linux-kernel - [PATCH v2 04/32] KVM: nVMX: Invalidate all L2 roots when emulating INVVPID without EPT

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Date:   Mon, 16 Mar 2020 21:52:10 -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 04/32] KVM: nVMX: Invalidate all L2 roots when emulating INVVPID without EPT

From: Junaid Shahid <junaids@...gle.com>

Free all L2 (guest_mmu) roots when emulating INVVPID for L1 and EPT is
disabled, as outstanding changes to the page tables managed by L1 need
to be recognized.

Similar to handle_invpcid() and handle_invept(), rely on
kvm_mmu_free_roots() to do a remote TLB flush if necessary, e.g. if L1
has never entered L2 then there is nothing to be done.

Fixes: 5c614b3583e7b ("KVM: nVMX: nested VPID emulation")
Signed-off-by: Junaid Shahid <junaids@...gle.com>
[sean: ported to upstream KVM, reworded the comment and changelog]
Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 arch/x86/kvm/vmx/nested.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 9624cea4ed9f..50bb7d8862aa 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -5250,6 +5250,17 @@ static int handle_invvpid(struct kvm_vcpu *vcpu)
 		return kvm_skip_emulated_instruction(vcpu);
 	}
 
+	/*
+	 * Sync L2's shadow page tables if EPT is disabled, L1 is effectively
+	 * invalidating linear mappings for L2 (tagged with L2's VPID).  Sync
+	 * all roots as VPIDs are not tracked in the MMU role.
+	 *
+	 * TODO: sync only the affected SPTEs for INVDIVIDUAL_ADDR.
+	 */
+	if (!enable_ept)
+		kvm_mmu_free_roots(vcpu, &vcpu->arch.guest_mmu,
+				   KVM_MMU_ROOTS_ALL);
+
 	return nested_vmx_succeed(vcpu);
 }
 
-- 
2.24.1