On 04.02.26 08:19, Jan Kiszka wrote: > On 04.02.26 08:00, Wei Liu wrote: >> On Tue, Feb 03, 2026 at 05:01:30PM +0100, Jan Kiszka wrote: >>> From: Jan Kiszka <[email protected]> >>> >>> Resolves the following lockdep report when booting PREEMPT_RT on Hyper-V >>> with related guest support enabled: >> >> So all it takes to reproduce this is to enabled PREEMPT_RT? >> > > ...and enable CONFIG_PROVE_LOCKING so that you do not have to wait for > your system to actually run into the bug. Lockdep already triggers > during bootup. > >> Asking because ... >> >>> struct pt_regs *old_regs = set_irq_regs(regs); >>> @@ -158,8 +196,12 @@ DEFINE_IDTENTRY_SYSVEC(sysvec_hyperv_callback) >>> if (mshv_handler) >>> mshv_handler(); >> >> ... to err on the safe side we should probably do the same for >> mshv_handler as well. >> > > Valid question. We so far worked based on lockdep reports, and the > mshv_handler didn't trigger yet. Either it is not run in our setup, or > it is actually already fine. But I have a code review on my agenda > regarding potential remaining issues in mshv. > > Is there something needed to trigger the mshv_handler so that we can > test it? >
Ah, that depends on CONFIG_MSHV_ROOT. Is that related to the accelerator mode that Magnus presented in [1]? We briefly chatted about it and also my problems with the drivers after his talk on Saturday. Jan [1] https://fosdem.org/2026/schedule/event/BFQ8XA-introducing-mshv-accelerator-in-qemu/ -- Siemens AG, Foundational Technologies Linux Expert Center
