Re: [PATCH AUTOSEL 6.17] x86/virt/tdx: Mark memory cache state incoherent when making SEAMCALL

[Sasha Levin <sashal@kernel.org>]

On Sun, Oct 26, 2025 at 10:25:02PM +0000, Huang, Kai wrote:
>On Sat, 2025-10-25 at 11:59 -0400, Sasha Levin wrote:
>> From: Kai Huang <kai.huang@intel.com>
>>
>> [ Upstream commit 10df8607bf1a22249d21859f56eeb61e9a033313 ]
>>
>>
>[...]
>
>> ---
>>
>> LLM Generated explanations, may be completely bogus:
>>
>> YES
>>
>> Why this fixes a real bug
>> - TDX can leave dirty cachelines for private memory with different
>>   encryption attributes (C-bit aliases). If kexec interrupts a CPU
>>   during a SEAMCALL, its dirty private cachelines can later be flushed
>>   in the wrong order and silently corrupt the new kernel’s memory.
>>   Marking the CPU’s cache state as “incoherent” before executing
>>   SEAMCALL ensures kexec will WBINVD on that CPU and avoid corruption.
>
>
>Hi,
>
>I don't think we should backport this for 6.17 stable.  Kexec/kdump and
>TDX are mutually exclusive in Kconfig in 6.17, therefore it's not possible
>for TDX to impact kexec/kdump.
>
>This patch is part of the series which enables kexec/kdump together with
>TDX in Kconfig (which landed in 6.18) and should not be backported alone.

I'll drop it, thanks for the review!

-- 
Thanks,
Sasha