[edk2-devel] [PATCH v6 0/5] Handling of multiple PCI

Tue Jun 21 21:27:26 UTC 2022

Increased control is provided in Ovmf platforms to define and configure
the specifications of multiple PCI host bridges in the hypervisor. The
host propagates this information to the guest, initially through fw-cfg
interface.

In some AWS EC2 platforms, we expose a PCI topology including several
root bridges portraying information about physical distribution that
enables the guest to optimize accesses. Current PCI driver for Ovmf
enables the explicit definition of multiple root bridges and contains
the logic to fix their resources based on platform-specific PCD
entries. However, we need a way to control, from the hypervisor, how
many and which resources each PCI root bridge can use. For this
reason, this patch series introduces a mechanism to provide PCI host
bridges information like bus number range, attributes, allocation
attributes, PIO aperture as well as 32 and 64- bit prefetchable and
non-prefetchable MMIO ranges through a fw-cfg item created by the
hypervisor and consumed by the guest firmware. In order to offer a
generic and extensible way to disclose non-discoverable hardware
information from the host to the guest, a new library called 
HardwareInfoLib is created in the OvmfPkg. In essence, this library
offers the functionality to parse a generic BLOB into a list as well
as the methods to iterate over such list, including filtering options.
The library is conceived in a generic way so that further hardware
elements can also be described using it. For such purpose the length
of the BLOB is not restricted but instead regarded as a sequence of
header-info elements that allow the parsing during runtime.
Furthermore, specific functionality is provided wrapping
QemuFwCfgReadBytes to extract hardware descriptions, in the
aforementioned format, in a static way so that early in the Pei
stage the library can be used to identify address space requirements.
The core of the library offers enough flexibility to process as many
elements, even from different hardware types (heterogenous), as needed
in a single run. This library is extended for the particular use case
already exposed, PCI host bridges, and this same code offers an
example of how to tailor it for further hardware components.

After acknowledgement from Gerd Hoffmann and fixing all warnings and
errors found by the CI pipeline (via draft pull request), here I send
a new revision of the patches for merging.

---
Notes:
  v6:
  Prepearation for upstream merge:
  - No functional change at all.
  - Small changes to fix all builds excercised by CI
    (https://github.com/tianocore/edk2/pull/2938)
  - Added libraries to furhter platforms as per dependencies requirements
  - Explicit casting of some values as required by build and
    verification of values when demoting values.
  - Arranged added files copyright to the format required.
  - Changed HOST_BRIDGE_INFO bitfield member to UINT32 to follow
    EDK2 guidelines motivated on build in 32-bit windows systems.
  - Added verification of Bus Number range when values provided by
    host to make sure Root Bridge is initialized with valid values

  v5:
  - Removed last 3 patches dealing with pre-populated resources to
    encapsulate related changes in more manageable chunks and while
    pre-populated changes are finalized.
  - Added Acked-by to all commits
  - Re-based on top of latest master and refactored changes in
    MemDetect.c to adapt to recently created
    PlatformInitLib/MemDetect.c

  v4:
  - Minor modification to use MAX_UINT64 as global invalid base address
    when reading PCI host bridge information provided by the host
    (Patch 1)
  - Refactor PciHostBridgeUtilityGetRootBridges into a thin wrapper that
    calls 2 new function: one (BusScan) that performs the legacy bus
    scan population process and a new one (HostProvided) that populates
    Root Bridges with host provided values. (Patch 5)
  - Move code that sets value of PcdPciPreservePopulatedMappings token
    based on host-provided fw-cfg file into the function that populates
    root bridges with host provided data (Patch 6)
  - Restructured base address retrieval to leave PCI Resource Allocation
    protocol untouched and instead augment the existing services to
    enable base address retrieval before allocation. (Patch 7)
  - Use new method to retrieve Root Bridge base addresses before
    allocation and use that to handle pre-populated BARs (Patch 8)

Nicolas Ojeda Leon (5):
  OvmfPkg/Library: Create base HardwareInfoLib for PCI Host Bridges
  Ovmf/HardwareInfoLib: Create Pei lib to parse directly from fw-cfg
  Ovmf/HardwareInfoLib: Add Dxe lib to dynamically parse heterogenous
    data
  Ovmf/PlatformPei: Use host-provided GPA end if available
  OvmfPkg/PciHostBridgeUtilityLib: Initialize RootBridges apertures with
    spec

 ArmVirtPkg/ArmVirtQemu.dsc                    |   2 +
 OvmfPkg/AmdSev/AmdSevX64.dsc                  |   2 +
 OvmfPkg/Bhyve/BhyveX64.dsc                    |   2 +
 OvmfPkg/CloudHv/CloudHvX64.dsc                |   2 +
 OvmfPkg/Include/Library/HardwareInfoLib.h     | 159 ++++++
 .../HardwareInfoLib/DxeHardwareInfoLib.inf    |  39 ++
 .../Library/HardwareInfoLib/HardwareInfoDxe.c | 254 +++++++++
 .../HardwareInfoPciHostBridgeLib.c            | 508 ++++++++++++++++++
 .../HardwareInfoPciHostBridgeLib.h            | 256 +++++++++
 .../Library/HardwareInfoLib/HardwareInfoPei.c |  79 +++
 .../HardwareInfoLib/HardwareInfoTypesLib.h    |  59 ++
 .../HardwareInfoLib/PeiHardwareInfoLib.inf    |  39 ++
 .../QemuFwCfgHardwareInfoLib.c                |  88 +++
 .../PciHostBridgeUtilityLib.c                 | 332 +++++++++++-
 .../PciHostBridgeUtilityLib.inf               |   1 +
 OvmfPkg/Library/PlatformInitLib/MemDetect.c   | 148 ++++-
 .../PlatformInitLib/PlatformInitLib.inf       |   1 +
 OvmfPkg/Microvm/MicrovmX64.dsc                |   2 +
 OvmfPkg/OvmfPkg.dec                           |   4 +
 OvmfPkg/OvmfPkgIa32.dsc                       |   2 +
 OvmfPkg/OvmfPkgIa32X64.dsc                    |   2 +
 OvmfPkg/OvmfPkgX64.dsc                        |   2 +
 OvmfPkg/OvmfXen.dsc                           |   2 +
 23 files changed, 1973 insertions(+), 12 deletions(-)
 create mode 100644 OvmfPkg/Include/Library/HardwareInfoLib.h
 create mode 100644 OvmfPkg/Library/HardwareInfoLib/DxeHardwareInfoLib.inf
 create mode 100644 OvmfPkg/Library/HardwareInfoLib/HardwareInfoDxe.c
 create mode 100644 OvmfPkg/Library/HardwareInfoLib/HardwareInfoPciHostBridgeLib.c
 create mode 100644 OvmfPkg/Library/HardwareInfoLib/HardwareInfoPciHostBridgeLib.h
 create mode 100644 OvmfPkg/Library/HardwareInfoLib/HardwareInfoPei.c
 create mode 100644 OvmfPkg/Library/HardwareInfoLib/HardwareInfoTypesLib.h
 create mode 100644 OvmfPkg/Library/HardwareInfoLib/PeiHardwareInfoLib.inf
 create mode 100644 OvmfPkg/Library/HardwareInfoLib/QemuFwCfgHardwareInfoLib.c

-- 
2.17.1

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Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss
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