KVM: x86: fix memoryleak in kvm_arch_vcpu_create()

When allocating memory for mci_ctl2_banks fails, KVM doesn't release
mce_banks leading to memoryleak. Fix this issue by calling kfree()
for it when kcalloc() fails.

Fixes: 281b5278 ("KVM: x86: Add emulation for MSR_IA32_MCx_CTL2 MSRs.")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Message-Id: <20220901122300.22298-1-linmiaohe@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

arch/x86/kvm/x86.c

@@ -11580,7 +11580,7 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 	vcpu->arch.mci_ctl2_banks = kcalloc(KVM_MAX_MCE_BANKS, sizeof(u64),
 					    GFP_KERNEL_ACCOUNT);
 	if (!vcpu->arch.mce_banks || !vcpu->arch.mci_ctl2_banks)
-		goto fail_free_pio_data;
+		goto fail_free_mce_banks;
 	vcpu->arch.mcg_cap = KVM_MAX_MCE_BANKS;
 
 	if (!zalloc_cpumask_var(&vcpu->arch.wbinvd_dirty_mask,
@@ -11634,7 +11634,6 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 fail_free_mce_banks:
 	kfree(vcpu->arch.mce_banks);
 	kfree(vcpu->arch.mci_ctl2_banks);
-fail_free_pio_data:
 	free_page((unsigned long)vcpu->arch.pio_data);
 fail_free_lapic:
 	kvm_free_lapic(vcpu);