linux-kernel - [PATCH v3] KVM: vgic: Use wrapper function to lock/unlock all vcpus in kvm_vgic

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Message-ID: <1575081918-11401-1-git-send-email-linmiaohe@huawei.com>
Date:   Sat, 30 Nov 2019 10:45:18 +0800
From:   linmiaohe <linmiaohe@...wei.com>
To:     <maz@...nel.org>, <pbonzini@...hat.com>, <rkrcmar@...hat.com>,
        <james.morse@....com>, <julien.thierry.kdev@...il.com>,
        <suzuki.poulose@....com>, <christoffer.dall@....com>,
        <catalin.marinas@....com>, <eric.auger@...hat.com>,
        <gregkh@...uxfoundation.org>, <will@...nel.org>,
        <andre.przywara@....com>, <tglx@...utronix.de>
CC:     <steven.price@....com>, <linmiaohe@...wei.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <kvmarm@...ts.cs.columbia.edu>, <linux-kernel@...r.kernel.org>,
        <kvm@...r.kernel.org>
Subject: [PATCH v3] KVM: vgic: Use wrapper function to lock/unlock all vcpus in kvm_vgic_create()

From: Miaohe Lin <linmiaohe@...wei.com>

Use wrapper function lock_all_vcpus()/unlock_all_vcpus()
in kvm_vgic_create() to remove duplicated code dealing
with locking and unlocking all vcpus in a vm.

Reviewed-by: Eric Auger <eric.auger@...hat.com>
Reviewed-by: Steven Price <steven.price@....com>
Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
---
-v2:
	Fix some spelling mistake in patch title and commit log.
-v3:
	Remove the comment that no longer makes sense.
---
 virt/kvm/arm/vgic/vgic-init.c | 19 ++++---------------
 1 file changed, 4 insertions(+), 15 deletions(-)

diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
index b3c5de48064c..22ff73ecac80 100644
--- a/virt/kvm/arm/vgic/vgic-init.c
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -70,7 +70,7 @@ void kvm_vgic_early_init(struct kvm *kvm)
  */
 int kvm_vgic_create(struct kvm *kvm, u32 type)
 {
-	int i, vcpu_lock_idx = -1, ret;
+	int i, ret;
 	struct kvm_vcpu *vcpu;
 
 	if (irqchip_in_kernel(kvm))
@@ -86,17 +86,9 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
 		!kvm_vgic_global_state.can_emulate_gicv2)
 		return -ENODEV;
 
-	/*
-	 * Any time a vcpu is run, vcpu_load is called which tries to grab the
-	 * vcpu->mutex.  By grabbing the vcpu->mutex of all VCPUs we ensure
-	 * that no other VCPUs are run while we create the vgic.
-	 */
 	ret = -EBUSY;
-	kvm_for_each_vcpu(i, vcpu, kvm) {
-		if (!mutex_trylock(&vcpu->mutex))
-			goto out_unlock;
-		vcpu_lock_idx = i;
-	}
+	if (!lock_all_vcpus(kvm))
+		return ret;
 
 	kvm_for_each_vcpu(i, vcpu, kvm) {
 		if (vcpu->arch.has_run_once)
@@ -125,10 +117,7 @@ int kvm_vgic_create(struct kvm *kvm, u32 type)
 		INIT_LIST_HEAD(&kvm->arch.vgic.rd_regions);
 
 out_unlock:
-	for (; vcpu_lock_idx >= 0; vcpu_lock_idx--) {
-		vcpu = kvm_get_vcpu(kvm, vcpu_lock_idx);
-		mutex_unlock(&vcpu->mutex);
-	}
+	unlock_all_vcpus(kvm);
 	return ret;
 }
 
-- 
2.19.1