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Message-ID: <aXHXtcdwFMESOxM4@yzhao56-desk.sh.intel.com>
Date: Thu, 22 Jan 2026 15:54:29 +0800
From: Yan Zhao <yan.y.zhao@...el.com>
To: Sean Christopherson <seanjc@...gle.com>
CC: Thomas Gleixner <tglx@...nel.org>, Ingo Molnar <mingo@...hat.com>,
Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>,
<x86@...nel.org>, Kiryl Shutsemau <kas@...nel.org>, Paolo Bonzini
<pbonzini@...hat.com>, <linux-kernel@...r.kernel.org>,
<linux-coco@...ts.linux.dev>, <kvm@...r.kernel.org>, Kai Huang
<kai.huang@...el.com>, Rick Edgecombe <rick.p.edgecombe@...el.com>, "Vishal
Annapurve" <vannapurve@...gle.com>, Ackerley Tng <ackerleytng@...gle.com>
Subject: Re: [PATCH] x86/tdx: Use pg_level in TDX APIs, not the TDX-Module's
0-based level
Reviewed-by: Yan Zhao <yan.y.zhao@...el.com>
Tested-by: Yan Zhao <yan.y.zhao@...el.com>
On Tue, Jan 20, 2026 at 12:39:37PM -0800, Sean Christopherson wrote:
> Rework the TDX APIs to take the kernel's 1-based pg_level enum, not the
> TDX-Module's 0-based level. The APIs are _kernel_ APIs, not TDX-Module
> APIs, and the kernel (and KVM) uses "enum pg_level" literally everywhere.
>
> Using "enum pg_level" eliminates ambiguity when looking at the APIs (it's
> NOT clear that "int level" refers to the TDX-Module's level), and will
> allow for using existing helpers like page_level_size() when support for
> hugepages is added to the S-EPT APIs.
>
> No functional change intended.
>
> Cc: Kai Huang <kai.huang@...el.com>
> Cc: Dave Hansen <dave.hansen@...ux.intel.com>
> Cc: Rick Edgecombe <rick.p.edgecombe@...el.com>
> Cc: Yan Zhao <yan.y.zhao@...el.com>
> Cc: Vishal Annapurve <vannapurve@...gle.com>
> Cc: Ackerley Tng <ackerleytng@...gle.com>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
> ---
>
> Compile-tested only. Came across this when looking at the S-EPT hugepage
> series, specifically this code:
>
> unsigned long npages = 1 << (level * PTE_SHIFT);
>
> which I was _sure_ was broken, until I realized @level wasn't what I thought
> it was.
>
> arch/x86/include/asm/tdx.h | 14 ++++----------
> arch/x86/kvm/vmx/tdx.c | 11 ++++-------
> arch/x86/virt/vmx/tdx/tdx.c | 26 ++++++++++++++++++--------
> 3 files changed, 26 insertions(+), 25 deletions(-)
>
> diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h
> index 6b338d7f01b7..bc0d03e70fd6 100644
> --- a/arch/x86/include/asm/tdx.h
> +++ b/arch/x86/include/asm/tdx.h
> @@ -189,19 +189,13 @@ static inline u64 mk_keyed_paddr(u16 hkid, struct page *page)
> return ret;
> }
>
> -static inline int pg_level_to_tdx_sept_level(enum pg_level level)
> -{
> - WARN_ON_ONCE(level == PG_LEVEL_NONE);
> - return level - 1;
> -}
> -
> u64 tdh_vp_enter(struct tdx_vp *vp, struct tdx_module_args *args);
> u64 tdh_mng_addcx(struct tdx_td *td, struct page *tdcs_page);
> u64 tdh_mem_page_add(struct tdx_td *td, u64 gpa, struct page *page, struct page *source, u64 *ext_err1, u64 *ext_err2);
> -u64 tdh_mem_sept_add(struct tdx_td *td, u64 gpa, int level, struct page *page, u64 *ext_err1, u64 *ext_err2);
> +u64 tdh_mem_sept_add(struct tdx_td *td, u64 gpa, enum pg_level level, struct page *page, u64 *ext_err1, u64 *ext_err2);
> u64 tdh_vp_addcx(struct tdx_vp *vp, struct page *tdcx_page);
