Re: [Qemu-devel] [PATCH] kvm: workaround build break on gcc-7.1.1 / fedora26

[Philippe Mathieu-Daudé]

Hi Greg,

On 08/02/2017 11:47 AM, Greg Kurz wrote:
> Building QEMU on fedora26 with the latest gcc package fails:
>
>    CC      ppc64-softmmu/target/ppc/kvm.o
> In file included from include/sysemu/hw_accel.h:16:0,
>                   from target/ppc/kvm.c:31:
> target/ppc/kvm.c: In function ‘kvmppc_booke_watchdog_enable’:
> include/sysemu/kvm.h:449:35: error: ‘args_tmp[i]’ may be used uninitialized
>   in this function [-Werror=maybe-uninitialized]
>               cap.args[i] = args_tmp[i];                               \
>                                     ^
> target/ppc/kvm.c: In function ‘kvmppc_set_papr’:
> include/sysemu/kvm.h:449:35: error: ‘args_tmp[i]’ may be used uninitialized
>   in this function [-Werror=maybe-uninitialized]
> cc1: all warnings being treated as errors

I'm trying to reproduce this in our docker images (all x86_64 based) but 
can't reproduce.

./configure shows:

KVM support       yes

but in "sysemu/kvm.h" CONFIG_KVM_IS_POSSIBLE is not defined

I can see CONFIG_KVM defined, but no NEED_CPU_H.

>
> $ rpm -q gcc
> gcc-7.1.1-3.fc26.ppc64le

I don't have native ppc64le to build, do you know if it is possible to 
cross-compile enabling kvm? It seems I have the correct Linux headers, I 
wonder if this isn't a ./configure test which disable the kvm cross-build.

Regards,

Phil.