[RFC PATCH 6/8] drm/xe/uapi: Add query ioctl for fabric connectivity
Maarten Lankhorst
dev at lankhorst.se
Fri Jun 13 13:45:25 UTC 2025
UMDs need to understand if two devices have connectivity, and what
that connectivity is.
Add to the query_ioctl the ability to determine if a fabric id and
current device have connectivity.
Signed-off-by: David Kershner <david.kershner at intel.com>
Signed-off-by: Maarten Lankhorst <dev at lankhorst.se>
---
drivers/gpu/drm/xe/xe_iaf.c | 13 ++++++++
drivers/gpu/drm/xe/xe_iaf.h | 9 ++++++
drivers/gpu/drm/xe/xe_query.c | 58 +++++++++++++++++++++++++++++++++++
include/uapi/drm/xe_drm.h | 32 +++++++++++++++++++
4 files changed, 112 insertions(+)
diff --git a/drivers/gpu/drm/xe/xe_iaf.c b/drivers/gpu/drm/xe/xe_iaf.c
index d93b13d30fbcd..431d20fea5369 100644
--- a/drivers/gpu/drm/xe/xe_iaf.c
+++ b/drivers/gpu/drm/xe/xe_iaf.c
@@ -403,3 +403,16 @@ u64 xe_iaf_dpa_base(struct xe_device *xe)
return xe->iaf->dpa;
}
+struct query_info *xe_iaf_connectivity_query(struct xe_iaf *iaf, u32 fabric_id)
+{
+ if (!iaf)
+ return ERR_PTR(-ENODEV);
+
+ if (iaf->fabric_id == fabric_id)
+ return NULL;
+
+ if (!iaf->ops)
+ return ERR_PTR(-EOPNOTSUPP);
+
+ return iaf->ops->connectivity_query(iaf->handle, fabric_id);
+}
diff --git a/drivers/gpu/drm/xe/xe_iaf.h b/drivers/gpu/drm/xe/xe_iaf.h
index 78d7cca447983..df6b8f9f2bc5f 100644
--- a/drivers/gpu/drm/xe/xe_iaf.h
+++ b/drivers/gpu/drm/xe/xe_iaf.h
@@ -8,6 +8,9 @@
#include <linux/types.h>
+struct query_info;
+struct xe_iaf;
+
/*
* Define the maximum number of devices instances based on the amount of
* FID space.
@@ -34,6 +37,7 @@ struct xe_device;
int xe_iaf_init(struct xe_device *xe);
int xe_iaf_init_aux(struct xe_device *xe);
u64 xe_iaf_dpa_base(struct xe_device *xe);
+struct query_info *xe_iaf_connectivity_query(struct xe_iaf *iaf, u32 fabric_id);
#else
@@ -52,6 +56,11 @@ static inline u64 xe_iaf_dpa_base(struct xe_device *xe)
return 0ULL;
}
+struct query_info *xe_iaf_connectivity_query(struct xe_iaf *iaf, u32 fabric_id)
+{
+ return ERR_PTR(-ENODEV);
+}
+
#endif
#endif
diff --git a/drivers/gpu/drm/xe/xe_query.c b/drivers/gpu/drm/xe/xe_query.c
index 2dbf4066d86ff..b7f8300ab34c2 100644
--- a/drivers/gpu/drm/xe/xe_query.c
+++ b/drivers/gpu/drm/xe/xe_query.c
@@ -12,6 +12,8 @@
#include <generated/xe_wa_oob.h>
#include <uapi/drm/xe_drm.h>
+#include <drm/intel/intel_iaf_platform.h>
+
#include "regs/xe_engine_regs.h"
#include "regs/xe_gt_regs.h"
#include "xe_bo.h"
@@ -22,6 +24,7 @@
#include "xe_ggtt.h"
#include "xe_gt.h"
#include "xe_guc_hwconfig.h"
+#include "xe_iaf.h"
#include "xe_macros.h"
#include "xe_mmio.h"
#include "xe_oa.h"
@@ -776,6 +779,60 @@ static int query_eu_stall(struct xe_device *xe,
return ret ? -EFAULT : 0;
}
+static int
+query_fabric_connectivity(struct xe_device *xe,
+ struct drm_xe_device_query *query)
+{
+ struct drm_xe_query_fabric_info __user *query_ptr;
+ struct drm_xe_query_fabric_info info;
+ struct query_info *qi;
+ u32 latency = 0;
+ int cnt;
+ int i;
+
+ query_ptr = u64_to_user_ptr(query->data);
+ if (copy_from_user(&info, query_ptr, sizeof(info)))
+ return -EFAULT;
+
+ if (XE_IOCTL_DBG(xe, info.pad))
+ return -EINVAL;
+
+ info.bandwidth = 0;
+ info.latency = 0;
+
+ qi = xe_iaf_connectivity_query(xe->iaf, info.fabric_id);
+ if (IS_ERR(qi))
+ return PTR_ERR(qi);
+
+ if (!qi)
+ goto done;
+ /*
+ * Examine the query information for connectivity.
