1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * VFIO PCI I/O Port & MMIO access
4 *
5 * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
6 *     Author: Alex Williamson <alex.williamson@redhat.com>
7 *
8 * Derived from original vfio:
9 * Copyright 2010 Cisco Systems, Inc.  All rights reserved.
10 * Author: Tom Lyon, pugs@cisco.com
11 */
12
13#include <linux/fs.h>
14#include <linux/pci.h>
15#include <linux/uaccess.h>
16#include <linux/io.h>
17#include <linux/vfio.h>
18#include <linux/vgaarb.h>
19
20#include "vfio_pci_private.h"
21
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
29#else
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
36#endif
37#define vfio_ioread8	ioread8
38#define vfio_iowrite8	iowrite8
39
40#define VFIO_IOWRITE(size) \
41static int vfio_pci_iowrite##size(struct vfio_pci_device *vdev,		\
42			bool test_mem, u##size val, void __iomem *io)	\
43{									\
44	if (test_mem) {							\
45		down_read(&vdev->memory_lock);				\
46		if (!__vfio_pci_memory_enabled(vdev)) {			\
47			up_read(&vdev->memory_lock);			\
48			return -EIO;					\
49		}							\
50	}								\
51									\
52	vfio_iowrite##size(val, io);					\
53									\
54	if (test_mem)							\
55		up_read(&vdev->memory_lock);				\
56									\
57	return 0;							\
58}
59
60VFIO_IOWRITE(8)
61VFIO_IOWRITE(16)
62VFIO_IOWRITE(32)
63#ifdef iowrite64
64VFIO_IOWRITE(64)
65#endif
66
67#define VFIO_IOREAD(size) \
68static int vfio_pci_ioread##size(struct vfio_pci_device *vdev,		\
69			bool test_mem, u##size *val, void __iomem *io)	\
70{									\
71	if (test_mem) {							\
72		down_read(&vdev->memory_lock);				\
73		if (!__vfio_pci_memory_enabled(vdev)) {			\
74			up_read(&vdev->memory_lock);			\
75			return -EIO;					\
76		}							\
77	}								\
78									\
79	*val = vfio_ioread##size(io);					\
80									\
81	if (test_mem)							\
82		up_read(&vdev->memory_lock);				\
83									\
84	return 0;							\
85}
86
87VFIO_IOREAD(8)
88VFIO_IOREAD(16)
89VFIO_IOREAD(32)
90
91/*
92 * Read or write from an __iomem region (MMIO or I/O port) with an excluded
93 * range which is inaccessible.  The excluded range drops writes and fills
94 * reads with -1.  This is intended for handling MSI-X vector tables and
95 * leftover space for ROM BARs.
96 */
97static ssize_t do_io_rw(struct vfio_pci_device *vdev, bool test_mem,
98			void __iomem *io, char __user *buf,
99			loff_t off, size_t count, size_t x_start,
100			size_t x_end, bool iswrite)
101{
102	ssize_t done = 0;
103	int ret;
104
105	while (count) {
106		size_t fillable, filled;
107
108		if (off < x_start)
109			fillable = min(count, (size_t)(x_start - off));
110		else if (off >= x_end)
111			fillable = count;
112		else
113			fillable = 0;
114
115		if (fillable >= 4 && !(off % 4)) {
116			u32 val;
117
118			if (iswrite) {
119				if (copy_from_user(&val, buf, 4))
120					return -EFAULT;
121
122				ret = vfio_pci_iowrite32(vdev, test_mem,
123							 val, io + off);
124				if (ret)
125					return ret;
126			} else {
