1 // SPDX-License-Identifier: GPL-2.0-only
3 * VFIO PCI I/O Port & MMIO access
5 * Copyright (C) 2012 Red Hat, Inc. All rights reserved.
6 * Author: Alex Williamson <alex.williamson@redhat.com>
8 * Derived from original vfio:
9 * Copyright 2010 Cisco Systems, Inc. All rights reserved.
10 * Author: Tom Lyon, pugs@cisco.com
14 #include <linux/pci.h>
15 #include <linux/uaccess.h>
17 #include <linux/vfio.h>
18 #include <linux/vgaarb.h>
20 #include "vfio_pci_private.h"
22 #ifdef __LITTLE_ENDIAN
23 #define vfio_ioread64 ioread64
24 #define vfio_iowrite64 iowrite64
25 #define vfio_ioread32 ioread32
26 #define vfio_iowrite32 iowrite32
27 #define vfio_ioread16 ioread16
28 #define vfio_iowrite16 iowrite16
30 #define vfio_ioread64 ioread64be
31 #define vfio_iowrite64 iowrite64be
32 #define vfio_ioread32 ioread32be
33 #define vfio_iowrite32 iowrite32be
34 #define vfio_ioread16 ioread16be
35 #define vfio_iowrite16 iowrite16be
37 #define vfio_ioread8 ioread8
38 #define vfio_iowrite8 iowrite8
41 * Read or write from an __iomem region (MMIO or I/O port) with an excluded
42 * range which is inaccessible. The excluded range drops writes and fills
43 * reads with -1. This is intended for handling MSI-X vector tables and
44 * leftover space for ROM BARs.
46 static ssize_t do_io_rw(void __iomem *io, char __user *buf,
47 loff_t off, size_t count, size_t x_start,
48 size_t x_end, bool iswrite)
53 size_t fillable, filled;
56 fillable = min(count, (size_t)(x_start - off));
57 else if (off >= x_end)
62 if (fillable >= 4 && !(off % 4)) {
66 if (copy_from_user(&val, buf, 4))
69 vfio_iowrite32(val, io + off);
71 val = vfio_ioread32(io + off);
73 if (copy_to_user(buf, &val, 4))
78 } else if (fillable >= 2 && !(off % 2)) {
82 if (copy_from_user(&val, buf, 2))
85 vfio_iowrite16(val, io + off);
87 val = vfio_ioread16(io + off);
89 if (copy_to_user(buf, &val, 2))
94 } else if (fillable) {
98 if (copy_from_user(&val, buf, 1))
101 vfio_iowrite8(val, io + off);
103 val = vfio_ioread8(io + off);
105 if (copy_to_user(buf, &val, 1))
111 /* Fill reads with -1, drop writes */
112 filled = min(count, (size_t)(x_end - off));
117 for (i = 0; i < filled; i++)
118 if (copy_to_user(buf + i, &val, 1))
132 static int vfio_pci_setup_barmap(struct vfio_pci_device *vdev, int bar)
134 struct pci_dev *pdev = vdev->pdev;
138 if (vdev->barmap[bar])
141 ret = pci_request_selected_regions(pdev, 1 << bar, "vfio");
145 io = pci_iomap(pdev, bar, 0);
147 pci_release_selected_regions(pdev, 1 << bar);
151 vdev->barmap[bar] = io;
156 ssize_t vfio_pci_bar_rw(struct vfio_pci_device *vdev, char __user *buf,
157 size_t count, loff_t *ppos, bool iswrite)
159 struct pci_dev *pdev = vdev->pdev;
160 loff_t pos = *ppos & VFIO_PCI_OFFSET_MASK;
161 int bar = VFIO_PCI_OFFSET_TO_INDEX(*ppos);
162 size_t x_start = 0, x_end = 0;
165 struct resource *res = &vdev->pdev->resource[bar];
168 if (pci_resource_start(pdev, bar))
169 end = pci_resource_len(pdev, bar);
170 else if (bar == PCI_ROM_RESOURCE &&
171 pdev->resource[bar].flags & IORESOURCE_ROM_SHADOW)
179 count = min(count, (size_t)(end - pos));
181 if (res->flags & IORESOURCE_MEM) {
182 down_read(&vdev->memory_lock);
183 if (!__vfio_pci_memory_enabled(vdev)) {
184 up_read(&vdev->memory_lock);
189 if (bar == PCI_ROM_RESOURCE) {
191 * The ROM can fill less space than the BAR, so we start the
192 * excluded range at the end of the actual ROM. This makes
193 * filling large ROM BARs much faster.