+ * Minimum bandwidth value is the bandwidth, 0 == no connectivity
+ * Latency is averaged.
+ */
+ cnt = qi->src_cnt * qi->dst_cnt;
+ if (!cnt) {
+ kfree(qi);
+ return -ENXIO;
+ }
+
+ info.bandwidth = 0xffffffff;
+ for (i = 0; i < cnt; i++) {
+ info.bandwidth = min(qi->sd2sd[i].bandwidth, info.bandwidth);
+ XE_WARN_ON(check_add_overflow(latency, qi->sd2sd[i].latency,
+ &latency));
+ }
+
+ info.latency = latency / cnt;
+
+ kfree(qi);
+done:
+ if (copy_to_user(query_ptr, &info, sizeof(info)))
+ return -EFAULT;
+ return 0;
+}
+
static int (* const xe_query_funcs[])(struct xe_device *xe,
struct drm_xe_device_query *query) = {
query_engines,
@@ -789,6 +846,7 @@ static int (* const xe_query_funcs[])(struct xe_device *xe,
query_oa_units,
query_pxp_status,
query_eu_stall,
+ query_fabric_connectivity,
};
int xe_query_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
diff --git a/include/uapi/drm/xe_drm.h b/include/uapi/drm/xe_drm.h
index 6a702ba7817c3..9d30876cc8e91 100644
--- a/include/uapi/drm/xe_drm.h
+++ b/include/uapi/drm/xe_drm.h
@@ -668,6 +668,33 @@ struct drm_xe_query_pxp_status {
__u32 supported_session_types;
};
+/**
+ * struct drm_xe_query_fabric_info
+ *
+ * With the given fabric id, query fabric info wrt the device.
+ * Higher bandwidth is better. 0 means no fabric.
+ * Latency is averaged latency (from all paths)
+ *
+ * fabric_id can be obtained from
+ * /sys/class/drm/cardx/device/iaf.y/iaf_fabric_id
+ * Bandwidth is in Gigabits per second (max value of 8 * 4 * 90)
+ * 8 possible ports
+ * 4 lanes max per port
+ * 90 gigabits per lane
+ * Latency is in tenths of path length. 10 == 1 fabric link between src and dst
+ * POR is max 1 link (zero hops).
+ */
+struct drm_xe_query_fabric_info {
+ /** @fabric_id: (in) Fabric id associated with info */
+ __u32 fabric_id;
+ /** @bandwidth: minimum bandwidth of all connected ports, if 0 no fabric */
+ __u32 bandwidth;
+ /** @latency: latency averaged across all connected ports. */
+ __u32 latency;
+ /** @pad: MBZ */
+ __u32 pad;
+};
+
/**
* struct drm_xe_device_query - Input of &DRM_IOCTL_XE_DEVICE_QUERY - main
* structure to query device information
@@ -687,7 +714,11 @@ struct drm_xe_query_pxp_status {
* attributes.
* - %DRM_XE_DEVICE_QUERY_GT_TOPOLOGY
* - %DRM_XE_DEVICE_QUERY_ENGINE_CYCLES
+ * - %DRM_XE_DEVICE_QUERY_UC_FW_VERSION
+ * - %DRM_XE_DEVICE_QUERY_OA_UNITS
* - %DRM_XE_DEVICE_QUERY_PXP_STATUS
+ * - %DRM_XE_DEVICE_QUERY_EU_STALL
+ * - %DRM_XE_DEVICE_QUERY_FABRIC_INFO
*
* If size is set to 0, the driver fills it with the required size for
* the requested type of data to query. If size is equal to the required
@@ -742,6 +773,7 @@ struct drm_xe_device_query {
#define DRM_XE_DEVICE_QUERY_OA_UNITS 8
#define DRM_XE_DEVICE_QUERY_PXP_STATUS 9
#define DRM_XE_DEVICE_QUERY_EU_STALL 10
+#define DRM_XE_DEVICE_QUERY_FABRIC_INFO 11
/** @query: The type of data to query */
__u32 query;
--
2.45.2
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