Re: [PATCH v3 7/7] OvmfPkg: CloudHv: Add README

["Gerd Hoffmann" <kraxel@redhat.com>]

On Thu, Feb 24, 2022 at 03:28:26PM +0100, sebastien.boeuf@intel.com wrote:
> From: Sebastien Boeuf <sebastien.boeuf@intel.com>
> 
> Add some documentation to the CloudHv target in order to clarify how to
> use it and what to expect from it.
> 
> Signed-off-by: Sebastien Boeuf <sebastien.boeuf@intel.com>
> ---
>  OvmfPkg/CloudHv/README | 66 ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 66 insertions(+)
>  create mode 100644 OvmfPkg/CloudHv/README
> 
> diff --git a/OvmfPkg/CloudHv/README b/OvmfPkg/CloudHv/README
> new file mode 100644
> index 0000000000..b5ef2a8be6
> --- /dev/null
> +++ b/OvmfPkg/CloudHv/README
> @@ -0,0 +1,66 @@
> +
> +CloudHv is a port of OVMF for the Cloud Hypervisor project.
> +
> +The Cloud Hypervisor project
> +----------------------------
> +
> +Cloud Hypervisor is a Virtual Machine Monitor that runs on top of KVM. The
> +project focuses on exclusively running modern, cloud workloads, on top of a
> +limited set of hardware architectures and platforms. Cloud workloads refers to
> +those that are usually run by customers inside a cloud provider. This means
> +modern operating systems with most I/O handled by paravirtualised devices
> +(i.e. virtio), no requirement for legacy devices, and 64-bit CPUs.
> +
> +https://github.com/cloud-hypervisor/cloud-hypervisor
> +
> +Design
> +------
> +
> +Based on Cloud Hypervisor's motto to reduce the emulation as much as possible,
> +the project logically decided to support the PVH boot specification as the only
> +way of booting virtual machines. That includes both direct kernel boot and OVMF
> +firmware which must be generated as PVH ELF binaries.
> +PVH allows information like location of ACPI tables and location of guest RAM
> +ranges to be shared without the need of an extra emulated device like a CMOS.
> +
> +Features
> +--------
> +
> +* Serial console
> +* EFI shell
> +* virtio-pci
> +
> +Build
> +-----
> +
> +The way to build the CloudHv target is as follows:
> +
> +OvmfPkg/build.sh -p OvmfPkg/CloudHv/CloudHvX64.dsc -a X64 -b DEBUG
> +
> +Usage
> +-----
> +
> +Assuming Cloud Hypervisor is already built, one can start a virtual machine as
> +follows:
> +
> +./cloud-hypervisor \
> +    --cpus boot=1 \
> +    --memory size=1G \
> +    --kernel Build/CloudHvX64/DEBUG_GCC5/FV/CLOUDHV.fd \
> +    --disk path=/path/to/disk.raw
> +
> +Releases
> +--------
> +
> +In edk2-stable202202, CloudHv is generated as data-only binary.
> +Starting with edk2-stable202205, CloudHv is generated as a PVH ELF binary to
> +reduce the amount of emulation needed from Cloud Hypervisor.
> +For TDX, things are handled differently and PVH is not used, which is why the
> +firmware is always generated as a data-only binary.
> +
> ++-------------------+----------------+-------------+
> +|      CloudHv      |    non-TDX     |     TDX     |
> ++-------------------+----------------+-------------+
> +| edk2-stable202202 | Data binary    | Data binary |
> +| edk2-stable202205 | PVH ELF binary | Data binary |
> ++-------------------+----------------+-------------+

Hmm, but current edk2 code has no support for tdx, correct?
I'd suggest to drop the tdx references then.

take care,
  Gerd