2 * VFIO PCI I/O Port & MMIO access
4 * Copyright (C) 2012 Red Hat, Inc. All rights reserved.
5 * Author: Alex Williamson <alex.williamson@redhat.com>
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
11 * Derived from original vfio:
12 * Copyright 2010 Cisco Systems, Inc. All rights reserved.
13 * Author: Tom Lyon, pugs@cisco.com
17 #include <linux/pci.h>
18 #include <linux/uaccess.h>
21 #include "vfio_pci_private.h"
23 /* I/O Port BAR access */
24 ssize_t vfio_pci_io_readwrite(struct vfio_pci_device *vdev, char __user *buf,
25 size_t count, loff_t *ppos, bool iswrite)
27 struct pci_dev *pdev = vdev->pdev;
28 loff_t pos = *ppos & VFIO_PCI_OFFSET_MASK;
29 int bar = VFIO_PCI_OFFSET_TO_INDEX(*ppos);
33 if (!pci_resource_start(pdev, bar))
36 if (pos + count > pci_resource_len(pdev, bar))
39 if (!vdev->barmap[bar]) {
42 ret = pci_request_selected_regions(pdev, 1 << bar, "vfio");
46 vdev->barmap[bar] = pci_iomap(pdev, bar, 0);
48 if (!vdev->barmap[bar]) {
49 pci_release_selected_regions(pdev, 1 << bar);
54 io = vdev->barmap[bar];
59 if (count >= 3 && !(pos % 4)) {
63 if (copy_from_user(&val, buf, 4))
66 iowrite32(le32_to_cpu(val), io + pos);
68 val = cpu_to_le32(ioread32(io + pos));
70 if (copy_to_user(buf, &val, 4))
76 } else if ((pos % 2) == 0 && count >= 2) {
80 if (copy_from_user(&val, buf, 2))
83 iowrite16(le16_to_cpu(val), io + pos);
85 val = cpu_to_le16(ioread16(io + pos));
87 if (copy_to_user(buf, &val, 2))
96 if (copy_from_user(&val, buf, 1))
99 iowrite8(val, io + pos);
101 val = ioread8(io + pos);
103 if (copy_to_user(buf, &val, 1))
123 * We handle two excluded ranges here as well, if the user tries to read
124 * the ROM beyond what PCI tells us is available or the MSI-X table region,
125 * we return 0xFF and writes are dropped.
127 ssize_t vfio_pci_mem_readwrite(struct vfio_pci_device *vdev, char __user *buf,
128 size_t count, loff_t *ppos, bool iswrite)
130 struct pci_dev *pdev = vdev->pdev;
131 loff_t pos = *ppos & VFIO_PCI_OFFSET_MASK;
132 int bar = VFIO_PCI_OFFSET_TO_INDEX(*ppos);
136 size_t x_start = 0, x_end = 0; /* excluded range */
138 if (!pci_resource_start(pdev, bar))
141 end = pci_resource_len(pdev, bar);
149 if (pos + count > end)
152 if (bar == PCI_ROM_RESOURCE) {
153 io = pci_map_rom(pdev, &x_start);
156 if (!vdev->barmap[bar]) {
159 ret = pci_request_selected_regions(pdev, 1 << bar,
164 vdev->barmap[bar] = pci_iomap(pdev, bar, 0);
166 if (!vdev->barmap[bar]) {
167 pci_release_selected_regions(pdev, 1 << bar);
172 io = vdev->barmap[bar];
174 if (bar == vdev->msix_bar) {
175 x_start = vdev->msix_offset;
176 x_end = vdev->msix_offset + vdev->msix_size;
184 size_t fillable, filled;
187 fillable = x_start - pos;
188 else if (pos >= x_end)
189 fillable = end - pos;
193 if (fillable >= 4 && !(pos % 4) && (count >= 4)) {
197 if (copy_from_user(&val, buf, 4))
200 iowrite32(le32_to_cpu(val), io + pos);
202 val = cpu_to_le32(ioread32(io + pos));
204 if (copy_to_user(buf, &val, 4))
209 } else if (fillable >= 2 && !(pos % 2) && (count >= 2)) {
213 if (copy_from_user(&val, buf, 2))
216 iowrite16(le16_to_cpu(val), io + pos);
218 val = cpu_to_le16(ioread16(io + pos));
220 if (copy_to_user(buf, &val, 2))
225 } else if (fillable) {
229 if (copy_from_user(&val, buf, 1))
232 iowrite8(val, io + pos);
234 val = ioread8(io + pos);
236 if (copy_to_user(buf, &val, 1))
242 /* Drop writes, fill reads with FF */
247 for (i = 0; i < x_end - pos; i++) {
248 if (put_user(val, buf + i))
253 filled = x_end - pos;
265 if (bar == PCI_ROM_RESOURCE)
266 pci_unmap_rom(pdev, io);
268 return count ? -EFAULT : done;