linux/drivers/xen/pcpu.c
Linus Torvalds 77be36de8b Features:
- Xen ACPI memory and CPU hotplug drivers - allowing Xen hypervisor
    to be aware of new CPU and new DIMMs
  - Cleanups
 Bug-fixes:
  - Fixes a long-standing bug in the PV spinlock wherein we did not
    kick VCPUs that were in a tight loop.
  - Fixes in the error paths for the event channel machinery.
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Merge tag 'stable/for-linus-3.9-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

Pull Xen update from Konrad Rzeszutek Wilk:
 "This has two new ACPI drivers for Xen - a physical CPU offline/online
  and a memory hotplug.  The way this works is that ACPI kicks the
  drivers and they make the appropiate hypercall to the hypervisor to
  tell it that there is a new CPU or memory.  There also some changes to
  the Xen ARM ABIs and couple of fixes.  One particularly nasty bug in
  the Xen PV spinlock code was fixed by Stefan Bader - and has been
  there since the 2.6.32!

  Features:
   - Xen ACPI memory and CPU hotplug drivers - allowing Xen hypervisor
     to be aware of new CPU and new DIMMs
   - Cleanups
  Bug-fixes:
   - Fixes a long-standing bug in the PV spinlock wherein we did not
     kick VCPUs that were in a tight loop.
   - Fixes in the error paths for the event channel machinery"

Fix up a few semantic conflicts with the ACPI interface changes in
drivers/xen/xen-acpi-{cpu,mem}hotplug.c.

* tag 'stable/for-linus-3.9-rc0-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  xen: event channel arrays are xen_ulong_t and not unsigned long
  xen: Send spinlock IPI to all waiters
  xen: introduce xen_remap, use it instead of ioremap
  xen: close evtchn port if binding to irq fails
  xen-evtchn: correct comment and error output
  xen/tmem: Add missing %s in the printk statement.
  xen/acpi: move xen_acpi_get_pxm under CONFIG_XEN_DOM0
  xen/acpi: ACPI cpu hotplug
  xen/acpi: Move xen_acpi_get_pxm to Xen's acpi.h
  xen/stub: driver for CPU hotplug
  xen/acpi: ACPI memory hotplug
  xen/stub: driver for memory hotplug
  xen: implement updated XENMEM_add_to_physmap_range ABI
  xen/smp: Move the common CPU init code a bit to prep for PVH patch.
2013-02-24 16:18:31 -08:00

