Re: [PATCH 1/2] KVM: device: add simple registration mechanism for kvm_device_ops

[Cornelia Huck <cornelia.huck@de.ibm.com>]

On Fri, 27 Jun 2014 16:17:57 +0200
Paolo Bonzini <pbonzini@redhat.com> wrote:

> Il 26/06/2014 19:30, Will Deacon ha scritto:
> > kvm_ioctl_create_device currently has knowledge of all the device types
> > and their associated ops. This is fairly inflexible when adding support
> > for new in-kernel device emulations, so move what we currently have out
> > into a table, which can support dynamic registration of ops by new
> > drivers for virtual hardware.
> >
> > I didn't try to port all current drivers over, as it's not always clear
> > which initialisation hook the ops should be registered from.
> 
> Conny, Alex (Graf & Williamson),
> 
> can you help Will here?  The idea looks sane, but I'd rather merge it 
> with all devices converted.

FWIW, the following patch on top works for me on s390:

>From 7cc0bf5b143c2e2c1971a65ef785050ece35faf3 Mon Sep 17 00:00:00 2001
From: Cornelia Huck <cornelia.huck@de.ibm.com>
Date: Mon, 30 Jun 2014 12:47:35 +0200
Subject: [PATCH] KVM: s390: register flic ops dynamically

Using the new kvm_register_device_ops() interface makes us get rid of
an #ifdef in commom code.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
---
 arch/s390/kvm/kvm-s390.c | 3 ++-
 arch/s390/kvm/kvm-s390.h | 1 +
 include/linux/kvm_host.h | 1 -
 virt/kvm/kvm_main.c      | 3 ---
 4 files changed, 3 insertions(+), 5 deletions(-)

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 2f3e14f..d1d5296 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -130,7 +130,8 @@ void kvm_arch_check_processor_compat(void *rtn)
 
 int kvm_arch_init(void *opaque)
 {
-	return 0;
+	/* Register floating interrupt controller interface. */
+	return kvm_register_device_ops(&kvm_flic_ops, KVM_DEV_TYPE_FLIC);
 }
 
 void kvm_arch_exit(void)
diff --git a/arch/s390/kvm/kvm-s390.h b/arch/s390/kvm/kvm-s390.h
index a8655ed..b236a8a 100644
--- a/arch/s390/kvm/kvm-s390.h
+++ b/arch/s390/kvm/kvm-s390.h
@@ -222,6 +222,7 @@ int kvm_cpu_has_interrupt(struct kvm_vcpu *vcpu);
 int psw_extint_disabled(struct kvm_vcpu *vcpu);
 void kvm_s390_destroy_adapters(struct kvm *kvm);
 int kvm_s390_si_ext_call_pending(struct kvm_vcpu *vcpu);
+extern struct kvm_device_ops kvm_flic_ops;
 
 /* implemented in guestdbg.c */
 void kvm_s390_backup_guest_per_regs(struct kvm_vcpu *vcpu);
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index b75faaf..72e12dd 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -1089,7 +1089,6 @@ extern struct kvm_device_ops kvm_mpic_ops;
 extern struct kvm_device_ops kvm_xics_ops;
 extern struct kvm_device_ops kvm_vfio_ops;
 extern struct kvm_device_ops kvm_arm_vgic_v2_ops;
-extern struct kvm_device_ops kvm_flic_ops;
 
 #ifdef CONFIG_HAVE_KVM_CPU_RELAX_INTERCEPT
 
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index a0c6cc3..c2a562b 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -2275,9 +2275,6 @@ static struct kvm_device_ops *kvm_device_ops_table[KVM_DEV_TYPE_MAX] = {
 	[KVM_DEV_TYPE_ARM_VGIC_V2]	= &kvm_arm_vgic_v2_ops,
 #endif
 
-#ifdef CONFIG_S390
-	[KVM_DEV_TYPE_FLIC]		= &kvm_flic_ops;
-#endif
 };
 
 int kvm_register_device_ops(struct kvm_device_ops *ops, u32 type)
-- 
1.8.5.5