Re: [PATCH v6 13/21] gunyah: vm_mgr: Introduce basic VM Manager

[Elliot Berman]

+Michael

On 11/1/2022 10:14 PM, Greg Kroah-Hartman wrote:
> On Wed, Oct 26, 2022 at 11:58:38AM -0700, Elliot Berman wrote:
> > +#define GH_CREATE_VM			_IO(GH_IOCTL_TYPE, 0x40) /* Returns a Gunyah VM fd */
>
> Why 0x40?  Why not just use the same KVM ioctl numbers and names as you
> are doing the same thing as them, right?

We've designed so that there are a few ioctls that will feel similar to 
KVM ioctls since we know this design has been successful, but we don't 
intend to support KVM ioctls 1:1. Gunyah has different semantics for 
many of the name-identical ioctls. It seems odd to mix some re-used KVM 
ioctls with novel Gunyah ioctls?

> Normally your first ioctl is "0x01", not "0x40", so this feels really
> odd.

Documentation/userspace-api/ioctl/iocl-number.rst advises to pick an 
unused block. We picked ioctl code 'G' and unused sequence numbers under 
that code. I'm ok to move the block around.

Thanks,
Elliot