2 files changed, 26 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
index 67b6274e25c8..09b94901faec 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
@@ -421,6 +421,24 @@ static int amdgpu_info_ioctl(struct drm_device *dev, void *data, struct drm_file
                                     min((size_t)size, sizeof(vram_gtt_total)))
                                     ? -EFAULT : 0;
         }
+        case AMDGPU_INFO_VRAM_GTT_MAX: {
+                struct drm_amdgpu_info_vram_gtt_max vram_gtt_max;
+                u64 max_size;
+
+                max_size = adev->mc.real_vram_size - adev->vram_pin_size;
+                vram_gtt_max.vram_max_size = max_size * 3 / 4;
+
+                max_size = adev->mc.visible_vram_size - (adev->vram_pin_size -
+                                adev->invisible_pin_size);
+                vram_gtt_max.vram_cpu_accessible_max_size = max_size * 3 / 4;
+
+                max_size = adev->mc.gtt_size - adev->gart_pin_size;
+                vram_gtt_max.gtt_max_size = max_size * 3 / 4;
+
+                return copy_to_user(out, &vram_gtt_max,
+                                    min((size_t)size, sizeof(vram_gtt_max)))
+                                    ? -EFAULT : 0;
+        }
         case AMDGPU_INFO_READ_MMR_REG: {
                 unsigned n, alloc_size;
                 uint32_t *regs;
diff --git a/include/uapi/drm/amdgpu_drm.h b/include/uapi/drm/amdgpu_drm.h
index dbfce2035b1f..0db0d66dc2ba 100644
--- a/include/uapi/drm/amdgpu_drm.h
+++ b/include/uapi/drm/amdgpu_drm.h
@@ -489,6 +489,8 @@ struct drm_amdgpu_cs_chunk_data {
 #define AMDGPU_INFO_NUM_EVICTIONS               0x18
 /* Query the total size of VRAM and GTT domains */
 #define AMDGPU_INFO_VRAM_GTT_TOTAL              0x19
+/* Query the max allocation size of VRAM and GTT domains */
+#define AMDGPU_INFO_VRAM_GTT_MAX                0x1a
 
 #define AMDGPU_INFO_MMR_SE_INDEX_SHIFT  0
 #define AMDGPU_INFO_MMR_SE_INDEX_MASK   0xff
@@ -580,6 +582,12 @@ struct drm_amdgpu_info_vram_gtt_total {
         __u64 gtt_total_size;
 };
 
+struct drm_amdgpu_info_vram_gtt_max {
+        __u64 vram_max_size;
+        __u64 vram_cpu_accessible_max_size;
+        __u64 gtt_max_size;
+};
+
 struct drm_amdgpu_info_firmware {
         __u32 ver;
         __u32 feature;