/* 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