linux-kernel - Re: [PATCH v4 0/7] TDX host: kexec/kdump support

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Message-ID: <66a71a55117b64cad61a9c9206f8142dca03e18b.camel@intel.com>
Date: Mon, 21 Jul 2025 21:30:53 +0000
From: "Huang, Kai" <kai.huang@...el.com>
To: "thomas.lendacky@....com" <thomas.lendacky@....com>, "tglx@...utronix.de"
	<tglx@...utronix.de>, "peterz@...radead.org" <peterz@...radead.org>, "Hansen,
 Dave" <dave.hansen@...el.com>, "mingo@...hat.com" <mingo@...hat.com>,
	"bp@...en8.de" <bp@...en8.de>, "hpa@...or.com" <hpa@...or.com>
CC: "ashish.kalra@....com" <ashish.kalra@....com>, "Edgecombe, Rick P"
	<rick.p.edgecombe@...el.com>, "seanjc@...gle.com" <seanjc@...gle.com>,
	"x86@...nel.org" <x86@...nel.org>, "kas@...nel.org" <kas@...nel.org>, "Gao,
 Chao" <chao.gao@...el.com>, "Chatre, Reinette" <reinette.chatre@...el.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "Williams, Dan
 J" <dan.j.williams@...el.com>, "sagis@...gle.com" <sagis@...gle.com>,
	"pbonzini@...hat.com" <pbonzini@...hat.com>, "kvm@...r.kernel.org"
	<kvm@...r.kernel.org>, "dwmw@...zon.co.uk" <dwmw@...zon.co.uk>, "Yamahata,
 Isaku" <isaku.yamahata@...el.com>, "nik.borisov@...e.com"
	<nik.borisov@...e.com>
Subject: Re: [PATCH v4 0/7] TDX host: kexec/kdump support

On Mon, 2025-07-21 at 09:50 -0500, Tom Lendacky wrote:
> On 7/21/25 08:08, Tom Lendacky wrote:
> > On 7/17/25 16:46, Kai Huang wrote:
> > > This series is the latest attempt to support kexec on TDX host following
> > > Dave's suggestion to use a percpu boolean to control WBINVD during
> > > kexec.
> > > 
> > > Hi Boris/Tom,
> > > 
> > > As requested, I added the first patch to cleanup the last two 'unsigned
> > > int' parameters of the relocate_kernel() into one 'unsigned int' and pass
> > > flags instead.  The patch 2 (patch 1 in v3) also gets updated based on
> > > that.  Would you help to review?  Thanks.
> > > 
> > > I tested that both normal kexec and preserve_context kexec works (using
> > > the tools/testing/selftests/kexec/test_kexec_jump.sh).  But I don't have
> > > SME capable machine to test.
> > > 
> > > Hi Tom, I added your Reviewed-by and Tested-by in the patch 2 anyway
> > > since I believe the change is trivial and straightforward).  But due to
> > > the cleanup patch, I appreciate if you can help to test the first two
> > > patches again.  Thanks a lot!
> > 
> > Everything is working, Thanks!
> 
> See my comments in patch #1. I didn't test with context preservation, so
> that bit was never set. If it was, I think things would have failed.

I actually tested the test_kexec_jump.sh in kselftest as mentioned above
in a VM.  I got "# kexec_jump succeeded [PASS]" so I think it worked :-) 
But unfortunately I don't know how to test preserve_context kexec in any
other way.