linux-kernel - Re: [PATCH v2 11/14] KVM: SVM: Move SEV VMCB tracking allocation to sev.c

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Message-ID: <10d43bb0-e19d-6d53-20f7-fa73983adb4a@amd.com>
Date:   Thu, 14 Jan 2021 15:37:19 -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 11/14] KVM: SVM: Move SEV VMCB tracking allocation to
 sev.c


On 1/13/21 6:37 PM, Sean Christopherson wrote:
> Move the allocation of the SEV VMCB array to sev.c to help pave the way
> toward encapsulating SEV enabling wholly within sev.c.
>
> No functional change intended.
>
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
> ---
>  arch/x86/kvm/svm/sev.c | 13 +++++++++++++
>  arch/x86/kvm/svm/svm.c | 17 ++++++++---------
>  arch/x86/kvm/svm/svm.h |  1 +
>  3 files changed, 22 insertions(+), 9 deletions(-)
>
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index 1a143340103e..a2c3e2d42a7f 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -1330,6 +1330,19 @@ void sev_hardware_teardown(void)
>  	sev_flush_asids();
>  }
>  
> +int sev_cpu_init(struct svm_cpu_data *sd)
> +{
> +	if (!svm_sev_enabled())
> +		return 0;
> +
> +	sd->sev_vmcbs = kmalloc_array(max_sev_asid + 1, sizeof(void *),
> +				      GFP_KERNEL | __GFP_ZERO);


I saw Tom recommended to use kzalloc.. instead of __GFP_ZERO in previous
patch. With that fixed,

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


> +	if (!sd->sev_vmcbs)
> +		return -ENOMEM;
> +
> +	return 0;
> +}
> +
>  /*
>   * Pages used by hardware to hold guest encrypted state must be flushed before
>   * returning them to the system.
> diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
> index bb7b99743bea..89b95fb87a0c 100644
> --- a/arch/x86/kvm/svm/svm.c
> +++ b/arch/x86/kvm/svm/svm.c
> @@ -552,23 +552,22 @@ static void svm_cpu_uninit(int cpu)
>  static int svm_cpu_init(int cpu)
>  {
>  	struct svm_cpu_data *sd;
> +	int ret;
>  
>  	sd = kzalloc(sizeof(struct svm_cpu_data), GFP_KERNEL);
>  	if (!sd)
>  		return -ENOMEM;
>  	sd->cpu = cpu;
>  	sd->save_area = alloc_page(GFP_KERNEL);
> -	if (!sd->save_area)
> +	if (!sd->save_area) {
> +		ret = -ENOMEM;
>  		goto free_cpu_data;
> +	}
>  	clear_page(page_address(sd->save_area));
>  
> -	if (svm_sev_enabled()) {
> -		sd->sev_vmcbs = kmalloc_array(max_sev_asid + 1,
> -					      sizeof(void *),
> -					      GFP_KERNEL | __GFP_ZERO);
> -		if (!sd->sev_vmcbs)
> -			goto free_save_area;
> -	}
> +	ret = sev_cpu_init(sd);
> +	if (ret)
> +		goto free_save_area;
>  
>  	per_cpu(svm_data, cpu) = sd;
>  
> @@ -578,7 +577,7 @@ static int svm_cpu_init(int cpu)
>  	__free_page(sd->save_area);
>  free_cpu_data:
>  	kfree(sd);
> -	return -ENOMEM;
> +	return ret;
>  
>  }
>  
> diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
> index 8e169835f52a..4eb4bab0ca3e 100644
> --- a/arch/x86/kvm/svm/svm.h
> +++ b/arch/x86/kvm/svm/svm.h
> @@ -583,6 +583,7 @@ int svm_unregister_enc_region(struct kvm *kvm,
>  void pre_sev_run(struct vcpu_svm *svm, int cpu);
>  void __init sev_hardware_setup(void);
>  void sev_hardware_teardown(void);
> +int sev_cpu_init(struct svm_cpu_data *sd);
>  void sev_free_vcpu(struct kvm_vcpu *vcpu);
>  int sev_handle_vmgexit(struct vcpu_svm *svm);
>  int sev_es_string_io(struct vcpu_svm *svm, int size, unsigned int port, int in);