[PATCH v5 23/23] drm/xe/uapi: Add UAPI for querying VMA count and memory attributes
Himal Prasad Ghimiray
himal.prasad.ghimiray at intel.com
Tue Jul 22 13:35:26 UTC 2025
Introduce the DRM_IOCTL_XE_VM_QUERY_MEMORY_RANGE_ATTRS ioctl to allow
userspace to query memory attributes of VMAs within a user specified
virtual address range.
Userspace first calls the ioctl with num_mem_ranges = 0,
sizeof_mem_ranges_attr = 0 and vector_of_vma_mem_attr = NULL to retrieve
the number of memory ranges (vmas) and size of each memory range attribute.
Then, it allocates a buffer of that size and calls the ioctl again to fill
the buffer with memory range attributes.
This two-step interface allows userspace to first query the required
buffer size, then retrieve detailed attributes efficiently.
v2 (Matthew Brost)
- Use same ioctl to overload functionality
v3
- Add kernel-doc
v4
- Make uapi future proof by passing struct size (Matthew Brost)
- make lock interruptible (Matthew Brost)
- set reserved bits to zero (Matthew Brost)
- s/__copy_to_user/copy_to_user (Matthew Brost)
- Avod using VMA term in uapi (Thomas)
- xe_vm_put(vm) is missing (Shuicheng)
Cc: Matthew Brost <matthew.brost at intel.com>
Cc: Shuicheng Lin <shuicheng.lin at intel.com>
Cc: Thomas Hellström <thomas.hellstrom at linux.intel.com>
Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray at intel.com>
---
drivers/gpu/drm/xe/xe_device.c | 2 +
drivers/gpu/drm/xe/xe_vm.c | 101 ++++++++++++++++++++++++
drivers/gpu/drm/xe/xe_vm.h | 2 +-
include/uapi/drm/xe_drm.h | 137 +++++++++++++++++++++++++++++++++
4 files changed, 241 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
index b02c4ae0fdbf..1e77570db531 100644
--- a/drivers/gpu/drm/xe/xe_device.c
+++ b/drivers/gpu/drm/xe/xe_device.c
@@ -202,6 +202,8 @@ static const struct drm_ioctl_desc xe_ioctls[] = {
DRM_RENDER_ALLOW),
DRM_IOCTL_DEF_DRV(XE_OBSERVATION, xe_observation_ioctl, DRM_RENDER_ALLOW),
DRM_IOCTL_DEF_DRV(XE_MADVISE, xe_vm_madvise_ioctl, DRM_RENDER_ALLOW),
+ DRM_IOCTL_DEF_DRV(XE_VM_QUERY_MEM_RANGE_ATTRS, xe_vm_query_vmas_attrs_ioctl,
+ DRM_RENDER_ALLOW),
};
static long xe_drm_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
diff --git a/drivers/gpu/drm/xe/xe_vm.c b/drivers/gpu/drm/xe/xe_vm.c
index bee849167c0d..e54ab4dce8df 100644
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -2297,6 +2297,107 @@ int xe_vm_destroy_ioctl(struct drm_device *dev, void *data,
return err;
}
+static int xe_vm_query_vmas(struct xe_vm *vm, u64 start, u64 end)
+{
