On Mon, Nov 21, 2016 at 07:44:26PM +0800, Zhi Wang wrote: > a PT page will be released if it doesn't contain any meaningful mappings > during PPGTT page table shrinking. The PT entry in the upper level will > be set to a scratch entry. > > Normally this works nicely, but in virtualization world, the PPGTT page > table is tracked by hypervisor. Releasing the PT page before modifying > the upper level PT entry would cause extra efforts. > > As the tracked page has been returned to OS before losing track from > hypervisor, it could be written in any pattern. Hypervisor has to recognize > if a page is still being used as a PT page by validating these writing > patterns. It's complicated. Better let the guest modify the PT entry in > upper level PT first, then release the PT page. Reviewed-by: Michał Winiarski <michal.winiarski@xxxxxxxxx> -Michał > Cc: Michał Winiarski <michal.winiarski@xxxxxxxxx> > Cc: Michel Thierry <michel.thierry@xxxxxxxxx> > Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx> > Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> > Cc: Zhenyu Wang <zhenyuw@xxxxxxxxxxxxxxx> > Cc: Zhiyuan Lv <zhiyuan.lv@xxxxxxxxx> > Signed-off-by: Zhi Wang <zhi.a.wang@xxxxxxxxx> > --- > drivers/gpu/drm/i915/i915_gem_gtt.c | 18 +++++++----------- > 1 file changed, 7 insertions(+), 11 deletions(-) _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
