linux-kernel - [PATCH] KVM: x86: Initialize tdp

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Date:   Wed, 27 May 2020 01:54:00 -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,
        syzbot+904752567107eefb728c@...kaller.appspotmail.com
Subject: [PATCH] KVM: x86: Initialize tdp_level during vCPU creation

Initialize vcpu->arch.tdp_level during vCPU creation to avoid consuming
garbage if userspace calls KVM_RUN without first calling KVM_SET_CPUID.

Fixes: e93fd3b3e89e9 ("KVM: x86/mmu: Capture TDP level when updating CPUID")
Reported-by: syzbot+904752567107eefb728c@...kaller.appspotmail.com
Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 arch/x86/kvm/x86.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index b226fb8abe41b..01a6304056197 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -9414,6 +9414,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 	fx_init(vcpu);
 
 	vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
+	vcpu->arch.tdp_level = kvm_x86_ops.get_tdp_level(vcpu);
 
 	vcpu->arch.pat = MSR_IA32_CR_PAT_DEFAULT;
 
-- 
2.26.0