linux-kernel - Re: [PATCH v2 12/14] KVM: SVM: Drop redundant svm_sev

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: <5cc747b6-f5c8-f23b-a341-d19a55007f3b@amd.com>
Date:   Thu, 14 Jan 2021 15:44:30 -0600
From:   Brijesh Singh <brijesh.singh@....com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Andy Lutomirski <luto@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>
Cc:     brijesh.singh@....com, Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-kernel@...r.kernel.org, Borislav Petkov <bp@...e.de>,
        Tom Lendacky <thomas.lendacky@....com>
Subject: Re: [PATCH v2 12/14] KVM: SVM: Drop redundant svm_sev_enabled()
 helper


On 1/13/21 6:37 PM, Sean Christopherson wrote:
> Replace calls to svm_sev_enabled() with direct checks on sev_enabled, or
> in the case of svm_mem_enc_op, simply drop the call to svm_sev_enabled().
> This effectively replaces checks against a valid max_sev_asid with checks
> against sev_enabled.  sev_enabled is forced off by sev_hardware_setup()
> if max_sev_asid is invalid, all call sites are guaranteed to run after
> sev_hardware_setup(), and all of the checks care about SEV being fully
> enabled (as opposed to intentionally handling the scenario where
> max_sev_asid is valid but SEV enabling fails due to OOM).
>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
> ---
>  arch/x86/kvm/svm/sev.c | 6 +++---
>  arch/x86/kvm/svm/svm.h | 5 -----
>  2 files changed, 3 insertions(+), 8 deletions(-)


Thanks

Reviewed-by: Brijesh Singh <brijesh.singh@....com>


> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index a2c3e2d42a7f..7e14514dd083 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -1057,7 +1057,7 @@ int svm_mem_enc_op(struct kvm *kvm, void __user *argp)
>  	struct kvm_sev_cmd sev_cmd;
>  	int r;
>  
> -	if (!svm_sev_enabled() || !sev_enabled)
> +	if (!sev_enabled)
>  		return -ENOTTY;
>  
>  	if (!argp)
> @@ -1321,7 +1321,7 @@ void __init sev_hardware_setup(void)
>  
>  void sev_hardware_teardown(void)
>  {
> -	if (!svm_sev_enabled())
> +	if (!sev_enabled)
>  		return;
>  
>  	bitmap_free(sev_asid_bitmap);
> @@ -1332,7 +1332,7 @@ void sev_hardware_teardown(void)
>  
>  int sev_cpu_init(struct svm_cpu_data *sd)
>  {
> -	if (!svm_sev_enabled())
> +	if (!sev_enabled)
>  		return 0;
>  
>  	sd->sev_vmcbs = kmalloc_array(max_sev_asid + 1, sizeof(void *),
> diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
> index 4eb4bab0ca3e..8cb4395b58a0 100644
> --- a/arch/x86/kvm/svm/svm.h
> +++ b/arch/x86/kvm/svm/svm.h
> @@ -569,11 +569,6 @@ void svm_vcpu_unblocking(struct kvm_vcpu *vcpu);
>  
>  extern unsigned int max_sev_asid;
>  
> -static inline bool svm_sev_enabled(void)
> -{
> -	return IS_ENABLED(CONFIG_KVM_AMD_SEV) ? max_sev_asid : 0;
> -}
> -
>  void sev_vm_destroy(struct kvm *kvm);
>  int svm_mem_enc_op(struct kvm *kvm, void __user *argp);
>  int svm_register_enc_region(struct kvm *kvm,