1 /* 2 * VFIO PCI I/O Port & MMIO access 3 * 4 * Copyright (C) 2012 Red Hat, Inc. All rights reserved. 5 * Author: Alex Williamson <alex.williamson@redhat.com> 6 * 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. 10 * 11 * Derived from original vfio: 12 * Copyright 2010 Cisco Systems, Inc. All rights reserved. 13 * Author: Tom Lyon, pugs@cisco.com 14 */ 15 16 #include <linux/fs.h> 17 #include <linux/pci.h> 18 #include <linux/uaccess.h> 19 #include <linux/io.h> 20 #include <linux/vgaarb.h> 21 22 #include "vfio_pci_private.h" 23 24 /* 25 * Read or write from an __iomem region (MMIO or I/O port) with an excluded 26 * range which is inaccessible. The excluded range drops writes and fills 27 * reads with -1. This is intended for handling MSI-X vector tables and 28 * leftover space for ROM BARs. 29 */ 30 static ssize_t do_io_rw(void __iomem *io, char __user *buf, 31 loff_t off, size_t count, size_t x_start, 32 size_t x_end, bool iswrite) 33 { 34 ssize_t done = 0; 35 36 while (count) { 37 size_t fillable, filled; 38 39 if (off < x_start) 40 fillable = min(count, (size_t)(x_start - off)); 41 else if (off >= x_end) 42 fillable = count; 43 else 44 fillable = 0; 45 46 if (fillable >= 4 && !(off % 4)) { 47 __le32 val; 48 49 if (iswrite) { 50 if (copy_from_user(&val, buf, 4)) 51 return -EFAULT; 52 53 iowrite32(le32_to_cpu(val), io + off); 54 } else { 55 val = cpu_to_le32(ioread32(io + off)); 56 57 if (copy_to_user(buf, &val, 4)) 58 return -EFAULT; 59 } 60 61 filled = 4; 62 } else if (fillable >= 2 && !(off % 2)) { 63 __le16 val; 64 65 if (iswrite) { 66 if (copy_from_user(&val, buf, 2)) 67 return -EFAULT; 68 69 iowrite16(le16_to_cpu(val), io + off); 70 } else { 71 val = cpu_to_le16(ioread16(io + off)); 72 73 if (copy_to_user(buf, &val, 2)) 74 return -EFAULT; 75 } 76 77 filled = 2; 78 } else if (fillable) { 79 u8 val; 80 81 if (iswrite) { 82 if (copy_from_user(&val, buf, 1)) 83 return -EFAULT; 84 85 iowrite8(val, io + off); 86 } else { 87 val = ioread8(io + off); 88 89 if (copy_to_user(buf, &val, 1)) 90 return -EFAULT; 91 } 92 93 filled = 1; 94 } else { 95 /* Fill reads with -1, drop writes */ 96 filled = min(count, (size_t)(x_end - off)); 97 if (!iswrite) { 98 u8 val = 0xFF; 99 size_t i; 100 101 for (i = 0; i < filled; i++) 102 if (copy_to_user(buf + i, &val, 1)) 103 return -EFAULT; 104 } 105 } 106 107 count -= filled; 108 done += filled; 109 off += filled; 110 buf += filled; 111 } 112 113 return done; 114 } 115 116 ssize_t vfio_pci_bar_rw(struct vfio_pci_device *vdev, char __user *buf, 117 size_t count, loff_t *ppos, bool iswrite) 118 { 119 struct pci_dev *pdev = vdev->pdev; 120 loff_t pos = *ppos & VFIO_PCI_OFFSET_MASK; 121 int bar = VFIO_PCI_OFFSET_TO_INDEX(*ppos); 122 size_t x_start = 0, x_end = 0; 123 resource_size_t end; 124 void __iomem *io; 