This can be uses to indicate to the caller that it should wait on the
barrier before returning as there is some asynchronous activity
triggered by the write which requires the KVM exit to block until it's
completed.
This is useful for having vCPU thread wait for the VMM thread to proceed
to activate the virtio devices.
See #1863
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
This removes the dependency of the pci crate on the devices crate which
now only contains the device implementations themselves.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
OVMF and other standard firmwares use I/O port 0x402 as a simple debug
port by writing ASCII characters to it. This is gated under a feature
that is not enabled by default.
Signed-off-by: Rob Bradford <robert.bradford@intel.com>
