linux-kernel - [PATCH v1 2/6] vfio: export function to map the VMA

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Message-ID: <20251117124159.3560-3-ankita@nvidia.com>
Date: Mon, 17 Nov 2025 12:41:55 +0000
From: <ankita@...dia.com>
To: <ankita@...dia.com>, <jgg@...pe.ca>, <yishaih@...dia.com>,
	<skolothumtho@...dia.com>, <kevin.tian@...el.com>, <alex@...zbot.org>,
	<aniketa@...dia.com>, <vsethi@...dia.com>, <mochs@...dia.com>
CC: <Yunxiang.Li@....com>, <yi.l.liu@...el.com>,
	<zhangdongdong@...incomputing.com>, <avihaih@...dia.com>,
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Subject: [PATCH v1 2/6] vfio: export function to map the VMA

From: Ankit Agrawal <ankita@...dia.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.

Signed-off-by: Ankit Agrawal <ankita@...dia.com>
---
 drivers/vfio/pci/vfio_pci_core.c | 46 ++++++++++++++++++++------------
 include/linux/vfio_pci_core.h    |  2 ++
 2 files changed, 31 insertions(+), 17 deletions(-)

diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index 7dcf5439dedc..29dcf78905a6 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -1640,6 +1640,34 @@ static unsigned long vma_to_pfn(struct vm_area_struct *vma)
 	return (pci_resource_start(vdev->pdev, index) >> PAGE_SHIFT) + pgoff;
 }
 
+vm_fault_t vfio_pci_map_pfn(struct vm_fault *vmf,
+			    unsigned long pfn,
+			    unsigned int order)
+{
+	vm_fault_t ret;
+
+	switch (order) {
+	case 0:
+		ret = vmf_insert_pfn(vmf->vma, vmf->address, pfn);
+		break;
+#ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP
+	case PMD_ORDER:
+		ret = vmf_insert_pfn_pmd(vmf, pfn, false);
+		break;
+#endif
+#ifdef CONFIG_ARCH_SUPPORTS_PUD_PFNMAP
+	case PUD_ORDER:
+		ret = vmf_insert_pfn_pud(vmf, pfn, false);
+		break;
+#endif
+	default:
+		ret = VM_FAULT_FALLBACK;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(vfio_pci_map_pfn);
+
 static vm_fault_t vfio_pci_mmap_huge_fault(struct vm_fault *vmf,
 					   unsigned int order)
 {
@@ -1662,23 +1690,7 @@ static vm_fault_t vfio_pci_mmap_huge_fault(struct vm_fault *vmf,
 	if (vdev->pm_runtime_engaged || !__vfio_pci_memory_enabled(vdev))
 		goto out_unlock;
 
-	switch (order) {
-	case 0:
-		ret = vmf_insert_pfn(vma, vmf->address, pfn);
-		break;
-#ifdef CONFIG_ARCH_SUPPORTS_PMD_PFNMAP
-	case PMD_ORDER:
-		ret = vmf_insert_pfn_pmd(vmf, pfn, false);
-		break;
-#endif
-#ifdef CONFIG_ARCH_SUPPORTS_PUD_PFNMAP
-	case PUD_ORDER:
-		ret = vmf_insert_pfn_pud(vmf, pfn, false);
-		break;
-#endif
-	default:
-		ret = VM_FAULT_FALLBACK;
-	}
+	ret = vfio_pci_map_pfn(vmf, pfn, order);
 
 out_unlock:
 	up_read(&vdev->memory_lock);
diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
index f541044e42a2..058acded858b 100644
--- a/include/linux/vfio_pci_core.h
+++ b/include/linux/vfio_pci_core.h
@@ -119,6 +119,8 @@ 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_map_pfn(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