[PATCH v4 6/7] drm/xe/guc: Dead CT helper
John.C.Harrison at Intel.com
John.C.Harrison at Intel.com
Mon Jun 10 22:56:39 UTC 2024
From: John Harrison <John.C.Harrison at Intel.com>
Add a worker function helper for asynchronously dumping state when an
internal/fatal error is detected in CT processing. Being asynchronous
is required to avoid deadlocks and scheduling-while-atomic or
process-stalled-for-too-long issues. Also check for a bunch more error
conditions and improve the handling of some existing checks.
Signed-off-by: John Harrison <John.C.Harrison at Intel.com>
---
.../drm/xe/abi/guc_communication_ctb_abi.h | 1 +
drivers/gpu/drm/xe/xe_guc_ct.c | 256 ++++++++++++++++--
drivers/gpu/drm/xe/xe_guc_ct_types.h | 22 ++
3 files changed, 258 insertions(+), 21 deletions(-)
diff --git a/drivers/gpu/drm/xe/abi/guc_communication_ctb_abi.h b/drivers/gpu/drm/xe/abi/guc_communication_ctb_abi.h
index 8f86a16dc577..f58198cf2cf6 100644
--- a/drivers/gpu/drm/xe/abi/guc_communication_ctb_abi.h
+++ b/drivers/gpu/drm/xe/abi/guc_communication_ctb_abi.h
@@ -52,6 +52,7 @@ struct guc_ct_buffer_desc {
#define GUC_CTB_STATUS_OVERFLOW (1 << 0)
#define GUC_CTB_STATUS_UNDERFLOW (1 << 1)
#define GUC_CTB_STATUS_MISMATCH (1 << 2)
+#define GUC_CTB_STATUS_DISABLED (1 << 3)
u32 reserved[13];
} __packed;
static_assert(sizeof(struct guc_ct_buffer_desc) == 64);
diff --git a/drivers/gpu/drm/xe/xe_guc_ct.c b/drivers/gpu/drm/xe/xe_guc_ct.c
index 83ac14b1eade..fb8469394a33 100644
--- a/drivers/gpu/drm/xe/xe_guc_ct.c
+++ b/drivers/gpu/drm/xe/xe_guc_ct.c
@@ -25,12 +25,58 @@
#include "xe_gt_sriov_pf_monitor.h"
#include "xe_gt_tlb_invalidation.h"
#include "xe_guc.h"
+#include "xe_guc_log.h"
#include "xe_guc_relay.h"
#include "xe_guc_submit.h"
#include "xe_map.h"
#include "xe_pm.h"
#include "xe_trace.h"
+#if IS_ENABLED(CONFIG_DRM_XE_DEBUG)
+enum {
+ CT_DEAD_ALIVE = 0,
+ CT_DEAD_RESET, /* 0x0001 */
+ CT_DEAD_SETUP, /* 0x0002 */
+ CT_DEAD_H2G_WRITE, /* 0x0004 */
+ CT_DEAD_H2G_HAS_ROOM, /* 0x0008 */
+ CT_DEAD_G2H_READ, /* 0x0010 */
+ CT_DEAD_G2H_RECV, /* 0x0020 */
+ CT_DEAD_G2H_RELEASE, /* 0x0040 */
+ CT_DEAD_DEADLOCK, /* 0x0080 */
+ CT_DEAD_PROCESS_FAILED, /* 0x0100 */
+ CT_DEAD_FAST_G2H, /* 0x0200 */
+ CT_DEAD_PARSE_G2H_RESPONSE, /* 0x0400 */
+ CT_DEAD_PARSE_G2H_UNKNOWN, /* 0x0800 */
+ CT_DEAD_PARSE_G2H_ORIGIN, /* 0x1000 */
+ CT_DEAD_PARSE_G2H_TYPE, /* 0x2000 */
+};
+
+static void ct_dead_worker_func(struct work_struct *w);
+
+#define CT_DEAD(ct, hxg, reason_code) \
+ do { \
+ struct guc_ctb *_hxg = (hxg); \
+ if (_hxg) \
+ _hxg->info.broken = true; \
