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X-MS-Exchange-AntiSpam-MessageData: =?utf-8?B?SHF1NHNHelBxUTFsb05lNE44SXMyQnBSNUpoc3FOTHF4OWVxankza0NXMlRl?= =?utf-8?B?Z2J2eDQreVByK2tqT0xMWkFUV2pyaHA4bTF4RnREN2t5Y25Pb3R0ZVIxQUNq?= =?utf-8?B?RnpJTGsxcTBMaHBROU91WGhPYy8vTkZpY2hjMS9TVEZPdStpZTdDM3F5ZTlz?= =?utf-8?B?SDBJbU9zQzZRNXlYK0llMFpIcHNGMW9pbW9PS25lUWtabEw3dW9TenB0bWNV?= =?utf-8?B?RjJGMnFscEhJVWRGdFZ1Rnc5ZERQM0o4RFhEeEhJQml6YXNpNzVMVEdhWTh5?= =?utf-8?B?djBablU2d0VwdGxGUGRvclJtQmw5U0Exbi9xQlhXeHNteVpEOGlDeC9kbktP?= =?utf-8?B?ZzJnRU9JczdXbDlWRGhBTzdPUUw4N2VoKzMrMFpKOUJURTF4Sm40OE1DMFNC?= =?utf-8?B?bEZUN3owRVZaY2c5UUw4NGJWODA5Ulo3RUZWaFFnRG9ycUR2cC9GckVRQkdD?= =?utf-8?B?UEVDTWxJZFBwbEs0a2xsa3h5ZUI2UVRnTWJOOXNXYjAwRGdZZCswMjdIbU1l?= =?utf-8?B?SzFxd2NMbVJvdWQvSnpHbTdETkZ6ak9xVFYvMFhvWSs4aFk3cWdTV2hrb1BQ?= =?utf-8?B?N1krbmROckkvM0ZnSHoyS0t6M040VWRNMW1LZ3hjMUFiME9NdFJuL1Z4SGtX?= =?utf-8?B?S1hkTER4SHNTamE4b2JDNmRsb3dPd1NNS2lwbFgyVnNMdGRuZVZuOGs5eFpW?= =?utf-8?B?K2RkYzdaZ3dwSVBKZnRleEdHSVU4MXhtWVVaOCthbEhKcW91anZCcWswTEZh?= =?utf-8?B?aEZFaGtBZ1U2bWFXMFR3d2JhM3A5U215alExUnJReDY5dEZZUlVOcWttdVpm?= =?utf-8?B?VVlHa2FiTUwvRTRmOExXNUFSM1Q1ejlTRjVSWUhVc2dFU2FBWFc5ZXkzV0I2?= =?utf-8?B?SzJnWjZIT2xvMkY5N0ZlOEJQZWxjQnlPdlluVVFCcG9aZk0yREUyWlU2N3o5?= =?utf-8?B?cVJMTi9RY0RpUWN3czNUeThkNjR2bVV0cmpaZTNOMFNBRU1CK0I3QnRVbTFR?= =?utf-8?B?dXhVay9qNm1iLzNTSFU3VlNwd09BdTV1ZEtOaDRYamNBa0ZlU0g0UjBiQW5U?= =?utf-8?B?bk9aSTVRNFhaeUt1SzNJSmF2aThUZ3pEai9Pbm9RTUxHZHlyRVJPQktpQUgz?= =?utf-8?B?MUFFRi9rM1d6OGl1ODdEcDkvOTFJOS9lS2lhSzJTL0grNlJ0Wm1wZUJYM0Fa?= =?utf-8?B?TjhxL1ZoNC8wTnUyc1U4OEJkNWgyeHRTVnBRaWhUWkdRajBUOGd3L3JxQUky?= =?utf-8?B?Q3dtWlcrV1RzQ3NvVEdmTktTMmd0ZTBwUEJyTU9KSEZ2cEVkMUN2WDZ5djV2?= =?utf-8?B?b0hmTUYwSEVmR3N3VjE2cmxsR3FSWFY4M2V2Sm9GbC9hR3FBNnpuQ0phTDV0?= =?utf-8?B?bDZMMXgyVmlKMHZBdERoYXVkbExLTkVEVk1oTDh0WW1ZUVRsUmZNcElRL0w1?= =?utf-8?B?ZC9lUlUxdGQxalo2OVlJcFZYK1NaNWRxUkNERDQvZXdVMm5jb0pFaVlOemVL?= =?utf-8?B?WTUwTXB6cVJsc2t6U1JXSkszUlBKUjQzek51NGc0UC9tMzZPRnRtd1RKU0F0?= =?utf-8?B?RDRFcjZHV0MzdDBiVnVZSDh5L2daZk1OWU5wYnVyaTBGT1FlSlNHbURzQzg5?= =?utf-8?B?a2o0L0JsRmNNR1pmZHpqZlhmNlk4bitJazBYa2plWTRKc2RpVWJld0JoSjly?= =?utf-8?B?ZjNPcktlc0xrYVBrbVRRVHNpanJ1aW1yaGEyMmw4N2RKWGZLd2ljVkQ3VDVC?= =?utf-8?Q?9ETcFUsZXXf8zdgyvB+we53RSet0uGKBA5gDEnG?= X-MS-Exchange-CrossTenant-Network-Message-Id: 350d46bb-da99-4f61-1cc9-08d8dfb06805 X-MS-Exchange-CrossTenant-AuthSource: DS7PR03MB5608.