+ struct drm_gpuva *gpuva;
+ u32 num_vmas = 0;
+
+ lockdep_assert_held(&vm->lock);
+ drm_gpuvm_for_each_va_range(gpuva, &vm->gpuvm, start, end)
+ num_vmas++;
+
+ return num_vmas;
+}
+
+static int get_mem_attrs(struct xe_vm *vm, u32 *num_vmas, u64 start,
+ u64 end, struct drm_xe_mem_range_attr *attrs)
+{
+ struct drm_gpuva *gpuva;
+ int i = 0;
+
+ lockdep_assert_held(&vm->lock);
+
+ drm_gpuvm_for_each_va_range(gpuva, &vm->gpuvm, start, end) {
+ struct xe_vma *vma = gpuva_to_vma(gpuva);
+
+ if (i == *num_vmas)
+ return -ENOSPC;
+
+ attrs[i].start = xe_vma_start(vma);
+ attrs[i].end = xe_vma_end(vma);
+ attrs[i].atomic.val = vma->attr.atomic_access;
+ attrs[i].pat_index.val = vma->attr.pat_index;
+ attrs[i].preferred_mem_loc.devmem_fd = vma->attr.preferred_loc.devmem_fd;
+ attrs[i].preferred_mem_loc.migration_policy =
+ vma->attr.preferred_loc.migration_policy;
+
+ i++;
+ }
+
+ if (i < (*num_vmas - 1))
+ *num_vmas = i;
+ return 0;
+}
+
+int xe_vm_query_vmas_attrs_ioctl(struct drm_device *dev, void *data, struct drm_file *file)
+{
+ struct xe_device *xe = to_xe_device(dev);
+ struct xe_file *xef = to_xe_file(file);
+ struct drm_xe_mem_range_attr *mem_attrs;
+ struct drm_xe_vm_query_mem_range_attr *args = data;
+ u64 __user *attrs_user = u64_to_user_ptr(args->vector_of_mem_attr);
+ struct xe_vm *vm;
+ int err = 0;
+
+ if (XE_IOCTL_DBG(xe,
+ ((args->num_mem_ranges == 0 &&
+ (attrs_user || args->sizeof_mem_range_attr != 0)) ||
+ (args->num_mem_ranges > 0 &&
+ (!attrs_user || args->sizeof_mem_range_attr == 0)))))
+ return -EINVAL;
+
+ vm = xe_vm_lookup(xef, args->vm_id);
+ if (XE_IOCTL_DBG(xe, !vm))
+ return -EINVAL;
+
+ err = down_read_interruptible(&vm->lock);
+ if (err)
+ goto put_vm;
+
+ attrs_user = u64_to_user_ptr(args->vector_of_mem_attr);
+
+ if (args->num_mem_ranges == 0 && !attrs_user) {
+ args->num_mem_ranges = xe_vm_query_vmas(vm, args->start, args->start + args->range);
+ args->sizeof_mem_range_attr = sizeof(struct drm_xe_mem_range_attr);
+ goto unlock_vm;
+ }
+
+ mem_attrs = kvmalloc_array(args->num_mem_ranges, args->sizeof_mem_range_attr,
+ GFP_KERNEL | __GFP_ACCOUNT |
+ __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
+ if (!mem_attrs) {
+ err = args->num_mem_ranges > 1 ? -ENOBUFS : -ENOMEM;
+ goto unlock_vm;
+ }
+
+ memset(mem_attrs, 0, args->num_mem_ranges * args->sizeof_mem_range_attr);
+ err = get_mem_attrs(vm, &args->num_mem_ranges, args->start,
+ args->start + args->range, mem_attrs);
+ if (err)
+ goto free_mem_attrs;
+