+ if (!(ct)->dead.reported) { \
+ struct xe_guc *guc = ct_to_guc(ct); \
+ spin_lock_irq(&ct->dead.lock); \
+ (ct)->dead.reason |= 1 << CT_DEAD_##reason_code; \
+ (ct)->dead.snapshot_log = xe_guc_log_snapshot_capture(&guc->log, true); \
+ (ct)->dead.snapshot_ct = xe_guc_ct_snapshot_capture((ct), true); \
+ spin_unlock_irq(&ct->dead.lock); \
+ queue_work(system_unbound_wq, &(ct)->dead.worker); \
+ } \
+ } while (0)
+#else
+#define CT_DEAD(ct, hxg, reason) \
+ do { \
+ struct guc_ctb *_hxg = (hxg); \
+ if (_hxg) \
+ _hxg->info.broken = true; \
+ } while (0)
+#endif
+
/* Used when a CT send wants to block and / or receive data */
struct g2h_fence {
u32 *response_buffer;
@@ -155,6 +201,10 @@ int xe_guc_ct_init(struct xe_guc_ct *ct)
spin_lock_init(&ct->fast_lock);
xa_init(&ct->fence_lookup);
INIT_WORK(&ct->g2h_worker, g2h_worker_func);
+#if IS_ENABLED(CONFIG_DRM_XE_DEBUG)
+ spin_lock_init(&ct->dead.lock);
+ INIT_WORK(&ct->dead.worker, ct_dead_worker_func);
+#endif
init_waitqueue_head(&ct->wq);
init_waitqueue_head(&ct->g2h_fence_wq);
@@ -350,10 +400,17 @@ int xe_guc_ct_enable(struct xe_guc_ct *ct)
wake_up_all(&ct->wq);
xe_gt_dbg(gt, "GuC CT communication channel enabled\n");
+#if IS_ENABLED(CONFIG_DRM_XE_DEBUG)
+ spin_lock_irq(&ct->dead.lock);
+ if (ct->dead.reason)
+ ct->dead.reason |= CT_DEAD_RESET;
+ spin_unlock_irq(&ct->dead.lock);
+#endif
return 0;
err_out:
xe_gt_err(gt, "Failed to enable GuC CT (%pe)\n", ERR_PTR(err));
+ CT_DEAD(ct, NULL, SETUP);
return err;
}
@@ -396,6 +453,19 @@ static bool h2g_has_room(struct xe_guc_ct *ct, u32 cmd_len)
if (cmd_len > h2g->info.space) {
h2g->info.head = desc_read(ct_to_xe(ct), h2g, head);
+
+ if (h2g->info.head > h2g->info.size) {
+ struct xe_device *xe = ct_to_xe(ct);
+ u32 desc_status = desc_read(xe, h2g, status);
+
+ desc_write(xe, h2g, status, desc_status | GUC_CTB_STATUS_OVERFLOW);
+
+ xe_gt_err(ct_to_gt(ct), "CT: invalid head offset %u >= %u)\n",
+ h2g->info.head, h2g->info.size);
+ CT_DEAD(ct, h2g, H2G_HAS_ROOM);
+ return false;
+ }
+
h2g->info.space = CIRC_SPACE(h2g->info.tail, h2g->info.head,
h2g->info.size) -
h2g->info.resv_space;
@@ -447,8 +517,16 @@ static void __g2h_reserve_space(struct xe_guc_ct *ct, u32 g2h_len, u32 num_g2h)
static void __g2h_release_space(struct xe_guc_ct *ct, u32 g2h_len)
{
lockdep_assert_held(&ct->fast_lock);
- xe_gt_assert(ct_to_gt(ct), ct->ctbs.g2h.info.space + g2h_len <=
- ct->ctbs.g2h.info.size - ct->ctbs.g2h.info.resv_space);
+ if (ct->ctbs.g2h.info.space + g2h_len >
+ ct->ctbs.g2h.info.size - ct->ctbs.g2h.info.resv_space) {
