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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_LOONGARCH_QSPINLOCK_H
#define _ASM_LOONGARCH_QSPINLOCK_H
#include <asm/kvm_para.h>
#include <asm/paravirt.h>
#ifdef CONFIG_PARAVIRT
#define virt_spin_lock virt_spin_lock
static inline bool virt_spin_lock(struct qspinlock *lock)
{
int val;
if (!static_branch_unlikely(&virt_spin_lock_key))
return false;
/*
* On hypervisors without PARAVIRT_SPINLOCKS support we fall
* back to a Test-and-Set spinlock, because fair locks have
* horrible lock 'holder' preemption issues.
*/
__retry:
val = atomic_read(&lock->val);
if (val || !atomic_try_cmpxchg(&lock->val, &val, _Q_LOCKED_VAL)) {
cpu_relax();
goto __retry;
}
return true;
}
/*
* Macro is better than inline function here
* With macro, parameter cpu is parsed only when it is used.
* With inline function, parameter cpu is parsed even though it is not used.
* This may cause cache line thrashing across NUMA nodes.
*/
#define vcpu_is_preempted(cpu) \
({ \
bool __val; \
\
if (!static_branch_unlikely(&virt_preempt_key)) \
__val = false; \
else { \
struct kvm_steal_time *src; \
src = &per_cpu(steal_time, cpu); \
__val = !!(READ_ONCE(src->preempted) & KVM_VCPU_PREEMPTED); \
} \
__val; \
})
#endif /* CONFIG_PARAVIRT */
#include <asm-generic/qspinlock.h>
#endif // _ASM_LOONGARCH_QSPINLOCK_H
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