Shrikanth Hegde <[email protected]> writes: > Christian reported that booting preemptible kernel on FSL Cyrus+ board > causes boot hang. > > The logs pointed that system was busy in printing below warning. > > WARNING: at .enable_kernel_fp+0x30/0x78, CPU#3: qemu-system-ppc/4884 > Modules linked in: > CPU: 3 UID: 1000 PID: 4884 Comm: qemu-system-ppc Not tainted > 7.3.0-rc1-powerpc64-smp-preempt #1 PREEMPT > NIP [c000000000003338] .enable_kernel_fp+0x30/0x78 > LR [c00000000005de84] .kvmppc_load_guest_fp+0x30/0x80 > Call Trace: > [c000000085ca7700] [c00000000005de84] .kvmppc_load_guest_fp+0x30/0x80 > [c000000085ca7780] [c00000000005f2a0] .kvmppc_handle_exit+0x5bc/0x5cc > [c000000085ca7830] [c00000000006204c] .kvmppc_resume_host+0xb8/0x10c > > Which is... > > void enable_kernel_fp(void) > { > unsigned long cpumsr; > WARN_ON(preemptible()); > > And... > > Though irq's are hard disabled after kvmppc_prepare_to_enter, but > kvmppc_fix_ee_before_entry enables the softmask's IRQ state. > That causes the irqs_disabled to return false. > Hence leading to the warnings. > > Fix it by re-ordering the code to load the FP and Altivec > before enabling the softmask IRQ state. > > Suggested-by: Narayana Murty N <[email protected]> > Fixes: 3efc7da61f6c ("KVM: PPC: Book3E: Increase FPU laziness") > Reported-by: Christian Zigotzky <[email protected]> > Closes: > https://lore.kernel.org/all/[email protected]/ > Tested-by: Christian Zigotzky <[email protected]> > Reviewed-by: Mukesh Kumar Chaurasiya (IBM) <[email protected]> > Signed-off-by: Shrikanth Hegde <[email protected]> > --- > arch/powerpc/kvm/booke.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-)
LGTM. So, please feel free to add: Reviewed-by: Ritesh Harjani (IBM) <[email protected]>
