[RFC PATCH v2 03/23] x86/tdx: Enhance tdh_phymem_page_wbinvd_hkid() to invalidate huge pages

[Yan Zhao <yan.y.zhao@intel.com>]

After removing a TD's private page, the TDX module does not write back and
invalidate cache lines associated with the page and its keyID (i.e., the
TD's guest keyID). The SEAMCALL wrapper tdh_phymem_page_wbinvd_hkid()
enables the caller to provide the TD's guest keyID and physical memory
address to invoke the SEAMCALL TDH_PHYMEM_PAGE_WBINVD to perform cache line
invalidation.

Enhance the SEAMCALL wrapper tdh_phymem_page_wbinvd_hkid() to support cache
line invalidation for huge pages by introducing the parameters "folio",
"start_idx", and "npages". These parameters specify the physical memory
starting from the page at "start_idx" within a "folio" and spanning
"npages" contiguous PFNs. Return TDX_OPERAND_INVALID if the specified
memory is not entirely contained within a single folio.

Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
Suggested-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
---
RFC v2:
- Enhance tdh_phymem_page_wbinvd_hkid() to invalidate multiple pages
  directly, rather than looping within KVM, following Dave's suggestion:
  "Don't wrap the wrappers." (Rick).

RFC v1:
- Split patch
- Aded a helper tdx_wbinvd_page() in TDX, which accepts param
  "struct page *".
---
 arch/x86/include/asm/tdx.h  |  4 ++--
 arch/x86/kvm/vmx/tdx.c      |  6 ++++--
 arch/x86/virt/vmx/tdx/tdx.c | 17 ++++++++++++++---
 3 files changed, 20 insertions(+), 7 deletions(-)

diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
index d2cf48e273d5..a125bb20a28a 100644
--- a/arch/x86/include/asm/tdx.h
+++ b/arch/x86/include/asm/tdx.h
@@ -194,8 +194,8 @@ u64 tdh_mem_track(struct tdx_td *tdr);
 u64 tdh_mem_page_remove(struct tdx_td *td, u64 gpa, u64 level, u64 *ext_err1, u64 *ext_err2);
 u64 tdh_phymem_cache_wb(bool resume);
 u64 tdh_phymem_page_wbinvd_tdr(struct tdx_td *td);
-u64 tdh_phymem_page_wbinvd_hkid(u64 hkid, struct page *page);
-
+u64 tdh_phymem_page_wbinvd_hkid(u64 hkid, struct folio *folio,
+				unsigned long start_idx, unsigned long npages);
 void tdx_meminfo(struct seq_file *m);
 #else
 static inline void tdx_init(void) { }
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 0a2b183899d8..8eaf8431c5f1 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -1694,6 +1694,7 @@ static int tdx_sept_drop_private_spte(struct kvm *kvm, gfn_t gfn,
 {
 	int tdx_level = pg_level_to_tdx_sept_level(level);
 	struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
+	struct folio *folio = page_folio(page);
 	gpa_t gpa = gfn_to_gpa(gfn);
 	u64 err, entry, level_state;
 
@@ -1728,8 +1729,9 @@ static int tdx_sept_drop_private_spte(struct kvm *kvm, gfn_t gfn,
 		return -EIO;
 	}
 
-	err = tdh_phymem_page_wbinvd_hkid((u16)kvm_tdx->hkid, page);
-
+	err = tdh_phymem_page_wbinvd_hkid((u16)kvm_tdx->hkid, folio,
+					  folio_page_idx(folio, page),
+					  KVM_PAGES_PER_HPAGE(level));
 	if (KVM_BUG_ON(err, kvm)) {
 		pr_tdx_error(TDH_PHYMEM_PAGE_WBINVD, err);
 		return -EIO;
diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
index d941f083f741..64219c659844 100644
--- a/arch/x86/virt/vmx/tdx/tdx.c
+++ b/arch/x86/virt/vmx/tdx/tdx.c
@@ -2030,13 +2030,24 @@ u64 tdh_phymem_page_wbinvd_tdr(struct tdx_td *td)
 }
 EXPORT_SYMBOL_GPL(tdh_phymem_page_wbinvd_tdr);
 
-u64 tdh_phymem_page_wbinvd_hkid(u64 hkid, struct page *page)
+u64 tdh_phymem_page_wbinvd_hkid(u64 hkid, struct folio *folio,
+				unsigned long start_idx, unsigned long npages)
 {
+	struct page *start = folio_page(folio, start_idx);
 	struct tdx_module_args args = {};
+	u64 err;
+
+	if (start_idx + npages > folio_nr_pages(folio))
+		return TDX_OPERAND_INVALID;
 
-	args.rcx = mk_keyed_paddr(hkid, page);
+	for (unsigned long i = 0; i < npages; i++) {
+		args.rcx = mk_keyed_paddr(hkid, nth_page(start, i));
 
-	return seamcall(TDH_PHYMEM_PAGE_WBINVD, &args);
+		err = seamcall(TDH_PHYMEM_PAGE_WBINVD, &args);
+		if (err)
+			break;
+	}
+	return err;
 }
 EXPORT_SYMBOL_GPL(tdh_phymem_page_wbinvd_hkid);
 
-- 
2.43.2