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>

1 files changed, 8 insertions, 0 deletions

diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
index 7f2360a46fc2..c70577cf67bc 100644
--- a/include/uapi/linux/kvm.h
+++ b/include/uapi/linux/kvm.h
@@ -637,6 +637,7 @@ struct kvm_ppc_smmu_info {
 #define KVM_CAP_PPC_BOOKE_WATCHDOG 83
 #define KVM_CAP_PPC_HTAB_FD 84
 #define KVM_CAP_ARM_PSCI 87
+#define KVM_CAP_ARM_SET_DEVICE_ADDR 88
 
 #ifdef KVM_CAP_IRQ_ROUTING
 
@@ -784,6 +785,11 @@ struct kvm_msi {
         __u8  pad[16];
 };
 
+struct kvm_arm_device_addr {
+        __u64 id;
+        __u64 addr;
+};
+
 /*
  * ioctls for VM fds
  */
@@ -869,6 +875,8 @@ struct kvm_s390_ucas_mapping {
 #define KVM_ALLOCATE_RMA          _IOR(KVMIO,  0xa9, struct kvm_allocate_rma)
 /* Available with KVM_CAP_PPC_HTAB_FD */
 #define KVM_PPC_GET_HTAB_FD       _IOW(KVMIO,  0xaa, struct kvm_get_htab_fd)
+/* Available with KVM_CAP_ARM_SET_DEVICE_ADDR */
+#define KVM_ARM_SET_DEVICE_ADDR   _IOW(KVMIO,  0xab, struct kvm_arm_device_addr)
 
 /*
  * ioctls for vcpu fds