[PATCH v4 19/20] drm/xe/uapi: Add UAPI for querying VMA count and memory attributes
Himal Prasad Ghimiray
himal.prasad.ghimiray at intel.com
Fri Jun 13 12:55:57 UTC 2025
Introduce the DRM_IOCTL_XE_VM_QUERY_VMAS_ATTRS ioctl to allow userspace
to query memory attributes of VMAs within a specified virtual address
range.
If num_vmas == 0 and vector_of_vma_mem_attr == NULL, the ioctl returns
the number of VMAs in the specified range.
If num_vmas > 0 and a valid user pointer is provided in
vector_of_vma_mem_attr, the ioctl fills the buffer with memory
attributes for each VMA.
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
Cc: Matthew Brost <matthew.brost at intel.com>
Signed-off-by: Himal Prasad Ghimiray <himal.prasad.ghimiray at intel.com>
---
drivers/gpu/drm/xe/xe_device.c | 1 +
drivers/gpu/drm/xe/xe_vm.c | 89 ++++++++++++++++++++++
drivers/gpu/drm/xe/xe_vm.h | 2 +-
include/uapi/drm/xe_drm.h | 130 +++++++++++++++++++++++++++++++++
4 files changed, 221 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
index 632d3ab12392..1f9969acbcd9 100644
--- a/drivers/gpu/drm/xe/xe_device.c
+++ b/drivers/gpu/drm/xe/xe_device.c
@@ -199,6 +199,7 @@ 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_VMAS_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 14e554f3f4d5..d9ce25f3abf4 100644
--- a/drivers/gpu/drm/xe/xe_vm.c
+++ b/drivers/gpu/drm/xe/xe_vm.c
@@ -2171,6 +2171,95 @@ int xe_vm_destroy_ioctl(struct drm_device *dev, void *data,
return err;
}
+static void xe_vm_query_vmas(struct xe_vm *vm, u32 *num_vmas, u64 start, u64 end)
+{
+ struct drm_gpuva *gpuva;
+
+ lockdep_assert_held(&vm->lock);
+ drm_gpuvm_for_each_va_range(gpuva, &vm->gpuvm, start, end)
+ (*num_vmas)++;
+}
+
+static int get_mem_attrs(struct xe_vm *vm, u32 *num_vmas, u64 start,
+ u64 end, struct drm_xe_vma_mem_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 -EINVAL;
+
+ 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_vma_mem_attr *mem_attrs;
+ struct drm_xe_vm_query_vmas_attr *args = data;
+ u64 __user *attrs_user = u64_to_user_ptr(args->vector_of_vma_mem_attr);
+ struct xe_vm *vm;
+ int err = 0;
+
+ if (XE_IOCTL_DBG(xe,
+ (args->num_vmas == 0 && attrs_user) ||
+ (args->num_vmas > 0 && !attrs_user)))
+ return -EINVAL;
+
+ vm = xe_vm_lookup(xef, args->vm_id);
+ if (XE_IOCTL_DBG(xe, !vm))
+ return -EINVAL;
+
+ down_read(&vm->lock);
+
+ attrs_user = u64_to_user_ptr(args->vector_of_vma_mem_attr);
+
+ if (args->num_vmas == 0 && !attrs_user) {
+ xe_vm_query_vmas(vm, &args->num_vmas, args->start, args->start + args->range);
+ goto unlock_vm;
+ }
+
+ mem_attrs = kvmalloc_array(args->num_vmas, sizeof(struct drm_xe_vma_mem_attr),
+ GFP_KERNEL | __GFP_ACCOUNT |
+ __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
+ if (!mem_attrs) {
+ err = args->num_vmas > 1 ? -ENOBUFS : -ENOMEM;
+ goto unlock_vm;
+ }
+
+ err = get_mem_attrs(vm, &args->num_vmas, args->start,
+ args->start + args->range, mem_attrs);
+ if (err)
+ goto free_mem_attrs;
+
+ err = __copy_to_user(attrs_user, mem_attrs,
+ sizeof(struct drm_xe_vma_mem_attr) * args->num_vmas);
+
+free_mem_attrs:
+ kvfree(mem_attrs);
+unlock_vm:
+ up_read(&vm->lock);
+ 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 1fb639a33ffb..e4a601a3583f 100644
--- a/drivers/gpu/drm/xe/xe_vm.h
+++ b/drivers/gpu/drm/xe/xe_vm.h
@@ -195,7 +195,7 @@ 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 81e90270313d..c0aa7c19870e 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_VMAS_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_VMAS_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_VMAS_ATTRS DRM_IOWR(DRM_COMMAND_BASE + DRM_XE_VM_QUERY_VMAS_ATTRS, struct drm_xe_vm_query_vmas_attr)
/**
* DOC: Xe IOCTL Extensions
@@ -2093,6 +2096,133 @@ struct drm_xe_madvise {
__u64 reserved[2];
};
+/**
+ * struct drm_xe_vma_mem_attr - Output of &DRM_IOCTL_XE_VM_QUERY_VMAS_ATTRS
+ *
+ * This structure is provided by userspace and filled by KMD in response to the
+ * DRM_IOCTL_XE_VM_QUERY_VMAS_ATTRS ioctl. It describes memory attributes of
+ * a VMA within a specified address range in a VM.
