Re: [PATCH v3 5/6] x86/virt/tdx: Re-initialize the extensions on runtime TDX module update

[Xu Yilun]

On Fri, Oct 09, 2026 at 07:20:05PM +0000, Edgecombe, Rick P wrote:
> On Tue, 2026-10-06 at 01:41 +0800, Xu Yilun wrote:
> > Runtime TDX module update introduces a mechanism to update the module
> > firmware while preserving and restoring TDX operations. The extensions
> > functionalities should also be re-initialized as part of the restoration
> > process.
> > 
> > The TDX architecture supports an update flow which allows updated
> > extensions to consume more memory than their original boot-time
> > requirement. So the arch defines the extensions re-initialization flow
> > the same as boot-up initialization: the host queries TDX module how much
> > additional memory needed, allocates it, adds it to the module via
> > TDH.EXT.MEM.ADD, then re-initializes the extensions via TDH.EXT.INIT.
> > 
> > Linux runs the updates in stop_machine() context, which prevents memory
> > allocation. So for Linux, a compatible update must not install updated
> > extensions that require additional memory.
> > 
> > Given that the memory for the extensions must not increase, the
> > re-initialization skips the memory adding steps. It is simplified as:
> > 
> >   - Check if the extensions are supported via TDX_FEATURES0_EXT. If not,
> >     skip the extensions re-initialization.
> > 
> >   - Re-initialize the extensions via TDH.EXT.INIT. The SEAMCALL leaf
> >     will fail if the updated extensions require more memory, which
> >     indicates the update image is not compatible.
> > 
> > Signed-off-by: Xu Yilun <yilun.xu@xxxxxxxxxxxxxxx>
> 
> Reviewed-by: Rick Edgecombe <rick.p.edgecome@xxxxxxxxx>
                                             ^
AI said you are edgecombe not edgecome. :)

I fixed them inplace.