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Subject[PATCH 2/2] KVM: arm/arm64: vgic: no need to call spin_lock_irqsave/restore when irq is disabled
Date
Because kvm_vgic_sync_hwstate currently is definitly in the context
which irq is disabled (local_irq_disable/enable). There is no need to
call spin_lock_irqsave/restore in vgic_fold_lr_state and vgic_prune_ap_list

This patch replace them with the spin_lock/unlock no irq version

Signed-off-by: Jia He <jia.he@hxt-semitech.com>
---
virt/kvm/arm/vgic/vgic-v2.c | 7 ++++---
virt/kvm/arm/vgic/vgic-v3.c | 7 ++++---
virt/kvm/arm/vgic/vgic.c | 13 +++++++------
3 files changed, 15 insertions(+), 12 deletions(-)

diff --git a/virt/kvm/arm/vgic/vgic-v2.c b/virt/kvm/arm/vgic/vgic-v2.c
index a5f2e44..487f5f2 100644
--- a/virt/kvm/arm/vgic/vgic-v2.c
+++ b/virt/kvm/arm/vgic/vgic-v2.c
@@ -62,7 +62,8 @@ void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu)
struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
struct vgic_v2_cpu_if *cpuif = &vgic_cpu->vgic_v2;
int lr;
- unsigned long flags;
+
+ DEBUG_SPINLOCK_BUG_ON(!irqs_disabled());

cpuif->vgic_hcr &= ~GICH_HCR_UIE;

@@ -83,7 +84,7 @@ void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu)

irq = vgic_get_irq(vcpu->kvm, vcpu, intid);

- spin_lock_irqsave(&irq->irq_lock, flags);
+ spin_lock(&irq->irq_lock);

/* Always preserve the active bit */
irq->active = !!(val & GICH_LR_ACTIVE_BIT);
@@ -126,7 +127,7 @@ void vgic_v2_fold_lr_state(struct kvm_vcpu *vcpu)
vgic_irq_set_phys_active(irq, false);
}

- spin_unlock_irqrestore(&irq->irq_lock, flags);
+ spin_unlock(&irq->irq_lock);
vgic_put_irq(vcpu->kvm, irq);
}

diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
index cdce653..b66b513 100644
--- a/virt/kvm/arm/vgic/vgic-v3.c
+++ b/virt/kvm/arm/vgic/vgic-v3.c
@@ -46,7 +46,8 @@ void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu)
struct vgic_v3_cpu_if *cpuif = &vgic_cpu->vgic_v3;
u32 model = vcpu->kvm->arch.vgic.vgic_model;
int lr;
- unsigned long flags;
+
+ DEBUG_SPINLOCK_BUG_ON(!irqs_disabled());

cpuif->vgic_hcr &= ~ICH_HCR_UIE;

@@ -75,7 +76,7 @@ void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu)
if (!irq) /* An LPI could have been unmapped. */
continue;

- spin_lock_irqsave(&irq->irq_lock, flags);
+ spin_lock(&irq->irq_lock);

/* Always preserve the active bit */
irq->active = !!(val & ICH_LR_ACTIVE_BIT);
@@ -118,7 +119,7 @@ void vgic_v3_fold_lr_state(struct kvm_vcpu *vcpu)
vgic_irq_set_phys_active(irq, false);
}

- spin_unlock_irqrestore(&irq->irq_lock, flags);
+ spin_unlock(&irq->irq_lock);
vgic_put_irq(vcpu->kvm, irq);
}

diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
index c22cea6..7cfdfbc 100644
--- a/virt/kvm/arm/vgic/vgic.c
+++ b/virt/kvm/arm/vgic/vgic.c
@@ -593,10 +593,11 @@ static void vgic_prune_ap_list(struct kvm_vcpu *vcpu)
{
struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
struct vgic_irq *irq, *tmp;
- unsigned long flags;
+
+ DEBUG_SPINLOCK_BUG_ON(!irqs_disabled());

retry:
- spin_lock_irqsave(&vgic_cpu->ap_list_lock, flags);
+ spin_lock(&vgic_cpu->ap_list_lock);

list_for_each_entry_safe(irq, tmp, &vgic_cpu->ap_list_head, ap_list) {
struct kvm_vcpu *target_vcpu, *vcpuA, *vcpuB;
@@ -637,7 +638,7 @@ static void vgic_prune_ap_list(struct kvm_vcpu *vcpu)
/* This interrupt looks like it has to be migrated. */

spin_unlock(&irq->irq_lock);
- spin_unlock_irqrestore(&vgic_cpu->ap_list_lock, flags);
+ spin_unlock(&vgic_cpu->ap_list_lock);

/*
* Ensure locking order by always locking the smallest
@@ -651,7 +652,7 @@ static void vgic_prune_ap_list(struct kvm_vcpu *vcpu)
vcpuB = vcpu;
}

- spin_lock_irqsave(&vcpuA->arch.vgic_cpu.ap_list_lock, flags);
+ spin_lock(&vcpuA->arch.vgic_cpu.ap_list_lock);
spin_lock_nested(&vcpuB->arch.vgic_cpu.ap_list_lock,
SINGLE_DEPTH_NESTING);
spin_lock(&irq->irq_lock);
@@ -676,7 +677,7 @@ static void vgic_prune_ap_list(struct kvm_vcpu *vcpu)

spin_unlock(&irq->irq_lock);
spin_unlock(&vcpuB->arch.vgic_cpu.ap_list_lock);
- spin_unlock_irqrestore(&vcpuA->arch.vgic_cpu.ap_list_lock, flags);
+ spin_unlock(&vcpuA->arch.vgic_cpu.ap_list_lock);

if (target_vcpu_needs_kick) {
kvm_make_request(KVM_REQ_IRQ_PENDING, target_vcpu);
@@ -686,7 +687,7 @@ static void vgic_prune_ap_list(struct kvm_vcpu *vcpu)
goto retry;
}

- spin_unlock_irqrestore(&vgic_cpu->ap_list_lock, flags);
+ spin_unlock(&vgic_cpu->ap_list_lock);
}

static inline void vgic_fold_lr_state(struct kvm_vcpu *vcpu)
--
1.8.3.1
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