From bd1f27476fc11dc0bc45eb1aa666e352f34a0168 Mon Sep 17 00:00:00 2001 From: Arthur Hanson Rasmusson Date: Tue, 27 Oct 2026 10:26:38 -0400 Subject: vgsp: client-session boundary fixes - WD ring scan gate + forced session flush Two changes from the r839/r840 multi-client forensics (session 147): 1. The guest-RAM content scan for a GR ring must not run for the kernel RC-watchdog channel (h=0x31415900). Its ring is a plain kernel allocation always resolvable through the driver-published VAS walk; on r840 the walk lost a registration race, the scan latched a foreign garbage page, and the bad latch poisoned the driver's DMA test ('Failed to initialize DMA', Xorg died). Gated, the walk retries per pass; r841 Xorg#1 passes DMA (DMAFAIL=0) where r840 failed. 2. sema_force_flush module parameter + gsp_sema_service_sess_flush_force(): execute the ISSUE-0002 client-session flush even with live channels. The channel-close trigger never fires on real boots (driver-global channels stay valid), so later client sessions inherited stale discovery state. Verified on r841: flush executes mid-boot, Xorg survives it and re-registers its channels. Remaining wall (addendum 9): GR client channels' pushbuffer reads return all-zero through the trusted translation (va=0x4000000-class, src=4), so first entries never complete and GL clients never render. --- kernel/gsp_sema_service.h | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'kernel/gsp_sema_service.h') diff --git a/kernel/gsp_sema_service.h b/kernel/gsp_sema_service.h index 63c7f82..2184826 100644 --- a/kernel/gsp_sema_service.h +++ b/kernel/gsp_sema_service.h @@ -120,6 +120,12 @@ void gsp_sema_service_vaspace_candidate_add(u32 h_vaspace, u64 pdb, * session flushes keep that state - see svc_session_flush. */ void gsp_sema_service_guest_reset(void); +/* + * ISSUE-0002 aid: force a client-session flush that executes even while + * channels are live (see addendum 8 and the sema_force_flush parameter). + */ +void gsp_sema_service_sess_flush_force(void); + int gsp_sema_service_start(void); void gsp_sema_service_stop(void); int gsp_sema_service_probe(u64 gpu_va, u32 count); -- cgit v1.2.3