[RFC 10/15] drm/xe/svm: Handle svm ranges on access ctr trigger

Himal Prasad Ghimiray
2026-03-18T07:10:32Z

Migrate ranges to local vram and setup pte for gpu access.

Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray@intel.com>
---
drivers/gpu/drm/xe/xe_access_counter.c | 30 ++++++-------
drivers/gpu/drm/xe/xe_svm.c | 59 +++++++++++++++++++-------
drivers/gpu/drm/xe/xe_svm.h | 4 ++
3 files changed, 63 insertions(+), 30 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_access_counter.c b/drivers/gpu/drm/xe/xe_access_counter.c
index f93618faab02..ba15f21c6803 100644
--- a/drivers/gpu/drm/xe/xe_access_counter.c
+++ b/drivers/gpu/drm/xe/xe_access_counter.c
@@ -13,6 +13,7 @@
#include "xe_device.h"
#include "xe_gt_printk.h"
#include "xe_hw_engine.h"
+#include "xe_svm.h"
#include "xe_trace_bo.h"
#include "xe_usm_queue.h"
#include "xe_vm.h"
@@ -42,20 +43,14 @@ static int xe_access_counter_sub_granularity_in_byte(int val)
return xe_access_counter_granularity_in_byte(val) / 32;
}

-static struct xe_vma *xe_access_counter_get_vma(struct xe_vm *vm,
- struct xe_access_counter *ac)
+static u64 xe_access_counter_get_va(struct xe_access_counter *ac)
{
- u64 page_va;
-
- if (ac->consumer.granularity != XE_ACCESS_COUNTER_GRANULARITY_128K) {
- page_va = ac->consumer.va_range_base;
- } else {
- page_va = ac->consumer.va_range_base +
- (ffs(ac->consumer.sub_granularity) - 1) *
- xe_access_counter_sub_granularity_in_byte(ac->consumer.granularity);
- }
+ if (ac->consumer.granularity != XE_ACCESS_COUNTER_GRANULARITY_128K)
+ return ac->consumer.va_range_base;

- return xe_vm_find_overlapping_vma(vm, page_va, SZ_4K);
+ return ac->consumer.va_range_base +
+ (ffs(ac->consumer.sub_granularity) - 1) *
+ xe_access_counter_sub_granularity_in_byte(ac->consumer.granularity);
}

static void xe_access_counter_print(struct xe_access_counter *ac)
@@ -88,6 +83,7 @@ static int xe_access_counter_service(struct xe_access_counter *ac)
struct dma_fence *fence;
struct xe_vm *vm;
struct xe_vma *vma;
+ u64 page_va;
int err = 0;

if (ac->consumer.counter_type > XE_ACCESS_COUNTER_TYPE_NOTIFY)
@@ -104,7 +100,8 @@ static int xe_access_counter_service(struct xe_access_counter *ac)
goto unlock_vm;
}
/* Lookup VMA */
- vma = xe_access_counter_get_vma(vm, ac);
+ page_va = xe_access_counter_get_va(ac);
+ vma = xe_vm_find_vma_by_addr(vm, page_va);
if (!vma) {
err = -EINVAL;
goto unlock_vm;
@@ -112,9 +109,12 @@ static int xe_access_counter_service(struct xe_access_counter *ac)

trace_xe_vma_acc(vma, ac->consumer.counter_type);

- /* TODO: Handle svm vma's */
- if (xe_vma_has_no_bo(vma))
+ if (xe_vma_has_no_bo(vma)) {
+ if (xe_vma_is_cpu_addr_mirror(vma))
+ err = xe_svm_range_setup(vm, vma, gt, page_va,
+ false, true);
goto unlock_vm;
+ }

/* Lock VM and BOs dma-resv */
xe_validation_ctx_init(&ctx, &vm->xe->val, &exec, (struct xe_val_flags) {});
diff --git a/drivers/gpu/drm/xe/xe_svm.c b/drivers/gpu/drm/xe/xe_svm.c
index a91c84487a67..fe0f86a2d0bf 100644
--- a/drivers/gpu/drm/xe/xe_svm.c
+++ b/drivers/gpu/drm/xe/xe_svm.c
@@ -1186,9 +1186,9 @@ DECL_SVM_RANGE_US_STATS(get_pages, GET_PAGES)
DECL_SVM_RANGE_US_STATS(bind, BIND)
DECL_SVM_RANGE_US_STATS(fault, PAGEFAULT)

-static int __xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
- struct xe_gt *gt, u64 fault_addr,
- bool need_vram)
+static int __xe_svm_range_setup(struct xe_vm *vm, struct xe_vma *vma,
+ struct xe_gt *gt, u64 fault_addr,
+ bool need_vram, bool acc_ctr_trigger)
{
int devmem_possible = IS_DGFX(vm->xe) &&
IS_ENABLED(CONFIG_DRM_XE_PAGEMAP);
@@ -1196,7 +1196,7 @@ static int __xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
.read_only = xe_vma_read_only(vma),
.devmem_possible = devmem_possible,
.check_pages_threshold = devmem_possible ? SZ_64K : 0,
- .devmem_only = need_vram && devmem_possible,
+ .devmem_only = (need_vram || acc_ctr_trigger) && devmem_possible,
.timeslice_ms = need_vram && devmem_possible ?
vm->xe->atomic_svm_timeslice_ms : 0,
};
@@ -1213,7 +1213,8 @@ static int __xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
lockdep_assert_held_write(&vm->lock);
xe_assert(vm->xe, xe_vma_is_cpu_addr_mirror(vma));

- xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_PAGEFAULT_COUNT, 1);
+ if (!acc_ctr_trigger)
+ xe_gt_stats_incr(gt, XE_GT_STATS_ID_SVM_PAGEFAULT_COUNT, 1);

retry:
/* Always process UNMAPs first so view SVM ranges is current */
@@ -1229,7 +1230,8 @@ static int __xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
if (IS_ERR(range))
return PTR_ERR(range);

- xe_svm_range_fault_count_stats_incr(gt, range);
+ if (!acc_ctr_trigger)
+ xe_svm_range_fault_count_stats_incr(gt, range);

if (ctx.devmem_only && !range->base.pages.flags.migrate_devmem) {
err = -EACCES;
@@ -1244,6 +1246,10 @@ static int __xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,

range_debug(range, "PAGE FAULT");

+ if (acc_ctr_trigger && !range->base.pages.flags.migrate_devmem) {
+ goto out;
+ }
+
if (--migrate_try_count >= 0 &&
xe_svm_range_needs_migrate_to_vram(range, vma, dpagemap)) {
ktime_t migrate_start = xe_gt_stats_ktime_get();
@@ -1307,6 +1313,7 @@ static int __xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
}

xe_svm_range_get_pages_us_stats_incr(gt, range, get_pages_start);
+
range_debug(range, "PAGE FAULT - BIND");

bind_start = xe_gt_stats_ktime_get();
@@ -1347,21 +1354,22 @@ static int __xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
}

/**
- * xe_svm_handle_pagefault() - SVM handle page fault
+ * xe_svm_range_setup - Setup range for GPU access
* @vm: The VM.
* @vma: The CPU address mirror VMA.
- * @gt: The gt upon the fault occurred.
- * @fault_addr: The GPU fault address.
+ * @gt: The gt for which binding.
+ * @addr: Addr for which need to bind svm range.
* @atomic: The fault atomic access bit.
+ * @acc_ctr_trigger: If true, always migrate to local device memory.
*
* Create GPU bindings for a SVM page fault. Optionally migrate to device
* memory.
*
* Return: 0 on success, negative error code on error.
*/
-int xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
- struct xe_gt *gt, u64 fault_addr,
- bool atomic)
+int xe_svm_range_setup(struct xe_vm *vm, struct xe_vma *vma,
+ struct xe_gt *gt, u64 addr,
+ bool atomic, bool acc_ctr_trigger)
{
int need_vram, ret;
retry:
@@ -1369,14 +1377,15 @@ int xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
if (need_vram < 0)
return need_vram;

- ret = __xe_svm_handle_pagefault(vm, vma, gt, fault_addr,
- need_vram ? true : false);
+ ret = __xe_svm_range_setup(vm, vma, gt, addr,
+ need_vram ? true : false,
+ acc_ctr_trigger);
if (ret == -EAGAIN) {
/*
* Retry once on -EAGAIN to re-lookup the VMA, as the original VMA
* may have been split by xe_svm_range_set_default_attr.
*/
- vma = xe_vm_find_vma_by_addr(vm, fault_addr);
+ vma = xe_vm_find_vma_by_addr(vm, addr);
if (!vma)
return -EINVAL;

@@ -1385,6 +1394,26 @@ int xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
return ret;
}

+/**
+ * xe_svm_handle_pagefault() - SVM handle page fault
+ * @vm: The VM.
+ * @vma: The CPU address mirror VMA.
+ * @gt: The gt upon the fault occurred.
+ * @fault_addr: The GPU fault address.
+ * @atomic: The fault atomic access bit.
+ *
+ * Create GPU bindings for a SVM page fault. Optionally migrate to device
+ * memory.
+ *
+ * Return: 0 on success, negative error code on error.
+ */
+int xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
+ struct xe_gt *gt, u64 fault_addr,
+ bool atomic)
+{
+ return xe_svm_range_setup(vm, vma, gt, fault_addr, atomic, false);
+}
+
/**
* xe_svm_has_mapping() - SVM has mappings
* @vm: The VM.
diff --git a/drivers/gpu/drm/xe/xe_svm.h b/drivers/gpu/drm/xe/xe_svm.h
index b7b8eeacf196..50861d93b12f 100644
--- a/drivers/gpu/drm/xe/xe_svm.h
+++ b/drivers/gpu/drm/xe/xe_svm.h
@@ -85,6 +85,10 @@ void xe_svm_fini(struct xe_vm *vm);

void xe_svm_close(struct xe_vm *vm);

+int xe_svm_range_setup(struct xe_vm *vm, struct xe_vma *vma,
+ struct xe_gt *gt, u64 addr,
+ bool atomic, bool acc_ctr_trigger);
+
int xe_svm_handle_pagefault(struct xe_vm *vm, struct xe_vma *vma,
struct xe_gt *gt, u64 fault_addr,
bool atomic);
--
2.34.1