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X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 11 Dec 2025 16:58:38.4766 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: cae362a6-6ffa-436b-fcc2-08de38d687d2 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: SJ1PEPF000026C5.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CH3PR12MB9121 On Thu Dec 11, 2025 at 4:38 PM CET, Andrew Cooper wrote: > On 11/12/2025 10:31 am, Alejandro Vallejo wrote: >> Seeing how both you and Andrew seem onboard with dropping cross-vendor s= upport > > I found another cross-vendor dropping which you'll want to look into. > > struct svm_vcpu contains three guest_sysenter_* MSRs. > > In AMD CPUs, these MSRs only have 32 bits of storage, with the upper > halfs write-discard.=C2=A0 They are switched via VMLOAD/VMSAVE. > > However, in the cross-vendor case, the upper halves are needed for 64bit > kernels setting up SYSENTER support.=C2=A0 Therefore, they're uncondition= ally > intercepted so we can avoid losing the upper half. > > By dropping cross-vendor support, we can get rid of these fields, allow > the guest unconditional access, and simply the MSR intercept logic a litt= le. > > ~Andrew Sounds straightforward, I'll add it to the pile. Cheers, Alejandro