Re: [libvirt] [RFC PATCH 6/6] qemu: Format pseries.cap-hpt-mps on the command line

On Mon, 2018-06-04 at 11:33 +1000, David Gibson wrote: > On Thu, May 24, 2018 at 07:34:25AM +0200, Peter Krempa wrote: > > On Wed, May 23, 2018 at 19:09:59 +0200, Andrea Bolognani wrote: > > > To be fair, it would perhaps make sense to perform the conversion > > > directly inside QEMU, in order to make it more convenient not only > > > for libvirt but for for people driving it directly as well. > > > > If strictly only powers of two make sense for this knob then this gives > > you input validation for free. On the other hand, specifying a big > > number can overflow internally if it is ever used in the non-exponent > > form. I think the format does not matter much, since libvirt's job is to > > shield users from such weirdness. > > Yeah, the above is basically my reasoning for using the exponent, not > the final page size. As Peter mentioned, what format is used doesn't matter much from libvirt's point of view, and in fact this RFC already implements the necessary format conversion; however, it might be convenient for people spawning QEMU directly to be able to specify the page size in a more human-friendly format. How do you feel about that? If that's off the table, we'll just go ahead with the current implementation.