2023-02-22 07:33:22

by Randy Dunlap

[permalink] [raw]
Subject: [PATCH] KVM: SVM: hyper-v: placate modpost section mismatch error

modpost reports section mismatch errors/warnings:
WARNING: modpost: vmlinux.o: section mismatch in reference: svm_hv_hardware_setup (section: .text) -> (unknown) (section: .init.data)
WARNING: modpost: vmlinux.o: section mismatch in reference: svm_hv_hardware_setup (section: .text) -> (unknown) (section: .init.data)
WARNING: modpost: vmlinux.o: section mismatch in reference: svm_hv_hardware_setup (section: .text) -> (unknown) (section: .init.data)

Marking svm_hv_hardware_setup() as __init fixes the warnings.

I don't know why this should be needed -- it seems like a compiler
problem to me since the calling function is marked as __init.

This "(unknown) (section: .init.data)" all refer to svm_x86_ops.

Fixes: 1e0c7d40758b ("KVM: SVM: hyper-v: Remote TLB flush for SVM")
Signed-off-by: Randy Dunlap <[email protected]>
Cc: Vineeth Pillai <[email protected]>
Cc: Paolo Bonzini <[email protected]>
Cc: Vitaly Kuznetsov <[email protected]>
Cc: Sean Christopherson <[email protected]>
Cc: [email protected]
---
arch/x86/kvm/svm/svm_onhyperv.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff -- a/arch/x86/kvm/svm/svm_onhyperv.h b/arch/x86/kvm/svm/svm_onhyperv.h
--- a/arch/x86/kvm/svm/svm_onhyperv.h
+++ b/arch/x86/kvm/svm/svm_onhyperv.h
@@ -30,7 +30,7 @@ static inline void svm_hv_init_vmcb(stru
hve->hv_enlightenments_control.msr_bitmap = 1;
}

-static inline void svm_hv_hardware_setup(void)
+static inline __init void svm_hv_hardware_setup(void)
{
if (npt_enabled &&
ms_hyperv.nested_features & HV_X64_NESTED_ENLIGHTENED_TLB) {


2023-02-22 14:16:17

by Vitaly Kuznetsov

[permalink] [raw]
Subject: Re: [PATCH] KVM: SVM: hyper-v: placate modpost section mismatch error

Randy Dunlap <[email protected]> writes:

> modpost reports section mismatch errors/warnings:
> WARNING: modpost: vmlinux.o: section mismatch in reference: svm_hv_hardware_setup (section: .text) -> (unknown) (section: .init.data)
> WARNING: modpost: vmlinux.o: section mismatch in reference: svm_hv_hardware_setup (section: .text) -> (unknown) (section: .init.data)
> WARNING: modpost: vmlinux.o: section mismatch in reference: svm_hv_hardware_setup (section: .text) -> (unknown) (section: .init.data)
>
> Marking svm_hv_hardware_setup() as __init fixes the warnings.
>
> I don't know why this should be needed -- it seems like a compiler
> problem to me since the calling function is marked as __init.
>
> This "(unknown) (section: .init.data)" all refer to svm_x86_ops.
>
> Fixes: 1e0c7d40758b ("KVM: SVM: hyper-v: Remote TLB flush for SVM")
> Signed-off-by: Randy Dunlap <[email protected]>
> Cc: Vineeth Pillai <[email protected]>
> Cc: Paolo Bonzini <[email protected]>
> Cc: Vitaly Kuznetsov <[email protected]>
> Cc: Sean Christopherson <[email protected]>
> Cc: [email protected]
> ---
> arch/x86/kvm/svm/svm_onhyperv.h | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff -- a/arch/x86/kvm/svm/svm_onhyperv.h b/arch/x86/kvm/svm/svm_onhyperv.h
> --- a/arch/x86/kvm/svm/svm_onhyperv.h
> +++ b/arch/x86/kvm/svm/svm_onhyperv.h
> @@ -30,7 +30,7 @@ static inline void svm_hv_init_vmcb(stru
> hve->hv_enlightenments_control.msr_bitmap = 1;
> }
>
> -static inline void svm_hv_hardware_setup(void)
> +static inline __init void svm_hv_hardware_setup(void)
> {
> if (npt_enabled &&
> ms_hyperv.nested_features & HV_X64_NESTED_ENLIGHTENED_TLB) {
>

There's a second empty svm_hv_hardware_setup() implementation 50 lines
below in the same file for !if IS_ENABLED(CONFIG_HYPERV) case and I
think it needs to be marked as '__init' as well.

--
Vitaly


2023-02-22 16:18:54

by Randy Dunlap

[permalink] [raw]
Subject: Re: [PATCH] KVM: SVM: hyper-v: placate modpost section mismatch error



On 2/22/23 06:15, Vitaly Kuznetsov wrote:
> Randy Dunlap <[email protected]> writes:
>
>> modpost reports section mismatch errors/warnings:
>> WARNING: modpost: vmlinux.o: section mismatch in reference: svm_hv_hardware_setup (section: .text) -> (unknown) (section: .init.data)
>> WARNING: modpost: vmlinux.o: section mismatch in reference: svm_hv_hardware_setup (section: .text) -> (unknown) (section: .init.data)
>> WARNING: modpost: vmlinux.o: section mismatch in reference: svm_hv_hardware_setup (section: .text) -> (unknown) (section: .init.data)
>>
>> Marking svm_hv_hardware_setup() as __init fixes the warnings.
>>
>> I don't know why this should be needed -- it seems like a compiler
>> problem to me since the calling function is marked as __init.
>>
>> This "(unknown) (section: .init.data)" all refer to svm_x86_ops.
>>
>> Fixes: 1e0c7d40758b ("KVM: SVM: hyper-v: Remote TLB flush for SVM")
>> Signed-off-by: Randy Dunlap <[email protected]>
>> Cc: Vineeth Pillai <[email protected]>
>> Cc: Paolo Bonzini <[email protected]>
>> Cc: Vitaly Kuznetsov <[email protected]>
>> Cc: Sean Christopherson <[email protected]>
>> Cc: [email protected]
>> ---
>> arch/x86/kvm/svm/svm_onhyperv.h | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff -- a/arch/x86/kvm/svm/svm_onhyperv.h b/arch/x86/kvm/svm/svm_onhyperv.h
>> --- a/arch/x86/kvm/svm/svm_onhyperv.h
>> +++ b/arch/x86/kvm/svm/svm_onhyperv.h
>> @@ -30,7 +30,7 @@ static inline void svm_hv_init_vmcb(stru
>> hve->hv_enlightenments_control.msr_bitmap = 1;
>> }
>>
>> -static inline void svm_hv_hardware_setup(void)
>> +static inline __init void svm_hv_hardware_setup(void)
>> {
>> if (npt_enabled &&
>> ms_hyperv.nested_features & HV_X64_NESTED_ENLIGHTENED_TLB) {
>>
>
> There's a second empty svm_hv_hardware_setup() implementation 50 lines
> below in the same file for !if IS_ENABLED(CONFIG_HYPERV) case and I
> think it needs to be marked as '__init' as well.
>

I saw that. I can make that change also. I was optimistic that since it is
empty, gcc would not be fooled by it.

v2 later today.

thanks.
--
~Randy