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To:     isaku.yamahata@intel.com, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
        "H . Peter Anvin" <hpa@zytor.com>,
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        Connor Kuehl <ckuehl@redhat.com>,
        Sean Christopherson <seanjc@google.com>, x86@kernel.org,
        linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc:     isaku.yamahata@gmail.com,
        Sean Christopherson <sean.j.christopherson@intel.com>
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 <1ef40d74af89c4e347e46412a5d07f6e7eebf839.1625186503.git.isaku.yamahata@intel.com>
From:   Paolo Bonzini <pbonzini@redhat.com>
Subject: Re: [RFC PATCH v2 40/69] KVM: Export kvm_is_reserved_pfn() for use by
 TDX
Message-ID: <8bfa2859-1d6e-858a-85f9-2e61b4f74f32@redhat.com>
Date:   Tue, 6 Jul 2021 16:32:53 +0200
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On 03/07/21 00:04, isaku.yamahata@intel.com wrote:
> From: Sean Christopherson <sean.j.christopherson@intel.com>
> 
> TDX will use kvm_is_reserved_pfn() to prevent installing a reserved PFN
> int SEPT.  Or rather, to prevent such an attempt, as reserved PFNs are
> not covered by TDMRs.
> 
> Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@intel.com>
> ---
>   virt/kvm/kvm_main.c | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 8b075b5e7303..dd6492b526c9 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -188,6 +188,7 @@ bool kvm_is_reserved_pfn(kvm_pfn_t pfn)
>   
>   	return true;
>   }
> +EXPORT_SYMBOL_GPL(kvm_is_reserved_pfn);
>   
>   bool kvm_is_transparent_hugepage(kvm_pfn_t pfn)
>   {
> 

As before, there's no problem in squashing this in the patch that 
introduces the use of kvm_is_reserved_pfn.  You could also move 
kvm_is_reserved_pfn and kvm_is_zone_device_pfn to a .h file.

Paolo