On Tue, Sep 02, 2025 at 10:56:25AM +0800, Binbin Wu wrote: > > > On 8/7/2025 5:42 PM, Yan Zhao wrote: > > After removing or reclaiming a guest private page or a control page from a > > TD, zero the physical page using movdir64b(), enabling the kernel to reuse > > the pages. > > > > Introduce the function tdx_clear_folio() to zero out physical memory using > > movdir64b(), starting from the page at "start_idx" within a "folio" and > > spanning "npages" contiguous PFNs. > > > > Convert tdx_clear_page() to be a helper function to facilitate the > > zeroing of 4KB pages. > > I think this sentence is outdated? No? tdx_clear_page() is still invoked to clear tdr_page. > > > > Signed-off-by: Xiaoyao Li <xiaoyao.li@xxxxxxxxx> > > Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx> > > Signed-off-by: Yan Zhao <yan.y.zhao@xxxxxxxxx> > > --- > > RFC v2: > > - Add tdx_clear_folio(). > > - Drop inner loop _tdx_clear_page() and move __mb() outside of the loop. > > (Rick) > > - Use C99-style definition of variables inside a for loop. > > - Note: [1] also changes tdx_clear_page(). RFC v2 is not based on [1] now. > > > > [1] https://lore.kernel.org/all/20250724130354.79392-2-adrian.hunter@xxxxxxxxx > > > > RFC v1: > > - split out, let tdx_clear_page() accept level. > > --- > > arch/x86/kvm/vmx/tdx.c | 22 ++++++++++++++++------ > > 1 file changed, 16 insertions(+), 6 deletions(-) > > > > diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c > > index 8eaf8431c5f1..4fabefb27135 100644 > > --- a/arch/x86/kvm/vmx/tdx.c > > +++ b/arch/x86/kvm/vmx/tdx.c > > @@ -277,18 +277,21 @@ static inline void tdx_disassociate_vp(struct kvm_vcpu *vcpu) > > vcpu->cpu = -1; > > } > > -static void tdx_clear_page(struct page *page) > > +static void tdx_clear_folio(struct folio *folio, unsigned long start_idx, > > + unsigned long npages) > > { > > const void *zero_page = (const void *) page_to_virt(ZERO_PAGE(0)); > > - void *dest = page_to_virt(page); > > - unsigned long i; > > /* > > * The page could have been poisoned. MOVDIR64B also clears > > * the poison bit so the kernel can safely use the page again. > > */ > > - for (i = 0; i < PAGE_SIZE; i += 64) > > - movdir64b(dest + i, zero_page); > > + for (unsigned long j = 0; j < npages; j++) { > > + void *dest = page_to_virt(folio_page(folio, start_idx + j)); > > + > > + for (unsigned long i = 0; i < PAGE_SIZE; i += 64) > > + movdir64b(dest + i, zero_page); > > + } > > /* > > * MOVDIR64B store uses WC buffer. Prevent following memory reads > > * from seeing potentially poisoned cache. > > @@ -296,6 +299,13 @@ static void tdx_clear_page(struct page *page) > > __mb(); > > } > > +static inline void tdx_clear_page(struct page *page) > No need to tag a local static function with "inline". Ok.