+ xe_gt_err(ct_to_gt(ct), "Invalid G2H release: %d + %d vs %d - %d -> %d vs %d!\n",
+ ct->ctbs.g2h.info.space, g2h_len,
+ ct->ctbs.g2h.info.size, ct->ctbs.g2h.info.resv_space,
+ ct->ctbs.g2h.info.space + g2h_len,
+ ct->ctbs.g2h.info.size - ct->ctbs.g2h.info.resv_space);
+ CT_DEAD(ct, &ct->ctbs.g2h, G2H_RELEASE);
+ return;
+ }
ct->ctbs.g2h.info.space += g2h_len;
--ct->g2h_outstanding;
@@ -474,12 +552,44 @@ static int h2g_write(struct xe_guc_ct *ct, const u32 *action, u32 len,
u32 full_len;
struct iosys_map map = IOSYS_MAP_INIT_OFFSET(&h2g->cmds,
tail * sizeof(u32));
+ u32 desc_status;
full_len = len + GUC_CTB_HDR_LEN;
lockdep_assert_held(&ct->lock);
xe_gt_assert(gt, full_len <= GUC_CTB_MSG_MAX_LEN);
- xe_gt_assert(gt, tail <= h2g->info.size);
+
+ desc_status = desc_read(xe, h2g, status);
+ if (desc_status) {
+ xe_gt_err(gt, "CT write: non-zero status: %u\n", desc_status);
+ goto corrupted;
+ }
+
+#if IS_ENABLED(CONFIG_DRM_XE_DEBUG)
+{
+ u32 desc_tail = desc_read(xe, h2g, tail);
+ u32 desc_head = desc_read(xe, h2g, head);
+
+ if (tail != desc_tail) {
+ desc_write(xe, h2g, status, desc_status | GUC_CTB_STATUS_MISMATCH);
+ xe_gt_err(gt, "CT write: tail was modified %u != %u\n", desc_tail, tail);
+ goto corrupted;
+ }
+
+ if (tail > h2g->info.size) {
+ desc_write(xe, h2g, status, desc_status | GUC_CTB_STATUS_OVERFLOW);
+ xe_gt_err(gt, "CT write: tail out of range: %u vs %u\n", tail, h2g->info.size);
+ goto corrupted;
+ }
+
+ if (desc_head >= h2g->info.size) {
+ desc_write(xe, h2g, status, desc_status | GUC_CTB_STATUS_OVERFLOW);
+ xe_gt_err(gt, "CT write: invalid head offset %u >= %u)\n",
+ desc_head, h2g->info.size);
+ goto corrupted;
+ }
+}
+#endif
/* Command will wrap, zero fill (NOPs), return and check credits again */
if (tail + full_len > h2g->info.size) {
@@ -532,6 +642,10 @@ static int h2g_write(struct xe_guc_ct *ct, const u32 *action, u32 len,
desc_read(xe, h2g, head), h2g->info.tail);
return 0;
+
+corrupted:
+ CT_DEAD(ct, &ct->ctbs.h2g, H2G_WRITE);
+ return -EPIPE;
}
/*
@@ -642,7 +756,6 @@ static int guc_ct_send_locked(struct xe_guc_ct *ct, const u32 *action, u32 len,
struct g2h_fence *g2h_fence)
{
struct xe_gt *gt = ct_to_gt(ct);
- struct drm_printer p = xe_gt_info_printer(gt);
unsigned int sleep_period_ms = 1;
int ret;
@@ -695,8 +808,13 @@ static int guc_ct_send_locked(struct xe_guc_ct *ct, const u32 *action, u32 len,
goto broken;
#undef g2h_avail
- if (dequeue_one_g2h(ct) < 0)
+ ret = dequeue_one_g2h(ct);
+ if (ret < 0) {
+ if (ret != -ECANCELED)
+ xe_gt_err(ct_to_gt(ct), "CTB receive failed (%pe)",
+ ERR_PTR(ret));
goto broken;
+ }
