resources+pci: allocator rework (allocation tags)

AddressAllocator now maintains a HashMap<Alloc, (u64, u64, u64)>,
which uniquely maps a Allocation enum (e.g: PciBar(bus, dev, bar),
GpuRenderNode, etc...) to it's address, size, and human-readable tag
/ description.

The interface has also been modified to use Error instead of Option.

Aside from improving debugging, tracking allocations will have
numerous uses in the future. For example, when allocating guest memory
over VmControl sockets, it will be possible to restrict allocations to
pre-allocated slices of memory owned by the requesting device.

To plumb through PCI information to PCI devices, this CL necessitated
the addition of a PciDevice method called `assign_bus_dev`, which
notifies PCI devices of their uniquely assigned Bus and Device numbers.

BUG=chromium:936567
TEST=cargo test -p resources && cargo build --features="gpu gpu-forward"

Change-Id: I8b4b0e32c6f3168138739249ede53d03143ee5c3
Reviewed-on: https://chromium-review.googlesource.com/1536207
Commit-Ready: Daniel Prilik <prilik@google.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Zach Reizner <zachr@chromium.org>

1 files changed, 4 insertions, 0 deletions

diff --git a/devices/src/pci/pci_configuration.rs b/devices/src/pci/pci_configuration.rs
index 1cfa6bb..ab969f7 100644
--- a/devices/src/pci/pci_configuration.rs
+++ b/devices/src/pci/pci_configuration.rs
@@ -490,6 +490,10 @@ impl PciBarConfiguration {
         self
     }
 
+    pub fn get_register_index(&self) -> usize {
+        self.reg_idx
+    }
+
     pub fn set_address(mut self, addr: u64) -> Self {
         self.addr = addr;
         self