linux/arch/x86/xen/platform-pci-unplug.c

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/******************************************************************************
* platform-pci-unplug.c
*
* Xen platform PCI device driver
* Copyright (c) 2010, Citrix
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
* You should have received a copy of the GNU General Public License along with
* this program; if not, write to the Free Software Foundation, Inc., 59 Temple
* Place - Suite 330, Boston, MA 02111-1307 USA.
*
*/
#include <linux/init.h>
#include <linux/io.h>
#include <linux/module.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
#ifdef CONFIG_XEN_PVHVM
/* 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) {
printk(KERN_ERR "Xen Platform PCI: unrecognised magic value\n");
return XEN_PLATFORM_ERR_MAGIC;
}
protocol = inb(XEN_IOPORT_PROTOVER);
printk(KERN_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) {
printk(KERN_ERR "Xen Platform: blacklisted by host\n");
return XEN_PLATFORM_ERR_BLACKLIST;
}
break;
default:
printk(KERN_WARNING "Xen Platform PCI: unknown I/O protocol version");
return XEN_PLATFORM_ERR_PROTOCOL;
}
return 0;
}
xen/pvhvm: If xen_platform_pci=0 is set don't blow up (v4). The user has the option of disabling the platform driver: 00:02.0 Unassigned class [ff80]: XenSource, Inc. Xen Platform Device (rev 01) which is used to unplug the emulated drivers (IDE, Realtek 8169, etc) and allow the PV drivers to take over. If the user wishes to disable that they can set: xen_platform_pci=0 (in the guest config file) or xen_emul_unplug=never (on the Linux command line) except it does not work properly. The PV drivers still try to load and since the Xen platform driver is not run - and it has not initialized the grant tables, most of the PV drivers stumble upon: input: Xen Virtual Keyboard as /devices/virtual/input/input5 input: Xen Virtual Pointer as /devices/virtual/input/input6M ------------[ cut here ]------------ kernel BUG at /home/konrad/ssd/konrad/linux/drivers/xen/grant-table.c:1206! invalid opcode: 0000 [#1] SMP Modules linked in: xen_kbdfront(+) xenfs xen_privcmd CPU: 6 PID: 1389 Comm: modprobe Not tainted 3.13.0-rc1upstream-00021-ga6c892b-dirty #1 Hardware name: Xen HVM domU, BIOS 4.4-unstable 11/26/2013 RIP: 0010:[<ffffffff813ddc40>] [<ffffffff813ddc40>] get_free_entries+0x2e0/0x300 Call Trace: [<ffffffff8150d9a3>] ? evdev_connect+0x1e3/0x240 [<ffffffff813ddd0e>] gnttab_grant_foreign_access+0x2e/0x70 [<ffffffffa0010081>] xenkbd_connect_backend+0x41/0x290 [xen_kbdfront] [<ffffffffa0010a12>] xenkbd_probe+0x2f2/0x324 [xen_kbdfront] [<ffffffff813e5757>] xenbus_dev_probe+0x77/0x130 [<ffffffff813e7217>] xenbus_frontend_dev_probe+0x47/0x50 [<ffffffff8145e9a9>] driver_probe_device+0x89/0x230 [<ffffffff8145ebeb>] __driver_attach+0x9b/0xa0 [<ffffffff8145eb50>] ? driver_probe_device+0x230/0x230 [<ffffffff8145eb50>] ? driver_probe_device+0x230/0x230 [<ffffffff8145cf1c>] bus_for_each_dev+0x8c/0xb0 [<ffffffff8145e7d9>] driver_attach+0x19/0x20 [<ffffffff8145e260>] bus_add_driver+0x1a0/0x220 [<ffffffff8145f1ff>] driver_register+0x5f/0xf0 [<ffffffff813e55c5>] xenbus_register_driver_common+0x15/0x20 [<ffffffff813e76b3>] xenbus_register_frontend+0x23/0x40 [<ffffffffa0015000>] ? 0xffffffffa0014fff [<ffffffffa001502b>] xenkbd_init+0x2b/0x1000 [xen_kbdfront] [<ffffffff81002049>] do_one_initcall+0x49/0x170 .. snip.. which is hardly nice. This patch fixes this by having each PV driver check for: - if running in PV, then it is fine to execute (as that is their native environment). - if running in HVM, check if user wanted 'xen_emul_unplug=never', in which case bail out and don't load any PV drivers. - if running in HVM, and if PCI device 5853:0001 (xen_platform_pci) does not exist, then bail out and not load PV drivers. - (v2) if running in HVM, and if the user wanted 'xen_emul_unplug=ide-disks', then bail out for all PV devices _except_ the block one. Ditto for the network one ('nics'). - (v2) if running in HVM, and if the user wanted 'xen_emul_unplug=unnecessary' then load block PV driver, and also setup the legacy IDE paths. In (v3) make it actually load PV drivers. Reported-by: Sander Eikelenboom <linux@eikelenboom.it Reported-by: Anthony PERARD <anthony.perard@citrix.com> Reported-and-Tested-by: Fabio Fantoni <fabio.fantoni@m2r.biz> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> [v2: Add extra logic to handle the myrid ways 'xen_emul_unplug' can be used per Ian and Stefano suggestion] [v3: Make the unnecessary case work properly] [v4: s/disks/ide-disks/ spotted by Fabio] Reviewed-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> [for PCI parts] CC: stable@vger.kernel.org
2013-11-26 20:05:40 +00:00
bool xen_has_pv_devices()
{
if (!xen_domain())
return false;
/* PV domains always have them. */
if (xen_pv_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;
/* 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()) {
printk(KERN_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()) {
printk(KERN_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
printk(KERN_WARNING "unrecognised option '%s' "
"in parameter 'xen_emul_unplug'\n", p);
}
return 0;
}
early_param("xen_emul_unplug", parse_xen_emul_unplug);
#endif