RE: [PATCH v2 4/6] x86/tdx: Expand __tdx_hypercall() to handle more arguments

[Dexuan Cui]

> From: Sathyanarayanan Kuppuswamy
> Sent: Wednesday, December 7, 2022 2:14 PM
>  [...]
> > --- a/arch/x86/coco/tdx/tdcall.S
> > +++ b/arch/x86/coco/tdx/tdcall.S
> > @@ -13,6 +13,12 @@
> >  /*
> >   * Bitmasks of exposed registers (with VMM).
> >   */
> > +#define TDX_RDX		BIT(2)
> > +#define TDX_RBX		BIT(3)
> > +#define TDX_RSI		BIT(6)
> > +#define TDX_RDI		BIT(7)
> > +#define TDX_R8		BIT(8)
> > +#define TDX_R9		BIT(9)
> >  #define TDX_R10		BIT(10)
> >  #define TDX_R11		BIT(11)
> >  #define TDX_R12		BIT(12)
> > @@ -27,9 +33,9 @@
> >   * details can be found in TDX GHCI specification, section
> >   * titled "TDCALL [TDG.VP.VMCALL] leaf".
> >   */
> > -#define TDVMCALL_EXPOSE_REGS_MASK	( TDX_R10 | TDX_R11 | \
> > -					  TDX_R12 | TDX_R13 | \
> > -					  TDX_R14 | TDX_R15 )
> > +#define TDVMCALL_EXPOSE_REGS_MASK	\
> > +	( TDX_RDX | TDX_RBX | TDX_RSI | TDX_RDI | TDX_R8  | TDX_R9  | \
> > +	  TDX_R10 | TDX_R11 | TDX_R12 | TDX_R13 | TDX_R14 | TDX_R15 )
> >
> 
> You seem to have expanded the list to include all VMCALL supported
> registers except RBP. Why not include it as well? That way, it will be
> a complete support.

Hi Kirill, can you please share your thoughts?