[PATCH v4 2/3] drm/xe/sriov: Shifting GGTT area post migration
Tomasz Lis
tomasz.lis at intel.com
Fri Dec 20 23:34:08 UTC 2024
We have only one GGTT for all IOV functions, with each VF having assigned
a range of addresses for its use. After migration, a VF can receive a
different range of addresses than it had initially.
This implements shifting GGTT addresses within drm_mm nodes, so that
VMAs stay valid after migration. This will make the driver use new
addresses when accessing GGTT from the moment the shifting ends.
By taking the ggtt->lock for the period of VMA fixups, this change
also adds constraint on that mutex. Any locks used during the recovery
cannot ever wait for hardware response - because after migration,
the hardware will not do anything until fixups are finished.
v2: Moved some functs to xe_ggtt.c; moved shift computation to just
after querying; improved documentation; switched some warns to asserts;
skipping fixups when GGTT shift eq 0; iterating through tiles (Michal)
v3: Updated kerneldocs, removed unused funct, properly allocate
balloning nodes if non existent
Signed-off-by: Tomasz Lis <tomasz.lis at intel.com>
---
drivers/gpu/drm/xe/xe_ggtt.c | 163 ++++++++++++++++++++++
drivers/gpu/drm/xe/xe_ggtt.h | 2 +
drivers/gpu/drm/xe/xe_gt_sriov_vf.c | 26 ++++
drivers/gpu/drm/xe/xe_gt_sriov_vf.h | 1 +
drivers/gpu/drm/xe/xe_gt_sriov_vf_types.h | 2 +
drivers/gpu/drm/xe/xe_sriov_vf.c | 22 +++
6 files changed, 216 insertions(+)
diff --git a/drivers/gpu/drm/xe/xe_ggtt.c b/drivers/gpu/drm/xe/xe_ggtt.c
index 05154f9de1a6..284221d4558d 100644
--- a/drivers/gpu/drm/xe/xe_ggtt.c
+++ b/drivers/gpu/drm/xe/xe_ggtt.c
@@ -489,6 +489,169 @@ void xe_ggtt_node_remove_balloon(struct xe_ggtt_node *node)
xe_ggtt_node_fini(node);
}
+static u64 drm_mm_node_end(struct drm_mm_node *node)
+{
+ return node->start + node->size;
+}
+
+static void xe_ggtt_mm_shift_nodes(struct xe_ggtt *ggtt, struct drm_mm_node *balloon_beg,
+ struct drm_mm_node *balloon_fin, s64 shift)
+{
+ struct drm_mm_node *node, *tmpn;
+ LIST_HEAD(temp_list_head);
+ int err;
+
+ lockdep_assert_held(&ggtt->lock);
+
+ /*
+ * Move nodes, from range previously assigned to this VF, into temp list.
+ *
+ * The balloon_beg and balloon_fin nodes are there to eliminate unavailable
+ * ranges from use: first reserves the GGTT area below the range for current VF,
+ * and second reserves area above.
+ *
+ * Below is a GGTT layout of example VF, with a certain address range assigned to
+ * said VF, and inaccessible areas above and below:
+ *
+ * 0 4GiB
+ * |<--------------------------- Total GGTT size ----------------------------->|
+ * WOPCM GUC_TOP
+ * |<-------------- Area mappable by xe_ggtt instance ---------------->|
+ *
+ * +---+---------------------------------+----------+----------------------+---+
+ * |\\\|/////////////////////////////////| VF mem |//////////////////////|\\\|
+ * +---+---------------------------------+----------+----------------------+---+
+ *
+ * Hardware enforced access rules before migration:
+ *
+ * |<------- inaccessible for VF ------->|<VF owned>|<-- inaccessible for VF ->|
+ *
+ * drm_mm nodes used for tracking allocations:
+ *
+ * |<----------- balloon ------------>|<- nodes->|<----- balloon ------>|
+ *
+ * After the migration, GGTT area assigned to the VF might have shifted, either
+ * to lower or to higher address. But we expect the total size and extra areas to
+ * be identical, as migration can only happen between matching platforms.
