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

["Boeuf, Sebastien" <sebastien.boeuf@intel.com>]

On Fri, 2022-02-25 at 10:43 +0100, Gerd Hoffmann wrote:
> 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.

Yes you're right. I'll remove it.

> 
> take care,
>   Gerd
> 

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