1 // SPDX-License-Identifier: GPL-2.0 2 3 /****************************************************************************** 4 * platform-pci-unplug.c 5 * 6 * Xen platform PCI device driver 7 * Copyright (c) 2010, Citrix 8 */ 9 10 #include <linux/init.h> 11 #include <linux/io.h> 12 #include <linux/export.h> 13 14 #include <xen/xen.h> 15 #include <xen/platform_pci.h> 16 #include "xen-ops.h" 17 18 #define XEN_PLATFORM_ERR_MAGIC -1 19 #define XEN_PLATFORM_ERR_PROTOCOL -2 20 #define XEN_PLATFORM_ERR_BLACKLIST -3 21 22 /* store the value of xen_emul_unplug after the unplug is done */ 23 static int xen_platform_pci_unplug; 24 static int xen_emul_unplug; 25 26 static int check_platform_magic(void) 27 { 28 short magic; 29 char protocol; 30 31 magic = inw(XEN_IOPORT_MAGIC); 32 if (magic != XEN_IOPORT_MAGIC_VAL) { 33 printk(KERN_ERR "Xen Platform PCI: unrecognised magic value\n"); 34 return XEN_PLATFORM_ERR_MAGIC; 35 } 36 37 protocol = inb(XEN_IOPORT_PROTOVER); 38 39 printk(KERN_DEBUG "Xen Platform PCI: I/O protocol version %d\n", 40 protocol); 41 42 switch (protocol) { 43 case 1: 44 outw(XEN_IOPORT_LINUX_PRODNUM, XEN_IOPORT_PRODNUM); 45 outl(XEN_IOPORT_LINUX_DRVVER, XEN_IOPORT_DRVVER); 46 if (inw(XEN_IOPORT_MAGIC) != XEN_IOPORT_MAGIC_VAL) { 47 printk(KERN_ERR "Xen Platform: blacklisted by host\n"); 48 return XEN_PLATFORM_ERR_BLACKLIST; 49 } 50 break; 51 default: 52 printk(KERN_WARNING "Xen Platform PCI: unknown I/O protocol version\n"); 53 return XEN_PLATFORM_ERR_PROTOCOL; 54 } 55 56 return 0; 57 } 58 59 bool xen_has_pv_devices(void) 60 { 61 if (!xen_domain()) 62 return false; 63 64 /* PV and PVH domains always have them. */ 65 if (xen_pv_domain() || xen_pvh_domain()) 66 return true; 67 68 /* And user has xen_platform_pci=0 set in guest config as 69 * driver did not modify the value. */ 70 if (xen_platform_pci_unplug == 0) 71 return false; 72 73 if (xen_platform_pci_unplug & XEN_UNPLUG_NEVER) 74 return false; 75 76 if (xen_platform_pci_unplug & XEN_UNPLUG_ALL) 77 return true; 78 79 /* This is an odd one - we are going to run legacy 80 * and PV drivers at the same time. */ 81 if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY) 82 return true; 83 84 /* And the caller has to follow with xen_pv_{disk,nic}_devices 85 * to be certain which driver can load. */ 86 return false; 87 } 88 EXPORT_SYMBOL_GPL(xen_has_pv_devices); 89 90 static bool __xen_has_pv_device(int state) 91 { 92 /* HVM domains might or might not */ 93 if (xen_hvm_domain() && (xen_platform_pci_unplug & state)) 94 return true; 95 96 return xen_has_pv_devices(); 97 } 98 99 bool xen_has_pv_nic_devices(void) 100 { 101 return __xen_has_pv_device(XEN_UNPLUG_ALL_NICS | XEN_UNPLUG_ALL); 102 } 103 EXPORT_SYMBOL_GPL(xen_has_pv_nic_devices); 104 105 bool xen_has_pv_disk_devices(void) 106 { 107 return __xen_has_pv_device(XEN_UNPLUG_ALL_IDE_DISKS | 108 XEN_UNPLUG_AUX_IDE_DISKS | XEN_UNPLUG_ALL); 109 } 110 EXPORT_SYMBOL_GPL(xen_has_pv_disk_devices); 111 112 /* 113 * This one is odd - it determines whether you want to run PV _and_ 114 * legacy (IDE) drivers together. This combination is only