195 io = pci_map_rom(pdev, &x_start);
202 int ret = vfio_pci_setup_barmap(vdev, bar);
208 io = vdev->barmap[bar];
211 if (bar == vdev->msix_bar) {
212 x_start = vdev->msix_offset;
213 x_end = vdev->msix_offset + vdev->msix_size;
216 done = do_io_rw(io, buf, pos, count, x_start, x_end, iswrite);
221 if (bar == PCI_ROM_RESOURCE)
222 pci_unmap_rom(pdev, io);
224 if (res->flags & IORESOURCE_MEM)
225 up_read(&vdev->memory_lock);
230 ssize_t vfio_pci_vga_rw(struct vfio_pci_device *vdev, char __user *buf,
231 size_t count, loff_t *ppos, bool iswrite)
234 loff_t off, pos = *ppos & VFIO_PCI_OFFSET_MASK;
235 void __iomem *iomem = NULL;
247 case 0xa0000 ... 0xbffff:
248 count = min(count, (size_t)(0xc0000 - pos));
249 iomem = ioremap(0xa0000, 0xbffff - 0xa0000 + 1);
251 rsrc = VGA_RSRC_LEGACY_MEM;
254 case 0x3b0 ... 0x3bb:
255 count = min(count, (size_t)(0x3bc - pos));
256 iomem = ioport_map(0x3b0, 0x3bb - 0x3b0 + 1);
258 rsrc = VGA_RSRC_LEGACY_IO;
261 case 0x3c0 ... 0x3df:
262 count = min(count, (size_t)(0x3e0 - pos));
263 iomem = ioport_map(0x3c0, 0x3df - 0x3c0 + 1);
265 rsrc = VGA_RSRC_LEGACY_IO;
275 ret = vga_get_interruptible(vdev->pdev, rsrc);
277 is_ioport ? ioport_unmap(iomem) : iounmap(iomem);
281 done = do_io_rw(iomem, buf, off, count, 0, 0, iswrite);
283 vga_put(vdev->pdev, rsrc);
285 is_ioport ? ioport_unmap(iomem) : iounmap(iomem);
293 static int vfio_pci_ioeventfd_handler(void *opaque, void *unused)
295 struct vfio_pci_ioeventfd *ioeventfd = opaque;
297 switch (ioeventfd->count) {
299 vfio_iowrite8(ioeventfd->data, ioeventfd->addr);
302 vfio_iowrite16(ioeventfd->data, ioeventfd->addr);
305 vfio_iowrite32(ioeventfd->data, ioeventfd->addr);
309 vfio_iowrite64(ioeventfd->data, ioeventfd->addr);
317 long vfio_pci_ioeventfd(struct vfio_pci_device *vdev, loff_t offset,
318 uint64_t data, int count, int fd)
320 struct pci_dev *pdev = vdev->pdev;
321 loff_t pos = offset & VFIO_PCI_OFFSET_MASK;
322 int ret, bar = VFIO_PCI_OFFSET_TO_INDEX(offset);
323 struct vfio_pci_ioeventfd *ioeventfd;
325 /* Only support ioeventfds into BARs */
326 if (bar > VFIO_PCI_BAR5_REGION_INDEX)
329 if (pos + count > pci_resource_len(pdev, bar))
332 /* Disallow ioeventfds working around MSI-X table writes */
333 if (bar == vdev->msix_bar &&
334 !(pos + count <= vdev->msix_offset ||
335 pos >= vdev->msix_offset + vdev->msix_size))
343 ret = vfio_pci_setup_barmap(vdev, bar);
347 mutex_lock(&vdev->ioeventfds_lock);
349 list_for_each_entry(ioeventfd, &vdev->ioeventfds_list, next) {
350 if (ioeventfd->pos == pos && ioeventfd->bar == bar &&
351 ioeventfd->data == data && ioeventfd->count == count) {
353 vfio_virqfd_disable(&ioeventfd->virqfd);
354 list_del(&ioeventfd->next);
355 vdev->ioeventfds_nr--;
370 if (vdev->ioeventfds_nr >= VFIO_PCI_IOEVENTFD_MAX) {
375 ioeventfd = kzalloc(sizeof(*ioeventfd), GFP_KERNEL);
381 ioeventfd->addr = vdev->barmap[bar] + pos;
382 ioeventfd->data = data;
383 ioeventfd->pos = pos;
384 ioeventfd->bar = bar;
385 ioeventfd->count = count;
387 ret = vfio_virqfd_enable(ioeventfd, vfio_pci_ioeventfd_handler,
388 NULL, NULL, &ioeventfd->virqfd, fd);
394 list_add(&ioeventfd->next, &vdev->ioeventfds_list);
395 vdev->ioeventfds_nr++;
398 mutex_unlock(&vdev->ioeventfds_lock);