linux-kernel - [RFC 4/9] Add release function for direct build ept when guest VM exit

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Message-Id: <20200805141344.9038-1-yulei.kernel@gmail.com>
Date:   Wed,  5 Aug 2020 22:13:43 +0800
From:   Yulei Zhang <yulei.kernel@...il.com>
To:     pbonzini@...hat.com
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        sean.j.christopherson@...el.com, jmattson@...gle.com,
        vkuznets@...hat.com, xiaoguangrong.eric@...il.com,
        kernellwp@...il.com, lihaiwei.kernel@...il.com,
        Yulei Zhang <yuleixzhang@...cent.com>
Subject: [RFC 4/9] Add release function for direct build ept when guest VM exit

From: Yulei Zhang <yuleixzhang@...cent.com>

Release the pre-pinned memory in direct build ept when guest VM
exit.

Signed-off-by: Yulei Zhang <yuleixzhang@...cent.com>
---
 arch/x86/kvm/mmu/mmu.c | 39 ++++++++++++++++++++++++++++++---------
 1 file changed, 30 insertions(+), 9 deletions(-)

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 539974183653..df703deac928 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c
@@ -4360,8 +4360,11 @@ static void __kvm_mmu_new_cr3(struct kvm_vcpu *vcpu, gpa_t new_cr3,
 
 void kvm_mmu_new_cr3(struct kvm_vcpu *vcpu, gpa_t new_cr3, bool skip_tlb_flush)
 {
-	__kvm_mmu_new_cr3(vcpu, new_cr3, kvm_mmu_calc_root_page_role(vcpu),
-			  skip_tlb_flush);
+	if (!vcpu->arch.direct_build_tdp)
+		__kvm_mmu_new_cr3(vcpu, new_cr3, kvm_mmu_calc_root_page_role(vcpu),
+				  skip_tlb_flush);
+	else
+		vcpu->arch.mmu->root_hpa = INVALID_PAGE;
 }
 EXPORT_SYMBOL_GPL(kvm_mmu_new_cr3);
 
@@ -5204,10 +5207,16 @@ EXPORT_SYMBOL_GPL(kvm_mmu_load);
 
 void kvm_mmu_unload(struct kvm_vcpu *vcpu)
 {
-	kvm_mmu_free_roots(vcpu, &vcpu->arch.root_mmu, KVM_MMU_ROOTS_ALL);
-	WARN_ON(VALID_PAGE(vcpu->arch.root_mmu.root_hpa));
-	kvm_mmu_free_roots(vcpu, &vcpu->arch.guest_mmu, KVM_MMU_ROOTS_ALL);
-	WARN_ON(VALID_PAGE(vcpu->arch.guest_mmu.root_hpa));
+
+	if (!vcpu->arch.direct_build_tdp) {
+		kvm_mmu_free_roots(vcpu, &vcpu->arch.root_mmu, KVM_MMU_ROOTS_ALL);
+		WARN_ON(VALID_PAGE(vcpu->arch.root_mmu.root_hpa));
+		kvm_mmu_free_roots(vcpu, &vcpu->arch.guest_mmu, KVM_MMU_ROOTS_ALL);
+		WARN_ON(VALID_PAGE(vcpu->arch.guest_mmu.root_hpa));
+	}
+
+	vcpu->arch.direct_build_tdp = false;
+	vcpu->arch.mmu->root_hpa = INVALID_PAGE;
 }
 EXPORT_SYMBOL_GPL(kvm_mmu_unload);
 
@@ -6510,6 +6519,14 @@ void kvm_direct_tdp_remove_page_table(struct kvm *kvm, struct kvm_memory_slot *s
 	kvm_flush_remote_tlbs(kvm);
 }
 
+void kvm_direct_tdp_release_global_root(struct kvm *kvm)
+{
+	if (kvm->arch.global_root_hpa)
+		__kvm_walk_global_page(kvm, kvm->arch.global_root_hpa, kvm_x86_ops.get_tdp_level(NULL));
+
+	return;
+}
+
 /*
  * Calculate mmu pages needed for kvm.
  */
@@ -6536,9 +6553,13 @@ unsigned long kvm_mmu_calculate_default_mmu_pages(struct kvm *kvm)
 
 void kvm_mmu_destroy(struct kvm_vcpu *vcpu)
 {
-	kvm_mmu_unload(vcpu);
-	free_mmu_pages(&vcpu->arch.root_mmu);
-	free_mmu_pages(&vcpu->arch.guest_mmu);
+	if (vcpu->arch.direct_build_tdp) {
+		vcpu->arch.mmu->root_hpa = INVALID_PAGE;
+	} else {
+		kvm_mmu_unload(vcpu);
+		free_mmu_pages(&vcpu->arch.root_mmu);
+		free_mmu_pages(&vcpu->arch.guest_mmu);
+	}
 	mmu_free_memory_caches(vcpu);
 }
 
-- 
2.17.1