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Date:   Tue, 28 Jun 2022 08:48:35 +0800
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Subject: Re: [PATCH v5 15/22] x86/virt/tdx: Allocate and set up PAMTs for
 TDMRs
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To:     Dave Hansen <dave.hansen@intel.com>,
        Kai Huang <kai.huang@intel.com>, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org
Cc:     seanjc@google.com, pbonzini@redhat.com, len.brown@intel.com,
        tony.luck@intel.com, rafael.j.wysocki@intel.com,
        reinette.chatre@intel.com, dan.j.williams@intel.com,
        peterz@infradead.org, ak@linux.intel.com,
        kirill.shutemov@linux.intel.com,
        sathyanarayanan.kuppuswamy@linux.intel.com,
        isaku.yamahata@intel.com
References: <cover.1655894131.git.kai.huang@intel.com>
 <c504a8acd06dc455050c25e2a4cc70aef5eb9358.1655894131.git.kai.huang@intel.com>
 <e72703b0-767a-ec88-7cb6-f95a3564d823@intel.com>
 <b376aef05bc032fdf8cc23762ce77a14830440cd.camel@intel.com>
 <b43bf089-1202-a1fe-cbb3-d4e0926cab67@intel.com>
From:   Xiaoyao Li <xiaoyao.li@intel.com>
In-Reply-To: <b43bf089-1202-a1fe-cbb3-d4e0926cab67@intel.com>
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On 6/28/2022 4:41 AM, Dave Hansen wrote:
> On 6/27/22 03:31, Kai Huang wrote:
>>>> +/* Page sizes supported by TDX */
>>>> +enum tdx_page_sz {
>>>> +	TDX_PG_4K,
>>>> +	TDX_PG_2M,
>>>> +	TDX_PG_1G,
>>>> +	TDX_PG_MAX,
>>>> +};
>>> Are these the same constants as the magic numbers in Kirill's
>>> try_accept_one()?
>> try_accept_once() uses 'enum pg_level' PG_LEVEL_{4K,2M,1G} directly.  They can
>> be used directly too, but 'enum pg_level' has more than we need here:
> 
> I meant this:
> 
> +       switch (level) {
> +       case PG_LEVEL_4K:
> +               page_size = 0;
> +               break;
> 
> Because TDX_PG_4K==page_size==0, and for this:
> 
> +       case PG_LEVEL_2M:
> +               page_size = 1;

here we can just do

	page_size = level - 1;

or
	
	tdx_page_level = level - 1;

yes, TDX's page level definition is one level smaller of Linux's definition.

> where TDX_PG_2M==page_size==1
> 
> See?
> 
> Are Kirill's magic 0/1/2 numbers the same as
> 
> 	TDX_PG_4K,
> 	TDX_PG_2M,
> 	TDX_PG_1G,
> 
> ?