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LoongArch: KVM: Add paravirt vcpu_is_preempted() support in guest side

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Function vcpu_is_preempted() is used to check whether vCPU is preempted
or not. Here add the implementation with vcpu_is_preempted() when option
CONFIG_PARAVIRT is enabled.

Acked-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Bibo Mao <maobibo@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
This commit is contained in:
Bibo Mao 2026-02-06 09:28:01 +08:00 committed by Huacai Chen
parent 9b486cdd03
commit 872d277a1e
2 changed files with 24 additions and 1 deletions
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4
arch/loongarch/include/asm/qspinlock.h
View File

@ -34,6 +34,10 @@ static inline bool virt_spin_lock(struct qspinlock *lock)
return true;
}
#define vcpu_is_preempted vcpu_is_preempted
bool vcpu_is_preempted(int cpu);
#endif /* CONFIG_PARAVIRT */
#include <asm-generic/qspinlock.h>

21
arch/loongarch/kernel/paravirt.c
View File

@ -12,6 +12,7 @@ static int has_steal_clock;
struct static_key paravirt_steal_enabled;
struct static_key paravirt_steal_rq_enabled;
static DEFINE_PER_CPU(struct kvm_steal_time, steal_time) __aligned(64);
static DEFINE_STATIC_KEY_FALSE(virt_preempt_key);
DEFINE_STATIC_KEY_FALSE(virt_spin_lock_key);
static u64 native_steal_clock(int cpu)
@ -267,6 +268,18 @@ static int pv_time_cpu_down_prepare(unsigned int cpu)
return 0;
}
bool vcpu_is_preempted(int cpu)
{
struct kvm_steal_time *src;
if (!static_branch_unlikely(&virt_preempt_key))
return false;
src = &per_cpu(steal_time, cpu);
return !!(src->preempted & KVM_VCPU_PREEMPTED);
}
EXPORT_SYMBOL(vcpu_is_preempted);
#endif
static void pv_cpu_reboot(void *unused)
@ -308,6 +321,9 @@ int __init pv_time_init(void)
pr_err("Failed to install cpu hotplug callbacks\n");
return r;
}
if (kvm_para_has_feature(KVM_FEATURE_PREEMPT))
static_branch_enable(&virt_preempt_key);
#endif
static_call_update(pv_steal_clock, paravt_steal_clock);
@ -318,7 +334,10 @@ int __init pv_time_init(void)
static_key_slow_inc(&paravirt_steal_rq_enabled);
#endif
pr_info("Using paravirt steal-time\n");
if (static_key_enabled(&virt_preempt_key))
pr_info("Using paravirt steal-time with preempt enabled\n");
else
pr_info("Using paravirt steal-time with preempt disabled\n");
return 0;
}