Re: [PATCH v5 04/17] x86/acrn: Introduce hypercall interfaces

[Segher Boessenkool]

On Mon, Nov 02, 2020 at 03:56:57PM +0100, Borislav Petkov wrote:
> On Mon, Oct 19, 2020 at 02:17:50PM +0800, shuo.a.liu@xxxxxxxxx wrote:
> > +static inline long acrn_hypercall0(unsigned long hcall_id)
> > +{
> > +	long result;
> > +
> > +	asm volatile("movl %1, %%r8d\n\t"
> > +		     "vmcall\n\t"
> > +		     : "=a" (result)
> > +		     : "ir" (hcall_id)
> 			^^
> 
> Not "irm"? Or simply "g" in that case?

I think that will work for x86_64.  But it won't matter much, most of
the time you give an immediate number.  It is a tiny bit neater of
course (if anyone still remembers what "g" is, you cannot use it much
these days).


Segher