127				ret = vfio_pci_ioread32(vdev, test_mem,
128							&val, io + off);
129				if (ret)
130					return ret;
131
132				if (copy_to_user(buf, &val, 4))
133					return -EFAULT;
134			}
135
136			filled = 4;
137		} else if (fillable >= 2 && !(off % 2)) {
138			u16 val;
139
140			if (iswrite) {
141				if (copy_from_user(&val, buf, 2))
142					return -EFAULT;
143
144				ret = vfio_pci_iowrite16(vdev, test_mem,
145							 val, io + off);
146				if (ret)
147					return ret;
148			} else {
149				ret = vfio_pci_ioread16(vdev, test_mem,
150							&val, io + off);
151				if (ret)
152					return ret;
153
154				if (copy_to_user(buf, &val, 2))
155					return -EFAULT;
156			}
157
158			filled = 2;
159		} else if (fillable) {
160			u8 val;
161
162			if (iswrite) {
163				if (copy_from_user(&val, buf, 1))
164					return -EFAULT;
165
166				ret = vfio_pci_iowrite8(vdev, test_mem,
167							val, io + off);
168				if (ret)
169					return ret;
170			} else {
171				ret = vfio_pci_ioread8(vdev, test_mem,
172						       &val, io + off);
173				if (ret)
174					return ret;
175
176				if (copy_to_user(buf, &val, 1))
177					return -EFAULT;
178			}
179
180			filled = 1;
181		} else {
182			/* Fill reads with -1, drop writes */
183			filled = min(count, (size_t)(x_end - off));
184			if (!iswrite) {
185				u8 val = 0xFF;
186				size_t i;
187
188				for (i = 0; i < filled; i++)
189					if (copy_to_user(buf + i, &val, 1))
190						return -EFAULT;
191			}
192		}
193
194		count -= filled;
195		done += filled;
196		off += filled;
197		buf += filled;
198	}
199
200	return done;
201}
202
203static int vfio_pci_setup_barmap(struct vfio_pci_device *vdev, int bar)
204{
205	struct pci_dev *pdev = vdev->pdev;
206	int ret;
207	void __iomem *io;
208
209	if (vdev->barmap[bar])
210		return 0;
211
212	ret = pci_request_selected_regions(pdev, 1 << bar, "vfio");
213	if (ret)
214		return ret;
215
216	io = pci_iomap(pdev, bar, 0);
217	if (!io) {
218		pci_release_selected_regions(pdev, 1 << bar);
219		return -ENOMEM;
220	}
221
222	vdev->barmap[bar] = io;
223
224	return 0;
225}
226
227ssize_t vfio_pci_bar_rw(struct vfio_pci_device *vdev, char __user *buf,
228			size_t count, loff_t *ppos, bool iswrite)
229{
230	struct pci_dev *pdev = vdev->pdev;
231	loff_t pos = *ppos & VFIO_PCI_OFFSET_MASK;
232	int bar = VFIO_PCI_OFFSET_TO_INDEX(*ppos);
233	size_t x_start = 0, x_end = 0;
234	resource_size_t end;
235	void __iomem *io;
236	struct resource *res = &vdev->pdev->resource[bar];
237	ssize_t done;
238
239	if (pci_resource_start(pdev, bar))
240		end = pci_resource_len(pdev, bar);
241	else if (bar == PCI_ROM_RESOURCE &&
242		 pdev->resource[bar].flags & IORESOURCE_ROM_SHADOW)
243		end = 0x20000;
244	else
245		return -EINVAL;
246
247	if (pos >= end)
248		return -EINVAL;
249
250	count = min(count, (size_t)(end - pos));
251
252	if (bar == PCI_ROM_RESOURCE) {
253		/*
254		 * The ROM can fill less space than the BAR, so we start the
255		 * excluded range at the end of the actual ROM.  This makes
256		 * filling large ROM BARs much faster.
