KVM: arm/arm64: rework MMIO abort handling to use KVM MMIO bus

Currently we have struct kvm_exit_mmio for encapsulating MMIO abort
data to be passed on from syndrome decoding all the way down to the
VGIC register handlers. Now as we switch the MMIO handling to be
routed through the KVM MMIO bus, it does not make sense anymore to
use that structure already from the beginning. So we keep the data in
local variables until we put them into the kvm_io_bus framework.
Then we fill kvm_exit_mmio in the VGIC only, making it a VGIC private
structure. On that way we replace the data buffer in that structure
with a pointer pointing to a single location in a local variable, so
we get rid of some copying on the way.
With all of the virtual GIC emulation code now being registered with
the kvm_io_bus, we can remove all of the old MMIO handling code and
its dispatching functionality.

I didn't bother to rename kvm_exit_mmio (to vgic_mmio or something),
because that touches a lot of code lines without any good reason.

This is based on an original patch by Nikolay.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Cc: Nikolay Nikolaev <n.nikolaev@virtualopensystems.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
diff --git a/virt/kvm/arm/vgic.h b/virt/kvm/arm/vgic.h
index 28fa3aa..0df74cb 100644
--- a/virt/kvm/arm/vgic.h
+++ b/virt/kvm/arm/vgic.h
@@ -59,6 +59,14 @@
 bool vgic_queue_irq(struct kvm_vcpu *vcpu, u8 sgi_source_id, int irq);
 void vgic_unqueue_irqs(struct kvm_vcpu *vcpu);
 
+struct kvm_exit_mmio {
+	phys_addr_t	phys_addr;
+	void		*data;
+	u32		len;
+	bool		is_write;
+	void		*private;
+};
+
 void vgic_reg_access(struct kvm_exit_mmio *mmio, u32 *reg,
 		     phys_addr_t offset, int mode);
 bool handle_mmio_raz_wi(struct kvm_vcpu *vcpu, struct kvm_exit_mmio *mmio,
@@ -99,11 +107,6 @@
 struct vgic_io_range *vgic_find_range(const struct vgic_io_range *ranges,
 				      int len, gpa_t offset);
 
-bool vgic_handle_mmio_range(struct kvm_vcpu *vcpu, struct kvm_run *run,
-			    struct kvm_exit_mmio *mmio,
-			    const struct vgic_io_range *ranges,
-			    unsigned long mmio_base);
-
 bool vgic_handle_enable_reg(struct kvm *kvm, struct kvm_exit_mmio *mmio,
 			    phys_addr_t offset, int vcpu_id, int access);