Re: [PATCH V3 03/13] x86/HV: Add new hvcall guest address host visibility support

[Tianyu Lan <ltykernel@xxxxxxxxx>]

On 8/10/2021 6:12 AM, Dave Hansen wrote:
> On 8/9/21 10:56 AM, Tianyu Lan wrote:
> > From: Tianyu Lan <Tianyu.Lan@xxxxxxxxxxxxx>
> >
> > Add new hvcall guest address host visibility support to mark
> > memory visible to host. Call it inside set_memory_decrypted
> > /encrypted(). Add HYPERVISOR feature check in the
> > hv_is_isolation_supported() to optimize in non-virtualization
> > environment.
>  From an x86/mm perspective:
>
> Acked-by: Dave Hansen <dave.hansen@xxxxxxxxx>
Thanks for your ACK.


> A tiny nit:
>
> > diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
> > index 0bb4d9ca7a55..b3683083208a 100644
> > --- a/arch/x86/hyperv/hv_init.c
> > +++ b/arch/x86/hyperv/hv_init.c
> > @@ -607,6 +607,12 @@ EXPORT_SYMBOL_GPL(hv_get_isolation_type);
> >   
> >   bool hv_is_isolation_supported(void)
> >   {
> > +       if (!cpu_feature_enabled(X86_FEATURE_HYPERVISOR))
> > +               return 0;
> > +
> > +       if (!hypervisor_is_type(X86_HYPER_MS_HYPERV))
> > +               return 0;
> > +
> >         return hv_get_isolation_type() != HV_ISOLATION_TYPE_NONE;
> >   }
> This might be worthwhile to move to a header.  That ensures that
> hv_is_isolation_supported() use can avoid even a function call.  But, I
> see this is used in modules and its use here is also in a slow path, so
> it's not a big deal
I will move it to header in the following version.


Thanks.