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// SPDX-License-Identifier: GPL-2.0
/******************************************************************************
* platform-pci-unplug.c
*
* Xen platform PCI device driver
* Copyright (c) 2010, Citrix
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/init.h>
#include <linux/io.h>
#include <linux/export.h>
#include <xen/xen.h>
#include <xen/platform_pci.h>
#include "xen-ops.h"
#define XEN_PLATFORM_ERR_MAGIC -1
#define XEN_PLATFORM_ERR_PROTOCOL -2
#define XEN_PLATFORM_ERR_BLACKLIST -3
/* store the value of xen_emul_unplug after the unplug is done */
static int xen_platform_pci_unplug;
static int xen_emul_unplug;
static int check_platform_magic(void)
{
short magic;
char protocol;
magic = inw(XEN_IOPORT_MAGIC);
if (magic != XEN_IOPORT_MAGIC_VAL) {
pr_err("Xen Platform PCI: unrecognised magic value\n");
return XEN_PLATFORM_ERR_MAGIC;
}
protocol = inb(XEN_IOPORT_PROTOVER);
pr_debug("Xen Platform PCI: I/O protocol version %d\n",
protocol);
switch (protocol) {
case 1:
outw(XEN_IOPORT_LINUX_PRODNUM, XEN_IOPORT_PRODNUM);
outl(XEN_IOPORT_LINUX_DRVVER, XEN_IOPORT_DRVVER);
if (inw(XEN_IOPORT_MAGIC) != XEN_IOPORT_MAGIC_VAL) {
pr_err("Xen Platform: blacklisted by host\n");
return XEN_PLATFORM_ERR_BLACKLIST;
}
break;
default:
pr_warn("Xen Platform PCI: unknown I/O protocol version\n");
return XEN_PLATFORM_ERR_PROTOCOL;
}
return 0;
}
bool xen_has_pv_devices(void)
{
if (!xen_domain())
return false;
/* PV and PVH domains always have them. */
if (xen_pv_domain() || xen_pvh_domain())
return true;
/* And user has xen_platform_pci=0 set in guest config as
* driver did not modify the value. */
if (xen_platform_pci_unplug == 0)
return false;
if (xen_platform_pci_unplug & XEN_UNPLUG_NEVER)
return false;
if (xen_platform_pci_unplug & XEN_UNPLUG_ALL)
return true;
/* This is an odd one - we are going to run legacy
* and PV drivers at the same time. */
if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY)
return true;
/* And the caller has to follow with xen_pv_{disk,nic}_devices
* to be certain which driver can load. */
return false;
}
EXPORT_SYMBOL_GPL(xen_has_pv_devices);
static bool __xen_has_pv_device(int state)
{
/* HVM domains might or might not */
if (xen_hvm_domain() && (xen_platform_pci_unplug & state))
return true;
return xen_has_pv_devices();
}
bool xen_has_pv_nic_devices(void)
{
return __xen_has_pv_device(XEN_UNPLUG_ALL_NICS | XEN_UNPLUG_ALL);
}
EXPORT_SYMBOL_GPL(xen_has_pv_nic_devices);
bool xen_has_pv_disk_devices(void)
{
return __xen_has_pv_device(XEN_UNPLUG_ALL_IDE_DISKS |
XEN_UNPLUG_AUX_IDE_DISKS | XEN_UNPLUG_ALL);
}
EXPORT_SYMBOL_GPL(xen_has_pv_disk_devices);
/*
* This one is odd - it determines whether you want to run PV _and_
* legacy (IDE) drivers together. This combination is only possible
* under HVM.
*/
bool xen_has_pv_and_legacy_disk_devices(void)
{
if (!xen_domain())
return false;
/* N.B. This is only ever used in HVM mode */
if (xen_pv_domain())
return false;
if (xen_platform_pci_unplug & XEN_UNPLUG_UNNECESSARY)
return true;
return false;
}
EXPORT_SYMBOL_GPL(xen_has_pv_and_legacy_disk_devices);
void xen_unplug_emulated_devices(void)
{
int r;
/* PVH guests don't have emulated devices. */
if (xen_pvh_domain())
return;
/* user explicitly requested no unplug */
if (xen_emul_unplug & XEN_UNPLUG_NEVER)
return;
/* check the version of the xen platform PCI device */
r = check_platform_magic();
/* If the version matches enable the Xen platform PCI driver.
* Also enable the Xen platform PCI driver if the host does
* not support the unplug protocol (XEN_PLATFORM_ERR_MAGIC)
* but the user told us that unplugging is unnecessary. */
if (r && !(r == XEN_PLATFORM_ERR_MAGIC &&
(xen_emul_unplug & XEN_UNPLUG_UNNECESSARY)))
return;
/* Set the default value of xen_emul_unplug depending on whether or
* not the Xen PV frontends and the Xen platform PCI driver have
* been compiled for this kernel (modules or built-in are both OK). */
if (!xen_emul_unplug) {
if (xen_must_unplug_nics()) {
pr_info("Netfront and the Xen platform PCI driver have "
"been compiled for this kernel: unplug emulated NICs.\n");
xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
}
if (xen_must_unplug_disks()) {
pr_info("Blkfront and the Xen platform PCI driver have "
"been compiled for this kernel: unplug emulated disks.\n"
"You might have to change the root device\n"
"from /dev/hd[a-d] to /dev/xvd[a-d]\n"
"in your root= kernel command line option\n");
xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
}
}
/* Now unplug the emulated devices */
if (!(xen_emul_unplug & XEN_UNPLUG_UNNECESSARY))
outw(xen_emul_unplug, XEN_IOPORT_UNPLUG);
xen_platform_pci_unplug = xen_emul_unplug;
}
static int __init parse_xen_emul_unplug(char *arg)
{
char *p, *q;
int l;
for (p = arg; p; p = q) {
q = strchr(p, ',');
if (q) {
l = q - p;
q++;
} else {
l = strlen(p);
}
if (!strncmp(p, "all", l))
xen_emul_unplug |= XEN_UNPLUG_ALL;
else if (!strncmp(p, "ide-disks", l))
xen_emul_unplug |= XEN_UNPLUG_ALL_IDE_DISKS;
else if (!strncmp(p, "aux-ide-disks", l))
xen_emul_unplug |= XEN_UNPLUG_AUX_IDE_DISKS;
else if (!strncmp(p, "nics", l))
xen_emul_unplug |= XEN_UNPLUG_ALL_NICS;
else if (!strncmp(p, "unnecessary", l))
xen_emul_unplug |= XEN_UNPLUG_UNNECESSARY;
else if (!strncmp(p, "never", l))
xen_emul_unplug |= XEN_UNPLUG_NEVER;
else
pr_warn("unrecognised option '%s' "
"in parameter 'xen_emul_unplug'\n", p);
}
return 0;
}
early_param("xen_emul_unplug", parse_xen_emul_unplug);
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