Re: KVM-PR no longer works when compiled with new GCC compilers

Hi Christian,

On Thu, 2026-04-23 at 18:50 +0200, Christian Zigotzky wrote:
> On 02/10/25 08:37, Christian Zigotzky wrote:
> > Hello,
> >=20
> > KVM-PR (-enable-kvm) doesn't work anymore on our PA Semi Nemo boards=
=20
> > [1] if we compiled it with new GCC compilers.
> > The VM can't boot. There aren't any messages on the serial console of=
=20
> > QEMU.
> >=20
> > It boots without KVM-PR.
> >=20
> > Kernel config with new GCC compiler [2]:
> >=20
> > - CONFIG_CC_VERSION_TEXT=3D"powerpc64-suse-linux-gcc (SUSE Linux) 11.5.=
0"
> > - CONFIG_TARGET_CPU=3D"power4"
> > - CONFIG_TUNE_CPU=3D"-mtune=3Dpower10"
> >=20
> > It works if I compile it with an old GCC compiler [3]:
> >=20
> > - CONFIG_CC_VERSION_TEXT=3D"powerpc-linux-gnu-gcc (Ubuntu=20
> > 9.4.0-1ubuntu1~20.04.1) 9.4.0"
> > - CONFIG_TARGET_CPU=3D"power4"
> > - CONFIG_TUNE_CPU=3D"-mtune=3Dpower9"
> >=20
> > Mtune changes to power9 automatically if I compiled it with an old GCC=
=20
> > compiler. If I compile it with a new GCC compiler again it changes=20
> > automatically to mtune=3Dpower10.
> >=20
> > Is mtune the reason of the KVM-PR issue? I think the issue is the new=
=20
> > GCC. [4]
> >=20
> > Could you please check whether KVM-PR is compatible with new versions=
=20
> > of GCC compilers?
> >=20
> > Thanks in advance,
> >=20
> > Christian
> >=20
> >=20
> >=20
> > [1] https://en.wikipedia.org/wiki/AmigaOne_X1000
> >=20
> > [2]=20
> > https://github.com/chzigotzky/kernels/blob/45186997e6f347fd092f9ab629d6=
2d6041426227/configs/x1000_defconfig
> >=20
> > [3]=20
> > https://github.com/chzigotzky/kernels/blob/bc7a3e27b3fcdee52a8135435f02=
cf807a43872a/configs/x1000_defconfig
> >=20
> > [4] KVM-PR no longer works on an X1000 if the kernel has been compiled=
=20
> > with a new GCC:=20
> > https://forum.hyperion-entertainment.com/viewtopic.php?p=3D57146#p57146
> >=20
> Error messages (kvm-pr compiled with powerpc64-linux-gnu-gcc 14.1.1=20
> 20240507 Red Hat Cross 14.1.1-1, GNU ld version 2.41-2.el10_0):
>=20
> [=C2=A0 800.274759] Couldn't emulate instruction 0x00000000 (op 0 xop 0)
> [=C2=A0 800.274767] kvmppc_exit_pr_progint: emulation at 100 failed (0000=
0000)

I don't think "mtune=3Dpower9" or "mtune=3Dpower10" will work. Did you try =
"mtune=3Dpower4"?

Adrian

--=20
 .''`.  John Paul Adrian Glaubitz
: :' :  Debian Developer
`. `'   Physicist
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