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Date:   Fri, 24 Jun 2022 10:12:05 +0800
From:   Chao Gao <chao.gao@intel.com>
To:     Kai Huang <kai.huang@intel.com>
Cc:     linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
        linux-mm@kvack.org, seanjc@google.com, pbonzini@redhat.com,
        dave.hansen@intel.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, akpm@linux-foundation.org
Subject: Re: [PATCH v5 05/22] x86/virt/tdx: Prevent hot-add driver managed
 memory
Message-ID: <20220624021200.GB15566@gao-cwp>
References: <cover.1655894131.git.kai.huang@intel.com>
 <173e1f9b2348f29e5f7d939855b8dd98625bcb35.1655894131.git.kai.huang@intel.com>
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On Wed, Jun 22, 2022 at 11:16:19PM +1200, Kai Huang wrote:
>@@ -55,6 +55,7 @@
> #include <asm/uv/uv.h>
> #include <asm/setup.h>
> #include <asm/ftrace.h>
>+#include <asm/tdx.h>
> 
> #include "mm_internal.h"
> 
>@@ -972,6 +973,26 @@ int arch_add_memory(int nid, u64 start, u64 size,
> 	return add_pages(nid, start_pfn, nr_pages, params);
> }
> 
>+int arch_memory_add_precheck(int nid, u64 start, u64 size, mhp_t mhp_flags)
>+{
>+	if (!platform_tdx_enabled())
>+		return 0;

add a new cc attribute (if existing ones don't fit) for TDX host platform and
check the attribute here. So that the code here can be reused by other cc
platforms if they have the same requirement.