On Wed, May 14, 2025 at 04:10:10AM +0800, Edgecombe, Rick P wrote: > On Thu, 2025-04-24 at 11:06 +0800, Yan Zhao wrote: > > Allow TDX's .private_max_mapping_level hook to return 2MB after the TD is > > RUNNABLE, enabling KVM to map TDX private pages at the 2MB level. Remove > > TODOs and adjust KVM_BUG_ON()s accordingly. > > > > Note: Instead of placing this patch at the tail of the series, it's > > positioned here to show the code changes for basic mapping of private huge > > pages (i.e., transitioning from non-present to present). > > > > However, since this patch also allows KVM to trigger the merging of small > > entries into a huge leaf entry or the splitting of a huge leaf entry into > > small entries, errors are expected if any of these operations are triggered > > due to the current lack of splitting/merging support. > > > > 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> > > --- > > arch/x86/kvm/vmx/tdx.c | 16 +++++++--------- > > 1 file changed, 7 insertions(+), 9 deletions(-) > > > > diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c > > index e23dce59fc72..6b3a8f3e6c9c 100644 > > --- a/arch/x86/kvm/vmx/tdx.c > > +++ b/arch/x86/kvm/vmx/tdx.c > > @@ -1561,10 +1561,6 @@ int tdx_sept_set_private_spte(struct kvm *kvm, gfn_t gfn, > > struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm); > > struct page *page = pfn_to_page(pfn); > > > > - /* TODO: handle large pages. */ > > - if (KVM_BUG_ON(level != PG_LEVEL_4K, kvm)) > > - return -EINVAL; > > - > > /* > > * Because guest_memfd doesn't support page migration with > > * a_ops->migrate_folio (yet), no callback is triggered for KVM on page > > @@ -1612,8 +1608,7 @@ static int tdx_sept_drop_private_spte(struct kvm *kvm, gfn_t gfn, > > gpa_t gpa = gfn_to_gpa(gfn); > > u64 err, entry, level_state; > > > > - /* TODO: handle large pages. */ > > - if (KVM_BUG_ON(level != PG_LEVEL_4K, kvm)) > > + if (KVM_BUG_ON(kvm_tdx->state != TD_STATE_RUNNABLE && level != PG_LEVEL_4K, kvm)) > > It's not clear why some of these warnings are here and some are in patch 4. Patch 4 contains only changes for !TD_STATE_RUNNABLE stage. This patch is to allow huge page after TD_STATE_RUNNABLE. So, relaxed the condition to trigger BUG_ON in this patch, i.e., before this patch, always bug on level > 4K; after this patch, only bug on level > 4K before TD is runnable. > > return -EINVAL; > > > > if (KVM_BUG_ON(!is_hkid_assigned(kvm_tdx), kvm)) > > @@ -1714,8 +1709,8 @@ static int tdx_sept_zap_private_spte(struct kvm *kvm, gfn_t gfn, > > gpa_t gpa = gfn_to_gpa(gfn) & KVM_HPAGE_MASK(level); > > u64 err, entry, level_state; > > > > - /* For now large page isn't supported yet. */ > > - WARN_ON_ONCE(level != PG_LEVEL_4K); > > + /* Before TD runnable, large page is not supported */ > > + WARN_ON_ONCE(kvm_tdx->state != TD_STATE_RUNNABLE && level != PG_LEVEL_4K); > > > > err = tdh_mem_range_block(&kvm_tdx->td, gpa, tdx_level, &entry, &level_state); > > > > @@ -1817,6 +1812,9 @@ int tdx_sept_remove_private_spte(struct kvm *kvm, gfn_t gfn, > > struct page *page = pfn_to_page(pfn); > > int ret; > > > > + WARN_ON_ONCE(folio_page_idx(page_folio(page), page) + KVM_PAGES_PER_HPAGE(level) > > > + folio_nr_pages(page_folio(page))); > > + > > /* > > * HKID is released after all private pages have been removed, and set > > * before any might be populated. Warn if zapping is attempted when > > @@ -3265,7 +3263,7 @@ int tdx_gmem_private_max_mapping_level(struct kvm *kvm, kvm_pfn_t pfn) > > if (unlikely(to_kvm_tdx(kvm)->state != TD_STATE_RUNNABLE)) > > return PG_LEVEL_4K; > > > > - return PG_LEVEL_4K; > > + return PG_LEVEL_2M; > > Maybe combine this with patch 4, or split them into sensible categories. Sorry to bring confusion. As explained in the patch msg, this patch to return PG_LEVEL_2M actually needs to be placed at the end of the series, after patches for page splitting/merging. As inital RFC, it's placed earlier to show changes to enable basic TDX huge page (without splitting/merging). > > } > > > > static int tdx_online_cpu(unsigned int cpu) >
