vgsp-sema: walk-authoritative GR ring pin when content not yet readable; walk-verdict telemetry (FORENSICS-grv6-ring fix A)

1 files changed, 53 insertions, 2 deletions

diff --git a/kernel/gsp_sema_service.c b/kernel/gsp_sema_service.c
index 800b256..4ba37d9 100644
--- a/kernel/gsp_sema_service.c
+++ b/kernel/gsp_sema_service.c
@@ -7995,6 +7995,7 @@ unsigned gsp_sema_ce_grace_ms = 25000;
 unsigned gsp_sema_push_hold_ms = 2500;
 
 static unsigned long svc_gr_ring_tried;	/* ranks that got a diagnostic line */
+static unsigned long svc_gr_walk_dbg;	/* ranks that got a walk-verdict line */
 
 static void svc_gr_ring_autopin(struct nv_vgpu_device *vgpu,
 				struct svc_channel *ch)
@@ -8199,9 +8200,11 @@ static void svc_gr_ring_autopin(struct nv_vgpu_device *vgpu,
 	{
 		u64 wpa = 0;
 		int wap = SVC_APERTURE_SYS;
+		int wrc;
+		u8 wprobe[8];
 
-		if (!svc_lookup_trusted(vgpu, ch->gpfifo_va, &wpa, &wap) &&
-		    svc_gr_ring_candidate(vgpu, ch, wpa, wap, &va, &len, &put,
+		wrc = svc_lookup_trusted(vgpu, ch->gpfifo_va, &wpa, &wap);
+		if (!wrc && svc_gr_ring_candidate(vgpu, ch, wpa, wap, &va, &len, &put,
 					  &get)) {
 			svc_pin_store(ch->gpfifo_va, wpa, wap);
 			svc_lat_store(ch->gpfifo_va, wpa, wap);
@@ -8216,6 +8219,54 @@ static void svc_gr_ring_autopin(struct nv_vgpu_device *vgpu,
 				wpa, wap, va, len, put, get);
 			return;
 		}
+		/*
+		 * FORENSICS-grv6-ring (SA-RING fix A): the trusted walk is
+		 * driver-published truth, but the candidate gate rejects it
+		 * while the ring page is still empty (grv6: entry0 e0/e1=0
+		 * and the USERD probe rc=-11, so the ring NEVER resolved and
+		 * no GR push was ever decoded). Latch the walked translation
+		 * when the page is at least READABLE, without marking the
+		 * ring done: the pump then has a real target, svc_chan_userd
+		 * can latch the USERD as soon as it shows activity, and the
+		 * next autopin pass upgrades to the full pin once entry0
+		 * lands. A bad aperture cannot be latched (readability gate);
+		 * ring_done stays unset so the content paths still run.
+		 */
+		if (!wrc &&
+		    !svc_read_ap(vgpu, wpa, wap, wprobe, sizeof(wprobe))) {
+			svc_pin_store(ch->gpfifo_va, wpa, wap);
+			svc_lat_store(ch->gpfifo_va, wpa, wap);
+			ch->userd_pa = wpa + SVC_GR_USERD_OFF;
+			ch->userd_as = wap;
+			if (gsp_sema_dbg &&
+			    !test_and_set_bit(ch->gr_index, &svc_gr_walk_dbg))
+				pr_info("sema-chan: GR walk-pinned (await content) h=0x%x rank=%u va=0x%llx -> pa=0x%llx ap=%d\n",
+					ch->h_object, ch->gr_index,
+					ch->gpfifo_va, wpa, wap);
+		}
+		/*
+		 * FORENSICS-grv6 (SA-FORENSICS-2): the H1 branch used to log
+		 * only successes, so a walk miss and a candidate reject were
+		 * indistinguishable. One verdict line per rank (dbg-gated).
+		 */
+		if (gsp_sema_dbg &&
+		    !test_and_set_bit(ch->gr_index, &svc_gr_walk_dbg)) {
+			if (wrc) {
+				pr_info("sema-chan: GR walk miss h=0x%x rank=%u va=0x%llx rc=%d\n",
+					ch->h_object, ch->gr_index,
+					ch->gpfifo_va, wrc);
+			} else {
+				u64 r0 = 0, r1 = 0;
+
+				(void)svc_read_ap(vgpu, wpa, wap, &r0,
+						  sizeof(r0));
+				(void)svc_read_ap(vgpu, wpa + 8, wap, &r1,
+						  sizeof(r1));
+				pr_info("sema-chan: GR walk hit/reject h=0x%x rank=%u va=0x%llx pa=0x%llx ap=%d w0=0x%llx w1=0x%llx\n",
+					ch->h_object, ch->gr_index,
+					ch->gpfifo_va, wpa, wap, r0, r1);
+			}
+		}
 	}
 
 	if (!test_and_set_bit(ch->gr_index, &svc_gr_ring_tried)) {