Re: [BUG} libxl.c:5947:libxl_send_trigger: Send trigger 'reset' failed: Function not implemented

["Alex Braunegg" <alex.braunegg@gmail.com>]

Hi Ian,

> There is a function internal to libxl (libxl__domain_pvcontrol) which
> answers this question (by looking at the callback IRQ).

I looked at this function yesterday and it appears that it calls:

	ret = libxl__domain_pvcontrol_available(gc, domid);

which in turn calls:

	ret = xc_hvm_param_get(ctx->xch, domid, HVM_PARAM_CALLBACK_IRQ, &pvdriver);

which is defined in xenctrl.h, this is why I thought it may have been easier to call "xc_hvm_param_get" directly inside the 'xl vm-list' function with the applicable header applied.

> I suppose it would be reasonable to expose that formally in the libxl
> public API in some form, although it is also the case that any function
> which uses PV control mechanisms performs (or at least should perform) this
> check and return ERROR_NOPARAVIRT if pv control is not avaiable, so
> application code can try PV and fallback to other methods (as xl does).

> libxc (xenctrl.h) is not a stable interface and it is a design goal of
> libxl that toolstacks should only need to use libxl interfaces for their
> toolstack oriented operations. So this functionality would need to be
> reflected in the stable libxl API for use by xl (and libvirt, and other
> toolstacks people might write)

So potentially before trying to make use of libxl__domain_pvcontrol for the 'xl vm-list' command to provide feedback if PV control is available, I will need to wait for the functionality to be exposed via an applicable libxl header.

Best regards,

Alex