+ * Below is an example of GGTT layout of the VF after migration. Content of the
+ * GGTT for VF has been moved to a new area, and we receive its address from GuC:
+ *
+ * +---+----------------------+----------+---------------------------------+---+
+ * |\\\|//////////////////////| VF mem |/////////////////////////////////|\\\|
+ * +---+----------------------+----------+---------------------------------+---+
+ *
+ * Hardware enforced access rules after migration:
+ *
+ * |<- inaccessible for VF -->|<VF owned>|<------- inaccessible for VF ------->|
+ *
+ * So the VF has a new slice of GGTT assigned, and during migration process, the
+ * memory content was copied to that new area. But the drm_mm nodes within xe kmd
+ * are still tracking allocations using the old addresses. The nodes within VF
+ * owned area have to be shifted, and balloon nodes need to be resized to
+ * properly mask out areas not owned by the VF.
+ *
+ * Fixed drm_mm nodes used for tracking allocations:
+ *
+ * |<------ balloon ------>|<- nodes->|<----------- balloon ----------->|
+ *
+ * Due to use of GPU profiles, we do not expect the old and new GGTT ares to
+ * overlap; but our node shifting will fix addresses properly regardless.
+ *
+ */
+ drm_mm_for_each_node_in_range_safe(node, tmpn, &ggtt->mm,
+ drm_mm_node_end(balloon_beg),
+ balloon_fin->start) {
+ drm_mm_remove_node(node);
+ list_add(&node->node_list, &temp_list_head);
+ }
+
+ /* shift and re-add ballooning nodes */
+ if (drm_mm_node_allocated(balloon_beg))
+ drm_mm_remove_node(balloon_beg);
+ if (drm_mm_node_allocated(balloon_fin))
+ drm_mm_remove_node(balloon_fin);
+ balloon_beg->size += shift;
+ balloon_fin->start += shift;
+ balloon_fin->size -= shift;
+ if (balloon_beg->size != 0) {
+ err = drm_mm_reserve_node(&ggtt->mm, balloon_beg);
+ xe_tile_assert(ggtt->tile, !err);
+ }
+ if (balloon_fin->size != 0) {
+ err = drm_mm_reserve_node(&ggtt->mm, balloon_fin);
+ xe_tile_assert(ggtt->tile, !err);
+ }
+
+ /*
+ * Now the GGTT VM contains only nodes outside of area assigned to this VF.
+ * We can re-add all VF nodes with shifted offsets.
+ */
+ list_for_each_entry_safe(node, tmpn, &temp_list_head, node_list) {
+ list_del(&node->node_list);
+ node->start += shift;
+ err = drm_mm_reserve_node(&ggtt->mm, node);
+ xe_tile_assert(ggtt->tile, !err);
+ }
+}
+
+/**
+ * xe_ggtt_node_shift_nodes - Shift GGTT nodes to adjust for a change in usable address range.
