From 1f135a1ee9d2f80c56531971901ed87538f709b7 Mon Sep 17 00:00:00 2001 From: Matthew Brost Date: Wed, 8 Oct 2025 14:45:17 -0700 Subject: [PATCH] drm/xe/vf: Use GUC_HXG_TYPE_EVENT for GuC context register The only case where the GuC submission backend cannot reason 100% correctly is when a GuC context is registered during VF post-migration recovery. In this scenario, it's possible that the GuC context register H2G is processed, but the immediately following schedule-enable H2G gets lost. The schedule-enable G2H "done" response is how the GuC state machine determines whether context registration has completed. A double register is harmless when using `GUC_HXG_TYPE_EVENT`, as GuC simply drops the duplicate H2G. To keep things simple, use `GUC_HXG_TYPE_EVENT` for all context registrations on VFs. v5: - Check for xe_sriov_vf_migration_supported (Tomasz) v7: - Add comment about subsequent protocol failures (Tomasz) - Modify commit message (Michal) Signed-off-by: Matthew Brost Reviewed-by: Michal Wajdeczko Reviewed-by: Tomasz Lis Link: https://lore.kernel.org/r/20251008214532.3442967-20-matthew.brost@intel.com --- drivers/gpu/drm/xe/xe_guc_ct.c | 35 ++++++++++++++++++++++++++-------- 1 file changed, 27 insertions(+), 8 deletions(-) diff --git a/drivers/gpu/drm/xe/xe_guc_ct.c b/drivers/gpu/drm/xe/xe_guc_ct.c index 9f0090ae64a60..f63ce0cec3575 100644 --- a/drivers/gpu/drm/xe/xe_guc_ct.c +++ b/drivers/gpu/drm/xe/xe_guc_ct.c @@ -32,6 +32,7 @@ #include "xe_guc_tlb_inval.h" #include "xe_map.h" #include "xe_pm.h" +#include "xe_sriov_vf.h" #include "xe_trace_guc.h" static void receive_g2h(struct xe_guc_ct *ct); @@ -736,6 +737,28 @@ static u16 next_ct_seqno(struct xe_guc_ct *ct, bool is_g2h_fence) return seqno; } +#define MAKE_ACTION(type, __action) \ +({ \ + FIELD_PREP(GUC_HXG_MSG_0_TYPE, type) | \ + FIELD_PREP(GUC_HXG_EVENT_MSG_0_ACTION | \ + GUC_HXG_EVENT_MSG_0_DATA0, __action); \ +}) + +static bool vf_action_can_safely_fail(struct xe_device *xe, u32 action) +{ + /* + * When resuming a VF, we can't reliably track whether context + * registration has completed in the GuC state machine. It is harmless + * to resend the request, as it will fail silently if GUC_HXG_TYPE_EVENT + * is used. Additionally, if there is an H2G protocol issue on a VF, + * subsequent H2G messages sent as GUC_HXG_TYPE_FAST_REQUEST will likely + * fail. + */ + return IS_SRIOV_VF(xe) && xe_sriov_vf_migration_supported(xe) && + (action == XE_GUC_ACTION_REGISTER_CONTEXT_MULTI_LRC || + action == XE_GUC_ACTION_REGISTER_CONTEXT); +} + #define H2G_CT_HEADERS (GUC_CTB_HDR_LEN + 1) /* one DW CTB header and one DW HxG header */ static int h2g_write(struct xe_guc_ct *ct, const u32 *action, u32 len, @@ -807,18 +830,14 @@ static int h2g_write(struct xe_guc_ct *ct, const u32 *action, u32 len, FIELD_PREP(GUC_CTB_MSG_0_NUM_DWORDS, len) | FIELD_PREP(GUC_CTB_MSG_0_FENCE, ct_fence_value); if (want_response) { - cmd[1] = - FIELD_PREP(GUC_HXG_MSG_0_TYPE, GUC_HXG_TYPE_REQUEST) | - FIELD_PREP(GUC_HXG_EVENT_MSG_0_ACTION | - GUC_HXG_EVENT_MSG_0_DATA0, action[0]); + cmd[1] = MAKE_ACTION(GUC_HXG_TYPE_REQUEST, action[0]); + } else if (vf_action_can_safely_fail(xe, action[0])) { + cmd[1] = MAKE_ACTION(GUC_HXG_TYPE_EVENT, action[0]); } else { fast_req_track(ct, ct_fence_value, FIELD_GET(GUC_HXG_EVENT_MSG_0_ACTION, action[0])); - cmd[1] = - FIELD_PREP(GUC_HXG_MSG_0_TYPE, GUC_HXG_TYPE_FAST_REQUEST) | - FIELD_PREP(GUC_HXG_EVENT_MSG_0_ACTION | - GUC_HXG_EVENT_MSG_0_DATA0, action[0]); + cmd[1] = MAKE_ACTION(GUC_HXG_TYPE_FAST_REQUEST, action[0]); } /* H2G header in cmd[1] replaces action[0] so: */ -- 2.47.3