Re: [PATCH v2 5/6] mshv: clean up SynIC state on kexec for L1VH

[Anirudh Rayabharam]

On Fri, Apr 03, 2026 at 12:06:11PM -0700, Jork Loeser wrote:
> Register the mshv reboot notifier for all parent partitions, not just
> root. Previously the notifier was gated on hv_root_partition(), so on
> L1VH (where hv_root_partition() is false) SINT0, SINT5, and SIRBP were
> never cleaned up before kexec. The kexec'd kernel then inherited stale
> unmasked SINTs and an enabled SIRBP pointing to freed memory.
> 
> The L1VH SIRBP also needs special handling: unlike the root partition
> where the hypervisor provides the SIRBP page, L1VH must allocate its
> own page and program the GPA into the MSR. Add this allocation to
> mshv_synic_init() and the corresponding free to mshv_synic_cleanup().
> 
> Remove the unnecessary mshv_root_partition_init/exit wrappers and
> register the reboot notifier directly in mshv_parent_partition_init().
> Make mshv_reboot_nb static since it no longer needs external linkage.
> 
> Signed-off-by: Jork Loeser <jloeser@xxxxxxxxxxxxxxxxxxx>
> ---
>  drivers/hv/mshv_root_main.c | 21 ++++-----------------
>  1 file changed, 4 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/hv/mshv_root_main.c b/drivers/hv/mshv_root_main.c
> index e6509c980763..281f530b68a9 100644
> --- a/drivers/hv/mshv_root_main.c
> +++ b/drivers/hv/mshv_root_main.c
> @@ -2256,20 +2256,10 @@ static int mshv_reboot_notify(struct notifier_block *nb,
>  	return 0;
>  }
>  
> -struct notifier_block mshv_reboot_nb = {

I believe this code has moved to mshv_synic.c in hyperv-fixes. So, this
probably won't apply.

Thanks,
Anirudh.