+ * @ggtt: the &xe_ggtt struct instance
+ * @balloon_beg: ggtt balloon node which preceds the area provisioned for current VF
+ * @balloon_fin: ggtt balloon node which follows the area provisioned for current VF
+ * @shift: change to the location of area provisioned for current VF
+ */
+void xe_ggtt_node_shift_nodes(struct xe_ggtt *ggtt, struct xe_ggtt_node **balloon_beg,
+ struct xe_ggtt_node **balloon_fin, s64 shift)
+{
+ struct drm_mm_node *balloon_mm_beg, *balloon_mm_end;
+ struct xe_ggtt_node *node;
+
+ if (!*balloon_beg)
+ {
+ node = xe_ggtt_node_init(ggtt);
+ if (IS_ERR(node))
+ goto out;
+ node->base.color = 0;
+ node->base.flags = 0;
+ node->base.start = xe_wopcm_size(ggtt->tile->xe);
+ node->base.size = 0;
+ *balloon_beg = node;
+ }
+ balloon_mm_beg = &(*balloon_beg)->base;
+
+ if (!*balloon_fin)
+ {
+ node = xe_ggtt_node_init(ggtt);
+ if (IS_ERR(node))
+ goto out;
+ node->base.color = 0;
+ node->base.flags = 0;
+ node->base.start = GUC_GGTT_TOP;
+ node->base.size = 0;
+ *balloon_fin = node;
+ }
+ balloon_mm_end = &(*balloon_fin)->base;
+
+ xe_tile_assert(ggtt->tile, (*balloon_beg)->ggtt);
+ xe_tile_assert(ggtt->tile, (*balloon_fin)->ggtt);
+
+ xe_ggtt_mm_shift_nodes(ggtt, balloon_mm_beg, balloon_mm_end, shift);
+out:
+ if (*balloon_beg && !xe_ggtt_node_allocated(*balloon_beg))
+ {
+ node = *balloon_beg;
+ *balloon_beg = NULL;
+ xe_ggtt_node_fini(node);
+ }
+ if (*balloon_fin && !xe_ggtt_node_allocated(*balloon_fin))
+ {
+ node = *balloon_fin;
+ *balloon_fin = NULL;
+ xe_ggtt_node_fini(node);
+ }
+}
+
/**
* xe_ggtt_node_insert_locked - Locked version to insert a &xe_ggtt_node into the GGTT
* @node: the &xe_ggtt_node to be inserted
diff --git a/drivers/gpu/drm/xe/xe_ggtt.h b/drivers/gpu/drm/xe/xe_ggtt.h
index 27e7d67de004..d9e133a155e6 100644
--- a/drivers/gpu/drm/xe/xe_ggtt.h
+++ b/drivers/gpu/drm/xe/xe_ggtt.h
@@ -18,6 +18,8 @@ void xe_ggtt_node_fini(struct xe_ggtt_node *node);
int xe_ggtt_node_insert_balloon(struct xe_ggtt_node *node,
u64 start, u64 size);
void xe_ggtt_node_remove_balloon(struct xe_ggtt_node *node);
+void xe_ggtt_node_shift_nodes(struct xe_ggtt *ggtt, struct xe_ggtt_node **balloon_beg,
+ struct xe_ggtt_node **balloon_fin, s64 shift);
int xe_ggtt_node_insert(struct xe_ggtt_node *node, u32 size, u32 align);
int xe_ggtt_node_insert_locked(struct xe_ggtt_node *node,
diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_vf.c b/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
index cca5d5732802..9513cfffe3d8 100644
--- a/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
+++ b/drivers/gpu/drm/xe/xe_gt_sriov_vf.c
@@ -389,6 +389,7 @@ static int vf_get_ggtt_info(struct xe_gt *gt)
xe_gt_sriov_dbg_verbose(gt, "GGTT %#llx-%#llx = %lluK\n",
start, start + size - 1, size / SZ_1K);
+ config->ggtt_shift = start - (s64)config->ggtt_base;
config->ggtt_base = start;
config->ggtt_size = size;
@@ -912,6 +913,31 @@ int xe_gt_sriov_vf_query_runtime(struct xe_gt *gt)
return err;
}
+/**
+ * xe_gt_sriov_vf_fixup_ggtt_nodes - Shift GGTT allocations to match assigned range.
+ * @gt: the &xe_gt struct instance
+ * Return: 0 on success, ENODATA if fixups are unnecessary
+ *
+ * Since Global GTT is not virtualized, each VF has an assigned range
+ * within the global space. This range might have changed during migration,
+ * which requires all memory addresses pointing to GGTT to be shifted.
