linux-kernel - Re: [PATCH v3 3/8] KVM: X86: Introduce kvm_check

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Date:   Wed, 8 Jul 2020 20:28:06 +0800
From:   Xiaoyao Li <xiaoyao.li@...el.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Jim Mattson <jmattson@...gle.com>
Cc:     kvm@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-doc@...r.kernel.org, Jonathan Corbet <corbet@....net>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Joerg Roedel <joro@...tes.org>
Subject: Re: [PATCH v3 3/8] KVM: X86: Introduce kvm_check_cpuid()

On 7/8/2020 2:50 PM, Xiaoyao Li wrote:
> Use kvm_check_cpuid() to validate if userspace provides legal cpuid
> settings and call it before KVM updates CPUID.
> 
> Signed-off-by: Xiaoyao Li <xiaoyao.li@...el.com>
[...]
> @@ -202,12 +208,16 @@ int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu,
>   		vcpu->arch.cpuid_entries[i].padding[2] = 0;
>   	}
>   	vcpu->arch.cpuid_nent = cpuid->nent;
> +	r = kvm_check_cpuid(vcpu);
> +	if (r) {
> +		vcpu->arch.cpuid_nent = 0;

Paolo,

here lack a kvfree(cpuid_entries);
Can you help fix it?

Apologize for it.


> +		goto out;
> +	}
> +
>   	cpuid_fix_nx_cap(vcpu);
>   	kvm_apic_set_version(vcpu);
>   	kvm_x86_ops.cpuid_update(vcpu);
> -	r = kvm_update_cpuid(vcpu);
> -	if (r)
> -		vcpu->arch.cpuid_nent = 0;
> +	kvm_update_cpuid(vcpu);
>   
>   	kvfree(cpuid_entries);
>   out: