KVM: arm64: vgic-its: Introduce new KVM ITS device

Introduce a new KVM device that represents an ARM Interrupt Translation
Service (ITS) controller. Since there can be multiple of this per guest,
we can't piggy back on the existing GICv3 distributor device, but create
a new type of KVM device.
On the KVM_CREATE_DEVICE ioctl we allocate and initialize the ITS data
structure and store the pointer in the kvm_device data.
Upon an explicit init ioctl from userland (after having setup the MMIO
address) we register the handlers with the kvm_io_bus framework.
Any reference to an ITS thus has to go via this interface.

Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>
Tested-by: Eric Auger <eric.auger@redhat.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

1 files changed, 19 insertions, 6 deletions

diff --git a/Documentation/virtual/kvm/devices/arm-vgic.txt b/Documentation/virtual/kvm/devices/arm-vgic.txt
index 59541d49e15c..89182f80cc7f 100644
--- a/Documentation/virtual/kvm/devices/arm-vgic.txt
+++ b/Documentation/virtual/kvm/devices/arm-vgic.txt
@@ -4,16 +4,22 @@ ARM Virtual Generic Interrupt Controller (VGIC)
 Device types supported:
   KVM_DEV_TYPE_ARM_VGIC_V2     ARM Generic Interrupt Controller v2.0
   KVM_DEV_TYPE_ARM_VGIC_V3     ARM Generic Interrupt Controller v3.0
+  KVM_DEV_TYPE_ARM_VGIC_ITS    ARM Interrupt Translation Service Controller
 
-Only one VGIC instance may be instantiated through either this API or the
-legacy KVM_CREATE_IRQCHIP api.  The created VGIC will act as the VM interrupt
-controller, requiring emulated user-space devices to inject interrupts to the
-VGIC instead of directly to CPUs.
+Only one VGIC instance of the V2/V3 types above may be instantiated through
+either this API or the legacy KVM_CREATE_IRQCHIP api.  The created VGIC will
+act as the VM interrupt controller, requiring emulated user-space devices to
+inject interrupts to the VGIC instead of directly to CPUs.
 
 Creating a guest GICv3 device requires a host GICv3 as well.
 GICv3 implementations with hardware compatibility support allow a guest GICv2
 as well.
 
+Creating a virtual ITS controller requires a host GICv3 (but does not depend
+on having physical ITS controllers).
+There can be multiple ITS controllers per guest, each of them has to have
+a separate, non-overlapping MMIO region.
+
 Groups:
   KVM_DEV_ARM_VGIC_GRP_ADDR
   Attributes:
@@ -39,6 +45,13 @@ Groups:
       Only valid for KVM_DEV_TYPE_ARM_VGIC_V3.
       This address needs to be 64K aligned.
 
+    KVM_VGIC_V3_ADDR_TYPE_ITS (rw, 64-bit)
+      Base address in the guest physical address space of the GICv3 ITS
+      control register frame. The ITS allows MSI(-X) interrupts to be
+      injected into guests. This extension is optional. If the kernel
+      does not support the ITS, the call returns -ENODEV.
+      Only valid for KVM_DEV_TYPE_ARM_VGIC_ITS.
+      This address needs to be 64K aligned and the region covers 128K.
 
   KVM_DEV_ARM_VGIC_GRP_DIST_REGS
   Attributes:
@@ -109,8 +122,8 @@ Groups:
   KVM_DEV_ARM_VGIC_GRP_CTRL
   Attributes:
     KVM_DEV_ARM_VGIC_CTRL_INIT
-      request the initialization of the VGIC, no additional parameter in
-      kvm_device_attr.addr.
+      request the initialization of the VGIC or ITS, no additional parameter
+      in kvm_device_attr.addr.
   Errors:
     -ENXIO: VGIC not properly configured as required prior to calling
      this attribute