Re: [Xen-devel] [PATCH 9/9] x86: move declaration of arch_set_info_hvm_guest and provide stub

[Wei Liu <wei.liu2@xxxxxxxxxx>]

On Tue, Aug 07, 2018 at 05:46:06AM -0600, Jan Beulich wrote:
> >>> On 07.08.18 at 12:00, <wei.liu2@xxxxxxxxxx> wrote:
> > --- a/xen/include/asm-x86/hvm/domain.h
> > +++ b/xen/include/asm-x86/hvm/domain.h
> > @@ -34,6 +34,7 @@
> >  #include <public/hvm/save.h>
> >  #include <public/hvm/hvm_op.h>
> >  #include <public/hvm/dm_op.h>
> > +#include <public/hvm/hvm_vcpu.h>
> 
> Why? struct vcpu_hvm_context only needs a forward declaration, just
> like was the case originally. Full structure/union definitions are needed
> only if you de-reference the type, instantiate it, or apply sizeof() and
> alike to it.

Alright, I'm not too fussed about this.

> 
> In fact I suspect we could reduce header dependencies quite a bit if
> we followed that model more widely.
> 
> > @@ -204,6 +205,22 @@ struct hvm_domain {
> >  
> >  #define hap_enabled(d)  ((d)->arch.hvm_domain.hap_enabled)
> >  
> > +#if CONFIG_HVM
> > +
> > +int arch_set_info_hvm_guest(struct vcpu *v, const struct vcpu_hvm_context 
> > *ctx);
> > +
> > +#else
> > +
> > +#include <xen/errno.h>
> > +
> > +static inline
> > +int arch_set_info_hvm_guest(struct vcpu *v, const struct vcpu_hvm_context 
> > *ctx)
> > +{
> > +    return -EINVAL;
> > +}
> > +
> > +#endif
> 
> All uses sit either in HVM-specific code or inside is_hvm_...()
> conditionals: Why do we need the inline stub? If the declaration
> was visible independent of CONFIG_HVM, code would compile
> fine, and references to the function would be removed by the
> compiler, so linking would also succeed despite there not being
> any definition of the function.

Last time I tried DCE wasn't working so well. Let me try again and if
DCE works it would save me a lot of effort to provide stubs.

Wei.

> 
> Jan
> 
> 

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel