Re: [PATCH 2/2] x86/virt/tdx: Use PFN directly for unmapping guest private memory

[Xiaoyao Li]

On 3/19/2026 2:45 PM, Yan Zhao wrote:
> On Thu, Mar 19, 2026 at 11:20:48AM +0800, Xiaoyao Li wrote:
> > On 3/19/2026 8:58 AM, Yan Zhao wrote:
> > > From: Sean Christopherson <seanjc@xxxxxxxxxx>
[...]
> > > diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
> > > index a9dd75190c67..2f9d07ad1a9a 100644
> > > --- a/arch/x86/virt/vmx/tdx/tdx.c
> > > +++ b/arch/x86/virt/vmx/tdx/tdx.c
> > > @@ -730,9 +730,9 @@ static void tdx_quirk_reset_paddr(unsigned long base, unsigned long size)
> > >    	mb();
> > >    }
> > > -void tdx_quirk_reset_page(struct page *page)
> > > +void tdx_quirk_reset_page(kvm_pfn_t pfn)
> >
> > So why keep the function tdx_quirk_reset_page() but expect passing in the
> > kvm_pfn_t? It looks werid that the name indicates to reset a page but what
> > gets passed in is a pfn.
> I thought about introducing tdx_quirk_reset_pfn(). But considering
> tdx_quirk_reset_pfn() has to be an exported API, I'm reluctant to do that.
>
> Given that even with tdx_quirk_reset_pfn(), it still expects TDX convertible
> RAM, I think having tdx_quirk_reset_page() to take pfn is still acceptable.
>
> We just don't want KVM to do pfn --> struct page --> pfn conversions.

Only tdx_sept_remove_private_spte() is doing such conversions. While 
tdx_reclaim_page() and tdx_reclaim_td_control_pages() already have the 
struct page natively.

So why not considering option 2?

  2. keep tdx_quirk_reset_page() as-is for the cases of
     tdx_reclaim_page() and tdx_reclaim_td_control_pages() that have the
     struct page. But only change tdx_sept_remove_private_spte() to use
     tdx_quirk_reset_paddr() directly.

It will need export tdx_quirk_reset_paddr() for KVM. I think it will be OK?