[RFC] Support for Arm CCA VMs on Linux

[Jean-Philippe Brucker]

On Thu, Mar 02, 2023 at 07:12:24AM +0900, Itaru Kitayama wrote:
> On Wed, Mar 1, 2023 at 6:20 PM Jean-Philippe Brucker
> <jean-philippe at linaro.org> wrote:
> >
> > Hi Itaru,
> >
> > On Wed, Mar 01, 2023 at 08:35:05AM +0900, Itaru Kitayama wrote:
> > > Hi Jean,
> > > I've tried your series in Real on CCA Host, but the KVM arch init
> > > emits an Invalid argument error and terminates.
> >
> > Do you know which call returns this error?  Normally the RMEGuest support
> > should print more detailed errors. Are you able to launch normal guests
> > (without the rme-guest object and confidential-guest-support machine
> > parameter)?  Could you give the complete QEMU command-line?
> 
> No, I cant say which. Yes, the CCA-capable QEMU boots if I don't set
> RME-related options.
> 
> Here's mine (based upon your command-line):
> qemu-system-aarch64 -cpu host -accel kvm -machine
> virt,gic-version=3,confidential-guest-support=rme0 -smp 2 -m 256M
> -nographic -object rme-guest,id=rme0,measurement-algo=sha512 -kernel
> Image -initrd rootfs.ext2 -append 'console=ttyAMA0 earlycon'
> -overcommit mem-lock=on

Thank you, this works on my setup so I'm not sure what's wrong. Check that
KVM initialized successfully, with this in the host kernel log:
"[    0.267019] kvm [1]: Using prototype RMM support (version 56.0)"

Next step would be to find out where the EINVAL comes from, with printfs
or GDB. This seems rather specific so I'll email you directly to avoid
filling up everyone's inbox.

Thanks,
Jean