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Date: Thu, 21 Mar 2024 09:48:28 +1300
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Subject: Re: [PATCH v2 2/5] x86/kexec: do unconditional WBINVD in
 relocate_kernel()
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To: Tom Lendacky <thomas.lendacky@amd.com>, "Kirill A. Shutemov"
	<kirill.shutemov@linux.intel.com>
CC: <linux-kernel@vger.kernel.org>, <x86@kernel.org>, <dave.hansen@intel.com>,
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	<nik.borisov@suse.com>, <pbonzini@redhat.com>, <seanjc@google.com>
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From: "Huang, Kai" <kai.huang@intel.com>
In-Reply-To: <5a2441a3-4d7e-4fee-bfa7-65b53376b0ab@amd.com>
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>> Hi Tom,
>>
>> I am not aware of kexec() support status for SEV-ES/SEV-SNP guests. 
>> Does patch 1 break them?
> 
> SNP guests can kexec with some patches that are currently in process 
> around shared to private memory conversions. ES guests can only kexec 
> with a single vCPU. There was a recent patch series to add support for 
> multiple vCPUs.
> 
> Patch #1 doesn't break either ES or SNP because we still have an IDT and 
> traditional kernel addressing in place, so the #VC can be handled.

How about plain SEV guest?

> 
> Whereas patch #2 has switched to identity mapping and removed the IDT, 
> so a #VC causes a triple fault.

That makes sense.  Thanks.

Hi Kirill,

Does TDX guest have similar behaviour -- that WBINVD in stop_this_cpu() 
can be handled although it causes #VE, while WBINVD in relocate_kernel() 
will just triple fault the guest?