linux-kernel - Re: [PATCH v3 3/6] x86/kexec: Disable kexec/kdump on platforms with TDX partial write erratum

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Message-ID: <f8dcbe257b3931aec9e199132b678bd7681b7efa.camel@intel.com>
Date: Wed, 2 Jul 2025 23:57:48 +0000
From: "Edgecombe, Rick P" <rick.p.edgecombe@...el.com>
To: "Annapurve, Vishal" <vannapurve@...gle.com>, "Huang, Kai"
	<kai.huang@...el.com>
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Subject: Re: [PATCH v3 3/6] x86/kexec: Disable kexec/kdump on platforms with
 TDX partial write erratum

On Wed, 2025-07-02 at 15:16 -0700, Vishal Annapurve wrote:
> > As you said it *should* be safe.  The kdump kernel should only read TDX
> > private memory but not write.  But I cannot say I am 100% sure (there are
> > many things involved when generating the kdump file such as memory
> > compression) so in internal discussion we thought we should just disable it.
> 
> So what's the side-effect of enabling kdump, in the worst case kdump
> kernel crashes and in the most likely scenario kdump will generate a
> lot of important data to analyze from the host failure.
> 
> Allowing kdump seems to be a net positive outcome to me. Am I missing
> something? If not, my vote would be to enable/allow kdump for such
> platforms in this series itself.

This reasoning makes sense. But today there is no way to even configure kexec
when TDX is configured. It blocks TDX for distro based hosts. Kdump can always
be expanded in a follow up. The series has been tricky and so it's nice to not
have to tackle all the angles before getting at least some support back.