[PATCH 1/1] Drivers: hv: Remove !CPU_BIG_ENDIAN qualifier for arm64

[PATCH 1/1] Drivers: hv: Remove !CPU_BIG_ENDIAN qualifier for arm64

[Michael Kelley]

Support for CPU_BIG_ENDIAN configurations on arm64 was deprecated
in commit 1cf89b6bf660 ("arm64: Kconfig: Make CPU_BIG_ENDIAN depend
on BROKEN"). The support is now in the process of being completely
removed.

The Kconfig for Hyper-V guests on arm64 currently has a
!CPU_BIG_ENDIAN qualifier since Hyper-V only supports little
endian. But with Linux on arm64 restricted to little endian,
that qualifier is no longer necessary. Remove it.

Signed-off-by: Michael Kelley <mhklinux@outlook.com>
---
 drivers/hv/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
index aa11bcefddf2..db8464fcd119 100644
--- a/drivers/hv/Kconfig
+++ b/drivers/hv/Kconfig
@@ -5,7 +5,7 @@ menu "Microsoft Hyper-V guest support"
 config HYPERV
 	bool "Microsoft Hyper-V core hypervisor support"
 	depends on (X86 && X86_LOCAL_APIC && HYPERVISOR_GUEST) \
-		|| (ARM64 && !CPU_BIG_ENDIAN)
+		|| ARM64
 	select PARAVIRT
 	select X86_HV_CALLBACK_VECTOR if X86
 	select OF_EARLY_FLATTREE if OF
-- 
2.25.1

Re: [PATCH 1/1] Drivers: hv: Remove !CPU_BIG_ENDIAN qualifier for arm64

[Hamza Mahfooz]

On Thu, Aug 27, 2026 at 08:44:48PM -0700, Michael Kelley wrote:
> Support for CPU_BIG_ENDIAN configurations on arm64 was deprecated
> in commit 1cf89b6bf660 ("arm64: Kconfig: Make CPU_BIG_ENDIAN depend
> on BROKEN"). The support is now in the process of being completely
> removed.
> 
> The Kconfig for Hyper-V guests on arm64 currently has a
> !CPU_BIG_ENDIAN qualifier since Hyper-V only supports little
> endian. But with Linux on arm64 restricted to little endian,
> that qualifier is no longer necessary. Remove it.
> 
> Signed-off-by: Michael Kelley <mhklinux@outlook.com>
> ---
>  drivers/hv/Kconfig | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
> index aa11bcefddf2..db8464fcd119 100644
> --- a/drivers/hv/Kconfig
> +++ b/drivers/hv/Kconfig
> @@ -5,7 +5,7 @@ menu "Microsoft Hyper-V guest support"
>  config HYPERV
>  	bool "Microsoft Hyper-V core hypervisor support"
>  	depends on (X86 && X86_LOCAL_APIC && HYPERVISOR_GUEST) \
> -		|| (ARM64 && !CPU_BIG_ENDIAN)
> +		|| ARM64

Personally, I think we should leave it be until aarch64_be support is
completely stripped out of the kernel.

Hamza

>  	select PARAVIRT
>  	select X86_HV_CALLBACK_VECTOR if X86
>  	select OF_EARLY_FLATTREE if OF
> -- 
> 2.25.1
> 

RE: [PATCH 1/1] Drivers: hv: Remove !CPU_BIG_ENDIAN qualifier for arm64

[Michael Kelley]

