Re: [PATCH] x86/acrn: Improve ACRN hypercalls

[Dave Hansen]

On 8/4/22 11:03, Uros Bizjak wrote:
> As explained in section 6.47.5.2, "Specifying Registers for Local Variables"
> of the GCC info documentation, the correct way to specify register for
> input operands when calling Extended 'asm' is to define a local register
> variable and associate it with a specified register:
> 
> 	register unsigned long r8 asm ("r8") = hcall_id;

IIRC, that's what the ACRN folks proposed first.  But, it's more fragile
because you can't, for instance, put a printk() in that function between
the variable definition and assebly.