KVM: ARM: Introduce KVM_ARM_SET_DEVICE_ADDR ioctl
On ARM some bits are specific to the model being emulated for the guest and
user space needs a way to tell the kernel about those bits. An example is mmio
device base addresses, where KVM must know the base address for a given device
to properly emulate mmio accesses within a certain address range or directly
map a device with virtualiation extensions into the guest address space.
We make this API ARM-specific as we haven't yet reached a consensus for a
generic API for all KVM architectures that will allow us to do something like
this.
Reviewed-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Christoffer Dall <c.dall@virtualopensystems.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
index c25439a..4505f86 100644
--- a/Documentation/virtual/kvm/api.txt
+++ b/Documentation/virtual/kvm/api.txt
@@ -2210,6 +2210,43 @@
KVM_GET_ONE_REG/KVM_SET_ONE_REG calls.
+4.80 KVM_ARM_SET_DEVICE_ADDR
+
+Capability: KVM_CAP_ARM_SET_DEVICE_ADDR
+Architectures: arm
+Type: vm ioctl
+Parameters: struct kvm_arm_device_address (in)
+Returns: 0 on success, -1 on error
+Errors:
+ ENODEV: The device id is unknown
+ ENXIO: Device not supported on current system
+ EEXIST: Address already set
+ E2BIG: Address outside guest physical address space
+
+struct kvm_arm_device_addr {
+ __u64 id;
+ __u64 addr;
+};
+
+Specify a device address in the guest's physical address space where guests
+can access emulated or directly exposed devices, which the host kernel needs
+to know about. The id field is an architecture specific identifier for a
+specific device.
+
+ARM divides the id field into two parts, a device id and an address type id
+specific to the individual device.
+
+ bits: | 63 ... 32 | 31 ... 16 | 15 ... 0 |
+ field: | 0x00000000 | device id | addr type id |
+
+ARM currently only require this when using the in-kernel GIC support for the
+hardware VGIC features, using KVM_ARM_DEVICE_VGIC_V2 as the device id. When
+setting the base address for the guest's mapping of the VGIC virtual CPU
+and distributor interface, the ioctl must be called after calling
+KVM_CREATE_IRQCHIP, but before calling KVM_RUN on any of the VCPUs. Calling
+this ioctl twice for any of the base addresses will return -EEXIST.
+
+
5. The kvm_run structure
------------------------