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From:   isaku.yamahata@intel.com
To:     kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     isaku.yamahata@intel.com, isaku.yamahata@gmail.com,
        Paolo Bonzini <pbonzini@redhat.com>, erdemaktas@google.com,
        Sean Christopherson <seanjc@google.com>,
        Sagi Shahar <sagis@google.com>
Subject: [RFC PATCH v6 046/104] KVM: x86/tdp_mmu: refactor kvm_tdp_mmu_map()
Date:   Thu,  5 May 2022 11:14:40 -0700
Message-Id: <4744ed20a4d9db95b515559e7525623781261b0c.1651774250.git.isaku.yamahata@intel.com>
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From: Isaku Yamahata <isaku.yamahata@intel.com>

Factor out non-leaf SPTE population logic from kvm_tdp_mmu_map().  MapGPA
hypercall needs to populate non-leaf SPTE to record which GPA, private or
shared, is allowed in the leaf EPT entry.

Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
---
 arch/x86/kvm/mmu/tdp_mmu.c | 26 +++++++++++++++++++-------
 1 file changed, 19 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/mmu/tdp_mmu.c b/arch/x86/kvm/mmu/tdp_mmu.c
index b7e13061e57d..9e015b3e0578 100644
--- a/arch/x86/kvm/mmu/tdp_mmu.c
+++ b/arch/x86/kvm/mmu/tdp_mmu.c
@@ -1149,6 +1149,24 @@ static int tdp_mmu_link_sp(struct kvm *kvm, struct tdp_iter *iter,
 	return 0;
 }
 
+static int tdp_mmu_populate_nonleaf(
+	struct kvm_vcpu *vcpu, struct tdp_iter *iter, bool account_nx)
+{
+	struct kvm_mmu_page *sp;
+	int ret;
+
+	WARN_ON(is_shadow_present_pte(iter->old_spte));
+	WARN_ON(is_removed_spte(iter->old_spte));
+
+	sp = tdp_mmu_alloc_sp(vcpu);
+	tdp_mmu_init_child_sp(sp, iter);
+
+	ret = tdp_mmu_link_sp(vcpu->kvm, iter, sp, account_nx, true);
+	if (ret)
+		tdp_mmu_free_sp(sp);
+	return ret;
+}
+
 /*
  * Handle a TDP page fault (NPT/EPT violation/misconfiguration) by installing
  * page tables and SPTEs to translate the faulting guest physical address.
@@ -1157,7 +1175,6 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
 {
 	struct kvm_mmu *mmu = vcpu->arch.mmu;
 	struct tdp_iter iter;
-	struct kvm_mmu_page *sp;
 	int ret;
 
 	kvm_mmu_hugepage_adjust(vcpu, fault);
@@ -1203,13 +1220,8 @@ int kvm_tdp_mmu_map(struct kvm_vcpu *vcpu, struct kvm_page_fault *fault)
 			if (is_removed_spte(iter.old_spte))
 				break;
 
-			sp = tdp_mmu_alloc_sp(vcpu);
-			tdp_mmu_init_child_sp(sp, &iter);
-
-			if (tdp_mmu_link_sp(vcpu->kvm, &iter, sp, account_nx, true)) {
-				tdp_mmu_free_sp(sp);
+			if (tdp_mmu_populate_nonleaf(vcpu, &iter, account_nx))
 				break;
-			}
 		}
 	}
 
-- 
2.25.1