KVM: x86: Set so called 'reserved CR3 bits in LM mask' at vCPU reset

stable inclusion
from stable-5.10.15
commit 7159239d2de1eea77b322e661141a36c6a909b05
bugzilla: 48167

--------------------------------

commit 031b91a5 upstream.

Set cr3_lm_rsvd_bits, which is effectively an invalid GPA mask, at vCPU
reset.  The reserved bits check needs to be done even if userspace never
configures the guest's CPUID model.

Cc: stable@vger.kernel.org
Fixes: 0107973a ("KVM: x86: Introduce cr3_lm_rsvd_bits in kvm_vcpu_arch")
Signed-off-by: NSean Christopherson <seanjc@google.com>
Message-Id: <20210204000117.3303214-2-seanjc@google.com>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>
Acked-by: NXie XiuQi <xiexiuqi@huawei.com>

arch/x86/kvm/x86.c

@@ -9985,6 +9985,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 	fx_init(vcpu);
 
 	vcpu->arch.maxphyaddr = cpuid_query_maxphyaddr(vcpu);
+	vcpu->arch.cr3_lm_rsvd_bits = rsvd_bits(cpuid_maxphyaddr(vcpu), 63);
 
 	vcpu->arch.pat = MSR_IA32_CR_PAT_DEFAULT;