Re: [PATCH] accel/kvm: Make "kernel_irqchip" default on

[Xiaoyao Li <xiaoyao.li@intel.com>]

On Sat, 2019-12-28 at 10:02 +0000, Paolo Bonzini wrote:
> 
> 
> Il sab 28 dic 2019, 09:48 Xiaoyao Li <xiaoyao.li@intel.com> ha scritto:
> > Commit 11bc4a13d1f4 ("kvm: convert "-machine kernel_irqchip" to an
> > accelerator property") moves kernel_irqchip property from "-machine" to
> > "-accel kvm", but it forgets to set the default value of
> > kernel_irqchip_allowed and kernel_irqchip_split.
> > 
> > Also cleaning up the three useless members (kernel_irqchip_allowed,
> > kernel_irqchip_required, kernel_irqchip_split) in struct MachineState.
> > 
> > Fixes: 11bc4a13d1f4 ("kvm: convert "-machine kernel_irqchip" to an
> > accelerator property")
> > Signed-off-by: Xiaoyao Li <xiaoyao.li@intel.com>
> 
> Please also add a Reported-by line for Vitaly Kuznetsov.

Sure.

> > ---
> >  accel/kvm/kvm-all.c | 3 +++
> >  include/hw/boards.h | 3 ---
> >  2 files changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/accel/kvm/kvm-all.c b/accel/kvm/kvm-all.c
> > index b2f1a5bcb5ef..40f74094f8d3 100644
> > --- a/accel/kvm/kvm-all.c
> > +++ b/accel/kvm/kvm-all.c
> > @@ -3044,8 +3044,11 @@ bool kvm_kernel_irqchip_split(void)
> >  static void kvm_accel_instance_init(Object *obj)
> >  {
> >      KVMState *s = KVM_STATE(obj);
> > +    MachineClass *mc = MACHINE_GET_CLASS(current_machine);
> > 
> >      s->kvm_shadow_mem = -1;
> > +    s->kernel_irqchip_allowed = true;
> > +    s->kernel_irqchip_split = mc->default_kernel_irqchip_split;
> 
> Can you initialize this from the init_machine method instead of assuming that
> current_machine has been initialized earlier?

OK, will do it in v2.

> Thanks for the quick fix!

BTW, it seems that this patch makes kernel_irqchip default on to workaround the
bug. 
However, when explicitly configuring kernel_irqchip=off, guest still fails
booting due to "KVM: failed to send PV IPI: -95" with a latest upstream kernel
ubuntu guest. Any idea about this? 

> Paolo
> >  }
> > 
> >  static void kvm_accel_class_init(ObjectClass *oc, void *data)
> > diff --git a/include/hw/boards.h b/include/hw/boards.h
> > index 61f8bb8e5a42..fb1b43d5b972 100644
> > --- a/include/hw/boards.h
> > +++ b/include/hw/boards.h
> > @@ -271,9 +271,6 @@ struct MachineState {
> > 
> >      /*< public >*/
> > 
> > -    bool kernel_irqchip_allowed;
> > -    bool kernel_irqchip_required;
> > -    bool kernel_irqchip_split;
> >      char *dtb;
> >      char *dumpdtb;
> >      int phandle_start;