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Message-ID: <20260129011517.3545883-36-seanjc@google.com>
Date: Wed, 28 Jan 2026 17:15:07 -0800
From: Sean Christopherson <seanjc@...gle.com>
To: 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>, Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>
Cc: 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>, Yan Zhao <yan.y.zhao@...el.com>,
Vishal Annapurve <vannapurve@...gle.com>, Ackerley Tng <ackerleytng@...gle.com>,
Sagi Shahar <sagis@...gle.com>, Binbin Wu <binbin.wu@...ux.intel.com>,
Xiaoyao Li <xiaoyao.li@...el.com>, Isaku Yamahata <isaku.yamahata@...el.com>
Subject: [RFC PATCH v5 35/45] KVM: TDX: Add helper to handle mapping leaf SPTE
into S-EPT
Add a helper, tdx_sept_map_leaf_spte(), to wrap and isolate PAGE.ADD and
PAGE.AUG operations, and thus complete tdx_sept_set_private_spte()'s
transition into a "dispatch" routine for setting/writing S-EPT entries.
Opportunistically tweak the prototypes for tdx_sept_remove_private_spte()
and tdx_sept_link_private_spt() to align with tdx_sept_set_private_spte()
and tdx_sept_map_leaf_spte().
No functional change intended.
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
arch/x86/kvm/vmx/tdx.c | 97 ++++++++++++++++++++++--------------------
1 file changed, 51 insertions(+), 46 deletions(-)
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index 9f7789c5f0a7..e6ac4aca8114 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -1670,6 +1670,50 @@ static int tdx_mem_page_aug(struct kvm *kvm, gfn_t gfn,
return 0;
}
+static int tdx_sept_map_leaf_spte(struct kvm *kvm, gfn_t gfn, u64 new_spte,
+ enum pg_level level)
+{
+ struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
+ struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
+ kvm_pfn_t pfn = spte_to_pfn(new_spte);
+ int ret;
+
+ /* TODO: handle large pages. */
+ if (KVM_BUG_ON(level != PG_LEVEL_4K, kvm))
+ return -EIO;
+
+ if (KVM_BUG_ON(!vcpu, kvm))
+ return -EINVAL;
+
+ WARN_ON_ONCE((new_spte & VMX_EPT_RWX_MASK) != VMX_EPT_RWX_MASK);
+
+ ret = tdx_pamt_get(pfn, level, &to_tdx(vcpu)->pamt_cache);
+ if (ret)
+ return ret;
+
+ /*
+ * Ensure pre_fault_allowed is read by kvm_arch_vcpu_pre_fault_memory()
+ * before kvm_tdx->state. Userspace must not be allowed to pre-fault
+ * arbitrary memory until the initial memory image is finalized. Pairs
+ * with the smp_wmb() in tdx_td_finalize().
+ */
+ smp_rmb();
+
+ /*
+ * If the TD isn't finalized/runnable, then userspace is initializing
+ * the VM image via KVM_TDX_INIT_MEM_REGION; ADD the page to the TD.
+ */
+ if (likely(kvm_tdx->state == TD_STATE_RUNNABLE))
+ ret = tdx_mem_page_aug(kvm, gfn, level, pfn);
+ else
+ ret = tdx_mem_page_add(kvm, gfn, level, pfn);
+
+ if (ret)
+ tdx_pamt_put(pfn, level);
+
+ return ret;
+}
+
/*
* Ensure shared and private EPTs to be flushed on all vCPUs.
* tdh_mem_track() is the only caller that increases TD epoch. An increase in
@@ -1729,14 +1773,14 @@ static struct page *tdx_spte_to_external_spt(struct kvm *kvm, gfn_t gfn,
return virt_to_page(sp->external_spt);
}
-static int tdx_sept_link_private_spt(struct kvm *kvm, gfn_t gfn,
- enum pg_level level, u64 mirror_spte)
+static int tdx_sept_link_private_spt(struct kvm *kvm, gfn_t gfn, u64 new_spte,
+ enum pg_level level)
{
gpa_t gpa = gfn_to_gpa(gfn);
u64 err, entry, level_state;
struct page *external_spt;
- external_spt = tdx_spte_to_external_spt(kvm, gfn, mirror_spte, level);
+ external_spt = tdx_spte_to_external_spt(kvm, gfn, new_spte, level);
if (!external_spt)
return -EIO;
@@ -1752,7 +1796,7 @@ static int tdx_sept_link_private_spt(struct kvm *kvm, gfn_t gfn,
}
static int tdx_sept_remove_private_spte(struct kvm *kvm, gfn_t gfn,
- enum pg_level level, u64 old_spte)
+ u64 old_spte, enum pg_level level)
{
struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
kvm_pfn_t pfn = spte_to_pfn(old_spte);
@@ -1806,55 +1850,16 @@ static int tdx_sept_remove_private_spte(struct kvm *kvm, gfn_t gfn,
static int tdx_sept_set_private_spte(struct kvm *kvm, gfn_t gfn, u64 old_spte,
u64 new_spte, enum pg_level level)
{
- struct kvm_vcpu *vcpu = kvm_get_running_vcpu();
- struct kvm_tdx *kvm_tdx = to_kvm_tdx(kvm);
- kvm_pfn_t pfn = spte_to_pfn(new_spte);
- struct vcpu_tdx *tdx = to_tdx(vcpu);
- int ret;
-
if (is_shadow_present_pte(old_spte))
- return tdx_sept_remove_private_spte(kvm, gfn, level, old_spte);
-
- if (KVM_BUG_ON(!vcpu, kvm))
- return -EINVAL;
+ return tdx_sept_remove_private_spte(kvm, gfn, old_spte, level);
if (KVM_BUG_ON(!is_shadow_present_pte(new_spte), kvm))
return -EIO;
if (!is_last_spte(new_spte, level))
- return tdx_sept_link_private_spt(kvm, gfn, level, new_spte);
+ return tdx_sept_link_private_spt(kvm, gfn, new_spte, level);
- /* TODO: handle large pages. */
- if (KVM_BUG_ON(level != PG_LEVEL_4K, kvm))
- return -EIO;
-
- WARN_ON_ONCE((new_spte & VMX_EPT_RWX_MASK) != VMX_EPT_RWX_MASK);
-
- ret = tdx_pamt_get(pfn, level, &tdx->pamt_cache);
- if (ret)
- return ret;
-
- /*
- * Ensure pre_fault_allowed is read by kvm_arch_vcpu_pre_fault_memory()
- * before kvm_tdx->state. Userspace must not be allowed to pre-fault
- * arbitrary memory until the initial memory image is finalized. Pairs
- * with the smp_wmb() in tdx_td_finalize().
- */
- smp_rmb();
-
- /*
- * If the TD isn't finalized/runnable, then userspace is initializing
- * the VM image via KVM_TDX_INIT_MEM_REGION; ADD the page to the TD.
- */
- if (likely(kvm_tdx->state == TD_STATE_RUNNABLE))
- ret = tdx_mem_page_aug(kvm, gfn, level, pfn);
- else
- ret = tdx_mem_page_add(kvm, gfn, level, pfn);
-
- if (ret)
- tdx_pamt_put(pfn, level);
-
- return ret;
+ return tdx_sept_map_leaf_spte(kvm, gfn, new_spte, level);
}
static void tdx_sept_reclaim_private_sp(struct kvm *kvm, gfn_t gfn,
--
2.53.0.rc1.217.geba53bf80e-goog
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