Contributors: 36
| Author |
Tokens |
Token Proportion |
Commits |
Commit Proportion |
| Vitaly Kuznetsov |
884 |
52.34% |
6 |
7.50% |
| Jeremy Fitzhardinge |
384 |
22.74% |
14 |
17.50% |
| Konrad Rzeszutek Wilk |
155 |
9.18% |
11 |
13.75% |
| Alex Nixon |
58 |
3.43% |
3 |
3.75% |
| Boris Ostrovsky |
34 |
2.01% |
7 |
8.75% |
| Lin Ming |
25 |
1.48% |
1 |
1.25% |
| Andrew Lutomirski |
23 |
1.36% |
1 |
1.25% |
| Thomas Gleixner |
18 |
1.07% |
5 |
6.25% |
| Jens Axboe |
15 |
0.89% |
1 |
1.25% |
| Juergen Gross |
13 |
0.77% |
2 |
2.50% |
| Mukesh Rathor |
11 |
0.65% |
2 |
2.50% |
| Paul E. McKenney |
10 |
0.59% |
1 |
1.25% |
| Miroslav Benes |
7 |
0.41% |
1 |
1.25% |
| Jan Beulich |
5 |
0.30% |
1 |
1.25% |
| Stefano Stabellini |
5 |
0.30% |
1 |
1.25% |
| Linus Torvalds (pre-git) |
5 |
0.30% |
3 |
3.75% |
| Yury Norov |
3 |
0.18% |
1 |
1.25% |
| Ingo Molnar |
3 |
0.18% |
1 |
1.25% |
| Alok N Kataria |
3 |
0.18% |
1 |
1.25% |
| Rafael J. Wysocki |
3 |
0.18% |
1 |
1.25% |
| Christophe Leroy |
3 |
0.18% |
1 |
1.25% |
| Xiu Jianfeng |
3 |
0.18% |
1 |
1.25% |
| Ben Guthro |
3 |
0.18% |
1 |
1.25% |
| Mark Brown |
2 |
0.12% |
1 |
1.25% |
| Jaswinder Singh Rajput |
2 |
0.12% |
1 |
1.25% |
| Rusty Russell |
2 |
0.12% |
1 |
1.25% |
| Robert P. J. Day |
1 |
0.06% |
1 |
1.25% |
| Mike Travis |
1 |
0.06% |
1 |
1.25% |
| Julien Grall |
1 |
0.06% |
1 |
1.25% |
| Lv Zheng |
1 |
0.06% |
1 |
1.25% |
| Glauber de Oliveira Costa |
1 |
0.06% |
1 |
1.25% |
| Linus Torvalds |
1 |
0.06% |
1 |
1.25% |
| Greg Kroah-Hartman |
1 |
0.06% |
1 |
1.25% |
| Ankur Arora |
1 |
0.06% |
1 |
1.25% |
| Mike Rapoport |
1 |
0.06% |
1 |
1.25% |
| Daniel Kiper |
1 |
0.06% |
1 |
1.25% |
| Total |
1689 |
|
80 |
|
// SPDX-License-Identifier: GPL-2.0
/*
* Xen SMP support
*
* This file implements the Xen versions of smp_ops. SMP under Xen is
* very straightforward. Bringing a CPU up is simply a matter of
* loading its initial context and setting it running.
*
* IPIs are handled through the Xen event mechanism.
*
* Because virtual CPUs can be scheduled onto any real CPU, there's no
* useful topology information for the kernel to make use of. As a
* result, all CPUs are treated as if they're single-core and
* single-threaded.
