audk/OvmfPkg/Microvm
Min Xu 57bcfc3b06 OvmfPkg: Create initial version of PlatformInitLib
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=3863

There are 3 variants of PlatformPei in OvmfPkg:
 - OvmfPkg/PlatformPei
 - OvmfPkg/XenPlatformPei
 - OvmfPkg/Bhyve/PlatformPei/PlatformPei.inf
These PlatformPeis can share many common codes, such as
Cmos / Hob / Memory / Platform related functions. This commit
(and its following several patches) are to create a PlatformInitLib
which wraps the common code called in above PlatformPeis.

In this initial version of PlatformInitLib, below Cmos related functions
are introduced:
 - PlatformCmosRead8
 - PlatformCmosWrite8
 - PlatformDebugDumpCmos

They correspond to the functions in OvmfPkg/PlatformPei:
 - CmosRead8
 - CmosWrite8
 - DebugDumpCmos

Considering this PlatformInitLib will be used in SEC phase, global
variables and dynamic PCDs are avoided. We use PlatformInfoHob
to exchange information between functions.

EFI_HOB_PLATFORM_INFO is the data struct which contains the platform
information, such as HostBridgeDevId, BootMode, S3Supported,
SmmSmramRequire, etc.

After PlatformInitLib is created, OvmfPkg/PlatformPei is refactored
with this library.

Cc: Ard Biesheuvel <ardb+tianocore@kernel.org>
Cc: Jordan Justen <jordan.l.justen@intel.com>
Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Erdem Aktas <erdemaktas@google.com>
Cc: James Bottomley <jejb@linux.ibm.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>
Signed-off-by: Min Xu <min.m.xu@intel.com>
2022-04-02 08:15:12 +00:00
..
MicrovmX64.dsc OvmfPkg: Create initial version of PlatformInitLib 2022-04-02 08:15:12 +00:00
MicrovmX64.fdf OvmfPkg/Microvm/virtio: add virtio-mmio support 2021-12-13 12:16:32 +00:00
README OvmfPkg/Microvm: add README 2021-12-13 12:16:32 +00:00

README

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This is an *experimental* port of OVMF for the QEMU microvm
machine type.

microvm background info
-----------------------

microvm is designed for modern, virtio-based workloads.  Most legacy
lpc/isa devices like pit and pic can be turned off.  virtio-mmio
(i.e. '-device virtio-{blk,net,scsi,...}-device') is used for
storage/network/etc.

Optional pcie support is available and any pcie device supported by
QEMU can be plugged in (including virtio-pci if you prefer that over
virtio-mmio).

https://qemu.readthedocs.io/en/latest/system/i386/microvm.html
https://www.kraxel.org/blog/2020/10/qemu-microvm-acpi/

design issues
-------------

Not fully clear yet how to do hardware detection best.  Right now
using device tree to find virtio-mmio devices and pcie host bridge,
can reuse existing ArmVirtPkg code that way.  Needs patched QEMU.

features
--------
 [working] serial console
 [working] direct kernel boot
 [working] virtio-mmio support
 [in progress] pcie support

known limitations
-----------------
 * rtc=on is required for now.
 * can't use separate code/vars (actually an microvm limitation,
   there is no pflash support).
 * transitional virtio-pci devices do not work.  microvm doesn't
   support ioports on pcie, and ovmf doesn't initialize pcie devices
   with ioports if there is no address space for them (even though
   pcie devices are required to be functional without ioports).

usage
-----
qemu-system-x86_64 \
    -nographic \
    -machine microvm,acpi=on,pit=off,pic=off,rtc=on \
    -bios /path/to/MICROVM.fd \
    [ ... more args here ... ]