257		 */
258		io = pci_map_rom(pdev, &x_start);
259		if (!io) {
260			done = -ENOMEM;
261			goto out;
262		}
263		x_end = end;
264	} else {
265		int ret = vfio_pci_setup_barmap(vdev, bar);
266		if (ret) {
267			done = ret;
268			goto out;
269		}
270
271		io = vdev->barmap[bar];
272	}
273
274	if (bar == vdev->msix_bar) {
275		x_start = vdev->msix_offset;
276		x_end = vdev->msix_offset + vdev->msix_size;
277	}
278
279	done = do_io_rw(vdev, res->flags & IORESOURCE_MEM, io, buf, pos,
280			count, x_start, x_end, iswrite);
281
282	if (done >= 0)
283		*ppos += done;
284
285	if (bar == PCI_ROM_RESOURCE)
286		pci_unmap_rom(pdev, io);
287out:
288	return done;
289}
290
291ssize_t vfio_pci_vga_rw(struct vfio_pci_device *vdev, char __user *buf,
292			       size_t count, loff_t *ppos, bool iswrite)
293{
294	int ret;
295	loff_t off, pos = *ppos & VFIO_PCI_OFFSET_MASK;
296	void __iomem *iomem = NULL;
297	unsigned int rsrc;
298	bool is_ioport;
299	ssize_t done;
300
301	if (!vdev->has_vga)
302		return -EINVAL;
303
304	if (pos > 0xbfffful)
305		return -EINVAL;
306
307	switch ((u32)pos) {
308	case 0xa0000 ... 0xbffff:
309		count = min(count, (size_t)(0xc0000 - pos));
310		iomem = ioremap(0xa0000, 0xbffff - 0xa0000 + 1);
311		off = pos - 0xa0000;
312		rsrc = VGA_RSRC_LEGACY_MEM;
313		is_ioport = false;
314		break;
315	case 0x3b0 ... 0x3bb:
316		count = min(count, (size_t)(0x3bc - pos));
317		iomem = ioport_map(0x3b0, 0x3bb - 0x3b0 + 1);
318		off = pos - 0x3b0;
319		rsrc = VGA_RSRC_LEGACY_IO;
320		is_ioport = true;
321		break;
322	case 0x3c0 ... 0x3df:
323		count = min(count, (size_t)(0x3e0 - pos));
324		iomem = ioport_map(0x3c0, 0x3df - 0x3c0 + 1);
325		off = pos - 0x3c0;
326		rsrc = VGA_RSRC_LEGACY_IO;
327		is_ioport = true;
328		break;
329	default:
330		return -EINVAL;
331	}
332
333	if (!iomem)
334		return -ENOMEM;
335
336	ret = vga_get_interruptible(vdev->pdev, rsrc);
337	if (ret) {
338		is_ioport ? ioport_unmap(iomem) : iounmap(iomem);
339		return ret;
340	}
341
342	/*
343	 * VGA MMIO is a legacy, non-BAR resource that hopefully allows
344	 * probing, so we don't currently worry about access in relation
345	 * to the memory enable bit in the command register.
346	 */
347	done = do_io_rw(vdev, false, iomem, buf, off, count, 0, 0, iswrite);
348
349	vga_put(vdev->pdev, rsrc);
350
351	is_ioport ? ioport_unmap(iomem) : iounmap(iomem);
352
353	if (done >= 0)
354		*ppos += done;
355
356	return done;
357}
358
359static void vfio_pci_ioeventfd_do_write(struct vfio_pci_ioeventfd *ioeventfd,
360					bool test_mem)
361{
362	switch (ioeventfd->count) {
363	case 1:
364		vfio_pci_iowrite8(ioeventfd->vdev, test_mem,
365				  ioeventfd->data, ioeventfd->addr);
366		break;
367	case 2:
368		vfio_pci_iowrite16(ioeventfd->vdev, test_mem,
369				   ioeventfd->data, ioeventfd->addr);
370		break;
371	case 4:
372		vfio_pci_iowrite32(ioeventfd->vdev, test_mem,
373				   ioeventfd->data, ioeventfd->addr);
374		break;
375#ifdef iowrite64
376	case 8:
377		vfio_pci_iowrite64(ioeventfd->vdev, test_mem,
378				   ioeventfd->data, ioeventfd->addr);
379		break;
380#endif
381	}
382}