*/
#include <linux/sched.h>
#include <linux/sched/task_stack.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/smp.h>
#include <linux/irq_work.h>
#include <linux/tick.h>
#include <linux/nmi.h>
#include <linux/cpuhotplug.h>
#include <linux/stackprotector.h>
#include <linux/pgtable.h>
#include <asm/paravirt.h>
#include <asm/idtentry.h>
#include <asm/desc.h>
#include <asm/cpu.h>
#include <asm/io_apic.h>
#include <xen/interface/xen.h>
#include <xen/interface/vcpu.h>
#include <xen/interface/xenpmu.h>
#include <asm/spec-ctrl.h>
#include <asm/xen/interface.h>
#include <asm/xen/hypercall.h>
#include <xen/xen.h>
#include <xen/page.h>
#include <xen/events.h>
#include <xen/hvc-console.h>
#include "xen-ops.h"
#include "mmu.h"
#include "smp.h"
#include "pmu.h"
cpumask_var_t xen_cpu_initialized_map;
static DEFINE_PER_CPU(struct xen_common_irq, xen_irq_work) = { .irq = -1 };
static DEFINE_PER_CPU(struct xen_common_irq, xen_pmu_irq) = { .irq = -1 };
static irqreturn_t xen_irq_work_interrupt(int irq, void *dev_id);
void asm_cpu_bringup_and_idle(void);
static void cpu_bringup(void)
{
int cpu;
cr4_init();
cpu_init();
touch_softlockup_watchdog();
/* PVH runs in ring 0 and allows us to do native syscalls. Yay! */
if (!xen_feature(XENFEAT_supervisor_mode_kernel)) {
xen_enable_sysenter();
xen_enable_syscall();
}
cpu = smp_processor_id();
smp_store_cpu_info(cpu);
cpu_data(cpu).x86_max_cores = 1;
set_cpu_sibling_map(cpu);
speculative_store_bypass_ht_init();
xen_setup_cpu_clockevents();
notify_cpu_starting(cpu);
set_cpu_online(cpu, true);
cpu_set_state_online(cpu); /* Implies full memory barrier. */
/* We can take interrupts now: we're officially "up". */
local_irq_enable();
}
asmlinkage __visible void cpu_bringup_and_idle(void)
{
cpu_bringup();
cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);
}
void xen_smp_intr_free_pv(unsigned int cpu)
{
kfree(per_cpu(xen_irq_work, cpu).name);
per_cpu(xen_irq_work, cpu).name = NULL;
if (per_cpu(xen_irq_work, cpu).irq >= 0) {
unbind_from_irqhandler(per_cpu(xen_irq_work, cpu).irq, NULL);
per_cpu(xen_irq_work, cpu).irq = -1;
}
kfree(per_cpu(xen_pmu_irq, cpu).name);
per_cpu(xen_pmu_irq, cpu).name = NULL;
if (per_cpu(xen_pmu_irq, cpu).irq >= 0) {
unbind_from_irqhandler(per_cpu(xen_pmu_irq, cpu).irq, NULL);
per_cpu(xen_pmu_irq, cpu).irq = -1;
}
}
int xen_smp_intr_init_pv(unsigned int cpu)
{
int rc;
char *callfunc_name, *pmu_name;
callfunc_name = kasprintf(GFP_KERNEL, "irqwork%d", cpu);
per_cpu(xen_irq_work, cpu).name = callfunc_name;
rc = bind_ipi_to_irqhandler(XEN_IRQ_WORK_VECTOR,
cpu,
xen_irq_work_interrupt,
IRQF_PERCPU|IRQF_NOBALANCING,
callfunc_name,
NULL);
if (rc < 0)
goto fail;
per_cpu(xen_irq_work, cpu).irq = rc;
if (is_xen_pmu) {
pmu_name = kasprintf(GFP_KERNEL, "pmu%d", cpu);
per_cpu(xen_pmu_irq, cpu).name = pmu_name;
rc = bind_virq_to_irqhandler(VIRQ_XENPMU, cpu,
xen_pmu_irq_handler,
IRQF_PERCPU|IRQF_NOBALANCING,
pmu_name, NULL);
if (rc < 0)
goto fail;
per_cpu(xen_pmu_irq, cpu).irq = rc;
}
return 0;
fail:
xen_smp_intr_free_pv(cpu);
return rc;
}
static void __init _get_smp_config(unsigned int early)
{
int i, rc;
unsigned int subtract = 0;
if (early)
return;
num_processors = 0;
disabled_cpus = 0;
for (i = 0; i < nr_cpu_ids; i++) {
rc = HYPERVISOR_vcpu_op(VCPUOP_is_up, i, NULL);
if (rc >= 0) {
num_processors++;
set_cpu_possible(i, true);
} else {
set_cpu_possible(i, false);
set_cpu_present(i, false);
subtract++;
}
}
#ifdef CONFIG_HOTPLUG_CPU
/* This is akin to using 'nr_cpus' on the Linux command line.
