linux-kernel - [PATCH 5.1 298/371] KVM: nVMX: Dont dump VMCS if virtual APIC page cant be mapped

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Message-Id: <20190724191746.740511100@linuxfoundation.org>
Date:   Wed, 24 Jul 2019 21:20:50 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>
Subject: [PATCH 5.1 298/371] KVM: nVMX: Dont dump VMCS if virtual APIC page cant be mapped

From: Sean Christopherson <sean.j.christopherson@...el.com>

commit 73cb85568433feadb79e963bf2efba9b3e9ae3df upstream.

... as a malicious userspace can run a toy guest to generate invalid
virtual-APIC page addresses in L1, i.e. flood the kernel log with error
messages.

Fixes: 690908104e39d ("KVM: nVMX: allow tests to use bad virtual-APIC page address")
Cc: stable@...r.kernel.org
Cc: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/x86/kvm/vmx/nested.c |    3 ---
 1 file changed, 3 deletions(-)

--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -2891,9 +2891,6 @@ static void nested_get_vmcs12_pages(stru
 			 */
 			vmcs_clear_bits(CPU_BASED_VM_EXEC_CONTROL,
 					CPU_BASED_TPR_SHADOW);
-		} else {
-			printk("bad virtual-APIC page address\n");
-			dump_vmcs();
 		}
 	}