Re: [PATCH] x86/paravirt: Fix build PARAVIRT_XXL=y without XEN_PV

[Dave Hansen <dave.hansen@intel.com>]

On 11/17/21 10:48 AM, Borislav Petkov wrote:
> On Wed, Nov 17, 2021 at 10:46:30AM -0800, Sathyanarayanan Kuppuswamy wrote:
>> TDX has a requirement to use HLT paravirt calls (which is currently
>> listed under PARAVIRT_XXL). Once we submit a patch to move it
>> under CONFIG_PARAVIRT, we will drop this dependency.
> You already have this patch in some set:
> 
> https://lore.kernel.org/r/20211009053747.1694419-2-sathyanarayanan.kuppuswamy@linux.intel.com
> 
> So what's this churn for?

The churn is my doing.  It occurred to me that we could toss the
aforementioned patch out of the set by using:

	depends on PARAVIRT_XXL

instead of:

	depends on PARAVIRT

Especially since PARAVIRT_XXL seems pretty common in distro kernels.
But, I didn't realize quite how reviled PARAVIRT_XXL was.

So, first of all, _this_ patch is a proper cleanup.  We should merge it
or something like it either way.

As for TDX, my preference (obviously) is to keep the "depends on
PARAVIRT_XXL", reviled as it may be.  It's the literal truth at this
point: TDX guest support depends on PARAVIRT_XXL functionality.  There
is no shortage of ways to remove that dependency (expand PARAVIRT or
custom idle), which makes me very confident that we are not painting
ourselves into a corner here.