linux-kernel - Re: [PATCH v4 14/14] KVM/nVMX: Use kvm_vcpu

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Date:   Thu, 06 Dec 2018 18:46:09 +0100
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     KarimAllah Ahmed <karahmed@...zon.de>
Cc:     rkrcmar@...hat.com, pbonzini@...hat.com,
        linux-kernel@...r.kernel.org, kvm@...r.kernel.org,
        jmattson@...gle.com
Subject: Re: [PATCH v4 14/14] KVM/nVMX: Use kvm_vcpu_map for accessing the enhanced VMCS

KarimAllah Ahmed <karahmed@...zon.de> writes:

> Use kvm_vcpu_map for accessing the enhanced VMCS since using

just a nitpick: "eVMCS" stands for Enlightened VMCS, not 'enhanced' :-)

> kvm_vcpu_gpa_to_page() and kmap() will only work for guest memory that has
> a "struct page".
>
> Signed-off-by: KarimAllah Ahmed <karahmed@...zon.de>
> ---
>  arch/x86/kvm/vmx.c | 16 ++++++----------
>  1 file changed, 6 insertions(+), 10 deletions(-)
>
> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
> index a958700..83a614f 100644
> --- a/arch/x86/kvm/vmx.c
> +++ b/arch/x86/kvm/vmx.c
> @@ -894,7 +894,7 @@ struct nested_vmx {
>  	} smm;
>  
>  	gpa_t hv_evmcs_vmptr;
> -	struct page *hv_evmcs_page;
> +	struct kvm_host_map hv_evmcs_map;
>  	struct hv_enlightened_vmcs *hv_evmcs;
>  };
>  
> @@ -8456,10 +8456,8 @@ static inline void nested_release_evmcs(struct kvm_vcpu *vcpu)
>  	if (!vmx->nested.hv_evmcs)
>  		return;
>  
> -	kunmap(vmx->nested.hv_evmcs_page);
> -	kvm_release_page_dirty(vmx->nested.hv_evmcs_page);
> +	kvm_vcpu_unmap(&vmx->nested.hv_evmcs_map);
>  	vmx->nested.hv_evmcs_vmptr = -1ull;
> -	vmx->nested.hv_evmcs_page = NULL;
>  	vmx->nested.hv_evmcs = NULL;
>  }
>  
> @@ -8559,7 +8557,7 @@ static int handle_vmclear(struct kvm_vcpu *vcpu)
>  		return nested_vmx_failValid(vcpu,
>  			VMXERR_VMCLEAR_VMXON_POINTER);
>  
> -	if (vmx->nested.hv_evmcs_page) {
> +	if (vmx->nested.hv_evmcs_map.hva) {
>  		if (vmptr == vmx->nested.hv_evmcs_vmptr)
>  			nested_release_evmcs(vcpu);
>  	} else {
> @@ -9355,13 +9353,11 @@ static int nested_vmx_handle_enlightened_vmptrld(struct kvm_vcpu *vcpu,
>  
>  		nested_release_evmcs(vcpu);
>  
> -		vmx->nested.hv_evmcs_page = kvm_vcpu_gpa_to_page(
> -			vcpu, assist_page.current_nested_vmcs);
> -
> -		if (unlikely(is_error_page(vmx->nested.hv_evmcs_page)))
> +		if (kvm_vcpu_map(vcpu, gpa_to_gfn(assist_page.current_nested_vmcs),
> +				 &vmx->nested.hv_evmcs_map))
>  			return 0;
>  
> -		vmx->nested.hv_evmcs = kmap(vmx->nested.hv_evmcs_page);
> +		vmx->nested.hv_evmcs = vmx->nested.hv_evmcs_map.hva;
>  
>  		/*
>  		 * Currently, KVM only supports eVMCS version 1

-- 
Vitaly