This series tries to send the vGPU display refresh event to user land. Instead of delivering page flip events only or vblank events only, we choose to combine two of them, i.e. post display refresh event at vblanks and skip some of them when no page flip happens. Vblanks as upper bound are safe and skipping no-page-flip vblanks guarantees both trivial performance impacts and good user experience without screen tearing. Plus, we have the mask/unmask mechansim providing user space flexibility to switch between event-notified refresh and classic timer-based refresh.
In addition, there are some cases that guest app only uses one framebuffer for both drawing and display. In such case, guest OS won't do the plane page flip when the framebuffer is updated, thus the user land won't be notified about the updated framebuffer. Hence, in single framebuffer case, we apply a heuristic to determine whether it is the case or not. If it is, notify user land when each vblank event triggers. v5: - Introduce a vGPU display irq cap which can notify user space with both primary and cursor plane update events through one eventfd. (Gerd & Alex) v4: - Deliver page flip event and single framebuffer refresh event bounded by display vblanks. (Kechen) v3: - Deliver display vblank event instead of page flip event. (Zhenyu) v2: - Use VFIO irq chain to get eventfds from userspace instead of adding a new ABI. (Alex) v1: - https://patchwork.kernel.org/cover/10962341/ Kechen Lu (2): drm/i915/gvt: Deliver async primary plane page flip events at vblank drm/i915/gvt: Add cursor plane reg update trap emulation handler Tina Zhang (4): vfio: Define device specific irq type capability vfio: Introduce vGPU display irq type drm/i915/gvt: Register vGPU display event irq drm/i915/gvt: Deliver vGPU refresh event to userspace drivers/gpu/drm/i915/gvt/cmd_parser.c | 6 +- drivers/gpu/drm/i915/gvt/display.c | 49 +++++- drivers/gpu/drm/i915/gvt/display.h | 3 + drivers/gpu/drm/i915/gvt/gvt.h | 6 + drivers/gpu/drm/i915/gvt/handlers.c | 32 +++- drivers/gpu/drm/i915/gvt/hypercall.h | 1 + drivers/gpu/drm/i915/gvt/interrupt.c | 7 + drivers/gpu/drm/i915/gvt/interrupt.h | 3 + drivers/gpu/drm/i915/gvt/kvmgt.c | 230 +++++++++++++++++++++++++- drivers/gpu/drm/i915/gvt/mpt.h | 17 ++ include/uapi/linux/vfio.h | 40 ++++- 11 files changed, 375 insertions(+), 19 deletions(-) -- 2.17.1