[PATCH v6 1/6] vfio: export function to map the VMA

ankita
2025-11-25T17:30:43Z

From: Ankit Agrawal <ankita@nvidia.com>

Take out the implementation to map the VMA to the PTE/PMD/PUD
as a separate function.

Export the function to be used by nvgrace-gpu module.

cc: Shameer Kolothum <skolothumtho@nvidia.com>
cc: Alex Williamson <alex@shazbot.org>
cc: Jason Gunthorpe <jgg@ziepe.ca>
Reviewed-by: Shameer Kolothum <skolothumtho@nvidia.com>
Signed-off-by: Ankit Agrawal <ankita@nvidia.com>
---
drivers/vfio/pci/vfio_pci_core.c | 50 ++++++++++++++++++++------------
include/linux/vfio_pci_core.h | 3 ++
2 files changed, 34 insertions(+), 19 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 7dcf5439dedc..c445a53ee12e 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -1640,31 +1640,21 @@ static unsigned long vma_to_pfn(struct vm_area_struct *vma)
return (pci_resource_start(vdev->pdev, index) >> PAGE_SHIFT) + pgoff;
}

-static vm_fault_t vfio_pci_mmap_huge_fault(struct vm_fault *vmf,
- unsigned int order)
+vm_fault_t vfio_pci_vmf_insert_pfn(struct vfio_pci_core_device *vdev,
+ struct vm_fault *vmf,
+ unsigned long pfn,
+ unsigned int order)
{
- struct vm_area_struct *vma = vmf->vma;
- struct vfio_pci_core_device *vdev = vma->vm_private_data;
- unsigned long addr = vmf->address & ~((PAGE_SIZE << order) - 1);
- unsigned long pgoff = (addr - vma->vm_start) >> PAGE_SHIFT;
- unsigned long pfn = vma_to_pfn(vma) + pgoff;
- vm_fault_t ret = VM_FAULT_SIGBUS;
+ vm_fault_t ret;

- if (order && (addr < vma->vm_start ||
- addr + (PAGE_SIZE << order) > vma->vm_end ||
- pfn & ((1 << order) - 1))) {
- ret = VM_FAULT_FALLBACK;
- goto out;
- }
-
- down_read(&vdev->memory_lock);
+ lockdep_assert_held_read(&vdev->memory_lock);

if (vdev->pm_runtime_engaged || !__vfio_pci_memory_enabled(vdev))
- goto out_unlock;
+ return VM_FAULT_SIGBUS;

switch (order) {
case 0:
- ret = vmf_insert_pfn(vma, vmf->address, pfn);
+ ret = vmf_insert_pfn(vmf->vma, vmf->address, pfn);
break;
#ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP
case PMD_ORDER:
@@ -1680,7 +1670,29 @@ static vm_fault_t vfio_pci_mmap_huge_fault(struct vm_fault *vmf,
ret = VM_FAULT_FALLBACK;
}

-out_unlock:
+ return ret;
+}
+EXPORT_SYMBOL_GPL(vfio_pci_vmf_insert_pfn);
+
+static vm_fault_t vfio_pci_mmap_huge_fault(struct vm_fault *vmf,
+ unsigned int order)
+{
+ struct vm_area_struct *vma = vmf->vma;
+ struct vfio_pci_core_device *vdev = vma->vm_private_data;
+ unsigned long addr = vmf->address & ~((PAGE_SIZE << order) - 1);
+ unsigned long pgoff = (addr - vma->vm_start) >> PAGE_SHIFT;
+ unsigned long pfn = vma_to_pfn(vma) + pgoff;
+ vm_fault_t ret = VM_FAULT_SIGBUS;
+
+ if (order && (addr < vma->vm_start ||
+ addr + (PAGE_SIZE << order) > vma->vm_end ||
+ pfn & ((1 << order) - 1))) {
+ ret = VM_FAULT_FALLBACK;
+ goto out;
+ }
+
+ down_read(&vdev->memory_lock);
+ ret = vfio_pci_vmf_insert_pfn(vdev, vmf, pfn, order);
up_read(&vdev->memory_lock);
out:
dev_dbg_ratelimited(&vdev->pdev->dev,
diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
index f541044e42a2..6f7c6c0d4278 100644
--- a/include/linux/vfio_pci_core.h
+++ b/include/linux/vfio_pci_core.h
@@ -119,6 +119,9 @@ ssize_t vfio_pci_core_read(struct vfio_device *core_vdev, char __user *buf,
size_t count, loff_t *ppos);
ssize_t vfio_pci_core_write(struct vfio_device *core_vdev, const char __user *buf,
size_t count, loff_t *ppos);
+vm_fault_t vfio_pci_vmf_insert_pfn(struct vfio_pci_core_device *vdev,
+ struct vm_fault *vmf, unsigned long pfn,
+ unsigned int order);
int vfio_pci_core_mmap(struct vfio_device *core_vdev, struct vm_area_struct *vma);
void vfio_pci_core_request(struct vfio_device *core_vdev, unsigned int count);
int vfio_pci_core_match(struct vfio_device *core_vdev, char *buf);
--
2.34.1