linux-kernel - [PATCH v2 32/32] KVM: nVMX: Free only the affected contexts when emulating INVEPT

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Date:   Mon, 16 Mar 2020 21:52:38 -0700
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>
Cc:     Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Ben Gardon <bgardon@...gle.com>,
        Junaid Shahid <junaids@...gle.com>,
        Liran Alon <liran.alon@...cle.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>,
        John Haxby <john.haxby@...cle.com>,
        Miaohe Lin <linmiaohe@...wei.com>,
        Tom Lendacky <thomas.lendacky@....com>
Subject: [PATCH v2 32/32] KVM: nVMX: Free only the affected contexts when emulating INVEPT

Add logic to handle_invept() to free only those roots that match the
target EPT context when emulating a single-context INVEPT.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 arch/x86/kvm/vmx/nested.c | 26 +++++++++++++++++++++-----
 1 file changed, 21 insertions(+), 5 deletions(-)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index a77eab5b0e8a..3652ac2ffa19 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -5139,12 +5139,14 @@ static int handle_invept(struct kvm_vcpu *vcpu)
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 	u32 vmx_instruction_info, types;
-	unsigned long type;
+	unsigned long type, roots_to_free;
+	struct kvm_mmu *mmu;
 	gva_t gva;
 	struct x86_exception e;
 	struct {
 		u64 eptp, gpa;
 	} operand;
+	int i;
 
 	if (!(vmx->nested.msrs.secondary_ctls_high &
 	      SECONDARY_EXEC_ENABLE_EPT) ||
@@ -5176,23 +5178,37 @@ static int handle_invept(struct kvm_vcpu *vcpu)
 		return 1;
 	}
 
+	mmu = &vcpu->arch.guest_mmu;
+
 	switch (type) {
 	case VMX_EPT_EXTENT_CONTEXT:
 		if (!nested_vmx_check_eptp(vcpu, operand.eptp))
 			return nested_vmx_failValid(vcpu,
 				VMXERR_INVALID_OPERAND_TO_INVEPT_INVVPID);
 
-		/* TODO: sync only the target EPTP context. */
-		fallthrough;
+		roots_to_free = 0;
+		if (nested_ept_root_matches(mmu->root_hpa, mmu->root_cr3,
+					    operand.eptp))
+			roots_to_free |= KVM_MMU_ROOT_CURRENT;
+
+		for (i = 0; i < KVM_MMU_NUM_PREV_ROOTS; i++) {
+			if (nested_ept_root_matches(mmu->prev_roots[i].hpa,
+						    mmu->prev_roots[i].cr3,
+						    operand.eptp))
+				roots_to_free |= KVM_MMU_ROOT_PREVIOUS(i);
+		}
+		break;
 	case VMX_EPT_EXTENT_GLOBAL:
-		kvm_mmu_free_roots(vcpu, &vcpu->arch.guest_mmu,
-				   KVM_MMU_ROOTS_ALL);
+		roots_to_free = KVM_MMU_ROOTS_ALL;
 		break;
 	default:
 		BUG_ON(1);
 		break;
 	}
 
+	if (roots_to_free)
+		kvm_mmu_free_roots(vcpu, mmu, roots_to_free);
+
 	return nested_vmx_succeed(vcpu);
 }
 
-- 
2.24.1