On Wed, 2025-01-29 at 11:51 -0800, Matthew Brost wrote:
> Add SVM init / close / fini to faulting VMs. Minimual implementation
> acting as a placeholder for follow on patches.
>
> v2:
> - Add close function
> v3:
> - Better commit message (Thomas)
> - Kernel doc (Thomas)
> - Update chunk array to be unsigned long (Thomas)
> - Use new drm_gpusvm.h header location (Thomas)
> - Newlines between functions in xe_svm.h (Thomas)
> - Call drm_gpusvm_driver_set_lock in init (Thomas)
>
> Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
Reviewed-by: Thomas Hellström <thomas.hellstrom@xxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/xe/Makefile | 1 +
> drivers/gpu/drm/xe/xe_svm.c | 73
> ++++++++++++++++++++++++++++++++
> drivers/gpu/drm/xe/xe_svm.h | 17 ++++++++
> drivers/gpu/drm/xe/xe_vm.c | 12 ++++++
> drivers/gpu/drm/xe/xe_vm_types.h | 7 +++
> 5 files changed, 110 insertions(+)
> create mode 100644 drivers/gpu/drm/xe/xe_svm.c
> create mode 100644 drivers/gpu/drm/xe/xe_svm.h
>
> diff --git a/drivers/gpu/drm/xe/Makefile
> b/drivers/gpu/drm/xe/Makefile
> index 328aff36831b..a078a8895ec5 100644
> --- a/drivers/gpu/drm/xe/Makefile
> +++ b/drivers/gpu/drm/xe/Makefile
> @@ -97,6 +97,7 @@ xe-y += xe_bb.o \
> xe_sched_job.o \
> xe_step.o \
> xe_survivability_mode.o \
> + xe_svm.o \
> xe_sync.o \
> xe_tile.o \
> xe_tile_sysfs.o \
> diff --git a/drivers/gpu/drm/xe/xe_svm.c
> b/drivers/gpu/drm/xe/xe_svm.c
> new file mode 100644
> index 000000000000..79da859f02b1
> --- /dev/null
> +++ b/drivers/gpu/drm/xe/xe_svm.c
> @@ -0,0 +1,73 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2024 Intel Corporation
> + */
> +
> +#include "xe_svm.h"
> +#include "xe_vm.h"
> +#include "xe_vm_types.h"
> +
> +static void xe_svm_invalidate(struct drm_gpusvm *gpusvm,
> + struct drm_gpusvm_notifier *notifier,
> + const struct mmu_notifier_range
> *mmu_range)
> +{
> + /* TODO: Implement */
> +}
> +
> +static const struct drm_gpusvm_ops gpusvm_ops = {
> + .invalidate = xe_svm_invalidate,
> +};
> +
> +static const unsigned long fault_chunk_sizes[] = {
> + SZ_2M,
> + SZ_64K,
> + SZ_4K,
> +};
> +
> +/**
> + * xe_svm_init() - SVM initialize
> + * @vm: The VM.
> + *
> + * Initialize SVM state which is embedded within the VM.
> + *
> + * Return: 0 on success, negative error code on error.
> + */
> +int xe_svm_init(struct xe_vm *vm)
> +{
> + int err;
> +
> + err = drm_gpusvm_init(&vm->svm.gpusvm, "Xe SVM", &vm->xe-
> >drm,
> + current->mm, NULL, 0, vm->size,
> + SZ_512M, &gpusvm_ops,
> fault_chunk_sizes,
> + ARRAY_SIZE(fault_chunk_sizes));
> + if (err)
> + return err;
> +
> + drm_gpusvm_driver_set_lock(&vm->svm.gpusvm, &vm->lock);
> +
> + return 0;
> +}
> +
> +/**
> + * xe_svm_close() - SVM close
> + * @vm: The VM.
> + *
> + * Close SVM state (i.e., stop and flush all SVM actions).
> + */
> +void xe_svm_close(struct xe_vm *vm)
> +{
> + xe_assert(vm->xe, xe_vm_is_closed(vm));
> +}
> +
> +/**
> + * xe_svm_fini() - SVM finalize
> + * @vm: The VM.
