KVM: Document KVM_SET_IDENTITY_MAP ioctl

This ioctl is only useful after KVM_CREATE_IRQCHIP.  Without an in-kernel

irqchip, the multiprocessing state must be maintained by userspace.

4.39 KVM_SET_IDENTITY_MAP_ADDR

Capability: KVM_CAP_SET_IDENTITY_MAP_ADDR

Architectures: x86

Type: vm ioctl

Parameters: unsigned long identity (in)

Returns: 0 on success, -1 on error

This ioctl defines the physical address of a one-page region in the guest

physical address space.  The region must be within the first 4GB of the

guest physical address space and must not conflict with any memory slot

or any mmio address.  The guest may malfunction if it accesses this memory

region.

This ioctl is required on Intel-based hosts.  This is needed on Intel hardware

because of a quirk in the virtualization implementation (see the internals

documentation when it pops into existence).

5. The kvm_run structure

Application code obtains a pointer to the kvm_run structure by