Re: linux-next: build failure after merge of the iommu tree

From: "Lendacky, Thomas" <Thomas.Lendacky@amd.com>
To: Joerg Roedel <joro@8bytes.org>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	Thiago Jung Bauermann <bauerman@linux.ibm.com>,
	Michael Ellerman <mpe@ellerman.id.au>
Cc: Linux Next Mailing List <linux-next@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: linux-next: build failure after merge of the iommu tree
Date: Mon, 2 Sep 2019 14:26:40 +0000	[thread overview]
Message-ID: <d2493e6b-08fa-9ea8-a0a4-076def54e91b@amd.com> (raw)
In-Reply-To: <20190902140347.GA23482@8bytes.org>

On 9/2/19 9:03 AM, Joerg Roedel wrote:
> Hi,
> 
> tl;dr: And IOMMU commit introduces a new user for sme_active() in
>         generic code, and commit
> 
>         	284e21fab2cf x86, s390/mm: Move sme_active() and sme_me_mask to x86-specific header
> 
>         breaks the build of drivers/iommu/ for all architectures not
>         implementing sme_active().
> 
> On Mon, Sep 02, 2019 at 04:39:51PM +1000, Stephen Rothwell wrote:
>> drivers/iommu/iommu.c: In function 'iommu_subsys_init':
>> drivers/iommu/iommu.c:123:38: error: implicit declaration of function 'sme_active'; did you mean 'cpu_active'? [-Werror=implicit-function-declaration]
>>    123 |   if (iommu_default_passthrough() && sme_active()) {

Maybe we should make this mem_encrypt_active(), since this will probably
be needed if/when an IOMMU device is eventually added to a guest, and the
referenced commit below doesn't remove that call.

Thanks,
Tom

>>        |                                      ^~~~~~~~~~
>>        |                                      cpu_active
>>
>> Caused by commit
>>
>>    2cc13bb4f59f ("iommu: Disable passthrough mode when SME is active")
> 
> 
> Actually it is caused by:
> 
> 	commit 284e21fab2cfcf90dacce565e0b12f29e5df00c1
> 	Author: Thiago Jung Bauermann <bauerman@linux.ibm.com>
> 	Date:   Tue Aug 6 01:49:17 2019 -0300
> 
> 	    x86, s390/mm: Move sme_active() and sme_me_mask to x86-specific header
> 
> which removes the sme_active prototype from the generic headers. The
> iommu commit is in next already for a couple of days and didn't cause
> problems before.
> 
>> sme_active() seems to be only relevant to X86.
> 
> It has an implementation on x86 and s390.
> 
>> I have reverted that commit for today.
> 
> Thanks, but I suggest reverting above commit instead.
> 
> 
> Regards,
> 
> 	Joerg
> 