Re: [PATCH] KVM: Add KVM_CAP_IRQ_ARCH capability

[Scott Wood <scottwood@freescale.com>]

On 03/14/2013 02:03:30 PM, Alexander Graf wrote:
> 
> On 14.03.2013, at 19:35, Scott Wood wrote:
> 
> > On 03/14/2013 01:33:30 PM, Alexander Graf wrote:
> >> On 14.03.2013, at 19:20, Scott Wood wrote:
> >> > On 03/13/2013 08:20:44 PM, Paul Mackerras wrote:
> >> >> Setting this capability on a vcpu connects that vcpu to an  
> interrupt
> >> >> controller device.  The args[0] field of the argument  
> kvm_enable_cap
> >> >> struct specifies the overall architecture of the interrupt
> >> >> controller.  The args[1] field specifies the CPU number for the  
> vcpu
> >> >> from the interrupt controller's point of view.
> >> >> Signed-off-by: Paul Mackerras <paulus@samba.org>
> >> >> ---
> >> >> arch/powerpc/include/asm/kvm_host.h |    3 +++
> >> >> arch/powerpc/kvm/powerpc.c          |   29  
> +++++++++++++++++++++++++++++
> >> >> include/uapi/linux/kvm.h            |    1 +
> >> >> 3 files changed, 33 insertions(+)
> >> >> diff --git a/arch/powerpc/include/asm/kvm_host.h  
> b/arch/powerpc/include/asm/kvm_host.h
> >> >> index f4ba881..dd167e4 100644
> >> >> --- a/arch/powerpc/include/asm/kvm_host.h
> >> >> +++ b/arch/powerpc/include/asm/kvm_host.h
> >> >> @@ -373,6 +373,9 @@ struct kvmppc_booke_debug_reg {
> >> >> struct kvm_vcpu_arch {
> >> >> 	ulong host_stack;
> >> >> 	u32 host_pid;
> >> >> +
> >> >> +	u32 intr_ctrler;
> >> >> +
> >> >
> >> > That abbreviation seems a bit awkward, and we should also have a
> >> > private-data pointer.
> >> >
> >> > How about:
> >> >
> >> > 	u32 irq_arch;
> >> We also want int pic_fd, no?
> >
> > Not sure we really need that on the vcpu.  We'll need it on the vm  
> unless we add it as an arg to the vcpu cap enable.
> 
> I don't think we need anything vm global for the cpu <-> PIC  
> connections.

The two components have to link up somehow.  If the vcpu cap enable  
ioctl doesn't specify it, then the device creation will have to stick a  
reference to itself somewhere in the vm.

> Also, if you want to deregister a CPU (hotplug remove), you probably  
> want to tell the PIC that the CPU has gone.

Yes, I mentioned that in my previous e-mail.

-Scott