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Message-ID: <bea44699-f0c0-4904-bbed-a987b1b97cf0@intel.com>
Date: Thu, 16 May 2024 11:14:54 +1200
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH 08/16] KVM: x86/mmu: Bug the VM if kvm_zap_gfn_range() is
 called for TDX
To: "Edgecombe, Rick P" <rick.p.edgecombe@intel.com>, "kvm@vger.kernel.org"
	<kvm@vger.kernel.org>, "pbonzini@redhat.com" <pbonzini@redhat.com>,
	"seanjc@google.com" <seanjc@google.com>
CC: "Zhao, Yan Y" <yan.y.zhao@intel.com>, "sagis@google.com"
	<sagis@google.com>, "dmatlack@google.com" <dmatlack@google.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"isaku.yamahata@gmail.com" <isaku.yamahata@gmail.com>, "Aktas, Erdem"
	<erdemaktas@google.com>
References: <20240515005952.3410568-1-rick.p.edgecombe@intel.com>
 <20240515005952.3410568-9-rick.p.edgecombe@intel.com>
 <621f313d3ab43e3d5988a7192a047de588e4c1f5.camel@intel.com>
 <d0c16dc46ca0b21bffb2abeb3227d4d7f63ebaac.camel@intel.com>
Content-Language: en-US
From: "Huang, Kai" <kai.huang@intel.com>
In-Reply-To: <d0c16dc46ca0b21bffb2abeb3227d4d7f63ebaac.camel@intel.com>
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On 16/05/2024 3:22 am, Edgecombe, Rick P wrote:
> On Wed, 2024-05-15 at 13:27 +0000, Huang, Kai wrote:
>>
>> kvm_zap_gfn_range() looks a generic function.  I think it makes more sense
>> to let the callers to explicitly check whether VM is TDX guest and do the
>> KVM_BUG_ON()?
> 
> Other TDX changes will prevent this function getting called. So basically like
> you are suggesting. This change is to catch any new cases that pop up, which we
> can't do at the caller.

But I think we need to see whether calling kvm_zap_gfn_range() is legal 
or not for TDX guest case by case, but not having a universal rule that 
this cannot be called for TDX guest, right?