goto try_again;
}
@@ -705,8 +823,7 @@ static int guc_ct_send_locked(struct xe_guc_ct *ct, const u32 *action, u32 len,
broken:
xe_gt_err(gt, "No forward process on H2G, reset required\n");
- xe_guc_ct_print(ct, &p, true);
- ct->ctbs.h2g.info.broken = true;
+ CT_DEAD(ct, &ct->ctbs.h2g, DEADLOCK);
return -EDEADLK;
}
@@ -933,6 +1050,7 @@ static int parse_g2h_response(struct xe_guc_ct *ct, u32 *msg, u32 len)
else
xe_gt_err(gt, "unexpected response %u for FAST_REQ H2G fence 0x%x!\n",
type, fence);
+ CT_DEAD(ct, NULL, PARSE_G2H_RESPONSE);
return -EPROTO;
}
@@ -941,8 +1059,9 @@ static int parse_g2h_response(struct xe_guc_ct *ct, u32 *msg, u32 len)
if (unlikely(!g2h_fence)) {
/* Don't tear down channel, as send could've timed out */
xe_gt_warn(gt, "G2H fence (%u) not found!\n", fence);
+ CT_DEAD(ct, NULL, PARSE_G2H_UNKNOWN);
g2h_release_space(ct, GUC_CTB_HXG_MSG_MAX_LEN);
- return 0;
+ return -EPROTO;
}
xe_gt_assert(gt, fence == g2h_fence->seqno);
@@ -984,7 +1103,7 @@ static int parse_g2h_msg(struct xe_guc_ct *ct, u32 *msg, u32 len)
if (unlikely(origin != GUC_HXG_ORIGIN_GUC)) {
xe_gt_err(gt, "G2H channel broken on read, origin=%u, reset required\n",
origin);
- ct->ctbs.g2h.info.broken = true;
+ CT_DEAD(ct, &ct->ctbs.g2h, PARSE_G2H_ORIGIN);
return -EPROTO;
}
@@ -1002,7 +1121,7 @@ static int parse_g2h_msg(struct xe_guc_ct *ct, u32 *msg, u32 len)
default:
xe_gt_err(gt, "G2H channel broken on read, type=%u, reset required\n",
type);
- ct->ctbs.g2h.info.broken = true;
+ CT_DEAD(ct, &ct->ctbs.g2h, PARSE_G2H_TYPE);
ret = -EOPNOTSUPP;
}
@@ -1079,9 +1198,11 @@ static int process_g2h_msg(struct xe_guc_ct *ct, u32 *msg, u32 len)
xe_gt_err(gt, "unexpected G2H action 0x%04x\n", action);
}
- if (ret)
+ if (ret) {
xe_gt_err(gt, "G2H action 0x%04x failed (%pe)\n",
action, ERR_PTR(ret));
+ CT_DEAD(ct, NULL, PROCESS_FAILED);
+ }
return 0;
}
@@ -1091,7 +1212,7 @@ static int g2h_read(struct xe_guc_ct *ct, u32 *msg, bool fast_path)
struct xe_device *xe = ct_to_xe(ct);
struct xe_gt *gt = ct_to_gt(ct);
struct guc_ctb *g2h = &ct->ctbs.g2h;
- u32 tail, head, len;
+ u32 tail, head, len, desc_status;
s32 avail;
u32 action;
u32 *hxg;
@@ -1110,6 +1231,52 @@ static int g2h_read(struct xe_guc_ct *ct, u32 *msg, bool fast_path)
xe_gt_assert(gt, xe_guc_ct_enabled(ct));
+ desc_status = desc_read(xe, g2h, status);
+ if (desc_status) {
+ if (desc_status & GUC_CTB_STATUS_DISABLED) {
+ /*
+ * Potentially valid if a CLIENT_RESET request resulted in
+ * contexts/engines being reset. But should never happen as
+ * no contexts should be active when CLIENT_RESET is sent.