125 ssize_t done; 126 127 if (pci_resource_start(pdev, bar)) 128 end = pci_resource_len(pdev, bar); 129 else if (bar == PCI_ROM_RESOURCE && 130 pdev->resource[bar].flags & IORESOURCE_ROM_SHADOW) 131 end = 0x20000; 132 else 133 return -EINVAL; 134 135 if (pos >= end) 136 return -EINVAL; 137 138 count = min(count, (size_t)(end - pos)); 139 140 if (bar == PCI_ROM_RESOURCE) { 141 /* 142 * The ROM can fill less space than the BAR, so we start the 143 * excluded range at the end of the actual ROM. This makes 144 * filling large ROM BARs much faster. 145 */ 146 io = pci_map_rom(pdev, &x_start); 147 if (!io) 148 return -ENOMEM; 149 x_end = end; 150 } else if (!vdev->barmap[bar]) { 151 int ret; 152 153 ret = pci_request_selected_regions(pdev, 1 << bar, "vfio"); 154 if (ret) 155 return ret; 156 157 io = pci_iomap(pdev, bar, 0); 158 if (!io) { 159 pci_release_selected_regions(pdev, 1 << bar); 160 return -ENOMEM; 161 } 162 163 vdev->barmap[bar] = io; 164 } else 165 io = vdev->barmap[bar]; 166 167 if (bar == vdev->msix_bar) { 168 x_start = vdev->msix_offset; 169 x_end = vdev->msix_offset + vdev->msix_size; 170 } 171 172 done = do_io_rw(io, buf, pos, count, x_start, x_end, iswrite); 173 174 if (done >= 0) 175 *ppos += done; 176 177 if (bar == PCI_ROM_RESOURCE) 178 pci_unmap_rom(pdev, io); 179 180 return done; 181 } 182 183 ssize_t vfio_pci_vga_rw(struct vfio_pci_device *vdev, char __user *buf, 184 size_t count, loff_t *ppos, bool iswrite) 185 { 186 int ret; 187 loff_t off, pos = *ppos & VFIO_PCI_OFFSET_MASK; 188 void __iomem *iomem = NULL; 189 unsigned int rsrc; 190 bool is_ioport; 191 ssize_t done; 192 193 if (!vdev->has_vga) 194 return -EINVAL; 195 196 switch (pos) { 197 case 0xa0000 ... 0xbffff: 198 count = min(count, (size_t)(0xc0000 - pos)); 199 iomem = ioremap_nocache(0xa0000, 0xbffff - 0xa0000 + 1); 200 off = pos - 0xa0000; 201 rsrc = VGA_RSRC_LEGACY_MEM; 202 is_ioport = false; 203 break; 204 case 0x3b0 ... 0x3bb: 205 count = min(count, (size_t)(0x3bc - pos)); 206 iomem = ioport_map(0x3b0, 0x3bb - 0x3b0 + 1); 207 off = pos - 0x3b0; 208 rsrc = VGA_RSRC_LEGACY_IO; 209 is_ioport = true; 210 break; 211 case 0x3c0 ... 0x3df: 212 count = min(count, (size_t)(0x3e0 - pos)); 213 iomem = ioport_map(0x3c0, 0x3df - 0x3c0 + 1); 214 off = pos - 0x3c0; 215 rsrc = VGA_RSRC_LEGACY_IO; 216 is_ioport = true; 217 break; 218 default: 219 return -EINVAL; 220 } 221 222 if (!iomem) 223 return -ENOMEM; 224 225 ret = vga_get_interruptible(vdev->pdev, rsrc); 226 if (ret) { 227 is_ioport ? ioport_unmap(iomem) : iounmap(iomem); 228 return ret; 229 } 230 231 done = do_io_rw(iomem, buf, off, count, 0, 0, iswrite); 232 233 vga_put(vdev->pdev, rsrc); 234 235 is_ioport ? ioport_unmap(iomem) : iounmap(iomem); 236 237 if (done >= 0) 238 *ppos += done; 239 240 return done; 241 } 242