This brings the initial PCI support to the VFIO crate.
The VfioPciDevice is the main structure and holds an inner VfioDevice.

VfioPciDevice implements the PCI trait, leaving the IRQ assignments
empty as this will be driven by both the guest and the VFIO PCI device,
not by the VMM.

As we must trap BAR programming from the guest (We don't want to program
the actual device with guest addresses), we use our local PCI
configuration cache to read and write BARs.

Signed-off-by: Zhang, Xiong Y <[email protected]>
Signed-off-by: Chao Peng <[email protected]>
Signed-off-by: Samuel Ortiz <[email protected]>

In order to properly manage the VFIO device interrupt settings, we need
to keep track of both MSI and MSI-X PCI config capabilities changes.

When the guest programs the device for interrupt delivery, it writes to
the MSI and MSI-X capabilities. This information must be trapped and
cached in order to map the physical device interrupt delivery path to
the guest one. In other words, tracking MSI and MSI-X capabilites will
allow us to accurately build the KVM interrupt routes.

Signed-off-by: Sebastien Boeuf <[email protected]>
Signed-off-by: Samuel Ortiz <[email protected]>

We track all MSI and MSI-X capabilities changes, which allows us to also
track all MSI and MSI-X table changes.

With both pieces of information we can build kvm irq routing tables and
map the physical device MSI/X vectors to the guest ones. Once that
mapping is in place we can toggle the VFIO IRQ API accordingly and
enable disable MSI or MSI-X interrupts, from the physical device up to
the guest.

Signed-off-by: Sebastien Boeuf <[email protected]>
Signed-off-by: Samuel Ortiz <[email protected]>

VFIO explictly tells us if a MMIO region can be mapped into the guest
address space or not. Except for MSI-X table BARs, we try to map them
into the guest whenever VFIO allows us to do so. This avoids unnecessary
VM exits when the guest tries to access those regions.

Signed-off-by: Zhang, Xiong Y <[email protected]>
Signed-off-by: Chao Peng <[email protected]>
Signed-off-by: Samuel Ortiz <[email protected]>

With the VFIO crate, we can now support directly assigned PCI devices
into cloud-hypervisor guests.

We support assigning multiple host devices, through the --device command
line parameter. This parameter takes the host device sysfs path.

Fixes: cloud-hypervisor#60

Signed-off-by: Samuel Ortiz <[email protected]>

The VFIO integration test first boots a QEMU guest and then assigns the
QEMU virtio-pci networking device into a nested cloud-hypervisor guest.
We then check that we can ssh into the nested guest and verify that it's
running with the right kernel command line.

Signed-off-by: Samuel Ortiz <[email protected]>