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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: fbflLSIEPnj5CR+y29BAT8f+ZRb480juKB9Mp8WOLcOiJqs/q6OmmLUyXv+/GAmTpuL/zTHjJ6W1sft+jqv6ZytBphoNe+gwhFUKYPS3XMFcAwx3f3x/XF29/TE2YBl9GVmR7zUGAS4/2G9aUdBFRNIOiRJYJn5GU823z/mpJawvieMqNm7wx7Ue+7nobhnP/8W/KA7zDAUkjvqxC3jaCwo15EDPJg2VFVsbWzHGx3eDMQ0L0vyvuxfymiouXoNNTjp3dCKOxBB90aXXqGfM/0k710tqoRptzHahfHsQcRzhRdxL/D1c5fQEsK2envTNoHykxIS8SFkLUptFsezFeFi+gPjlbBTy+SkgI6VmqiabXkuNHhDomq+gj/ovRNJ5/M/Dl/Gfv/Vh3hFiE0Pqh78ujARs1IyuIOUPPuOX86C+NodOCdnMU/f925UpYObh X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 Feb 2026 09:22:10.3935 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: a9ea69fd-0ac9-4b48-86c3-08de656134c3 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: DS3PEPF0000C380.namprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: CY5PR12MB6597 Hi, Here is the newly published FRED virtualization spec by AMD for reference: https://docs.amd.com/v/u/en-US/69191-PUB Please feel free to share any feedback or questions. Regards, Shivansh On 29-01-2026 12:06, Shivansh Dhiman wrote: > This series adds SVM support for FRED (Flexible Return and Event Delivery) > virtualization in KVM. > > FRED introduces simplified privilege level transitions to replace IDT-based > event delivery and IRET returns, providing lower latency event handling while > ensuring complete supervisor context on delivery and full user context on > return. FRED defines event delivery for both ring 3->0 and ring 0->0 > transitions, and introduces ERETU for returning to ring 3 and ERETS for > remaining in ring 0. > > AMD hardware extends the VMCB to support FRED virtualization with dedicated > save area fields for FRED MSRs (RSP0-3, SSP1-3, STKLVLS, CONFIG) and control > fields for event injection data (EXITINTDATA, EVENTINJDATA). > > The implementation spans seven patches. The important changes are: > > 1) Extend VMCB structures with FRED fields mentioned above and disable MSR > interception for FRED-enabled guests to avoid unnecessary VM exits. > > 2) Support for nested exceptions where we populate event injection data > when delivering exceptions like page faults and debug traps. > > This series is based on top of FRED support for VMX patchset [1], > patches 1-17. The VMX patchset was rebased on top of v6.18.0 kernel. > > [1] https://lore.kernel.org/kvm/20251026201911.505204-1-xin@zytor.com > > Regards, > Shivansh > --- > Neeraj Upadhyay (5): > KVM: SVM: Initialize FRED VMCB fields > KVM: SVM: Disable interception of FRED MSRs for FRED supported guests > KVM: SVM: Save restore FRED_RSP0 for FRED supported guests > KVM: SVM: Populate FRED event data on event injection > KVM: SVM: Support FRED nested exception injection > > Shivansh Dhiman (2): > KVM: SVM: Dump FRED context in dump_vmcb() > KVM: SVM: Enable save/restore of FRED MSRs > > arch/x86/include/asm/svm.h | 35 ++++++++++- > arch/x86/kvm/svm/svm.c | 116 +++++++++++++++++++++++++++++++++++-- > 2 files changed, 144 insertions(+), 7 deletions(-) > > > base-commit: f76e83ecf6bce6d3793f828d92170b69e636f3c9