Re: [PATCH V5 1/4] x86/paravirt: Move halt paravirt calls under CONFIG_PARAVIRT

["Jürgen Groß" <jgross@suse.com>]

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On 28.02.25 22:47, Konrad Rzeszutek Wilk wrote:
> On Thu, Feb 20, 2025 at 09:16:25PM +0000, Vishal Annapurve wrote:
>> From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
>>
>> CONFIG_PARAVIRT_XXL is mainly defined/used by XEN PV guests. For
>> other VM guest types, features supported under CONFIG_PARAVIRT
>> are self sufficient. CONFIG_PARAVIRT mainly provides support for
>> TLB flush operations and time related operations.
>>
>> For TDX guest as well, paravirt calls under CONFIG_PARVIRT meets
>> most of its requirement except the need of HLT and SAFE_HLT
>> paravirt calls, which is currently defined under
>> CONFIG_PARAVIRT_XXL.
>>
>> Since enabling CONFIG_PARAVIRT_XXL is too bloated for TDX guest
>> like platforms, move HLT and SAFE_HLT paravirt calls under
>> CONFIG_PARAVIRT.
> 
> Could you use the bloat-o-meter to give an idea of the savings?
> 
> Also .. aren't most distros building with Xen support so they will
> always have the full paravirt support?

Adding PARAVIRT_XXL users should be avoided if possible.

Main reason is that the work to make PVH dom0 fully functional compared
to PV dom0 will make it possible to deprecate PV mode in the long run.


Juergen

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