+ */
+ xe_gt_err(gt, "CT read: unexpected G2H after GuC has stopped!\n");
+ desc_status &= ~GUC_CTB_STATUS_DISABLED;
+ }
+
+ if (desc_status) {
+ xe_gt_err(gt, "CT read: non-zero status: %u\n", desc_status);
+ goto corrupted;
+ }
+ }
+
+#if IS_ENABLED(CONFIG_DRM_XE_DEBUG)
+{
+ u32 desc_tail = desc_read(xe, g2h, tail);
+ u32 desc_head = desc_read(xe, g2h, head);
+
+ if (g2h->info.head != desc_head) {
+ desc_write(xe, g2h, status, desc_status | GUC_CTB_STATUS_MISMATCH);
+ xe_gt_err(gt, "CT read: head was modified %u != %u\n",
+ desc_head, g2h->info.head);
+ goto corrupted;
+ }
+
+ if (g2h->info.head > g2h->info.size) {
+ desc_write(xe, g2h, status, desc_status | GUC_CTB_STATUS_OVERFLOW);
+ xe_gt_err(gt, "CT read: head out of range: %u vs %u\n",
+ g2h->info.head, g2h->info.size);
+ goto corrupted;
+ }
+
+ if (desc_tail >= g2h->info.size) {
+ desc_write(xe, g2h, status, desc_status | GUC_CTB_STATUS_OVERFLOW);
+ xe_gt_err(gt, "CT read: invalid tail offset %u >= %u)\n",
+ desc_tail, g2h->info.size);
+ goto corrupted;
+ }
+}
+#endif
+
/* Calculate DW available to read */
tail = desc_read(xe, g2h, tail);
avail = tail - g2h->info.head;
@@ -1126,9 +1293,7 @@ static int g2h_read(struct xe_guc_ct *ct, u32 *msg, bool fast_path)
if (len > avail) {
xe_gt_err(gt, "G2H channel broken on read, avail=%d, len=%d, reset required\n",
avail, len);
- g2h->info.broken = true;
-
- return -EPROTO;
+ goto corrupted;
}
head = (g2h->info.head + 1) % g2h->info.size;
@@ -1174,6 +1339,10 @@ static int g2h_read(struct xe_guc_ct *ct, u32 *msg, bool fast_path)
g2h->info.head, tail);
return len;
+
+corrupted:
+ CT_DEAD(ct, &ct->ctbs.g2h, G2H_READ);
+ return -EPROTO;
}
static void g2h_fast_path(struct xe_guc_ct *ct, u32 *msg, u32 len)
@@ -1200,9 +1369,11 @@ static void g2h_fast_path(struct xe_guc_ct *ct, u32 *msg, u32 len)
xe_gt_warn(gt, "NOT_POSSIBLE");
}
- if (ret)
+ if (ret) {
xe_gt_err(gt, "G2H action 0x%04x failed (%pe)\n",
action, ERR_PTR(ret));
+ CT_DEAD(ct, NULL, FAST_G2H);
+ }
}
/**
@@ -1263,7 +1434,6 @@ static int dequeue_one_g2h(struct xe_guc_ct *ct)
static void g2h_worker_func(struct work_struct *w)
{
struct xe_guc_ct *ct = container_of(w, struct xe_guc_ct, g2h_worker);
- struct xe_gt *gt = ct_to_gt(ct);
bool ongoing;
int ret;
@@ -1300,9 +1470,8 @@ static void g2h_worker_func(struct work_struct *w)
mutex_unlock(&ct->lock);
if (unlikely(ret == -EPROTO || ret == -EOPNOTSUPP)) {
- struct drm_printer p = xe_gt_info_printer(gt);
-
- xe_guc_ct_print(ct, &p, false);
+ xe_gt_err(ct_to_gt(ct), "CT dequeue failed: %d", ret);
+ CT_DEAD(ct, NULL, G2H_RECV);
kick_reset(ct);
}
} while (ret == 1);
@@ -1325,7 +1494,7 @@ static void guc_ctb_snapshot_capture(struct xe_device *xe, struct guc_ctb *ctb,
atomic ? GFP_ATOMIC : GFP_KERNEL);
if (!snapshot->cmds) {
- drm_err(&xe->drm, "Skipping CTB commands snapshot. Only CTB info will be available.\n");
