linux-kernel - Re: [PATCH 6/6] KVM: X86/SVM: Use root_level in svm_load_mmu

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <YqDUQxnDS+qoaJhH@google.com>
Date:   Wed, 8 Jun 2022 16:54:27 +0000
From:   David Matlack <dmatlack@...gle.com>
To:     Lai Jiangshan <jiangshanlai@...il.com>
Cc:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Maxim Levitsky <mlevitsk@...hat.com>,
        Lai Jiangshan <jiangshan.ljs@...group.com>
Subject: Re: [PATCH 6/6] KVM: X86/SVM: Use root_level in svm_load_mmu_pgd()

On Sun, Jun 05, 2022 at 02:34:17PM +0800, Lai Jiangshan wrote:
> From: Lai Jiangshan <jiangshan.ljs@...group.com>
> 
> The caller always call it with root_level = vcpu->arch.mmu->root_role.level.

It'd be helpful to be more specific about the caller. e.g.

  Use root_level in svm_load_mmu_pg() rather that looking up the root
  level in vcpu->arch.mmu->root_role.level. svm_load_mmu_pgd() has only
  one caller, kvm_mmu_load_pgd(), which always passes
  vcpu->arch.mmu->root_role.level as root_level.

  No functional change intended.

> 
> Signed-off-by: Lai Jiangshan <jiangshan.ljs@...group.com>
> ---
>  arch/x86/kvm/svm/svm.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index 3b49337998ec..f45d11739314 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -3951,7 +3951,7 @@ static void svm_load_mmu_pgd(struct kvm_vcpu *vcpu, hpa_t root_hpa,
>  		hv_track_root_tdp(vcpu, root_hpa);
>  
>  		cr3 = vcpu->arch.cr3;
> -	} else if (vcpu->arch.mmu->root_role.level >= PT64_ROOT_4LEVEL) {
> +	} else if (root_level >= PT64_ROOT_4LEVEL) {
>  		cr3 = __sme_set(root_hpa) | kvm_get_active_pcid(vcpu);
>  	} else {
>  		/* PCID in the guest should be impossible with a 32-bit MMU. */
> -- 
> 2.19.1.6.gb485710b
>