> -u64 tdh_mem_page_aug(struct tdx_td *td, u64 gpa, int level, struct page *page, u64 *ext_err1, u64 *ext_err2);
> -u64 tdh_mem_range_block(struct tdx_td *td, u64 gpa, int level, u64 *ext_err1, u64 *ext_err2);
> +u64 tdh_mem_page_aug(struct tdx_td *td, u64 gpa, enum pg_level level, struct page *page, u64 *ext_err1, u64 *ext_err2);
> +u64 tdh_mem_range_block(struct tdx_td *td, u64 gpa, enum pg_level level, u64 *ext_err1, u64 *ext_err2);
> u64 tdh_mng_key_config(struct tdx_td *td);
> u64 tdh_mng_create(struct tdx_td *td, u16 hkid);
> u64 tdh_vp_create(struct tdx_td *td, struct tdx_vp *vp);
> @@ -217,7 +211,7 @@ u64 tdh_vp_rd(struct tdx_vp *vp, u64 field, u64 *data);
> u64 tdh_vp_wr(struct tdx_vp *vp, u64 field, u64 data, u64 mask);
> u64 tdh_phymem_page_reclaim(struct page *page, u64 *tdx_pt, u64 *tdx_owner, u64 *tdx_size);
> 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_mem_page_remove(struct tdx_td *td, u64 gpa, enum pg_level 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);
> diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
> index 2d7a4d52ccfb..c47f4de2f19c 100644
> --- a/arch/x86/kvm/vmx/tdx.c
> +++ b/arch/x86/kvm/vmx/tdx.c
> @@ -1648,14 +1648,13 @@ static int tdx_mem_page_add(struct kvm *kvm, gfn_t gfn, enum pg_level level,
> static int tdx_mem_page_aug(struct kvm *kvm, gfn_t gfn,
> enum pg_level level, kvm_pfn_t pfn)
> {
> - int tdx_level = pg_level_to_tdx_sept_level(level);
> struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
> struct page *page = pfn_to_page(pfn);
> gpa_t gpa = gfn_to_gpa(gfn);
> u64 entry, level_state;
> u64 err;
>
> - err = tdh_mem_page_aug(&kvm_tdx->td, gpa, tdx_level, page, &entry, &level_state);
> + err = tdh_mem_page_aug(&kvm_tdx->td, gpa, level, page, &entry, &level_state);
> if (unlikely(tdx_operand_busy(err)))
> return -EBUSY;
>
> @@ -1699,12 +1698,11 @@ static int tdx_sept_set_private_spte(struct kvm *kvm, gfn_t gfn,
> static int tdx_sept_link_private_spt(struct kvm *kvm, gfn_t gfn,
> enum pg_level level, void *private_spt)
> {
> - int tdx_level = pg_level_to_tdx_sept_level(level);
> gpa_t gpa = gfn_to_gpa(gfn);
> struct page *page = virt_to_page(private_spt);
> u64 err, entry, level_state;
>
> - err = tdh_mem_sept_add(&to_kvm_tdx(kvm)->td, gpa, tdx_level, page, &entry,
> + err = tdh_mem_sept_add(&to_kvm_tdx(kvm)->td, gpa, level, page, &entry,
> &level_state);
> if (unlikely(tdx_operand_busy(err)))
> return -EBUSY;
> @@ -1788,7 +1786,6 @@ static void tdx_sept_remove_private_spte(struct kvm *kvm, gfn_t gfn,
> enum pg_level level, u64 mirror_spte)
> {
> struct page *page = pfn_to_page(spte_to_pfn(mirror_spte));
> - int tdx_level = pg_level_to_tdx_sept_level(level);
> struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
> gpa_t gpa = gfn_to_gpa(gfn);
> u64 err, entry, level_state;
> @@ -1808,7 +1805,7 @@ static void tdx_sept_remove_private_spte(struct kvm *kvm, gfn_t gfn,
> return;
>
> err = tdh_do_no_vcpus(tdh_mem_range_block, kvm, &kvm_tdx->td, gpa,
> - tdx_level, &entry, &level_state);
> + level, &entry, &level_state);
> if (TDX_BUG_ON_2(err, TDH_MEM_RANGE_BLOCK, entry, level_state, kvm))
> return;
>
> @@ -1824,7 +1821,7 @@ static void tdx_sept_remove_private_spte(struct kvm *kvm, gfn_t gfn,
> * Race with TDH.VP.ENTER due to (0-step mitigation) and Guest TDCALLs.