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 05 Mar 2021 08:26:42.6503 (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: UrwJ8g+hCjcAARTbq7ghuJ5f7xWGQJTMHVj5jtR2slrRPJ+oGjYvm1w2wBNNL1M2RsjFx5tBAKXtaPg3a/TCAA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS7PR03MB5607 X-OriginatorOrg: citrix.com On Thu, Mar 04, 2021 at 11:28:16PM +0000, Andrew Cooper wrote: > On 04/03/2021 23:09, Boris Ostrovsky wrote: > > On 3/4/21 9:47 AM, Roger Pau Monne wrote: > >> Introduce an option to allow selecting a less strict behaviour for > >> rdmsr accesses targeting a MSR not explicitly handled by Xen. Since > >> commit 84e848fd7a162f669 accesses to MSRs not explicitly handled by > >> Xen result in the injection of a #GP to the guest. This is a behavior > >> change since previously a #GP was only injected if accessing the MSR > >> on the real hardware will also trigger a #GP. > >> > >> This commit attempts to offer a fallback option similar to the > >> previous behavior. Note however that the value of the underlying MSR > >> is never leaked to the guest, as the newly introduced option only > >> changes whether a #GP is injected or not. > >> > >> Long term the plan is to properly handle all the MSRs, so the option > >> introduced here should be considered a temporary resort for OSes that > >> don't work properly with the new MSR policy. Any OS that requires this > >> option to be enabled should be reported to > >> xen-devel@lists.xenproject.org. > >> > >> Signed-off-by: Roger Pau Monné > >> --- > >> Changes since v1: > >> - Only apply the option to HVM guests. > >> - Only apply the special handling to MSR reads. > >> - Sanitize the newly introduced flags field. > >> - Print a warning message when the option is used. > >> --- > >> Cc: Boris Ostrovsky > >> --- > >> Boris, could you please test with Solaris to see if this fixes the > >> issue? > > > > Yes, still works. (It worked especially well after I noticed new option name ;-)) > > I'm afraid I want to break and rework how this bugfix happens.  Solaris > is still broken on all older branches and this isn't a suitable fix to > backport. Right, I think that's the reactive part of the fixing that we spoke with Jan, but I think we would still need something similar to rdmsr_relaxed. There's at least one other MSR which Jan identified that we also want to handle MSR_K7_HWCR. Thanks, Roger.