Doorbells need to be mapped to user space for UMD direct submisssion,
add support for this.
FIXME: Wildly insecure as anyone can pick MMIO doorbell offset, will
need to randomize and tie unique offset to FD. Can be done in later revs
before upstreaming.
Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx>
---
drivers/gpu/drm/xe/xe_bo.h | 3 ++
drivers/gpu/drm/xe/xe_device.c | 73 ++++++++++++++++++++++++++++++++++
2 files changed, 76 insertions(+)
diff --git a/drivers/gpu/drm/xe/xe_bo.h b/drivers/gpu/drm/xe/xe_bo.h
index e7724965d3f1..2772d42ac057 100644
--- a/drivers/gpu/drm/xe/xe_bo.h
+++ b/drivers/gpu/drm/xe/xe_bo.h
@@ -64,6 +64,9 @@
#define XE_BO_PROPS_INVALID (-1)
#define XE_PCI_BARRIER_MMAP_OFFSET (0x50 << XE_PTE_SHIFT)
+#define XE_MMIO_DOORBELL_MMAP_OFFSET (0x100 << XE_PTE_SHIFT)
+#define XE_MMIO_DOORBELL_PFN_START (SZ_4M >> XE_PTE_SHIFT)
+#define XE_MMIO_DOORBELL_PFN_COUNT (256)
struct sg_table;
diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
index f6069db795e7..bbdff4308b2e 100644
--- a/drivers/gpu/drm/xe/xe_device.c
+++ b/drivers/gpu/drm/xe/xe_device.c
@@ -316,6 +316,75 @@ static int xe_pci_barrier_mmap(struct file *filp,
return 0;
}
+static vm_fault_t doorbell_fault(struct vm_fault *vmf)
+{
+ struct drm_device *dev = vmf->vma->vm_private_data;
+ struct vm_area_struct *vma = vmf->vma;
+ vm_fault_t ret = VM_FAULT_NOPAGE;
+ pgprot_t prot;
+ int idx;
+
+ prot = vm_get_page_prot(vma->vm_flags);
+
+ if (drm_dev_enter(dev, &idx)) {
+ unsigned long pfn;
+
+ pfn = PHYS_PFN(pci_resource_start(to_pci_dev(dev->dev), 0) +
+ (XE_MMIO_DOORBELL_PFN_START << XE_PTE_SHIFT));
+ pfn += vma->vm_pgoff & (XE_MMIO_DOORBELL_PFN_COUNT - 1);
+
+ ret = vmf_insert_pfn_prot(vma, vma->vm_start, pfn,
+ pgprot_noncached(prot));
+ drm_dev_exit(idx);
+ } else {
+ struct page *page;
+
+ /* Allocate new dummy page to map all the VA range in this VMA to it*/
+ page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+ if (!page)
+ return VM_FAULT_OOM;
+
+ /* Set the page to be freed using drmm release action */
+ if (drmm_add_action_or_reset(dev, barrier_release_dummy_page, page))
+ return VM_FAULT_OOM;
+
+ ret = vmf_insert_pfn_prot(vma, vma->vm_start, page_to_pfn(page),
+ prot);
+ }
+
+ return ret;
+}
+
+static const struct vm_operations_struct vm_ops_doorbell = {
+ .open = barrier_open,
+ .close = barrier_close,
+ .fault = doorbell_fault,
+};
+
+static int xe_mmio_doorbell_mmap(struct file *filp,
+ struct vm_area_struct *vma)
+{
+ struct drm_file *priv = filp->private_data;
+ struct drm_device *dev = priv->minor->dev;
+
+ if (vma->vm_end - vma->vm_start > SZ_4K)
+ return -EINVAL;
+
+ if (is_cow_mapping(vma->vm_flags))
+ return -EINVAL;
+
+ if (vma->vm_flags & VM_EXEC)
+ return -EINVAL;
+
+ vm_flags_clear(vma, VM_MAYEXEC);
+ vm_flags_set(vma, VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP | VM_IO);
+ vma->vm_ops = &vm_ops_doorbell;
+ vma->vm_private_data = dev;
+ drm_dev_get(vma->vm_private_data);
+
+ return 0;
+}
+
static int xe_mmap(struct file *filp, struct vm_area_struct *vma)
{
struct drm_file *priv = filp->private_data;
@@ -327,6 +396,10 @@ static int xe_mmap(struct file *filp, struct vm_area_struct *vma)
switch (vma->vm_pgoff) {
case XE_PCI_BARRIER_MMAP_OFFSET >> XE_PTE_SHIFT:
return xe_pci_barrier_mmap(filp, vma);
+ case (XE_MMIO_DOORBELL_MMAP_OFFSET >> XE_PTE_SHIFT) ...
+ ((XE_MMIO_DOORBELL_MMAP_OFFSET >> XE_PTE_SHIFT) +
+ XE_MMIO_DOORBELL_PFN_COUNT - 1):
+ return xe_mmio_doorbell_mmap(filp, vma);
}
return drm_gem_mmap(filp, vma);
--
2.34.1