+ err = copy_to_user(attrs_user, mem_attrs,
+ args->sizeof_mem_range_attr * args->num_mem_ranges);
+
+free_mem_attrs:
+ kvfree(mem_attrs);
+unlock_vm:
+ up_read(&vm->lock);
+put_vm:
+ xe_vm_put(vm);
+ return err;
+}
+
static bool vma_matches(struct xe_vma *vma, u64 page_addr)
{
if (page_addr > xe_vma_end(vma) - 1 ||
diff --git a/drivers/gpu/drm/xe/xe_vm.h b/drivers/gpu/drm/xe/xe_vm.h
index f7b9ad83685a..6f25d6820991 100644
--- a/drivers/gpu/drm/xe/xe_vm.h
+++ b/drivers/gpu/drm/xe/xe_vm.h
@@ -199,7 +199,7 @@ int xe_vm_destroy_ioctl(struct drm_device *dev, void *data,
struct drm_file *file);
int xe_vm_bind_ioctl(struct drm_device *dev, void *data,
struct drm_file *file);
-
+int xe_vm_query_vmas_attrs_ioctl(struct drm_device *dev, void *data, struct drm_file *file);
void xe_vm_close_and_put(struct xe_vm *vm);
static inline bool xe_vm_in_fault_mode(struct xe_vm *vm)
diff --git a/include/uapi/drm/xe_drm.h b/include/uapi/drm/xe_drm.h
index 8f1d48664424..ee328bcb8bfa 100644
--- a/include/uapi/drm/xe_drm.h
+++ b/include/uapi/drm/xe_drm.h
@@ -82,6 +82,7 @@ extern "C" {
* - &DRM_IOCTL_XE_WAIT_USER_FENCE
* - &DRM_IOCTL_XE_OBSERVATION
* - &DRM_IOCTL_XE_MADVISE
+ * - &DRM_IOCTL_XE_VM_QUERY_MEM_RANGE_ATTRS
*/
/*
@@ -104,6 +105,7 @@ extern "C" {
#define DRM_XE_WAIT_USER_FENCE 0x0a
#define DRM_XE_OBSERVATION 0x0b
#define DRM_XE_MADVISE 0x0c
+#define DRM_XE_VM_QUERY_MEM_RANGE_ATTRS 0x0d
/* Must be kept compact -- no holes */
@@ -120,6 +122,7 @@ extern "C" {
#define DRM_IOCTL_XE_WAIT_USER_FENCE DRM_IOWR(DRM_COMMAND_BASE + DRM_XE_WAIT_USER_FENCE, struct drm_xe_wait_user_fence)
#define DRM_IOCTL_XE_OBSERVATION DRM_IOW(DRM_COMMAND_BASE + DRM_XE_OBSERVATION, struct drm_xe_observation_param)
#define DRM_IOCTL_XE_MADVISE DRM_IOW(DRM_COMMAND_BASE + DRM_XE_MADVISE, struct drm_xe_madvise)
+#define DRM_IOCTL_XE_VM_QUERY_MEM_RANGE_ATTRS DRM_IOWR(DRM_COMMAND_BASE + DRM_XE_VM_QUERY_MEM_RANGE_ATTRS, struct drm_xe_vm_query_mem_range_attr)
/**
* DOC: Xe IOCTL Extensions
@@ -2110,6 +2113,140 @@ struct drm_xe_madvise {
__u64 reserved[2];
};
+/**
+ * struct drm_xe_mem_range_attr - Output of &DRM_IOCTL_XE_VM_QUERY_MEM_RANGES_ATTRS
+ *
+ * This structure is provided by userspace and filled by KMD in response to the
+ * DRM_IOCTL_XE_VM_QUERY_MEM_RANGES_ATTRS ioctl. It describes memory attributes of
+ * a memory ranges within a user specified address range in a VM.
+ *
+ * The structure includes information such as atomic access policy,
+ * page attribute table (PAT) index, and preferred memory location.
