linux-kernel - [RFC PATCH v5 32/45] KVM: x86/mmu: Plumb the old_spte into kvm_x86_ops.set_external

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Message-ID: <20260129011517.3545883-33-seanjc@google.com>
Date: Wed, 28 Jan 2026 17:15:04 -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 32/45] KVM: x86/mmu: Plumb the old_spte into kvm_x86_ops.set_external_spte()

Plumb the old SPTE into .set_external_spte() so that the callback can be
used to handle removal and splitting of leaf SPTEs.  Rename mirror_spte to
new_spte to follow the TDP MMU's naming, and to make it more obvious what
value the parameter holds.

Opportunistically tweak the ordering of parameters to match the pattern of
most TDP MMU functions, which do "old, new, level".

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/x86/include/asm/kvm_host.h |  4 ++--
 arch/x86/kvm/mmu/tdp_mmu.c      |  4 ++--
 arch/x86/kvm/vmx/tdx.c          | 14 +++++++-------
 3 files changed, 11 insertions(+), 11 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index a6e4ab76b1b2..67deec8e205e 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1857,8 +1857,8 @@ struct kvm_x86_ops {
 	 */
 	unsigned long (*alloc_external_sp)(gfp_t gfp);
 	void (*free_external_sp)(unsigned long addr);
-	int (*set_external_spte)(struct kvm *kvm, gfn_t gfn, enum pg_level level,
-				 u64 mirror_spte);
+	int (*set_external_spte)(struct kvm *kvm, gfn_t gfn, u64 old_spte,
+				 u64 new_spte, enum pg_level level);
 	void (*reclaim_external_sp)(struct kvm *kvm, gfn_t gfn,
 				    struct kvm_mmu_page *sp);
 	void (*remove_external_spte)(struct kvm *kvm, gfn_t gfn, enum pg_level level,
diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index f8ebdd0c6114..271dd6f875a6 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -614,8 +614,8 @@ static inline int __must_check __tdp_mmu_set_spte_atomic(struct kvm *kvm,
 		 * the desired value.  On failure, restore the old SPTE so that
 		 * the SPTE isn't frozen in perpetuity.
 		 */
-		ret = kvm_x86_call(set_external_spte)(kvm, iter->gfn,
-						      iter->level, new_spte);
+		ret = kvm_x86_call(set_external_spte)(kvm, iter->gfn, iter->old_spte,
+						      new_spte, iter->level);
 		if (ret)
 			__kvm_tdp_mmu_write_spte(iter->sptep, iter->old_spte);
 		else
diff --git a/arch/x86/kvm/vmx/tdx.c b/arch/x86/kvm/vmx/tdx.c
index bd5d902da303..e451acdb0978 100644
--- a/arch/x86/kvm/vmx/tdx.c
+++ b/arch/x86/kvm/vmx/tdx.c
@@ -1705,29 +1705,29 @@ static int tdx_sept_link_private_spt(struct kvm *kvm, gfn_t gfn,
 	return 0;
 }
 
-static int tdx_sept_set_private_spte(struct kvm *kvm, gfn_t gfn,
-				     enum pg_level level, u64 mirror_spte)
+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(mirror_spte);
+	kvm_pfn_t pfn = spte_to_pfn(new_spte);
 	struct vcpu_tdx *tdx = to_tdx(vcpu);
 	int ret;
 
 	if (KVM_BUG_ON(!vcpu, kvm))
 		return -EINVAL;
 
-	if (KVM_BUG_ON(!is_shadow_present_pte(mirror_spte), kvm))
+	if (KVM_BUG_ON(!is_shadow_present_pte(new_spte), kvm))
 		return -EIO;
 
-	if (!is_last_spte(mirror_spte, level))
-		return tdx_sept_link_private_spt(kvm, gfn, level, mirror_spte);
+	if (!is_last_spte(new_spte, level))
+		return tdx_sept_link_private_spt(kvm, gfn, level, new_spte);
 
 	/* TODO: handle large pages. */
 	if (KVM_BUG_ON(level != PG_LEVEL_4K, kvm))
 		return -EIO;
 
-	WARN_ON_ONCE((mirror_spte & VMX_EPT_RWX_MASK) != VMX_EPT_RWX_MASK);
+	WARN_ON_ONCE((new_spte & VMX_EPT_RWX_MASK) != VMX_EPT_RWX_MASK);
 
 	ret = tdx_pamt_get(pfn, level, &tdx->pamt_cache);
 	if (ret)
-- 
2.53.0.rc1.217.geba53bf80e-goog