406 lines
8.9 KiB
C

/******************************************************************************
* pcpu.c
* Management physical cpu in dom0, get pcpu info and provide sys interface
*
* Copyright (c) 2012 Intel Corporation
* Author: Liu, Jinsong <jinsong.liu@intel.com>
* Author: Jiang, Yunhong <yunhong.jiang@intel.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License version 2
* as published by the Free Software Foundation; or, when distributed
* separately from the Linux kernel or incorporated into other
* software packages, subject to the following license:
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this source file (the "Software"), to deal in the Software without
* restriction, including without limitation the rights to use, copy, modify,
* merge, publish, distribute, sublicense, and/or sell copies of the Software,
* and to permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/cpu.h>
#include <linux/stat.h>
#include <linux/capability.h>
#include <xen/xen.h>
#include <xen/xenbus.h>
#include <xen/events.h>
#include <xen/interface/platform.h>
#include <asm/xen/hypervisor.h>
#include <asm/xen/hypercall.h>
#define XEN_PCPU "xen_cpu: "
/*
* @cpu_id: Xen physical cpu logic number
* @flags: Xen physical cpu status flag
* - XEN_PCPU_FLAGS_ONLINE: cpu is online
* - XEN_PCPU_FLAGS_INVALID: cpu is not present
*/
struct pcpu {
struct list_head list;
struct device dev;
uint32_t cpu_id;
uint32_t flags;
};
static struct bus_type xen_pcpu_subsys = {
.name = "xen_cpu",
.dev_name = "xen_cpu",
};
static DEFINE_MUTEX(xen_pcpu_lock);
static LIST_HEAD(xen_pcpus);
static int xen_pcpu_down(uint32_t cpu_id)
{
struct xen_platform_op op = {
.cmd = XENPF_cpu_offline,
.interface_version = XENPF_INTERFACE_VERSION,
.u.cpu_ol.cpuid = cpu_id,
};
return HYPERVISOR_dom0_op(&op);
}
static int xen_pcpu_up(uint32_t cpu_id)
{
struct xen_platform_op op = {
.cmd = XENPF_cpu_online,
.interface_version = XENPF_INTERFACE_VERSION,
.u.cpu_ol.cpuid = cpu_id,
};
return HYPERVISOR_dom0_op(&op);
}
static ssize_t show_online(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct pcpu *cpu = container_of(dev, struct pcpu, dev);
return sprintf(buf, "%u\n", !!(cpu->flags & XEN_PCPU_FLAGS_ONLINE));
}
static ssize_t __ref store_online(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t count)
{
struct pcpu *pcpu = container_of(dev, struct pcpu, dev);
unsigned long long val;
ssize_t ret;
if (!capable(CAP_SYS_ADMIN))
return -EPERM;
if (kstrtoull(buf, 0, &val) < 0)
return -EINVAL;
switch (val) {
case 0:
ret = xen_pcpu_down(pcpu->cpu_id);
break;
case 1:
ret = xen_pcpu_up(pcpu->cpu_id);
break;
default:
ret = -EINVAL;
}
if (ret >= 0)
ret = count;
return ret;
}
static DEVICE_ATTR(online, S_IRUGO | S_IWUSR, show_online, store_online);
static bool xen_pcpu_online(uint32_t flags)
{
return !!(flags & XEN_PCPU_FLAGS_ONLINE);
}
static void pcpu_online_status(struct xenpf_pcpuinfo *info,
struct pcpu *pcpu)
{
if (xen_pcpu_online(info->flags) &&
!xen_pcpu_online(pcpu->flags)) {
/* the pcpu is onlined */
pcpu->flags |= XEN_PCPU_FLAGS_ONLINE;
kobject_uevent(&pcpu->dev.kobj, KOBJ_ONLINE);
} else if (!xen_pcpu_online(info->flags) &&
xen_pcpu_online(pcpu->flags)) {
/* The pcpu is offlined */
pcpu->flags &= ~XEN_PCPU_FLAGS_ONLINE;
kobject_uevent(&pcpu->dev.kobj, KOBJ_OFFLINE);
}
}
static struct pcpu *get_pcpu(uint32_t cpu_id)
{
struct pcpu *pcpu;
list_for_each_entry(pcpu, &xen_pcpus, list) {
if (pcpu->cpu_id == cpu_id)
return pcpu;
}
return NULL;
}
static void pcpu_release(struct device *dev)
{
struct pcpu *pcpu = container_of(dev, struct pcpu, dev);
list_del(&pcpu->list);
kfree(pcpu);
}
static void unregister_and_remove_pcpu(struct pcpu *pcpu)
{
struct device *dev;
if (!pcpu)
return;
dev = &pcpu->dev;
if (dev->id)
device_remove_file(dev, &dev_attr_online);
/* pcpu remove would be implicitly done */
device_unregister(dev);
}
static int register_pcpu(struct pcpu *pcpu)
{