> */
> err = tdh_do_no_vcpus(tdh_mem_page_remove, kvm, &kvm_tdx->td, gpa,
> - tdx_level, &entry, &level_state);
> + level, &entry, &level_state);
> if (TDX_BUG_ON_2(err, TDH_MEM_PAGE_REMOVE, entry, level_state, kvm))
> return;
>
> diff --git a/arch/x86/virt/vmx/tdx/tdx.c b/arch/x86/virt/vmx/tdx/tdx.c
> index 5ce4ebe99774..22c0f832cb37 100644
> --- a/arch/x86/virt/vmx/tdx/tdx.c
> +++ b/arch/x86/virt/vmx/tdx/tdx.c
> @@ -1516,6 +1516,12 @@ static void tdx_clflush_page(struct page *page)
> clflush_cache_range(page_to_virt(page), PAGE_SIZE);
> }
>
> +static int pg_level_to_tdx_sept_level(enum pg_level level)
> +{
> + WARN_ON_ONCE(level == PG_LEVEL_NONE);
> + return level - 1;
> +}
> +
> noinstr u64 tdh_vp_enter(struct tdx_vp *td, struct tdx_module_args *args)
> {
> args->rcx = td->tdvpr_pa;
> @@ -1556,10 +1562,11 @@ u64 tdh_mem_page_add(struct tdx_td *td, u64 gpa, struct page *page, struct page
> }
> EXPORT_SYMBOL_FOR_KVM(tdh_mem_page_add);
>
> -u64 tdh_mem_sept_add(struct tdx_td *td, u64 gpa, int level, struct page *page, u64 *ext_err1, u64 *ext_err2)
> +u64 tdh_mem_sept_add(struct tdx_td *td, u64 gpa, enum pg_level level,
> + struct page *page, u64 *ext_err1, u64 *ext_err2)
> {
> struct tdx_module_args args = {
> - .rcx = gpa | level,
> + .rcx = gpa | pg_level_to_tdx_sept_level(level),
> .rdx = tdx_tdr_pa(td),
> .r8 = page_to_phys(page),
> };
> @@ -1587,10 +1594,11 @@ u64 tdh_vp_addcx(struct tdx_vp *vp, struct page *tdcx_page)
> }
> EXPORT_SYMBOL_FOR_KVM(tdh_vp_addcx);
>
> -u64 tdh_mem_page_aug(struct tdx_td *td, u64 gpa, int level, struct page *page, u64 *ext_err1, u64 *ext_err2)
> +u64 tdh_mem_page_aug(struct tdx_td *td, u64 gpa, enum pg_level level,
> + struct page *page, u64 *ext_err1, u64 *ext_err2)
> {
> struct tdx_module_args args = {
> - .rcx = gpa | level,
> + .rcx = gpa | pg_level_to_tdx_sept_level(level),
> .rdx = tdx_tdr_pa(td),
> .r8 = page_to_phys(page),
> };
> @@ -1606,10 +1614,11 @@ u64 tdh_mem_page_aug(struct tdx_td *td, u64 gpa, int level, struct page *page, u
> }
> EXPORT_SYMBOL_FOR_KVM(tdh_mem_page_aug);
>
> -u64 tdh_mem_range_block(struct tdx_td *td, u64 gpa, int level, u64 *ext_err1, u64 *ext_err2)
> +u64 tdh_mem_range_block(struct tdx_td *td, u64 gpa, enum pg_level level,
> + u64 *ext_err1, u64 *ext_err2)
> {
> struct tdx_module_args args = {
> - .rcx = gpa | level,
> + .rcx = gpa | pg_level_to_tdx_sept_level(level),
> .rdx = tdx_tdr_pa(td),
> };
> u64 ret;
> @@ -1822,10 +1831,11 @@ u64 tdh_mem_track(struct tdx_td *td)
> }
> EXPORT_SYMBOL_FOR_KVM(tdh_mem_track);
>
> -u64 tdh_mem_page_remove(struct tdx_td *td, u64 gpa, u64 level, u64 *ext_err1, u64 *ext_err2)
> +u64 tdh_mem_page_remove(struct tdx_td *td, u64 gpa, enum pg_level level,
> + u64 *ext_err1, u64 *ext_err2)
> {
> struct tdx_module_args args = {
> - .rcx = gpa | level,
> + .rcx = gpa | pg_level_to_tdx_sept_level(level),
> .rdx = tdx_tdr_pa(td),
> };
> u64 ret;
>
> base-commit: 24d479d26b25bce5faea3ddd9fa8f3a6c3129ea7
> --
> 2.52.0.457.g6b5491de43-goog
>
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