383
384static int vfio_pci_ioeventfd_handler(void *opaque, void *unused)
385{
386	struct vfio_pci_ioeventfd *ioeventfd = opaque;
387	struct vfio_pci_device *vdev = ioeventfd->vdev;
388
389	if (ioeventfd->test_mem) {
390		if (!down_read_trylock(&vdev->memory_lock))
391			return 1; /* Lock contended, use thread */
392		if (!__vfio_pci_memory_enabled(vdev)) {
393			up_read(&vdev->memory_lock);
394			return 0;
395		}
396	}
397
398	vfio_pci_ioeventfd_do_write(ioeventfd, false);
399
400	if (ioeventfd->test_mem)
401		up_read(&vdev->memory_lock);
402
403	return 0;
404}
405
406static void vfio_pci_ioeventfd_thread(void *opaque, void *unused)
407{
408	struct vfio_pci_ioeventfd *ioeventfd = opaque;
409
410	vfio_pci_ioeventfd_do_write(ioeventfd, ioeventfd->test_mem);
411}
412
413long vfio_pci_ioeventfd(struct vfio_pci_device *vdev, loff_t offset,
414			uint64_t data, int count, int fd)
415{
416	struct pci_dev *pdev = vdev->pdev;
417	loff_t pos = offset & VFIO_PCI_OFFSET_MASK;
418	int ret, bar = VFIO_PCI_OFFSET_TO_INDEX(offset);
419	struct vfio_pci_ioeventfd *ioeventfd;
420
421	/* Only support ioeventfds into BARs */
422	if (bar > VFIO_PCI_BAR5_REGION_INDEX)
423		return -EINVAL;
424
425	if (pos + count > pci_resource_len(pdev, bar))
426		return -EINVAL;
427
428	/* Disallow ioeventfds working around MSI-X table writes */
429	if (bar == vdev->msix_bar &&
430	    !(pos + count <= vdev->msix_offset ||
431	      pos >= vdev->msix_offset + vdev->msix_size))
432		return -EINVAL;
433
434#ifndef iowrite64
435	if (count == 8)
436		return -EINVAL;
437#endif
438
439	ret = vfio_pci_setup_barmap(vdev, bar);
440	if (ret)
441		return ret;
442
443	mutex_lock(&vdev->ioeventfds_lock);
444
445	list_for_each_entry(ioeventfd, &vdev->ioeventfds_list, next) {
446		if (ioeventfd->pos == pos && ioeventfd->bar == bar &&
447		    ioeventfd->data == data && ioeventfd->count == count) {
448			if (fd == -1) {
449				vfio_virqfd_disable(&ioeventfd->virqfd);
450				list_del(&ioeventfd->next);
451				vdev->ioeventfds_nr--;
452				kfree(ioeventfd);
453				ret = 0;
454			} else
455				ret = -EEXIST;
456
457			goto out_unlock;
458		}
459	}
460
461	if (fd < 0) {
462		ret = -ENODEV;
463		goto out_unlock;
464	}
465
466	if (vdev->ioeventfds_nr >= VFIO_PCI_IOEVENTFD_MAX) {
467		ret = -ENOSPC;
468		goto out_unlock;
469	}
470
471	ioeventfd = kzalloc(sizeof(*ioeventfd), GFP_KERNEL);
472	if (!ioeventfd) {
473		ret = -ENOMEM;
474		goto out_unlock;
475	}
476
477	ioeventfd->vdev = vdev;
478	ioeventfd->addr = vdev->barmap[bar] + pos;
479	ioeventfd->data = data;
480	ioeventfd->pos = pos;
481	ioeventfd->bar = bar;
482	ioeventfd->count = count;
483	ioeventfd->test_mem = vdev->pdev->resource[bar].flags & IORESOURCE_MEM;
484
485	ret = vfio_virqfd_enable(ioeventfd, vfio_pci_ioeventfd_handler,
486				 vfio_pci_ioeventfd_thread, NULL,
487				 &ioeventfd->virqfd, fd);
488	if (ret) {
489		kfree(ioeventfd);
490		goto out_unlock;
491	}
492
493	list_add(&ioeventfd->next, &vdev->ioeventfds_list);
494	vdev->ioeventfds_nr++;
495
496out_unlock:
497	mutex_unlock(&vdev->ioeventfds_lock);
498
499	return ret;
500}
501