Re: [PATCH 02/15] x86/virt/tdx: Add extra memory to TDX Module for Extensions

[Xu Yilun]

On Tue, Jun 09, 2026 at 04:38:31PM +0300, Adrian Hunter wrote:
> On 22/05/2026 06:41, Xu Yilun wrote:
> > +static int tdx_ext_mem_add(struct page *root, unsigned int nr_pages)
> > +{
> > +	struct tdx_module_args args = {
> > +		.rcx = to_hpa_list_info(root, nr_pages),
> > +	};
> > +	u64 r;
> > +
> > +	tdx_clflush_hpa_list(root, nr_pages);
> > +
> > +	do {
> > +		/*
> > +		 * TDH_EXT_MEM_ADD is designed to use output parameter RCX to
> > +		 * override/update input parameter RCX, so the caller doesn't
> > +		 * have to do manual parameter update on retry call.
> > +		 */
> > +		r = seamcall_ret(TDH_EXT_MEM_ADD, &args);
> > +	} while (r == TDX_INTERRUPTED_RESUMABLE);
> 
> Kishon already mentioned checking only the status

Could you elaborate on why we should mask? I assume the mask is only
needed when the lower bits ([31:0]) are defined to contain extra
information. TDX_INTERRUPTED_RESUMABLE is not the case so we could make
the code change simpler.

And if some non-zero bits appears there, it is a Module bug that we
should not skip.

> 
> > +
> > +	if (r != TDX_SUCCESS)
> 
> Similarly could this also be TDX_EXT_MEMORY_POOL_FULL?

I don't think we should pass the case. The Module provides the number of
required pages via metadata, host follows and feeds pages but the Module
said "Sorry, I'm already full". This is inconsistent behavior that we
should call out.

> 
> > +		return -EFAULT;
> > +
> > +	return 0;
> > +}
>