> + *
> + * Finalize SVM state which is embedded within the VM.
> + */
> +void xe_svm_fini(struct xe_vm *vm)
> +{
> + xe_assert(vm->xe, xe_vm_is_closed(vm));
> +
> + drm_gpusvm_fini(&vm->svm.gpusvm);
> +}
> diff --git a/drivers/gpu/drm/xe/xe_svm.h
> b/drivers/gpu/drm/xe/xe_svm.h
> new file mode 100644
> index 000000000000..49cfd938aa17
> --- /dev/null
> +++ b/drivers/gpu/drm/xe/xe_svm.h
> @@ -0,0 +1,17 @@
> +/* SPDX-License-Identifier: MIT */
> +/*
> + * Copyright © 2024 Intel Corporation
> + */
> +
> +#ifndef _XE_SVM_H_
> +#define _XE_SVM_H_
> +
> +struct xe_vm;
> +
> +int xe_svm_init(struct xe_vm *vm);
> +
> +void xe_svm_fini(struct xe_vm *vm);
> +
> +void xe_svm_close(struct xe_vm *vm);
> +
> +#endif
> diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
> index dff10dfa9c69..bc34e6738c8c 100644
> --- a/drivers/gpu/drm/xe/xe_vm.c
> +++ b/drivers/gpu/drm/xe/xe_vm.c
> @@ -34,6 +34,7 @@
> #include "xe_preempt_fence.h"
> #include "xe_pt.h"
> #include "xe_res_cursor.h"
> +#include "xe_svm.h"
> #include "xe_sync.h"
> #include "xe_trace_bo.h"
> #include "xe_wa.h"
> @@ -1504,6 +1505,12 @@ struct xe_vm *xe_vm_create(struct xe_device
> *xe, u32 flags)
> }
> }
>
> + if (flags & XE_VM_FLAG_FAULT_MODE) {
> + err = xe_svm_init(vm);
> + if (err)
> + goto err_close;
> + }
> +
> if (number_tiles > 1)
> vm->composite_fence_ctx =
> dma_fence_context_alloc(1);
>
> @@ -1549,6 +1556,8 @@ void xe_vm_close_and_put(struct xe_vm *vm)
> xe_vm_close(vm);
> if (xe_vm_in_preempt_fence_mode(vm))
> flush_work(&vm->preempt.rebind_work);
> + if (xe_vm_in_fault_mode(vm))
> + xe_svm_close(vm);
>
> down_write(&vm->lock);
> for_each_tile(tile, xe, id) {
> @@ -1617,6 +1626,9 @@ void xe_vm_close_and_put(struct xe_vm *vm)
> xe_vma_destroy_unlocked(vma);
> }
>
> + if (xe_vm_in_fault_mode(vm))
> + xe_svm_fini(vm);
> +
> up_write(&vm->lock);
>
> down_write(&xe->usm.lock);
> diff --git a/drivers/gpu/drm/xe/xe_vm_types.h
> b/drivers/gpu/drm/xe/xe_vm_types.h
> index f6855e4fb9e6..aa075d5e7a3f 100644
> --- a/drivers/gpu/drm/xe/xe_vm_types.h
> +++ b/drivers/gpu/drm/xe/xe_vm_types.h
> @@ -6,6 +6,7 @@
> #ifndef _XE_VM_TYPES_H_
> #define _XE_VM_TYPES_H_
>
> +#include <drm/drm_gpusvm.h>
> #include <drm/drm_gpuvm.h>
>
> #include <linux/dma-resv.h>
> @@ -140,6 +141,12 @@ struct xe_vm {
> /** @gpuvm: base GPUVM used to track VMAs */
> struct drm_gpuvm gpuvm;
>
> + /** @svm: Shared virtual memory state */
> + struct {
> + /** @svm.gpusvm: base GPUSVM used to track fault
> allocations */
> + struct drm_gpusvm gpusvm;
> + } svm;
> +
> struct xe_device *xe;
>
> /* exec queue used for (un)binding vma's */