struct device *dev;
int err = -EINVAL;
if (!pcpu)
return err;
dev = &pcpu->dev;
dev->bus = &xen_pcpu_subsys;
dev->id = pcpu->cpu_id;
dev->release = pcpu_release;
err = device_register(dev);
if (err) {
pcpu_release(dev);
return err;
}
/*
* Xen never offline cpu0 due to several restrictions
* and assumptions. This basically doesn't add a sys control
* to user, one cannot attempt to offline BSP.
*/
if (dev->id) {
err = device_create_file(dev, &dev_attr_online);
if (err) {
device_unregister(dev);
return err;
}
}
return 0;
}
static struct pcpu *create_and_register_pcpu(struct xenpf_pcpuinfo *info)
{
struct pcpu *pcpu;
int err;
if (info->flags & XEN_PCPU_FLAGS_INVALID)
return ERR_PTR(-ENODEV);
pcpu = kzalloc(sizeof(struct pcpu), GFP_KERNEL);
if (!pcpu)
return ERR_PTR(-ENOMEM);
INIT_LIST_HEAD(&pcpu->list);
pcpu->cpu_id = info->xen_cpuid;
pcpu->flags = info->flags;
/* Need hold on xen_pcpu_lock before pcpu list manipulations */
list_add_tail(&pcpu->list, &xen_pcpus);
err = register_pcpu(pcpu);
if (err) {
pr_warning(XEN_PCPU "Failed to register pcpu%u\n",
info->xen_cpuid);
return ERR_PTR(-ENOENT);
}
return pcpu;
}
/*
* Caller should hold the xen_pcpu_lock
*/
static int sync_pcpu(uint32_t cpu, uint32_t *max_cpu)
{
int ret;
struct pcpu *pcpu = NULL;
struct xenpf_pcpuinfo *info;
struct xen_platform_op op = {
.cmd = XENPF_get_cpuinfo,
.interface_version = XENPF_INTERFACE_VERSION,
.u.pcpu_info.xen_cpuid = cpu,
};
ret = HYPERVISOR_dom0_op(&op);
if (ret)
return ret;
info = &op.u.pcpu_info;
if (max_cpu)
*max_cpu = info->max_present;
pcpu = get_pcpu(cpu);
/*
* Only those at cpu present map has its sys interface.
*/
if (info->flags & XEN_PCPU_FLAGS_INVALID) {
unregister_and_remove_pcpu(pcpu);
return 0;
}
if (!pcpu) {
pcpu = create_and_register_pcpu(info);
if (IS_ERR_OR_NULL(pcpu))
return -ENODEV;
} else
pcpu_online_status(info, pcpu);
return 0;
}
/*
* Sync dom0's pcpu information with xen hypervisor's
*/
static int xen_sync_pcpus(void)
{
/*
* Boot cpu always have cpu_id 0 in xen
*/
uint32_t cpu = 0, max_cpu = 0;
int err = 0;
struct pcpu *pcpu, *tmp;
mutex_lock(&xen_pcpu_lock);
while (!err && (cpu <= max_cpu)) {
err = sync_pcpu(cpu, &max_cpu);
cpu++;
}
if (err)
list_for_each_entry_safe(pcpu, tmp, &xen_pcpus, list)
unregister_and_remove_pcpu(pcpu);
mutex_unlock(&xen_pcpu_lock);
return err;
}
static void xen_pcpu_work_fn(struct work_struct *work)
{
xen_sync_pcpus();
}
static DECLARE_WORK(xen_pcpu_work, xen_pcpu_work_fn);
static irqreturn_t xen_pcpu_interrupt(int irq, void *dev_id)
{
schedule_work(&xen_pcpu_work);
return IRQ_HANDLED;
}
/* Sync with Xen hypervisor after cpu hotadded */
void xen_pcpu_hotplug_sync(void)
{
schedule_work(&xen_pcpu_work);
}
EXPORT_SYMBOL_GPL(xen_pcpu_hotplug_sync);
/*
* For hypervisor presented cpu, return logic cpu id;
* For hypervisor non-presented cpu, return -ENODEV.
*/
int xen_pcpu_id(uint32_t acpi_id)
{
int cpu_id = 0, max_id = 0;
struct xen_platform_op op;
op.cmd = XENPF_get_cpuinfo;
while (cpu_id <= max_id) {
op.u.pcpu_info.xen_cpuid = cpu_id;
if (HYPERVISOR_dom0_op(&op)) {
cpu_id++;
continue;
}
if (acpi_id == op.u.pcpu_info.acpi_id)
return cpu_id;
if (op.u.pcpu_info.max_present > max_id)
max_id = op.u.pcpu_info.max_present;
cpu_id++;
}
return -ENODEV;
}
EXPORT_SYMBOL_GPL(xen_pcpu_id);
static int __init xen_pcpu_init(void)
{
int irq, ret;
if (!xen_initial_domain())
return -ENODEV;
irq = bind_virq_to_irqhandler(VIRQ_PCPU_STATE, 0,
xen_pcpu_interrupt, 0,
"xen-pcpu", NULL);
if (irq < 0) {
pr_warning(XEN_PCPU "Failed to bind pcpu virq\n");
return irq;
}
ret = subsys_system_register(&xen_pcpu_subsys, NULL);
if (ret) {
pr_warning(XEN_PCPU "Failed to register pcpu subsys\n");
goto err1;
}
ret = xen_sync_pcpus();
if (ret) {
pr_warning(XEN_PCPU "Failed to sync pcpu info\n");
goto err2;
}
return 0;
err2:
bus_unregister(&xen_pcpu_subsys);
err1:
unbind_from_irqhandler(irq, NULL);
return ret;
}
arch_initcall(xen_pcpu_init);