From 035d033c5a047e395a7b06bceea1dc5b594c3b90 Mon Sep 17 00:00:00 2001 From: Arthur Hanson Rasmusson Date: Sat, 7 Nov 2026 18:44:21 -0500 Subject: vgsp-disp: host-side EVO display engine (channels, push buffer, notifier, raster) The guest nvidia-modeset drives the display through per-channel NV-DMA push buffers kicked via the BAR0 UDISP control windows. Emulate that engine contract host-side, unmodified guest: - channel registration: display-channel RM objects (core 0xc57d, window 0xc57e, cursor 0xc57b, 0xc57a) are noted from the alloc stream, and the internal control NV2080_CTRL_CMD_INTERNAL_DISPLAY_CHANNEL_PUSHBUFFER (0x20800a58) records each push buffer (guest PA, size, class, instance, validity); - PUT polling + GET publication in the channel control pages (core 0x680000, window 0x690000+n*0x1000, cursor 0x6D8000+n*0x1000); - NV-DMA method parser (METHOD/ONE_INC/NONINC/JUMP/SET_SUBDEVICE_MASK) with the wrap-JUMP follow; - completion: SET_CONTEXT_DMA_NOTIFIER / SET_NOTIFIER_CONTROL tracking, exact notifier-surface resolution through the display instance hash table (no heuristic writes), NV_DISP_NOTIFIER FINISHED on UPDATE (0x200), and the channel completion event post; - free-running 1080p60 raster line for NVC57E_GET_LINE. All effects are behind independent knobs (disp_engine, disp_finish, disp_vblank, disp_events, disp_notifier_pa) with verbose diagnostics (disp_dbg, disp_dump), so the previous behaviour stays one load away. --- kernel/include/gsp_display_engine.h | 66 +++++++++++++++++++++++++++++++++++++ 1 file changed, 66 insertions(+) create mode 100644 kernel/include/gsp_display_engine.h (limited to 'kernel/include') diff --git a/kernel/include/gsp_display_engine.h b/kernel/include/gsp_display_engine.h new file mode 100644 index 0000000..bf2ee58 --- /dev/null +++ b/kernel/include/gsp_display_engine.h @@ -0,0 +1,66 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _GSP_DISPLAY_ENGINE_H_ +#define _GSP_DISPLAY_ENGINE_H_ + +/* + * Minimal host-side display (EVO) engine emulation for the emulated vGPU. + * + * The guest's nvidia-modeset programs the display channels through a small + * push buffer per channel and kicks it by writing the channel's PUT register + * in BAR0 (the UDISP channel control window). On real hardware the display + * engine consumes the methods, advances GET, and - when the push carries an + * UPDATE (NVC37D/NVC57D_UPDATE 0x200) with the completion notifier armed - + * writes an NV_DISP_NOTIFIER (status FINISHED) to the notifier surface the + * guest allocated for the channel. The driver then stops polling. + * + * This engine implements exactly that contract from the host side: + * - display channel registration from the RM control + * NV2080_CTRL_CMD_INTERNAL_DISPLAY_CHANNEL_PUSHBUFFER (0x20800a58), + * which carries the push-buffer guest physical address, size, class and + * instance; + * - the NVC57D method parser (METHOD/JUMP/NONINC/SET_SUBDEVICE_MASK), + * including the wrap JUMP the driver writes at the end of the ring; + * - GET emulation (write consumed offset into the channel control page); + * - SET_CONTEXT_DMA_NOTIFIER / SET_NOTIFIER_CONTROL tracking and the + * FINISHED notifier write on UPDATE; + * - a free-running raster line counter for NVC57E_GET_LINE so the driver's + * vblank/scanline reads make progress; + * - a vblank tick that posts the display event (best-effort; the mode set + * itself only needs the notifier). + * + * Everything here is host-side emulation of hardware behaviour; the guest + * driver is unmodified. + */ + +struct nv_vgpu_device; + +#define GSP_DISP_CLASS_CORE 0xc57d +#define GSP_DISP_CLASS_WINDOW 0xc57e +#define GSP_DISP_CLASS_CURSOR 0xc57b +#define GSP_DISP_CLASS_BASE 0xc57a + +/* Channel was announced by NV2080_CTRL_CMD_INTERNAL_DISPLAY_CHANNEL_PUSHBUFFER. */ +void gsp_disp_engine_channel_add(struct nv_vgpu_device *vgpu, u32 hclass, + u32 instance, u64 pb_pa, u64 limit, + u32 address_space, bool valid); + +/* + * A display channel object was allocated (RM handle). The push buffer's + * SET_CONTEXT_DMA_NOTIFIER carries a context-DMA handle, and the guest's + * display instance memory hash table maps that handle to the notifier + * surface address; the channel's own hObject is needed to post the + * completion event the driver registered on it. + */ +void gsp_disp_engine_note_object(struct nv_vgpu_device *vgpu, u32 hclass, + u32 instance, u32 h_object); + +/* Run one pass for a guest (called from the sema service thread). */ +void gsp_disp_engine_pump(struct nv_vgpu_device *vgpu); + +/* Drop all display channels of one guest (mdev cleanup). */ +void gsp_disp_engine_vgpu_cleanup(struct nv_vgpu_device *vgpu); + +int gsp_disp_engine_init(void); +void gsp_disp_engine_fini(void); + +#endif /* _GSP_DISPLAY_ENGINE_H_ */ -- cgit v1.2.3