+ *
+ * The structure includes information such as atomic access policy, purgeable
+ * state, 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 VMA
+ *
+ * @extensions: Pointer to the first extension struct, if any
+ * @start: Start address of the virtual memory area
+ * @end: End address of the virtual memory area
+ *
+ * @atomic.val: Value of atomic operation policy
+ * @atomic.reserved: Reserved, must be zero
+ *
+ * @purge_state_val.val: Value for DRM_XE_VMA_ATTR_PURGEABLE_STATE
+ * @purge_state_val.reserved: Reserved, must be zero
+ *
+ * @pat_index.val: Page Attribute Table (PAT) index
+ * @pat_index.reserved: Reserved, must be zero
+ *
+ * @preferred_mem_loc.devmem_fd: File descriptor for preferred device memory
+ * @preferred_mem_loc.migration_policy: Migration policy for memory placement
+ *
+ */
+struct drm_xe_vma_mem_attr {
+ /** @extensions: Pointer to the first extension struct, if any */
+ __u64 extensions;
+
+ /** @start: start of the vma */
+ __u64 start;
+
+ /** @end: end of the vma */
+ __u64 end;
+
+ struct {
+ struct {
+ /** @atomic.val: atomic attribute for vma*/
+ __u32 val;
+
+ /** @atomic.reserved: Reserved */
+ __u32 reserved;
+ } atomic;
+
+ struct {
+ /** @pat_index.val: PAT index of vma */
+ __u32 val;
+
+ /** @pat_index.reserved: Reserved */
+ __u32 reserved;
+ } pat_index;
+
+ /** @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;
+ };
+
+ /** @reserved: Reserved */
+ __u64 reserved[2];
+};
+
+/**
+ * struct drm_xe_vm_query_vmas_attr - Input of &DRM_IOCTL_XE_VM_QUERY_MEM_ATTRIBUTES
+ *
+ * This structure is used to query memory attributes of virtual memory areas
+ * (VMAs) within a specified address range in a VM. It provides detailed
+ * information about each VMA, including atomic access policy, purgeable state,
+ * page attribute table (PAT) index, and preferred memory location.
+ *
+ * Userspace first calls the ioctl with @num_vmas = 0 and
+ * @vector_of_vma_mem_attr = NULL to retrieve the number of VMAs in the range.
+ * Then, it allocates a buffer of that size and calls the ioctl again to fill
+ * the buffer with VMA attributes.
+ *
+ * Example:
+ *
+ * .. code-block:: C
+ *
+ * struct drm_xe_vma_mem_attr *attrs;
+ * __u32 num_vmas;
+ *
+ * // First call to get number of VMAs
+ * ioctl(fd, DRM_IOCTL_XE_VM_QUERY_VMAS_ATTRS, &query);
+ * num_vmas = query.num_vmas;
+ *
+ * // Allocate and query attributes
+ * attrs = malloc(num_vmas, sizeof(*attrs));
+ * query.vector_of_vma_mem_attr = (__u64)(uintptr_t)attrs;
+ * query.num_vmas = num_vmas;
+ * ioctl(fd, DRM_IOCTL_XE_VM_QUERY_VMAS_ATTRS, &query);
+ */
+struct drm_xe_vm_query_vmas_attr {
+ /** @extensions: Pointer to the first extension struct, if any */
+ __u64 extensions;
+
+ /** @vm_id: vm_id of the virtual range */
+ __u32 vm_id;
+
+ /** @num_vmas: number of vmas in range */
+ __u32 num_vmas;
+
+ /** @start: start of the virtual address range */
+ __u64 start;
+
+ /** @size: size of the virtual address range */
+ __u64 range;
+
+ /**
+ * @vector_of_ops: userptr to array of struct
+ * drm_xe_vma_mem_attr
+ */
+ __u64 vector_of_vma_mem_attr;
+
+ /** @reserved: Reserved */
+ __u64 reserved[2];
+
+};
+
#if defined(__cplusplus)
}
#endif
--
2.34.1
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