linux-kernel - Re: [PATCH v2 00/21] Runtime TDX Module update support

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Message-ID: <CAAhR5DE=Y_uU1N6NczvZ9AJ0C7K_KNU-9Y4bBcQLkoXUDkp9kg@mail.gmail.com>
Date: Wed, 19 Nov 2025 16:44:50 -0600
From: Sagi Shahar <sagis@...gle.com>
To: Chao Gao <chao.gao@...el.com>
Cc: Vishal Annapurve <vannapurve@...gle.com>, Sean Christopherson <seanjc@...gle.com>, dan.j.williams@...el.com, 
	Erdem Aktas <erdemaktas@...gle.com>, Dave Hansen <dave.hansen@...el.com>, 
	Elena Reshetova <elena.reshetova@...el.com>, 
	"linux-coco@...ts.linux.dev" <linux-coco@...ts.linux.dev>, 
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "x86@...nel.org" <x86@...nel.org>, 
	Reinette Chatre <reinette.chatre@...el.com>, Ira Weiny <ira.weiny@...el.com>, 
	Kai Huang <kai.huang@...el.com>, "yilun.xu@...ux.intel.com" <yilun.xu@...ux.intel.com>, 
	"paulmck@...nel.org" <paulmck@...nel.org>, "nik.borisov@...e.com" <nik.borisov@...e.com>, 
	Borislav Petkov <bp@...en8.de>, Dave Hansen <dave.hansen@...ux.intel.com>, 
	"H. Peter Anvin" <hpa@...or.com>, Ingo Molnar <mingo@...hat.com>, "Kirill A. Shutemov" <kas@...nel.org>, 
	Paolo Bonzini <pbonzini@...hat.com>, Rick P Edgecombe <rick.p.edgecombe@...el.com>, 
	Thomas Gleixner <tglx@...utronix.de>
Subject: Re: [PATCH v2 00/21] Runtime TDX Module update support

On Thu, Oct 30, 2025 at 9:53 PM Chao Gao <chao.gao@...el.com> wrote:
>
> >A reference patch we tested for "Avoid updates during update-sensitive
> >times" and one caveat was that
> >/sys/devices/virtual/tdx/tdx_tsm/version was not available post update
> >failure until a subsequent successful update:
>
> I also tested this. It works well to prevent updates during TD build, so,
>
>   Tested-by: Chao Gao <chao.gao@...el.com>
>
> And I can integrate this change into my next version if you don't object.
>
> Regarding the caveat, could you check if the diff [*] I posted earlier this
> week can fix it?
>
> [1]: https://lore.kernel.org/linux-coco/aQAwRrvYMcaMsu02@intel.com/

[Now in plaintext]

I tried testing it with the 1.5.24 TDX module and it sometimes fails,
but the failure does not appear consistent.

I added a local change to add the
TDX_SYS_SHUTDOWN_AVOID_COMPAT_SENSITIVE flag when calling
TDH_SYS_SHUTDOWN and TDH_SYS_SHUTDOWN fails as expected if a VM is
under build:
[ 1224.571177] virt/tdx: SEAMCALL (52) failed: 0x8000051200010000

But then sometimes trying to finalize the VM fail with the following error:
[ 1230.915145] kvm_intel: SEAMCALL TDH_MR_FINALIZE failed: 0x8000ff00ffff0000
[ 1230.948264] kvm_intel: tdh_mng_vpflushdone() failed. HKID 3 is leaked.

At this point the module seems to be in a broken state and trying to
create more TDs will fail:
[ 1543.745606] kvm_intel: SEAMCALL TDH_MNG_CREATE failed: 0x8000ff00ffff0000

Trying to update the module will fail shutdown with -ENODEV