drivers: hv: mshv_vtl: disable TSC_ADJUST handling for CONFIG_HYPERV_VTL_MODE#120
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Pull request overview
Disables x86 TSC_ADJUST-based synchronization/adjustment logic when running in Hyper-V Virtual Trust Level (VTL) mode, avoiding conflicts with Hyper-V’s partition time restore behavior.
Changes:
- Clear
X86_FEATURE_TSC_ADJUSTduring VTL platform initialization so TSC_ADJUST-dependent logic (e.g., periodic sync checks) is skipped. - Add an explanatory comment describing why TSC_ADJUST is disabled in this mode.
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arch/x86/hyperv/hv_vtl.c
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| * Disable TSC_ADJUST so that the periodic TSC sync check timer | ||
| * (start_sync_check_timer) and related TSC adjustment logic are | ||
| * skipped. The TSC exposed via Hyper-V will be consistent across | ||
| * processors. | ||
| */ |
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Block comment formatting is inconsistent with the rest of this file/kernel style: the lines inside the /* / should be indented as "\t * ..." (with a space after the tab), but they currently start with "\t". Please align the leading " *" on lines inside the comment (and the closing */) with other comments in this file (e.g., the one starting near line 51).
Suggested change
| * Disable TSC_ADJUST so that the periodic TSC sync check timer | |
| * (start_sync_check_timer) and related TSC adjustment logic are | |
| * skipped. The TSC exposed via Hyper-V will be consistent across | |
| * processors. | |
| */ | |
| * Disable TSC_ADJUST so that the periodic TSC sync check timer | |
| * (start_sync_check_timer) and related TSC adjustment logic are | |
| * skipped. The TSC exposed via Hyper-V will be consistent across | |
| * processors. | |
| */ |
…uests running in Hyper-V. For backward compatibility, turn it off only when built with CONFIG_HYPERV_VTL_MODE. This addresses an issue where the TSC_ADJUST runtime checks would conflict with restore_partition_time handling that would adjust the global TSC value using a Hyper-V hypercall. Signed-off-by: Brian Perkins <brian.perkins@microsoft.com>
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drivers: hv: mshv_vtl: TSC_ADJUST handling should not be needed for guests running in Hyper-V.
For backward compatibility, turn it off only when built with CONFIG_HYPERV_VTL_MODE. This addresses an issue where the TSC_ADJUST runtime checks would conflict with restore_partition_time handling that would adjust the global TSC value using a Hyper-V hypercall.