linux-kernel - Re: [PATCH 04/10] KVM: SVM: Add helper to deduplicate code for getting AVIC backing page

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Date:   Thu, 05 Oct 2023 15:50:15 +0300
From:   Maxim Levitsky <mlevitsk@...hat.com>
To:     Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Joerg Roedel <joro@...tes.org>
Cc:     kvm@...r.kernel.org, iommu@...ts.linux.dev,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 04/10] KVM: SVM: Add helper to deduplicate code for
 getting AVIC backing page

У вт, 2023-08-15 у 14:35 -0700, Sean Christopherson пише:
> Add a helper to get the physical address of the AVIC backing page, both
> to deduplicate code and to prepare for getting the address directly from
> apic->regs, at which point it won't be all that obvious that the address
> in question is what SVM calls the AVIC backing page.
> 
> No functional change intended.
> 
> Signed-off-by: Sean Christopherson <seanjc@...gle.com>
> ---
>  arch/x86/kvm/svm/avic.c | 14 +++++++++-----
>  1 file changed, 9 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/x86/kvm/svm/avic.c b/arch/x86/kvm/svm/avic.c
> index b8313f2d88fa..954bdb45033b 100644
> --- a/arch/x86/kvm/svm/avic.c
> +++ b/arch/x86/kvm/svm/avic.c
> @@ -241,14 +241,18 @@ int avic_vm_init(struct kvm *kvm)
>  	return err;
>  }
>  
> +static phys_addr_t avic_get_backing_page_address(struct vcpu_svm *svm)
> +{
> +	return __sme_set(page_to_phys(svm->avic_backing_page));
> +}
> +
>  void avic_init_vmcb(struct vcpu_svm *svm, struct vmcb *vmcb)
>  {
>  	struct kvm_svm *kvm_svm = to_kvm_svm(svm->vcpu.kvm);
> -	phys_addr_t bpa = __sme_set(page_to_phys(svm->avic_backing_page));
>  	phys_addr_t lpa = __sme_set(page_to_phys(kvm_svm->avic_logical_id_table_page));
>  	phys_addr_t ppa = __sme_set(page_to_phys(kvm_svm->avic_physical_id_table_page));
>  
> -	vmcb->control.avic_backing_page = bpa;
> +	vmcb->control.avic_backing_page = avic_get_backing_page_address(svm);
>  	vmcb->control.avic_logical_id = lpa;
>  	vmcb->control.avic_physical_id = ppa;
>  	vmcb->control.avic_vapic_bar = APIC_DEFAULT_PHYS_BASE;
> @@ -308,7 +312,7 @@ static int avic_init_backing_page(struct kvm_vcpu *vcpu)
>  	if (!entry)
>  		return -EINVAL;
>  
> -	new_entry = __sme_set(page_to_phys(svm->avic_backing_page)) |
> +	new_entry = avic_get_backing_page_address(svm) |
>  		    AVIC_PHYSICAL_ID_ENTRY_VALID_MASK;
>  	WRITE_ONCE(*entry, new_entry);
>  
> @@ -859,7 +863,7 @@ get_pi_vcpu_info(struct kvm *kvm, struct kvm_kernel_irq_routing_entry *e,
>  	pr_debug("SVM: %s: use GA mode for irq %u\n", __func__,
>  		 irq.vector);
>  	*svm = to_svm(vcpu);
> -	vcpu_info->pi_desc_addr = __sme_set(page_to_phys((*svm)->avic_backing_page));
> +	vcpu_info->pi_desc_addr = avic_get_backing_page_address(*svm);
>  	vcpu_info->vector = irq.vector;
>  
>  	return 0;
> @@ -917,7 +921,7 @@ int avic_pi_update_irte(struct kvm *kvm, unsigned int host_irq,
>  			struct amd_iommu_pi_data pi;
>  
>  			/* Try to enable guest_mode in IRTE */
> -			pi.base = __sme_set(page_to_phys(svm->avic_backing_page));
> +			pi.base = avic_get_backing_page_address(svm);
>  			pi.ga_tag = AVIC_GATAG(to_kvm_svm(kvm)->avic_vm_id,
>  						     svm->vcpu.vcpu_id);
>  			pi.is_guest_mode = true;

Reviewed-by: Maxim Levitsky <mlevitsk@...hat.com>

Best regards,
	Maxim Levitsky