On Tue, 2019-01-22 at 16:26 +1100, Paul Mackerras wrote:

On Mon, Jan 07, 2019 at 08:10:05PM +0100, Cédric Le Goater wrote:

quoted

Clear the ESB pages from the VMA of the IRQ being pass through to the
guest and let the fault handler repopulate the VMA when the ESB pages
are accessed for an EOI or for a trigger.

Why do we want to do this?

I don't see any possible advantage to removing the PTEs from the
userspace mapping.  You'll need to explain further.

Afaik bcs we change the mapping to point to the real HW irq ESB page
instead of the "IPI" that was there at VM init time.

Cedric, is that correct ?

Cheers,
Ben.