On Wed, Nov 03, 2021 at 03:10:16PM -0500, Brijesh Singh wrote:

Looking at the secondary CPU bring up path it seems that we will not be
getting #VC until the early_setup_idt() is called. I am thinking to add
function to register the GHCB from the early_setup_idt()

early_setup_idt()
{
  ...
  if (IS_ENABLED(CONFIG_MEM_ENCRYPT))
    sev_snp_register_ghcb()
  ...
}

The above will cover the APs

That will cover the APs during early boot as that is being called from
asm.

and for BSP case I can call the same function just after the final IDT
is loaded

Why after and not before?

cpu_init_exception_handling()
{
   ...
   ...
   /* Finally load the IDT */
   load_current_idt();

   if (IS_ENABLED(CONFIG_MEM_ENCRYPT))
     sev_snp_register_ghcb()

}

That is also called on the APs - not only the BSP. trap_init() calls it
from start_kernel() which is the BSP and cpu_init_secondary() calls it
too, which is ofc the APs.

I guess that should be ok since you're calling the same function from
both but WTH do I know...

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette