Re: [PATCH v4 2/2] Drivers: hv: Run VMBus kexec cleanup from syscore shutdown

[sashiko-bot]

> ARM64 Hyper-V guests do not run the VMBus kexec cleanup before
> secondary CPUs are stopped. Consequently, the old VMBus connection
> and SynIC state remain active when the kexec kernel starts.
> 
> Run the VMBus kexec handler from the existing VMBus syscore shutdown
> callback. syscore_shutdown() runs after device shutdown and before
> machine shutdown, while all CPUs needed by the SynIC CPU hotplug
> teardown are still available. Guard the callback with
> kexec_is_in_progress() so normal restart, halt, and poweroff paths are
> unchanged.
> 
> Use the same path on x86 and remove the architecture-specific handler
> pointer and the weak setup/remove interfaces. VMBus teardown now
> precedes hv_stimer_global_cleanup() on x86.
> 
> The new x86 ordering relies on commit be0cfab740e5 ("clocksource:
> hyper-v: Remove support for stimer interrupts in message mode"), which
> removed the synthetic timer's dependency on VMBus message delivery.
> Older kernels that retain message-mode stimer interrupts must preserve
> the existing x86 ordering and therefore require an ARM64-specific
> backport.
> 
> Document the VMBus cleanup path and its position in shutdown ordering.
> 
> Fixes: 9bbb888824e3 ("arm64: hyperv: Initialize hypervisor on boot")
> Link: https://lore.kernel.org/all/20260814093133.3191250-1-shradhagupta@xxxxxxxxxxxxxxxxxxx/
> Suggested-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> Suggested-by: Michael Kelley <mhklinux@xxxxxxxxxxx>
> Signed-off-by: Shradha Gupta <shradhagupta@xxxxxxxxxxxxxxxxxxx>

Sashiko has reviewed this patch and found no issues. It looks great!

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