From: Miaohe Lin <linmiaohe@huawei.com>
Date: Fri, 21 Feb 2020 14:04:46 +0000 (+0800)
Subject: KVM: apic: avoid calculating pending eoi from an uninitialized val
X-Git-Tag: v5.5.7~50
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=7cad6ccee697b8f425ecd2c9222784c7c16561ca;p=users%2Fdwmw2%2Flinux.git

KVM: apic: avoid calculating pending eoi from an uninitialized val

commit 23520b2def95205f132e167cf5b25c609975e959 upstream.

When pv_eoi_get_user() fails, 'val' may remain uninitialized and the return
value of pv_eoi_get_pending() becomes random. Fix the issue by initializing
the variable.

Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index cfa1120bb6913..f05123acaa64c 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -630,9 +630,11 @@ static inline bool pv_eoi_enabled(struct kvm_vcpu *vcpu)
 static bool pv_eoi_get_pending(struct kvm_vcpu *vcpu)
 {
 	u8 val;
-	if (pv_eoi_get_user(vcpu, &val) < 0)
+	if (pv_eoi_get_user(vcpu, &val) < 0) {
 		printk(KERN_WARNING "Can't read EOI MSR value: 0x%llx\n",
 			   (unsigned long long)vcpu->arch.pv_eoi.msr_val);
+		return false;
+	}
 	return val & 0x1;
 }