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Message-ID: <dd3f7acb-4a35-4a87-a664-1d02181fe090@intel.com>
Date: Wed, 28 Feb 2024 12:12:20 +1300
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCHv8 08/17] x86/tdx: Account shared memory
Content-Language: en-US
To: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, Thomas Gleixner
	<tglx@linutronix.de>, Ingo Molnar <mingo@redhat.com>, Borislav Petkov
	<bp@alien8.de>, Dave Hansen <dave.hansen@linux.intel.com>, <x86@kernel.org>
CC: "Rafael J. Wysocki" <rafael@kernel.org>, Peter Zijlstra
	<peterz@infradead.org>, Adrian Hunter <adrian.hunter@intel.com>, "Kuppuswamy
 Sathyanarayanan" <sathyanarayanan.kuppuswamy@linux.intel.com>, "Elena
 Reshetova" <elena.reshetova@intel.com>, Jun Nakajima
	<jun.nakajima@intel.com>, Rick Edgecombe <rick.p.edgecombe@intel.com>, Tom
 Lendacky <thomas.lendacky@amd.com>, "Kalra, Ashish" <ashish.kalra@amd.com>,
	"Sean Christopherson" <seanjc@google.com>, Baoquan He <bhe@redhat.com>,
	<kexec@lists.infradead.org>, <linux-coco@lists.linux.dev>,
	<linux-kernel@vger.kernel.org>
References: <20240227212452.3228893-1-kirill.shutemov@linux.intel.com>
 <20240227212452.3228893-9-kirill.shutemov@linux.intel.com>
From: "Huang, Kai" <kai.huang@intel.com>
In-Reply-To: <20240227212452.3228893-9-kirill.shutemov@linux.intel.com>
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On 28/02/2024 10:24 am, Kirill A. Shutemov wrote:
> The kernel will convert all shared memory back to private during kexec.
> The direct mapping page tables will provide information on which memory
> is shared.
> 
> It is extremely important to convert all shared memory. If a page is
> missed, it will cause the second kernel to crash when it accesses it.
> 
> Keep track of the number of shared pages. This will allow for
> cross-checking against the shared information in the direct mapping and
> reporting if the shared bit is lost.
> 
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>

Reviewed-by: Kai Huang <kai.huang@intel.com>