virt: acrn: Introduce interrupt injection interfaces

virt: acrn: Introduce interrupt injection interfaces

ACRN userspace need to inject virtual interrupts into a User VM in
devices emulation.

HSM needs provide interfaces to do so.

Introduce following interrupt injection interfaces:

ioctl ACRN_IOCTL_SET_IRQLINE:
  Pass data from userspace to the hypervisor, and inform the hypervisor
  to inject a virtual IOAPIC GSI interrupt to a User VM.

ioctl ACRN_IOCTL_INJECT_MSI:
  Pass data struct acrn_msi_entry from userspace to the hypervisor, and
  inform the hypervisor to inject a virtual MSI to a User VM.

ioctl ACRN_IOCTL_VM_INTR_MONITOR:
  Set a 4-Kbyte aligned shared page for statistics information of
  interrupts of a User VM.

Cc: Zhi Wang <zhi.a.wang@intel.com>
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Cc: Yu Wang <yu1.wang@intel.com>
Cc: Reinette Chatre <reinette.chatre@intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Shuo Liu <shuo.a.liu@intel.com>
Link: https://lore.kernel.org/r/20210207031040.49576-13-shuo.a.liu@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>