[Qemu-devel] [PATCH] isapc: Remove unnecessary migration compatibility code

[Qemu-devel] [PATCH] isapc: Remove unnecessary migration compatibility code

[Eduardo Habkost]

We don't touch isapc when we change guest ABI and add new entries
to PC_COMPAT_* or new PCMachineClass compat flags.  This means
isapc never guaranteed guest ABI and cross-QEMU-version live
migration compatibility.  There's no point in keeping code for
kvm-pv-eoi and APIC ID compatibility in pc_init_isa().

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
---
 hw/i386/pc_piix.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
index 9ff79b1fd9..31646e63c4 100644
--- a/hw/i386/pc_piix.c
+++ b/hw/i386/pc_piix.c
@@ -378,8 +378,6 @@ static void pc_compat_0_13(MachineState *machine)
 
 static void pc_init_isa(MachineState *machine)
 {
-    x86_cpu_change_kvm_default("kvm-pv-eoi", NULL);
-    enable_compat_apic_id_mode();
     pc_init1(machine, TYPE_I440FX_PCI_HOST_BRIDGE, TYPE_I440FX_PCI_DEVICE);
 }
 
-- 
2.13.6

Re: [Qemu-devel] [PATCH] isapc: Remove unnecessary migration compatibility code

[Igor Mammedov]

On Fri,  6 Oct 2017 10:25:02 -0300
Eduardo Habkost <ehabkost@redhat.com> wrote:

> We don't touch isapc when we change guest ABI and add new entries
> to PC_COMPAT_* or new PCMachineClass compat flags.  This means
> isapc never guaranteed guest ABI and cross-QEMU-version live
> migration compatibility.  There's no point in keeping code for
> kvm-pv-eoi and APIC ID compatibility in pc_init_isa().
> 
> Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>

> ---
>  hw/i386/pc_piix.c | 2 --
>  1 file changed, 2 deletions(-)
> 
> diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> index 9ff79b1fd9..31646e63c4 100644
> --- a/hw/i386/pc_piix.c
> +++ b/hw/i386/pc_piix.c
> @@ -378,8 +378,6 @@ static void pc_compat_0_13(MachineState *machine)
>  
>  static void pc_init_isa(MachineState *machine)
>  {
> -    x86_cpu_change_kvm_default("kvm-pv-eoi", NULL);
> -    enable_compat_apic_id_mode();
>      pc_init1(machine, TYPE_I440FX_PCI_HOST_BRIDGE, TYPE_I440FX_PCI_DEVICE);
>  }
>  

Re: [Qemu-devel] [PATCH] isapc: Remove unnecessary migration compatibility code

[Eduardo Habkost]

On Tue, Oct 10, 2017 at 01:42:04PM +0200, Igor Mammedov wrote:
> On Fri,  6 Oct 2017 10:25:02 -0300
> Eduardo Habkost <ehabkost@redhat.com> wrote:
> 
> > We don't touch isapc when we change guest ABI and add new entries
> > to PC_COMPAT_* or new PCMachineClass compat flags.  This means
> > isapc never guaranteed guest ABI and cross-QEMU-version live
> > migration compatibility.  There's no point in keeping code for
> > kvm-pv-eoi and APIC ID compatibility in pc_init_isa().
> > 
> > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
> Reviewed-by: Igor Mammedov <imammedo@redhat.com>

Thanks!

Michael, do you prefer those pc*.c patches that touch only
CPU-related code to go always through your tree, or can I merge
them through x86-next without your Acked-by if it's appropriate?

> 
> > ---
> >  hw/i386/pc_piix.c | 2 --
> >  1 file changed, 2 deletions(-)
> > 
> > diff --git a/hw/i386/pc_piix.c b/hw/i386/pc_piix.c
> > index 9ff79b1fd9..31646e63c4 100644
> > --- a/hw/i386/pc_piix.c
> > +++ b/hw/i386/pc_piix.c
> > @@ -378,8 +378,6 @@ static void pc_compat_0_13(MachineState *machine)
> >  
> >  static void pc_init_isa(MachineState *machine)
> >  {
> > -    x86_cpu_change_kvm_default("kvm-pv-eoi", NULL);
> > -    enable_compat_apic_id_mode();
> >      pc_init1(machine, TYPE_I440FX_PCI_HOST_BRIDGE, TYPE_I440FX_PCI_DEVICE);
> >  }
> >  
> 

-- 
Eduardo