+ * Userspace allocates an array of these structures and passes a pointer to the
+ * ioctl to retrieve attributes for each memory ranges
+ *
+ * @extensions: Pointer to the first extension struct, if any
+ * @start: Start address of the memory range
+ * @end: End address of the virtual memory range
+ *
+ */
+struct drm_xe_mem_range_attr {
+ /** @extensions: Pointer to the first extension struct, if any */
+ __u64 extensions;
+
+ /** @start: start of the memory range */
+ __u64 start;
+
+ /** @end: end of the memory range */
+ __u64 end;
+
+ /** @preferred_mem_loc: preferred memory location */
+ struct {
+ /** @preferred_mem_loc.devmem_fd: fd for preferred loc */
+ __u32 devmem_fd;
+
+ /** @preferred_mem_loc.migration_policy: Page migration policy */
+ __u32 migration_policy;
+ } preferred_mem_loc;
+
+ struct {
+ /** @atomic.val: atomic attribute */
+ __u32 val;
+
+ /** @atomic.reserved: Reserved */
+ __u32 reserved;
+ } atomic;
+
+ struct {
+ /** @pat_index.val: PAT index */
+ __u32 val;
+
+ /** @pat_index.reserved: Reserved */
+ __u32 reserved;
+ } pat_index;
+
+ /** @reserved: Reserved */
+ __u64 reserved[2];
+};
+
+/**
+ * struct drm_xe_vm_query_mem_range_attr - Input of &DRM_IOCTL_XE_VM_QUERY_MEM_ATTRIBUTES
+ *
+ * This structure is used to query memory attributes of memory regions
+ * within a user specified address range in a VM. It provides detailed
+ * information about each memory range, including atomic access policy,
+ * page attribute table (PAT) index, and preferred memory location.
+ *
+ * Userspace first calls the ioctl with @num_mem_ranges = 0,
+ * @sizeof_mem_ranges_attr = 0 and @vector_of_vma_mem_attr = NULL to retrieve
+ * the number of memory regions and size of each memory range attribute.
+ * Then, it allocates a buffer of that size and calls the ioctl again to fill
+ * the buffer with memory range attributes.
+ *
+ * If second call fails with -ENOSPC, it means memory ranges changed between
+ * first call and now, retry IOCTL again with @num_mem_ranges = 0,
+ * @sizeof_mem_ranges_attr = 0 and @vector_of_vma_mem_attr = NULL followed by
+ * Second ioctl call.
+ *
+ * Example:
+ *
+ * .. code-block:: C
+ * struct drm_xe_vm_query_mem_range_attr query = {
+ * .vm_id = vm_id,
+ * .start = 0x100000,
+ * .range = 0x2000,
+ * };
+ *
+ * // First ioctl call to get num of mem regions and sizeof each attribute
+ * ioctl(fd, DRM_IOCTL_XE_VM_QUERY_MEM_RANGE_ATTRS, &query);
+ *
+ * // Allocate buffer for the memory region attributes
+ * void *ptr = malloc(query.num_mem_ranges * query.sizeof_mem_range_attr);
+ *
+ * query.vector_of_mem_attr = (uintptr_t)ptr;
+ *
+ * // Second ioctl call to actually fill the memory attributes
+ * ioctl(fd, DRM_IOCTL_XE_VM_QUERY_MEM_RANGE_ATTRS, &query);
+ *
+ * // Iterate over the returned memory region attributes
+ * for (unsigned int i = 0; i < query.num_mem_ranges; ++i) {
+ * struct drm_xe_mem_range_attr *attr = (struct drm_xe_mem_range_attr *)ptr;
+ *
+ * // Do something with attr
+ *
+ * // Move pointer by one entry
+ * ptr += query.sizeof_mem_range_attr;
+ * }
+ *
+ * free(ptr);
+ */
+struct drm_xe_vm_query_mem_range_attr {
+ /** @extensions: Pointer to the first extension struct, if any */
+ __u64 extensions;
+
+ /** @vm_id: vm_id of the virtual range */
+ __u32 vm_id;
+
+ /** @num_mem_ranges: number of mem_ranges in range */
+ __u32 num_mem_ranges;
+
+ /** @start: start of the virtual address range */
+ __u64 start;
+
+ /** @range: size of the virtual address range */
+ __u64 range;
+
+ /** @sizeof_mem_range_attr: size of struct drm_xe_mem_range_attr */
+ __u64 sizeof_mem_range_attr;
+
+ /** @vector_of_ops: userptr to array of struct drm_xe_mem_range_attr */
+ __u64 vector_of_mem_attr;
+
+ /** @reserved: Reserved */
+ __u64 reserved[2];
+
+};
+
#if defined(__cplusplus)
}
#endif
--
2.34.1
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