* Which is OK as when we use 'dom0_max_vcpus=X' we can only
* have up to X, while nr_cpu_ids is greater than X. This
* normally is not a problem, except when CPU hotplugging
* is involved and then there might be more than X CPUs
* in the guest - which will not work as there is no
* hypercall to expand the max number of VCPUs an already
* running guest has. So cap it up to X. */
if (subtract)
set_nr_cpu_ids(nr_cpu_ids - subtract);
#endif
}
static void __init xen_pv_smp_prepare_boot_cpu(void)
{
BUG_ON(smp_processor_id() != 0);
native_smp_prepare_boot_cpu();
if (!xen_feature(XENFEAT_writable_page_tables))
/* We've switched to the "real" per-cpu gdt, so make
* sure the old memory can be recycled. */
make_lowmem_page_readwrite(xen_initial_gdt);
xen_setup_vcpu_info_placement();
/*
* The alternative logic (which patches the unlock/lock) runs before
* the smp bootup up code is activated. Hence we need to set this up
* the core kernel is being patched. Otherwise we will have only
* modules patched but not core code.
*/
xen_init_spinlocks();
}
static void __init xen_pv_smp_prepare_cpus(unsigned int max_cpus)
{
unsigned cpu;
if (skip_ioapic_setup) {
char *m = (max_cpus == 0) ?
"The nosmp parameter is incompatible with Xen; " \
"use Xen dom0_max_vcpus=1 parameter" :
"The noapic parameter is incompatible with Xen";
xen_raw_printk(m);
panic(m);
}
xen_init_lock_cpu(0);
smp_prepare_cpus_common();
cpu_data(0).x86_max_cores = 1;
speculative_store_bypass_ht_init();
xen_pmu_init(0);
if (xen_smp_intr_init(0) || xen_smp_intr_init_pv(0))
BUG();
if (!alloc_cpumask_var(&xen_cpu_initialized_map, GFP_KERNEL))
panic("could not allocate xen_cpu_initialized_map\n");
cpumask_copy(xen_cpu_initialized_map, cpumask_of(0));
/* Restrict the possible_map according to max_cpus. */
while ((num_possible_cpus() > 1) && (num_possible_cpus() > max_cpus)) {
for (cpu = nr_cpu_ids - 1; !cpu_possible(cpu); cpu--)
continue;
set_cpu_possible(cpu, false);
}
for_each_possible_cpu(cpu)
set_cpu_present(cpu, true);
}
static int
cpu_initialize_context(unsigned int cpu, struct task_struct *idle)
{
struct vcpu_guest_context *ctxt;
struct desc_struct *gdt;
unsigned long gdt_mfn;
/* used to tell cpu_init() that it can proceed with initialization */
cpumask_set_cpu(cpu, cpu_callout_mask);
if (cpumask_test_and_set_cpu(cpu, xen_cpu_initialized_map))
return 0;
ctxt = kzalloc(sizeof(*ctxt), GFP_KERNEL);
if (ctxt == NULL) {
cpumask_clear_cpu(cpu, xen_cpu_initialized_map);
cpumask_clear_cpu(cpu, cpu_callout_mask);
return -ENOMEM;
}
gdt = get_cpu_gdt_rw(cpu);
/*
* Bring up the CPU in cpu_bringup_and_idle() with the stack
* pointing just below where pt_regs would be if it were a normal
* kernel entry.
*/
ctxt->user_regs.eip = (unsigned long)asm_cpu_bringup_and_idle;
ctxt->flags = VGCF_IN_KERNEL;
ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */
ctxt->user_regs.ds = __USER_DS;
ctxt->user_regs.es = __USER_DS;
ctxt->user_regs.ss = __KERNEL_DS;
ctxt->user_regs.cs = __KERNEL_CS;
ctxt->user_regs.esp = (unsigned long)task_pt_regs(idle);
xen_copy_trap_info(ctxt->trap_ctxt);
BUG_ON((unsigned long)gdt & ~PAGE_MASK);
gdt_mfn = arbitrary_virt_to_mfn(gdt);
make_lowmem_page_readonly(gdt);
make_lowmem_page_readonly(mfn_to_virt(gdt_mfn));
ctxt->gdt_frames[0] = gdt_mfn;
ctxt->gdt_ents = GDT_ENTRIES;
/*
* Set SS:SP that Xen will use when entering guest kernel mode
* from guest user mode. Subsequent calls to load_sp0() can
* change this value.
