Re: Ranconfig failure between VT-d and HVM

[Jan Beulich <jbeulich@xxxxxxxx>]

On 20.04.2022 20:01, Andrew Cooper wrote:
> On 20/04/2022 18:49, Andrew Cooper wrote:
>> https://gitlab.com/xen-project/people/andyhhp/xen/-/jobs/2355562119
>>
>> ld: prelink.o: in function `vtd_setup':
>> drivers/passthrough/vtd/iommu.c:(.init.text+0x219f6): undefined
>> reference to `opt_hap_2mb'
>> drivers/passthrough/vtd/iommu.c:(.init.text+0x219f6): relocation
>> truncated to fit: R_X86_64_PC32 against undefined symbol `opt_hap_2mb'
>> ld: drivers/passthrough/vtd/iommu.c:(.init.text+0x21a23): undefined
>> reference to `opt_hap_1gb'
>> drivers/passthrough/vtd/iommu.c:(.init.text+0x21a23): relocation
>> truncated to fit: R_X86_64_PC32 against undefined symbol `opt_hap_1gb'
>> ld: ./.xen-syms.0: hidden symbol `opt_hap_2mb' isn't defined
>> ld: final link failed: bad value
>> make[3]: *** [arch/x86/Makefile:137: xen-syms] Error 1
>>
>> It's really not clear why this has first show up now.  There has been a
>> huge quantity of noise in Gitlab CI for the past 3 weeks with ARM being
>> offline, but I can't see anything relevant in the large number of IOMMU
>> changes in that period.
>>
>> Anyway, the issue is simple.  It's vtd_ept_page_compatible() in a
>> !CONFIG_HVM build.
> 
> And just after sending, I realised it's not an IOMMU change.
> 
> commit c479415610f0448bb07d39185e72ef36e08ebec0
> Author: Jan Beulich <jbeulich@xxxxxxxx>
> Date:   Fri Apr 8 13:50:29 2022
> 
>     x86/P2M: p2m.c is HVM-only
> 
> 
> CI disputes the claim.

Just as an intermediate result: In my !HVM build (with gcc11) this

        if ( !vtd_ept_page_compatible(iommu) )
            clear_iommu_hap_pt_share();

simply compiles to nothing, which I assume is the result of
clear_iommu_hap_pt_share() doing nothing in that case. Hence no
reference to opt_hap_{2mb,1gb}.

Jan