vfio/pci: rename and export do_io_rw()

do_io_rw() is used to read/write to the device MMIO. The grace hopper
VFIO PCI variant driver require this functionality to read/write to
its memory.

Rename this as vfio_pci_core functions and export as GPL.

Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Yishai Hadas <yishaih@nvidia.com>
Signed-off-by: Ankit Agrawal <ankita@nvidia.com>
Link: https://lore.kernel.org/r/20240220115055.23546-2-ankita@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

Author: ankita-nv

drivers/vfio/pci/vfio_pci_rdwr.c

@@ -96,10 +96,10 @@ VFIO_IOREAD(32)
  * reads with -1.  This is intended for handling MSI-X vector tables and
  * leftover space for ROM BARs.
  */
-static ssize_t do_io_rw(struct vfio_pci_core_device *vdev, bool test_mem,
-			void __iomem *io, char __user *buf,
-			loff_t off, size_t count, size_t x_start,
-			size_t x_end, bool iswrite)
+ssize_t vfio_pci_core_do_io_rw(struct vfio_pci_core_device *vdev, bool test_mem,
+			       void __iomem *io, char __user *buf,
+			       loff_t off, size_t count, size_t x_start,
+			       size_t x_end, bool iswrite)
 {
 	ssize_t done = 0;
 	int ret;
@@ -201,6 +201,7 @@ static ssize_t do_io_rw(struct vfio_pci_core_device *vdev, bool test_mem,
 
 	return done;
 }
+EXPORT_SYMBOL_GPL(vfio_pci_core_do_io_rw);
 
 int vfio_pci_core_setup_barmap(struct vfio_pci_core_device *vdev, int bar)
 {
@@ -279,8 +280,8 @@ ssize_t vfio_pci_bar_rw(struct vfio_pci_core_device *vdev, char __user *buf,
 		x_end = vdev->msix_offset + vdev->msix_size;
 	}
 
-	done = do_io_rw(vdev, res->flags & IORESOURCE_MEM, io, buf, pos,
-			count, x_start, x_end, iswrite);
+	done = vfio_pci_core_do_io_rw(vdev, res->flags & IORESOURCE_MEM, io, buf, pos,
+				      count, x_start, x_end, iswrite);
 
 	if (done >= 0)
 		*ppos += done;
@@ -348,7 +349,8 @@ ssize_t vfio_pci_vga_rw(struct vfio_pci_core_device *vdev, char __user *buf,
 	 * probing, so we don't currently worry about access in relation
 	 * to the memory enable bit in the command register.
 	 */
-	done = do_io_rw(vdev, false, iomem, buf, off, count, 0, 0, iswrite);
+	done = vfio_pci_core_do_io_rw(vdev, false, iomem, buf, off, count,
+				      0, 0, iswrite);
 
 	vga_put(vdev->pdev, rsrc);
 

include/linux/vfio_pci_core.h

@@ -130,7 +130,10 @@ void vfio_pci_core_finish_enable(struct vfio_pci_core_device *vdev);
 int vfio_pci_core_setup_barmap(struct vfio_pci_core_device *vdev, int bar);
 pci_ers_result_t vfio_pci_core_aer_err_detected(struct pci_dev *pdev,
 						pci_channel_state_t state);
-
+ssize_t vfio_pci_core_do_io_rw(struct vfio_pci_core_device *vdev, bool test_mem,
+			       void __iomem *io, char __user *buf,
+			       loff_t off, size_t count, size_t x_start,
+			       size_t x_end, bool iswrite);
 #define VFIO_IOWRITE_DECLATION(size) \
 int vfio_pci_core_iowrite##size(struct vfio_pci_core_device *vdev,	\
 			bool test_mem, u##size val, void __iomem *io);