Re: [PATCH v2 2/5] x86: hv: hv_init.c: Add functions to allocate/deallocate page for Hyper-V

[Maya Nakamura <m.maya.nakamura@gmail.com>]

On Wed, Jun 12, 2019 at 12:36:47PM +0200, Vitaly Kuznetsov wrote:
> Maya Nakamura <m.maya.nakamura@gmail.com> writes:
> 
> > Introduce two new functions, hv_alloc_hyperv_page() and
> > hv_free_hyperv_page(), to allocate/deallocate memory with the size and
> > alignment that Hyper-V expects as a page. Although currently they are
> > not used, they are ready to be used to allocate/deallocate memory on x86
> > when their ARM64 counterparts are implemented, keeping symmetry between
> > architectures with potentially different guest page sizes.
> >
> > Signed-off-by: Maya Nakamura <m.maya.nakamura@gmail.com>
> > ---
> >  arch/x86/hyperv/hv_init.c | 14 ++++++++++++++
> >  1 file changed, 14 insertions(+)
> >
> > diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
> > index e4ba467a9fc6..84baf0e9a2d4 100644
> > --- a/arch/x86/hyperv/hv_init.c
> > +++ b/arch/x86/hyperv/hv_init.c
> > @@ -98,6 +98,20 @@ EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg);
> >  u32 hv_max_vp_index;
> >  EXPORT_SYMBOL_GPL(hv_max_vp_index);
> >  
> > +void *hv_alloc_hyperv_page(void)
> > +{
> > +	BUILD_BUG_ON(!(PAGE_SIZE == HV_HYP_PAGE_SIZE));
> 
> (nit)
> 
> PAGE_SIZE != HV_HYP_PAGE_SIZE ?
> 
> > +
> > +	return (void *)__get_free_page(GFP_KERNEL);
> > +}
> > +EXPORT_SYMBOL_GPL(hv_alloc_hyperv_page);
> > +
> > +void hv_free_hyperv_page(unsigned long addr)
> > +{
> > +	free_page(addr);
> > +}
> > +EXPORT_SYMBOL_GPL(hv_free_hyperv_page);
> > +
> >  static int hv_cpu_init(unsigned int cpu)
> >  {
> >  	u64 msr_vp_index;
> 
> Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> 
> -- 
> Vitaly

Agreed. I will resubmit the patch set with this correction.