linux-kernel - Re: [PATCH v4 00/12] Unify TDCALL/SEAMCALL and TDVMCALL assembly

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Date:   Tue, 12 Sep 2023 15:37:49 +0200
From:   Paolo Bonzini <pbonzini@...hat.com>
To:     "Huang, Kai" <kai.huang@...el.com>,
        "kirill.shutemov@...ux.intel.com" <kirill.shutemov@...ux.intel.com>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Cc:     "Hansen, Dave" <dave.hansen@...el.com>,
        "Christopherson,, Sean" <seanjc@...gle.com>,
        "bp@...en8.de" <bp@...en8.de>, "x86@...nel.org" <x86@...nel.org>,
        "hpa@...or.com" <hpa@...or.com>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "tglx@...utronix.de" <tglx@...utronix.de>,
        "sathyanarayanan.kuppuswamy@...ux.intel.com" 
        <sathyanarayanan.kuppuswamy@...ux.intel.com>,
        "Yamahata, Isaku" <isaku.yamahata@...el.com>,
        "n.borisov.lkml@...il.com" <n.borisov.lkml@...il.com>
Subject: Re: [PATCH v4 00/12] Unify TDCALL/SEAMCALL and TDVMCALL assembly

On 9/12/23 02:57, Huang, Kai wrote:
>>> +#include <asm/tdx.h>
>>> 
>>> #include <asm-generic/asm-prototypes.h>
>>> 
>> Thanks Paolo!
>> 
>> I never met this issue, not even from LKP.  Do you happen to know
>> which Kconfig option can trigger this?  Or would you mind sharing
>> your .config?
> (replying via outlook due to some networking issue of my home
> network)
> 
> After digging, this is due to exporting __seamcall*() assembly
> functions while MODVERSIONS is enabled.
> 
> This series itself doesn't cause this warning.
> 
> I didn't export them in this series because I would like to leave to
> KVM patches when we are sure we need to export them.
> 
> E.g., I have seamcall*() wrappers to retry running out of entropy,
> and we may have concern exporting __seamcall*() low level functions
> directly and may wish to export higher level wrappers.
> 
> So I think the fix should be with the patch that truly exports those
> __seamcall*().  I'll talk to Isaku on this to get his idea.

Ah indeed it's not caused by your patches, but rather by the Isaku's KVM 
TDX support ("KVM: TDX: Add C wrapper functions for SEAMCALLs to the TDX 
module").  The fix is just to squash the #include into his patch.

Paolo