possible 115 * under HVM. 116 */ 117 bool xen_has_pv_and_legacy_disk_devices(void) 118 { 119 if (!xen_domain()) 120 return false; 121 122 /* N.B. This is only ever used in HVM mode */ 123 if (xen_pv_domain()) 124 return false; 125 126 if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY) 127 return true; 128 129 return false; 130 } 131 EXPORT_SYMBOL_GPL(xen_has_pv_and_legacy_disk_devices); 132 133 void xen_unplug_emulated_devices(void) 134 { 135 int r; 136 137 /* PVH guests don't have emulated devices. */ 138 if (xen_pvh_domain()) 139 return; 140 141 /* user explicitly requested no unplug */ 142 if (xen_emul_unplug & XEN_UNPLUG_NEVER) 143 return; 144 /* check the version of the xen platform PCI device */ 145 r = check_platform_magic(); 146 /* If the version matches enable the Xen platform PCI driver. 147 * Also enable the Xen platform PCI driver if the host does 148 * not support the unplug protocol (XEN_PLATFORM_ERR_MAGIC) 149 * but the user told us that unplugging is unnecessary. */ 150 if (r && !(r == XEN_PLATFORM_ERR_MAGIC && 151 (xen_emul_unplug & XEN_UNPLUG_UNNECESSARY))) 152 return; 153 /* Set the default value of xen_emul_unplug depending on whether or 154 * not the Xen PV frontends and the Xen platform PCI driver have 155 * been compiled for this kernel (modules or built-in are both OK). */ 156 if (!xen_emul_unplug) { 157 if (xen_must_unplug_nics()) { 158 printk(KERN_INFO "Netfront and the Xen platform PCI driver have " 159 "been compiled for this kernel: unplug emulated NICs.\n"); 160 xen_emul_unplug |= XEN_UNPLUG_ALL_NICS; 161 } 162 if (xen_must_unplug_disks()) { 163 printk(KERN_INFO "Blkfront and the Xen platform PCI driver have " 164 "been compiled for this kernel: unplug emulated disks.\n" 165 "You might have to change the root device\n" 166 "from /dev/hd[a-d] to /dev/xvd[a-d]\n" 167 "in your root= kernel command line option\n"); 168 xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS; 169 } 170 } 171 /* Now unplug the emulated devices */ 172 if (!(xen_emul_unplug & XEN_UNPLUG_UNNECESSARY)) 173 outw(xen_emul_unplug, XEN_IOPORT_UNPLUG); 174 xen_platform_pci_unplug = xen_emul_unplug; 175 } 176 177 static int __init parse_xen_emul_unplug(char *arg) 178 { 179 char *p, *q; 180 int l; 181 182 for (p = arg; p; p = q) { 183 q = strchr(p, ','); 184 if (q) { 185 l = q - p; 186 q++; 187 } else { 188 l = strlen(p); 189 } 190 if (!strncmp(p, "all", l)) 191 xen_emul_unplug |= XEN_UNPLUG_ALL; 192 else if (!strncmp(p, "ide-disks", l)) 193 xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS; 194 else if (!strncmp(p, "aux-ide-disks", l)) 195 xen_emul_unplug |= XEN_UNPLUG_AUX_IDE_DISKS; 196 else if (!strncmp(p, "nics", l)) 197 xen_emul_unplug |= XEN_UNPLUG_ALL_NICS; 198 else if (!strncmp(p, "unnecessary", l)) 199 xen_emul_unplug |= XEN_UNPLUG_UNNECESSARY; 200 else if (!strncmp(p, "never", l)) 201 xen_emul_unplug |= XEN_UNPLUG_NEVER; 202 else 203 printk(KERN_WARNING "unrecognised option '%s' " 204 "in parameter 'xen_emul_unplug'\n", p); 205 } 206 return 0; 207 } 208 early_param("xen_emul_unplug", parse_xen_emul_unplug); 209