*/
ctxt->kernel_ss = __KERNEL_DS;
ctxt->kernel_sp = task_top_of_stack(idle);
ctxt->gs_base_kernel = per_cpu_offset(cpu);
ctxt->event_callback_eip =
(unsigned long)xen_asm_exc_xen_hypervisor_callback;
ctxt->failsafe_callback_eip =
(unsigned long)xen_failsafe_callback;
per_cpu(xen_cr3, cpu) = __pa(swapper_pg_dir);
ctxt->ctrlreg[3] = xen_pfn_to_cr3(virt_to_gfn(swapper_pg_dir));
if (HYPERVISOR_vcpu_op(VCPUOP_initialise, xen_vcpu_nr(cpu), ctxt))
BUG();
kfree(ctxt);
return 0;
}
static int xen_pv_cpu_up(unsigned int cpu, struct task_struct *idle)
{
int rc;
rc = common_cpu_up(cpu, idle);
if (rc)
return rc;
xen_setup_runstate_info(cpu);
/*
* PV VCPUs are always successfully taken down (see 'while' loop
* in xen_cpu_die()), so -EBUSY is an error.
*/
rc = cpu_check_up_prepare(cpu);
if (rc)
return rc;
/* make sure interrupts start blocked */
per_cpu(xen_vcpu, cpu)->evtchn_upcall_mask = 1;
rc = cpu_initialize_context(cpu, idle);
if (rc)
return rc;
xen_pmu_init(cpu);
rc = HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL);
BUG_ON(rc);
while (cpu_report_state(cpu) != CPU_ONLINE)
HYPERVISOR_sched_op(SCHEDOP_yield, NULL);
return 0;
}
#ifdef CONFIG_HOTPLUG_CPU
static int xen_pv_cpu_disable(void)
{
unsigned int cpu = smp_processor_id();
if (cpu == 0)
return -EBUSY;
cpu_disable_common();
load_cr3(swapper_pg_dir);
return 0;
}
static void xen_pv_cpu_die(unsigned int cpu)
{
while (HYPERVISOR_vcpu_op(VCPUOP_is_up,
xen_vcpu_nr(cpu), NULL)) {
__set_current_state(TASK_UNINTERRUPTIBLE);
schedule_timeout(HZ/10);
}
if (common_cpu_die(cpu) == 0) {
xen_smp_intr_free(cpu);
xen_uninit_lock_cpu(cpu);
xen_teardown_timer(cpu);
xen_pmu_finish(cpu);
}
}
static void xen_pv_play_dead(void) /* used only with HOTPLUG_CPU */
{
play_dead_common();
HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(smp_processor_id()), NULL);
cpu_bringup();
/*
* commit 4b0c0f294 (tick: Cleanup NOHZ per cpu data on cpu down)
* clears certain data that the cpu_idle loop (which called us
* and that we return from) expects. The only way to get that
* data back is to call:
*/
tick_nohz_idle_enter();
tick_nohz_idle_stop_tick_protected();
cpuhp_online_idle(CPUHP_AP_ONLINE_IDLE);
}
#else /* !CONFIG_HOTPLUG_CPU */
static int xen_pv_cpu_disable(void)
{
return -ENOSYS;
}
static void xen_pv_cpu_die(unsigned int cpu)
{
BUG();
}
static void xen_pv_play_dead(void)
{
BUG();
}
#endif
static void stop_self(void *v)
{
int cpu = smp_processor_id();
/* make sure we're not pinning something down */
load_cr3(swapper_pg_dir);
/* should set up a minimal gdt */
set_cpu_online(cpu, false);
HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL);
BUG();
}
static void xen_pv_stop_other_cpus(int wait)
{
smp_call_function(stop_self, NULL, wait);
}
static irqreturn_t xen_irq_work_interrupt(int irq, void *dev_id)
{
irq_work_run();
inc_irq_stat(apic_irq_work_irqs);
return IRQ_HANDLED;
}
static const struct smp_ops xen_smp_ops __initconst = {
.smp_prepare_boot_cpu = xen_pv_smp_prepare_boot_cpu,
.smp_prepare_cpus = xen_pv_smp_prepare_cpus,
.smp_cpus_done = xen_smp_cpus_done,
.cpu_up = xen_pv_cpu_up,
.cpu_die = xen_pv_cpu_die,
.cpu_disable = xen_pv_cpu_disable,
.play_dead = xen_pv_play_dead,
.stop_other_cpus = xen_pv_stop_other_cpus,
.smp_send_reschedule = xen_smp_send_reschedule,
.send_call_func_ipi = xen_smp_send_call_function_ipi,
.send_call_func_single_ipi = xen_smp_send_call_function_single_ipi,
};
void __init xen_smp_init(void)
{
smp_ops = xen_smp_ops;
/* Avoid searching for BIOS MP tables */
x86_init.mpparse.find_smp_config = x86_init_noop;
x86_init.mpparse.get_smp_config = _get_smp_config;
}