From: Hamza Mahfooz <hamzamahfooz@linux.microsoft.com> Sent: Friday, August 28, 2026 6:32 AM
> 
> On Thu, Aug 27, 2026 at 08:44:48PM -0700, Michael Kelley wrote:
> > Support for CPU_BIG_ENDIAN configurations on arm64 was deprecated
> > in commit 1cf89b6bf660 ("arm64: Kconfig: Make CPU_BIG_ENDIAN depend
> > on BROKEN"). The support is now in the process of being completely
> > removed.
> >
> > The Kconfig for Hyper-V guests on arm64 currently has a
> > !CPU_BIG_ENDIAN qualifier since Hyper-V only supports little
> > endian. But with Linux on arm64 restricted to little endian,
> > that qualifier is no longer necessary. Remove it.
> >
> > Signed-off-by: Michael Kelley <mhklinux@outlook.com>
> > ---
> >  drivers/hv/Kconfig | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
> > index aa11bcefddf2..db8464fcd119 100644
> > --- a/drivers/hv/Kconfig
> > +++ b/drivers/hv/Kconfig
> > @@ -5,7 +5,7 @@ menu "Microsoft Hyper-V guest support"
> >  config HYPERV
> >  	bool "Microsoft Hyper-V core hypervisor support"
> >  	depends on (X86 && X86_LOCAL_APIC && HYPERVISOR_GUEST) \
> > -		|| (ARM64 && !CPU_BIG_ENDIAN)
> > +		|| ARM64
> 
> Personally, I think we should leave it be until aarch64_be support is
> completely stripped out of the kernel.
> 

The removal is in progress -- see [1].  As noted in that overview,
some kernel areas have already removed the big-endian support,
so the kernel is already irrevocably down the path. But there's
certainly no urgency to do it here as it has no operational effect.
It's just a cleanup item I noted and if the preference is to wait on
picking it up, that's fine.

Michael

[1] https://lore.kernel.org/lkml/20260811140132.22778-1-will@kernel.org/

RE: [PATCH 1/1] Drivers: hv: Remove !CPU_BIG_ENDIAN qualifier for arm64

[Michael Kelley]

From: Michael Kelley <mhklinux@outlook.com> Sent: Friday, August 28, 2026 8:13 AM
> From: Hamza Mahfooz <hamzamahfooz@linux.microsoft.com> Sent: Friday, August 28, 2026 6:32 AM
> >
> > On Thu, Aug 27, 2026 at 08:44:48PM -0700, Michael Kelley wrote:
> > > Support for CPU_BIG_ENDIAN configurations on arm64 was deprecated
> > > in commit 1cf89b6bf660 ("arm64: Kconfig: Make CPU_BIG_ENDIAN depend
> > > on BROKEN"). The support is now in the process of being completely
> > > removed.
> > >
> > > The Kconfig for Hyper-V guests on arm64 currently has a
> > > !CPU_BIG_ENDIAN qualifier since Hyper-V only supports little
> > > endian. But with Linux on arm64 restricted to little endian,
> > > that qualifier is no longer necessary. Remove it.
> > >
> > > Signed-off-by: Michael Kelley <mhklinux@outlook.com>
> > > ---
> > >  drivers/hv/Kconfig | 2 +-
> > >  1 file changed, 1 insertion(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/hv/Kconfig b/drivers/hv/Kconfig
> > > index aa11bcefddf2..db8464fcd119 100644
> > > --- a/drivers/hv/Kconfig
> > > +++ b/drivers/hv/Kconfig
> > > @@ -5,7 +5,7 @@ menu "Microsoft Hyper-V guest support"
> > >  config HYPERV
> > >  	bool "Microsoft Hyper-V core hypervisor support"
> > >  	depends on (X86 && X86_LOCAL_APIC && HYPERVISOR_GUEST) \
> > > -		|| (ARM64 && !CPU_BIG_ENDIAN)
> > > +		|| ARM64
> >
> > Personally, I think we should leave it be until aarch64_be support is
> > completely stripped out of the kernel.
> >
> 
> The removal is in progress -- see [1].  As noted in that overview,
> some kernel areas have already removed the big-endian support,
> so the kernel is already irrevocably down the path. But there's
> certainly no urgency to do it here as it has no operational effect.
> It's just a cleanup item I noted and if the preference is to wait on
> picking it up, that's fine.
> 
> Michael
> 
> [1] https://lore.kernel.org/lkml/20260811140132.22778-1-will@kernel.org/
>

This can be dropped as a separate patch. Will Deacon is making the
change in v2 of his series to remove and cleanup arm64 big-endian
support throughout the kernel [2]. He did not have the Hyper-V
change in v1 of his series.

Michael

[2] https://lore.kernel.org/lkml/20260907163726.17104-15-will@kernel.org/