mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-12-29 17:25:38 +00:00
9fe6a8c5b2
The xen_nopvspin boot parameter is deprecated since 2019. nopvspin can be used instead. Remove the xen_nopvspin boot parameter and replace the xen_pvspin variable use cases with nopvspin. This requires to move the nopvspin variable out of the .initdata section, as it needs to be accessed for cpuhotplug, too. Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com> Message-ID: <20240710110139.22300-1-jgross@suse.com> Signed-off-by: Juergen Gross <jgross@suse.com>
145 lines
3.5 KiB
C
145 lines
3.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* Split spinlock implementation out into its own file, so it can be
|
|
* compiled in a FTRACE-compatible way.
|
|
*/
|
|
#include <linux/kernel.h>
|
|
#include <linux/spinlock.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/atomic.h>
|
|
|
|
#include <asm/paravirt.h>
|
|
#include <asm/qspinlock.h>
|
|
|
|
#include <xen/events.h>
|
|
|
|
#include "xen-ops.h"
|
|
|
|
static DEFINE_PER_CPU(int, lock_kicker_irq) = -1;
|
|
static DEFINE_PER_CPU(char *, irq_name);
|
|
static DEFINE_PER_CPU(atomic_t, xen_qlock_wait_nest);
|
|
|
|
static void xen_qlock_kick(int cpu)
|
|
{
|
|
int irq = per_cpu(lock_kicker_irq, cpu);
|
|
|
|
/* Don't kick if the target's kicker interrupt is not initialized. */
|
|
if (irq == -1)
|
|
return;
|
|
|
|
xen_send_IPI_one(cpu, XEN_SPIN_UNLOCK_VECTOR);
|
|
}
|
|
|
|
/*
|
|
* Halt the current CPU & release it back to the host
|
|
*/
|
|
static void xen_qlock_wait(u8 *byte, u8 val)
|
|
{
|
|
int irq = __this_cpu_read(lock_kicker_irq);
|
|
atomic_t *nest_cnt = this_cpu_ptr(&xen_qlock_wait_nest);
|
|
|
|
/* If kicker interrupts not initialized yet, just spin */
|
|
if (irq == -1 || in_nmi())
|
|
return;
|
|
|
|
/* Detect reentry. */
|
|
atomic_inc(nest_cnt);
|
|
|
|
/* If irq pending already and no nested call clear it. */
|
|
if (atomic_read(nest_cnt) == 1 && xen_test_irq_pending(irq)) {
|
|
xen_clear_irq_pending(irq);
|
|
} else if (READ_ONCE(*byte) == val) {
|
|
/* Block until irq becomes pending (or a spurious wakeup) */
|
|
xen_poll_irq(irq);
|
|
}
|
|
|
|
atomic_dec(nest_cnt);
|
|
}
|
|
|
|
static irqreturn_t dummy_handler(int irq, void *dev_id)
|
|
{
|
|
BUG();
|
|
return IRQ_HANDLED;
|
|
}
|
|
|
|
void xen_init_lock_cpu(int cpu)
|
|
{
|
|
int irq;
|
|
char *name;
|
|
|
|
if (nopvspin)
|
|
return;
|
|
|
|
WARN(per_cpu(lock_kicker_irq, cpu) >= 0, "spinlock on CPU%d exists on IRQ%d!\n",
|
|
cpu, per_cpu(lock_kicker_irq, cpu));
|
|
|
|
name = kasprintf(GFP_KERNEL, "spinlock%d", cpu);
|
|
per_cpu(irq_name, cpu) = name;
|
|
irq = bind_ipi_to_irqhandler(XEN_SPIN_UNLOCK_VECTOR,
|
|
cpu,
|
|
dummy_handler,
|
|
IRQF_PERCPU|IRQF_NOBALANCING,
|
|
name,
|
|
NULL);
|
|
|
|
if (irq >= 0) {
|
|
disable_irq(irq); /* make sure it's never delivered */
|
|
per_cpu(lock_kicker_irq, cpu) = irq;
|
|
}
|
|
|
|
printk("cpu %d spinlock event irq %d\n", cpu, irq);
|
|
}
|
|
|
|
void xen_uninit_lock_cpu(int cpu)
|
|
{
|
|
int irq;
|
|
|
|
if (nopvspin)
|
|
return;
|
|
|
|
kfree(per_cpu(irq_name, cpu));
|
|
per_cpu(irq_name, cpu) = NULL;
|
|
/*
|
|
* When booting the kernel with 'mitigations=auto,nosmt', the secondary
|
|
* CPUs are not activated, and lock_kicker_irq is not initialized.
|
|
*/
|
|
irq = per_cpu(lock_kicker_irq, cpu);
|
|
if (irq == -1)
|
|
return;
|
|
|
|
unbind_from_irqhandler(irq, NULL);
|
|
per_cpu(lock_kicker_irq, cpu) = -1;
|
|
}
|
|
|
|
PV_CALLEE_SAVE_REGS_THUNK(xen_vcpu_stolen);
|
|
|
|
/*
|
|
* Our init of PV spinlocks is split in two init functions due to us
|
|
* using paravirt patching and jump labels patching and having to do
|
|
* all of this before SMP code is invoked.
|
|
*
|
|
* The paravirt patching needs to be done _before_ the alternative asm code
|
|
* is started, otherwise we would not patch the core kernel code.
|
|
*/
|
|
void __init xen_init_spinlocks(void)
|
|
{
|
|
/* Don't need to use pvqspinlock code if there is only 1 vCPU. */
|
|
if (num_possible_cpus() == 1)
|
|
nopvspin = true;
|
|
|
|
if (nopvspin) {
|
|
printk(KERN_DEBUG "xen: PV spinlocks disabled\n");
|
|
static_branch_disable(&virt_spin_lock_key);
|
|
return;
|
|
}
|
|
printk(KERN_DEBUG "xen: PV spinlocks enabled\n");
|
|
|
|
__pv_init_lock_hash();
|
|
pv_ops.lock.queued_spin_lock_slowpath = __pv_queued_spin_lock_slowpath;
|
|
pv_ops.lock.queued_spin_unlock =
|
|
PV_CALLEE_SAVE(__pv_queued_spin_unlock);
|
|
pv_ops.lock.wait = xen_qlock_wait;
|
|
pv_ops.lock.kick = xen_qlock_kick;
|
|
pv_ops.lock.vcpu_is_preempted = PV_CALLEE_SAVE(xen_vcpu_stolen);
|
|
}
|