1bVdWTkFnbEIwYUdNV3pMY3NwQ29rMDlnOWN1?= =?utf-8?B?aG5zRU5JMXVGYnhsaFp1R0hKYkJlVGtqU2U0RWxod1NXa293NEhUV2RiN2FH?= =?utf-8?B?VW1QQUV2Z1kyWXVZSnJmcmR4OFFWeW5xTEtZYmZQM01iVkFKR21naHorMmFZ?= =?utf-8?B?aENFTDR0SHRNSSswNEVMd0RCTzJLVTlkRHdNMFBjZzRWTzY4Ny9ENU9SeFZ0?= =?utf-8?B?cFUvZUk2cE1ZVlFLbTlCa1QyNjhZSnJ0NkJxU1M3L2JQSTdTaFU4eWRvZnYx?= =?utf-8?B?aWxoNVVSMWFMN2RIYUhsbmF5WUZLQ0Ivd3VTcGlOS1lJWk9OY3JKK2lvSElM?= =?utf-8?B?WE9VNzEyY3E5aGpSZXpQUGJ5YXFTNnhsMkNiUXNsaC95ZHA4eU1MMHZTVlRD?= =?utf-8?B?RHFPbmtZWDZUSnZuczFUZUlUNWE3K2tlYkdpb0ZUbmQ4a3BUVHZGTEN1Z3BX?= =?utf-8?B?K2tEU05HL3FESUc1SzdqQkQ4aGFkbElTMkZvdS9xbTByWVQvK3U1NHRjY2JJ?= =?utf-8?B?VVNqaEVKV3Ridm1QbGIvSkFKWU5WZG94N3YyZUJvaGVQcmZ0TG9nSVdTZTdT?= =?utf-8?B?a25lTkpRMUxtMzBxOS9lVmo3ai9lUnliSnB1c1d1Nk1PQ1ExOHF5akV0UHZS?= =?utf-8?B?ekF2cGVCcVFMQm10OVhJekVnOC9QakgvSUNTRndvN05mQ3ROTTVZaXgwanJI?= =?utf-8?B?VXdUalB3aWd4dEV4N3Z5UnJwVWZRL2VmTEN3azkvazJjSVkxUkZqTDgyM3N0?= =?utf-8?B?d2tSMWdFVnFzY3JKSmVKYTFTa1pIMDRBUkdpakIrc09rYnBrMjNRNXZvcnRp?= =?utf-8?B?YUdKQ3NyRnpRemVtYmVadm05VWZHdmJ1YkRxT2xHODk0VVFhZFpXL2dPaTlP?= =?utf-8?B?dkZmRHdkVWRQaCt5dXZVdjdmUUk5M29OR25FTzNNQmhvTERmV2RJL0gvOVoy?= =?utf-8?B?bkpER3pGaVFKWWtOcjNpZkNORlMwdSsrMzlnYWd0Tm5QVE9Pd3Rjc2puQVhP?= =?utf-8?B?aUl3eE1PMm1jL0VqRXlrR3p5UEJPOE9WUzRjWGlPMUFWemhNT0pjQUVsb2Ru?= =?utf-8?B?VkpNSzBCMEhqNGVQdjFYMkRJd1pwbjZ4VmJZN3NXMzZZdFBIY1MzS0xKZ0pE?= =?utf-8?Q?gijo8N6M/m+/uM5cvXRdx1ux+fMk07G3BgHwRjf?= X-MS-Exchange-CrossTenant-Network-Message-Id: 38889546-ee66-415b-522e-08d900e2e057 X-MS-Exchange-CrossTenant-AuthSource: BYAPR03MB3623.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 16 Apr 2021 14:21:07.7452 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 335836de-42ef-43a2-b145-348c2ee9ca5b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: 2trk0WAwN04/hJSRrlr16nEQsl9svw9IUdfRFKyzR9NjBldzjjBgtSfanUX++A9DlgrcLuM5ZPuq6kDoNH8zQEKPiTzyeUY651NQa5U5uS4= X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR03MB4245 X-OriginatorOrg: citrix.com On 16/04/2021 14:20, Jan Beulich wrote: > For Intel CPUs we record L3 cache size, hence we should also do so for > AMD and alike. > > While making these additions, also make sure (throughout the function) > that we don't needlessly overwrite prior values when the new value to be > stored is zero. > > Signed-off-by: Jan Beulich > --- > I have to admit though that I'm not convinced the sole real use of the > field (in flush_area_local()) is a good one - flushing an entire L3's > worth of lines via CLFLUSH may not be more efficient than using WBINVD. > But I didn't measure it (yet). WBINVD always needs a broadcast IPI to work correctly. CLFLUSH and friends let you do this from a single CPU, using cache coherency to DTRT with the line, wherever it is. Looking at that logic in flush_area_local(), I don't see how it can be correct.=C2=A0 The WBINVD path is a decomposition inside the IPI, but in th= e higher level helpers, I don't see how the "area too big, convert to WBINVD" can be safe. All users of FLUSH_CACHE are flush_all(), except two PCI Passthrough-restricted cases. MMUEXT_FLUSH_CACHE_GLOBAL looks to be safe, while vmx_do_resume() has very dubious reasoning, and is dead code I think, because I'm not aware of a VT-x capable CPU without WBINVD-exiting= . ~Andrew