+ */
+int xe_gt_sriov_vf_fixup_ggtt_nodes(struct xe_gt *gt)
+{
+ struct xe_gt_sriov_vf_selfconfig *config = >->sriov.vf.self_config;
+ struct xe_tile *tile = gt_to_tile(gt);
+ struct xe_ggtt *ggtt = tile->mem.ggtt;
+ s64 ggtt_shift;
+
+ mutex_lock(&ggtt->lock);
+ ggtt_shift = config->ggtt_shift;
+ if (ggtt_shift)
+ xe_ggtt_node_shift_nodes(ggtt, &tile->sriov.vf.ggtt_balloon[0],
+ &tile->sriov.vf.ggtt_balloon[1], ggtt_shift);
+ mutex_unlock(&ggtt->lock);
+ return ggtt_shift ? 0 : ENODATA;
+}
+
static int vf_runtime_reg_cmp(const void *a, const void *b)
{
const struct vf_runtime_reg *ra = a;
diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_vf.h b/drivers/gpu/drm/xe/xe_gt_sriov_vf.h
index 912d20814261..49af35484a57 100644
--- a/drivers/gpu/drm/xe/xe_gt_sriov_vf.h
+++ b/drivers/gpu/drm/xe/xe_gt_sriov_vf.h
@@ -17,6 +17,7 @@ int xe_gt_sriov_vf_query_config(struct xe_gt *gt);
int xe_gt_sriov_vf_connect(struct xe_gt *gt);
int xe_gt_sriov_vf_query_runtime(struct xe_gt *gt);
int xe_gt_sriov_vf_prepare_ggtt(struct xe_gt *gt);
+int xe_gt_sriov_vf_fixup_ggtt_nodes(struct xe_gt *gt);
int xe_gt_sriov_vf_notify_resfix_done(struct xe_gt *gt);
void xe_gt_sriov_vf_migrated_event_handler(struct xe_gt *gt);
diff --git a/drivers/gpu/drm/xe/xe_gt_sriov_vf_types.h b/drivers/gpu/drm/xe/xe_gt_sriov_vf_types.h
index a57f13b5afcd..5ccbdf8d08b6 100644
--- a/drivers/gpu/drm/xe/xe_gt_sriov_vf_types.h
+++ b/drivers/gpu/drm/xe/xe_gt_sriov_vf_types.h
@@ -40,6 +40,8 @@ struct xe_gt_sriov_vf_selfconfig {
u64 ggtt_base;
/** @ggtt_size: assigned size of the GGTT region. */
u64 ggtt_size;
+ /** @ggtt_shift: difference in ggtt_base on last migration */
+ s64 ggtt_shift;
/** @lmem_size: assigned size of the LMEM. */
u64 lmem_size;
/** @num_ctxs: assigned number of GuC submission context IDs. */
diff --git a/drivers/gpu/drm/xe/xe_sriov_vf.c b/drivers/gpu/drm/xe/xe_sriov_vf.c
index c1275e64aa9c..4ee8fc70a744 100644
--- a/drivers/gpu/drm/xe/xe_sriov_vf.c
+++ b/drivers/gpu/drm/xe/xe_sriov_vf.c
@@ -7,6 +7,7 @@
#include "xe_assert.h"
#include "xe_device.h"
+#include "xe_gt.h"
#include "xe_gt_sriov_printk.h"
#include "xe_gt_sriov_vf.h"
#include "xe_pm.h"
@@ -170,6 +171,26 @@ static bool vf_post_migration_imminent(struct xe_device *xe)
work_pending(&xe->sriov.vf.migration.worker);
}
+static int vf_post_migration_fixup_ggtt_nodes(struct xe_device *xe)
+{
+ struct xe_tile *tile;
+ unsigned int id;
+ int err;
+
+ for_each_tile(tile, xe, id) {
+ struct xe_gt *gt = tile->primary_gt;
+ int ret;
+
+ /* media doesn't have its own ggtt */
+ if (xe_gt_is_media_type(gt))
+ continue;
+ ret = xe_gt_sriov_vf_fixup_ggtt_nodes(gt);
+ if (ret != ENODATA)
+ err = ret;
+ }
+ return err;
+}
+
/*
* Notify all GuCs about resource fixups apply finished.
*/
@@ -201,6 +222,7 @@ static void vf_post_migration_recovery(struct xe_device *xe)
if (unlikely(err))
goto fail;
+ err = vf_post_migration_fixup_ggtt_nodes(xe);
/* FIXME: add the recovery steps */
vf_post_migration_notify_resfix_done(xe);
xe_pm_runtime_put(xe);
--
2.25.1
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