linux-kernel - Re: [RFC PATCH v2 03/23] x86/tdx: Enhance tdh_phymem_page_wbinvd

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Message-ID: <aRWe4VGgJdocYbHw@yzhao56-desk.sh.intel.com>
Date: Thu, 13 Nov 2025 17:03:29 +0800
From: Yan Zhao <yan.y.zhao@...el.com>
To: "Huang, Kai" <kai.huang@...el.com>
CC: "Du, Fan" <fan.du@...el.com>, "Li, Xiaoyao" <xiaoyao.li@...el.com>,
	"kvm@...r.kernel.org" <kvm@...r.kernel.org>, "Hansen, Dave"
	<dave.hansen@...el.com>, "david@...hat.com" <david@...hat.com>,
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	<tabba@...gle.com>, "vbabka@...e.cz" <vbabka@...e.cz>, "kas@...nel.org"
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	<vannapurve@...gle.com>, "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>,
	"Miao, Jun" <jun.miao@...el.com>, "x86@...nel.org" <x86@...nel.org>,
	"pgonda@...gle.com" <pgonda@...gle.com>
Subject: Re: [RFC PATCH v2 03/23] x86/tdx: Enhance
 tdh_phymem_page_wbinvd_hkid() to invalidate huge pages

On Thu, Nov 13, 2025 at 03:37:29PM +0800, Huang, Kai wrote:
> 
> Thanks for all the explanation.
> 
> [...]
> 
> 
> > In [6], the new folio_page() implementation is
> > 
> > static inline struct page *folio_page(struct folio *folio, unsigned long n)
> > {
> > 	return &folio->page + n;
> > }
> > 
> > So, invoking folio_page() should be equal to page++ in our case.
> > 
> > [6] https://lore.kernel.org/kvm/20250901150359.867252-13-david@redhat.com
> 
> Sure.  But it seems you will need to wait all patches that you mentioned to
> be merged to safely use 'page++' for pages in a folio?
Correct.

> And if you do:
> 
> 	for (i = 0; i < npages; i++)
> 	{
> 		struct page *p = folio_page(folio, start_idx + i);
> 		struct tdx_module_args args = {};
> 
> 		args.rcx = mk_keyed_paddr(hkid, p);
> 		...
> 	}
> 
> It should work w/o any dependency?
> 
> Anyway, I don't have any strong opinion, as long as it works.  You may
> choose what you want. :-)
I don't have a strong opinion either. However, based on previous reviews, it
seems people prefer while (npages--) over introducing an additional variable.
I guess I'll choose a version depending on whether these patches are merged when
I post the next version. :)