accel/habanalabs: support mapping cb with vmalloc-backed coherent memory

When IOMMU is enabled, dma_alloc_coherent() with GFP_USER may return
addresses from the vmalloc range. If such an address is mapped without
VM_MIXEDMAP, vm_insert_page() will trigger a BUG_ON due to the
VM_PFNMAP restriction.

Fix this by checking for vmalloc addresses and setting VM_MIXEDMAP
in the VMA before mapping. This ensures safe mapping and avoids kernel
crashes. The memory is still driver-allocated and cannot be accessed
directly by userspace.

Signed-off-by: Moti Haimovski  <moti.haimovski@intel.com>
Reviewed-by: Koby Elbaz <koby.elbaz@intel.com>
Signed-off-by: Koby Elbaz <koby.elbaz@intel.com>

diff --git a/drivers/accel/habanalabs/gaudi/gaudi.c b/drivers/accel/habanalabs/gaudi/gaudi.c
index fa893a9b826ec4d9e3fc3c867a969a2621ecaf42..34771d75da9d7e233cc6e3007fcca7c174678860 100644 (file)
--- a/drivers/accel/habanalabs/gaudi/gaudi.c
+++ b/drivers/accel/habanalabs/gaudi/gaudi.c
@@ -4168,10 +4168,29 @@ static int gaudi_mmap(struct hl_device *hdev, struct vm_area_struct *vma,
        vm_flags_set(vma, VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP |
                        VM_DONTCOPY | VM_NORESERVE);
 
+#ifdef _HAS_DMA_MMAP_COHERENT
+       /*
+        * If dma_alloc_coherent() returns a vmalloc address, set VM_MIXEDMAP
+        * so vm_insert_page() can handle it safely. Without this, the kernel
+        * may BUG_ON due to VM_PFNMAP.
+        */
+       if (is_vmalloc_addr(cpu_addr))
+               vm_flags_set(vma, VM_MIXEDMAP);
+
        rc = dma_mmap_coherent(hdev->dev, vma, cpu_addr,
                                (dma_addr - HOST_PHYS_BASE), size);
        if (rc)
                dev_err(hdev->dev, "dma_mmap_coherent error %d", rc);
+#else
+
+       rc = remap_pfn_range(vma, vma->vm_start,
+                               virt_to_phys(cpu_addr) >> PAGE_SHIFT,
+                               size, vma->vm_page_prot);
+       if (rc)
+               dev_err(hdev->dev, "remap_pfn_range error %d", rc);
+
+ #endif
+
 
        return rc;
 }

diff --git a/drivers/accel/habanalabs/gaudi2/gaudi2.c b/drivers/accel/habanalabs/gaudi2/gaudi2.c
index 72bfc5e639e413c3f5944a6225eb1efa6bb7d7d0..03dde63ed875506d8b4e81b2d158da54028163dc 100644 (file)
--- a/drivers/accel/habanalabs/gaudi2/gaudi2.c
+++ b/drivers/accel/habanalabs/gaudi2/gaudi2.c
@@ -6832,6 +6832,13 @@ static int gaudi2_mmap(struct hl_device *hdev, struct vm_area_struct *vma,
                        VM_DONTCOPY | VM_NORESERVE);
 
 #ifdef _HAS_DMA_MMAP_COHERENT
+       /*
+        * If dma_alloc_coherent() returns a vmalloc address, set VM_MIXEDMAP
+        * so vm_insert_page() can handle it safely. Without this, the kernel
+        * may BUG_ON due to VM_PFNMAP.
+        */
+       if (is_vmalloc_addr(cpu_addr))
+               vm_flags_set(vma, VM_MIXEDMAP);
 
        rc = dma_mmap_coherent(hdev->dev, vma, cpu_addr, dma_addr, size);
        if (rc)