vmm: Add support for explicit PCI device IDs - #7965

Allocating a device ID is crucial for assigning a specific ID to a
device. We need this to implement configurable PCI device ID.

Signed-off-by: Pascal Scholz <[email protected]>
On-behalf-of: SAP [email protected]
Signed-off-by: Rob Bradford <[email protected]>

Next to tests for `allocate_device_id`, we introduce a new constructor
`new_without_address_manager`, only available in the test build. As
there is no way to instantiate an `AddressManager` in the tests, we use
this constructor to work around this.

Signed-off-by: Pascal Scholz <[email protected]>
On-behalf-of: SAP [email protected]
Signed-off-by: Rob Bradford <[email protected]>

Signed-off-by: Rob Bradford <[email protected]>

This can be used in a two pass approach where all configs that can hold
PCI devices are evaluated to reserve any specific PCI device IDs they
may need. Those device IDs will later be allocated when the devices are
added to the bus. The tri-state Free, Reserved, Allocated also catches
the problem of hotplugging a device with a specific, already used,
device ID.

Signed-off-by: Rob Bradford <[email protected]>

This adds it to all device types that use the common PCI device
configuration.

Signed-off-by: Rob Bradford <[email protected]>

Also add pci_segment that was missing from vfio-user devices.

Signed-off-by: Rob Bradford <[email protected]>

For those devices types that have the the ability to support specifying
the PCI device ID add it to their help syntax.

Signed-off-by: Rob Bradford <[email protected]>

Validate the PCI device ID are within range and not using the reserved
value. We need this option to ensure that invalid device IDs received
via an API call result in an error as soon as possible. In this case,
this would be after deserialization. On this code path, validation via
`parse` is skipped and must be invoked by calling `validate`.

Signed-off-by: Pascal Scholz <[email protected]>
On-behalf-of: SAP [email protected]
Signed-off-by: Rob Bradford <[email protected]>

We pass the device ID from the config to the allocation routine, where
it is then used as the preferred device ID alongside the existing PCI
segment ID.

Signed-off-by: Pascal Scholz <[email protected]>
On-behalf-of: SAP [email protected]
Signed-off-by: Rob Bradford <[email protected]>

Use two passes to first reserve PCI device IDs and then allocate them
when adding the devices to the bus. This prevents a situation where an
anonymous PCI device allocation clashes with an explicitly allocated PCI
device ID.

Signed-off-by: Rob Bradford <[email protected]>

Some of the documentation references PCI segment ID. For those documents
add a mention of the new PCI device ID.

Signed-off-by: Rob Bradford <[email protected]>

If we want to test for error cases, it can be useful to inspect the
`stderr` of a `Command` to analyze the errors. For example, this allows
us to ensure that a `Command` returns an `IoError` by parsing the
error trace, if an `IoError` is expected.

This commit prepares the implementation of negative integration tests
for the configurable BDFs.

Signed-off-by: Pascal Scholz <[email protected]>
On-behalf-of: SAP [email protected]

This commit adds an integration test to verify that the guest sees the
correct BDF. Moreover, we check that we can allocate a random free BDF
and that freeing BDFs works.

Signed-off-by: Pascal Scholz <[email protected]>
On-behalf-of: SAP [email protected]
Signed-off-by: Rob Bradford <[email protected]>

This integration test verifies that the same device ID cannot be
allocated twice. Moreover, we check that the returned error matches our
expectations.

Signed-off-by: Pascal Scholz <[email protected]>
On-behalf-of: SAP [email protected]
Signed-off-by: Rob Bradford <[email protected]>

Adds a test that checks the correct error is returned on allocation of
an invalid device ID (one that is not in the range 0-31) and when trying
to allocate a reserved ID (such as that of the root bridge).

Signed-off-by: Pascal Scholz <[email protected]>
On-behalf-of: SAP [email protected]
Signed-off-by: Rob Bradford <[email protected]>