drivers: hv: mshv_vtl: Implement restore partition time IOCTL #116
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Pull request overview
This PR implements support for the Hyper-V restore partition time hypercall, which allows Windows guests to restore from hibernate by resetting the TSC to provided values. The implementation adds a new IOCTL that stops all CPUs, makes the hypercall to update the TSC, and updates clock state to maintain forward progress.
Changes:
- Adds
MSHV_RESTORE_PARTITION_TIMEIOCTL and associated data structures in UAPI headers - Implements the IOCTL handler that uses
stop_machineto safely update partition time - Exports
hv_save_sched_clock_stateandhv_restore_sched_clock_statefunctions for clock state management
Reviewed changes
Copilot reviewed 6 out of 6 changed files in this pull request and generated 8 comments.
Show a summary per file
| File | Description |
|---|---|
| include/uapi/linux/mshv.h | Adds mshv_partition_time struct and MSHV_RESTORE_PARTITION_TIME IOCTL definition |
| include/uapi/hyperv/hvgdk_mini.h | Adds HVCALL_RESTORE_PARTITION_TIME hypercall code and x86-64 specific hv_input_restore_partition_time struct |
| include/asm-generic/hyperv-tlfs.h | Adds HVCALL_RESTORE_PARTITION_TIME hypercall code and hv_input_restore_partition_time struct |
| drivers/hv/mshv_vtl_main.c | Implements the main IOCTL handler and stop_machine callback for restoring partition time |
| arch/x86/kernel/cpu/mshyperv.c | Changes visibility of clock state save/restore functions from static to exported |
| arch/x86/include/asm/mshyperv.h | Adds function declarations for exported clock state functions |
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Pull request overview
Copilot reviewed 6 out of 6 changed files in this pull request and generated 3 comments.
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Pull request overview
Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.
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|
The patch is OK to me for the UH kernel repo. |
hargar19
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hargar19
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This PR was reviewed by Dexuan. I am approving and merging it since the reviewers do not have the required permissions to merge.
3 participants
Hyper-V supports a restore partition time hypercall that resets the TSC to provided values. This call is typically made by a Windows guest when restoring from hibernate. The paravisor needs to support this call in order to allow the guest to be able to successfully perform the operation. Since the reference time is being changed, clocks need to be updated to maintain consistent foward progress.