Add Intel Virtualized PCIE device

[CookieComputing]

We are adding support for stage0 in Cloud Hypervisor and found that we were busy polling for a PCI device on the bridge... Eventually we discovered that Cloud Hypervisor actually has its own PciConfiguration here: https://github.com/cloud-hypervisor/cloud-hypervisor/blob/8248650e799457fee3068b0bf3b54ffcade4bce1/pci/src/bus.rs#L66-L82

Teach Stage0 about this so that we can init the machine with this new type

Changes

• Moved the mmio64_hole() method to a helper method which introduces an addr_size--This is solely just so that we can customize what arg is passed
• Added the IntelVirtualPcieHost machine type

Tests

$ nix develop
$ bazel test //stage0
...
INFO: Found 3 targets and 2 test targets...
INFO: Elapsed time: 183.706s, Critical Path: 172.55s
INFO: 1966 processes: 850 internal, 1116 linux-sandbox.
INFO: Build completed successfully, 1966 total actions
//stage0:stage0_test                                                     PASSED in 0.0s
//stage0/testing:stage0_kernel_test                                      PASSED in 0.9s

Executed 2 out of 2 tests: 2 tests pass.

I also launched a SEV-SNP VM using Cloud hypervisor. We're in the midst of adding this support, so please look at the steps in cloud-hypervisor/cloud-hypervisor#7942 (comment) for reproducing the binaries used for testing.

I also used the buildigvm binary from https://gitlab.com/qemu-project/buildigvm, which was checked in recently

stage0_pcie.txt

[conradgrobler]

Thanks.

[CookieComputing]

• Moved the helper function out of I440fx
• renamed some unit test which had a lint warning
  Re-ran the tests

INFO: Found 3 targets and 2 test targets...
INFO: Elapsed time: 164.315s, Critical Path: 145.89s
INFO: 1966 processes: 850 internal, 1116 linux-sandbox.
INFO: Build completed successfully, 1966 total actions
//stage0:stage0_test                                                     PASSED in 0.1s
//stage0/testing:stage0_kernel_test                                      PASSED in 1.3s

[conradgrobler]

Thank you. Imported as 07ddf17