+ drm_err(&xe->drm, "Skipping CTB commands snapshot. Only CT info will be available.\n");
return;
}
@@ -1483,3 +1652,48 @@ void xe_guc_ct_print(struct xe_guc_ct *ct, struct drm_printer *p, bool atomic)
xe_guc_ct_snapshot_print(snapshot, p);
xe_guc_ct_snapshot_free(snapshot);
}
+
+#if IS_ENABLED(CONFIG_DRM_XE_DEBUG)
+static void ct_dead_print(struct xe_dead_ct *dead)
+{
+ struct xe_guc_ct *ct = container_of(dead, struct xe_guc_ct, dead);
+ struct xe_gt *gt = ct_to_gt(ct);
+ static int g_count;
+ struct drm_printer ip = xe_gt_info_printer(gt);
+ struct drm_printer lp = drm_line_printer(&ip, "Capture", ++g_count);
+
+ if (!dead->reason) {
+ xe_gt_err(gt, "CTB is dead for no reason!?\n");
+ return;
+ }
+
+ drm_printf(&lp, "CTB is dead - reason=0x%X\n", dead->reason);
+
+ xe_guc_log_snapshot_print(ct_to_xe(ct), dead->snapshot_log, &lp, false);
+ xe_guc_ct_snapshot_print(dead->snapshot_ct, &lp);
+
+ drm_printf(&lp, "Done.\n");
+}
+
+static void ct_dead_worker_func(struct work_struct *w)
+{
+ struct xe_guc_ct *ct = container_of(w, struct xe_guc_ct, dead.worker);
+
+ if (!ct->dead.reported) {
+ ct->dead.reported = true;
+ ct_dead_print(&ct->dead);
+ }
+
+ spin_lock_irq(&ct->dead.lock);
+
+ xe_guc_log_snapshot_free(ct->dead.snapshot_log);
+ xe_guc_ct_snapshot_free(ct->dead.snapshot_ct);
+
+ if (ct->dead.reason & CT_DEAD_RESET) {
+ ct->dead.reason = CT_DEAD_ALIVE;
+ ct->dead.reported = false;
+ }
+
+ spin_unlock_irq(&ct->dead.lock);
+}
+#endif
diff --git a/drivers/gpu/drm/xe/xe_guc_ct_types.h b/drivers/gpu/drm/xe/xe_guc_ct_types.h
index fede4c6e93cb..49114868fe5e 100644
--- a/drivers/gpu/drm/xe/xe_guc_ct_types.h
+++ b/drivers/gpu/drm/xe/xe_guc_ct_types.h
@@ -86,6 +86,24 @@ enum xe_guc_ct_state {
XE_GUC_CT_STATE_ENABLED,
};
+#if IS_ENABLED(CONFIG_DRM_XE_DEBUG)
+/** struct xe_dead_ct - Information for debugging a dead CT */
+struct xe_dead_ct {
+ /** @lock: protects memory allocation/free operations, and @reason updates */
+ spinlock_t lock;
+ /** @reason: bit mask of CT_DEAD_* reason codes */
+ int reason;
+ /** @reported: for preventing multiple dumps per error sequence */
+ bool reported;
+ /** @worker: worker thread to get out of interrupt context before dumping */
+ struct work_struct worker;
+ /** snapshot_ct: copy of CT state and CTB content at point of error */
+ struct xe_guc_ct_snapshot *snapshot_ct;
+ /** snapshot_log: copy of GuC log at point of error */
+ struct xe_guc_log_snapshot *snapshot_log;
+};
+#endif
+
/**
* struct xe_guc_ct - GuC command transport (CT) layer
*
@@ -126,6 +144,10 @@ struct xe_guc_ct {
u32 msg[GUC_CTB_MSG_MAX_LEN];
/** @fast_msg: Message buffer */
u32 fast_msg[GUC_CTB_MSG_MAX_LEN];
+
+#if IS_ENABLED(CONFIG_DRM_XE_DEBUG)
+ struct xe_dead_ct dead;
+#endif
};
#endif
--
2.43.2
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