linux-kernel - [PATCH 1/6] KVM: X86: Reset vcpu->arch.cpuid_nent to 0 if SET

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Message-Id: <20200529085545.29242-2-xiaoyao.li@intel.com>
Date:   Fri, 29 May 2020 16:55:40 +0800
From:   Xiaoyao Li <xiaoyao.li@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        kvm@...r.kernel.org
Cc:     Vitaly Kuznetsov <vkuznets@...hat.com>,
        Jim Mattson <jmattson@...gle.com>,
        linux-kernel@...r.kernel.org, Xiaoyao Li <xiaoyao.li@...el.com>
Subject: [PATCH 1/6] KVM: X86: Reset vcpu->arch.cpuid_nent to 0 if SET_CPUID fails

It needs to invalidate CPUID configruations if usersapce provides
illegal input.

Signed-off-by: Xiaoyao Li <xiaoyao.li@...el.com>
---
 arch/x86/kvm/cpuid.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c
index cd708b0b460a..2f1a9650b7f2 100644
--- a/arch/x86/kvm/cpuid.c
+++ b/arch/x86/kvm/cpuid.c
@@ -210,6 +210,8 @@ int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
 	kvm_apic_set_version(vcpu);
 	kvm_x86_ops.cpuid_update(vcpu);
 	r = kvm_update_cpuid(vcpu);
+	if (r)
+		vcpu->arch.cpuid_nent = 0;
 
 out:
 	vfree(cpuid_entries);
@@ -233,6 +235,8 @@ int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu,
 	kvm_apic_set_version(vcpu);
 	kvm_x86_ops.cpuid_update(vcpu);
 	r = kvm_update_cpuid(vcpu);
+	if (r)
+		vcpu->arch.cpuid_nent = 0;
 out:
 	return r;
 }
-- 
2.18.2