Re: [PATCH] mshv: hide x86-specific functions on arm64

[Wei Liu]

On Tue, Dec 16, 2025 at 04:45:12PM -0800, Stanislav Kinsburskii wrote:
> On Tue, Dec 16, 2025 at 10:21:29PM +0000, Wei Liu wrote:
> > On Tue, Dec 16, 2025 at 10:36:12PM +0100, Arnd Bergmann wrote:
> > > From: Arnd Bergmann <arnd@xxxxxxxx>
> > > 
> > > The hv_sleep_notifiers_register() and hv_machine_power_off() functions are
> > > only called and declared on x86, but cause a warning on arm64:
> > > 
> > > drivers/hv/mshv_common.c:210:6: error: no previous prototype for 'hv_sleep_notifiers_register' [-Werror=missing-prototypes]
> > >   210 | void hv_sleep_notifiers_register(void)
> > >       |      ^~~~~~~~~~~~~~~~~~~~~~~~~~~
> > > drivers/hv/mshv_common.c:224:6: error: no previous prototype for 'hv_machine_power_off' [-Werror=missing-prototypes]
> > >   224 | void hv_machine_power_off(void)
> > >       |      ^~~~~~~~~~~~~~~~~~~~
> > > 
> > > Hide both inside of an #ifdef block.
> > > 
> > > Fixes: f0be2600ac55 ("mshv: Use reboot notifier to configure sleep state")
> > > Fixes: 615a6e7d83f9 ("mshv: Cleanly shutdown root partition with MSHV")
> > > Signed-off-by: Arnd Bergmann <arnd@xxxxxxxx>
> > 
> > Thanks Arnd. I have a queued up a patch which make available the
> > declarations to arm64. Let me think about whether to use your patch
> > instead.
> > 
> > Anyway, this issue will be fixed one way or the other once I send a PR
> > to Linus.
> > 
> 
> The whole idea of mshv_common.c is to have common code for all archs.
> It would be nice to keep this file as it is.

The path forward is either to move these functions to an x86-specific
file or to make arm64 work the same way. I'm not too sure about the
latter yet given the port is yet to be done. For the time being, I am
going to drop my own patch and take Arnd's patch. We can figure out
which of the two approaches to take later.

Wei