linux-kernel - [ 18/56] KVM: Clean up error handling during VCPU creation

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Date:	Tue,  2 Apr 2013 15:49:45 -0700
From:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:	linux-kernel@...r.kernel.org
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	stable@...r.kernel.org, Jan Kiszka <jan.kiszka@...mens.com>,
	Avi Kivity <avi@...hat.com>, Jiri Slaby <jslaby@...e.cz>
Subject: [ 18/56] KVM: Clean up error handling during VCPU creation

3.0-stable review patch.  If anyone has any objections, please let me know.

------------------


From: Jan Kiszka <jan.kiszka@...mens.com>

commit d780592b99d7d8a5ff905f6bacca519d4a342c76 upstream.

So far kvm_arch_vcpu_setup is responsible for freeing the vcpu struct if
it fails. Move this confusing resonsibility back into the hands of
kvm_vm_ioctl_create_vcpu. Only kvm_arch_vcpu_setup of x86 is affected,
all other archs cannot fail.

Signed-off-by: Jan Kiszka <jan.kiszka@...mens.com>
Signed-off-by: Avi Kivity <avi@...hat.com>
Signed-off-by: Jiri Slaby <jslaby@...e.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/x86/kvm/x86.c  |    5 -----
 virt/kvm/kvm_main.c |   11 ++++++-----
 2 files changed, 6 insertions(+), 10 deletions(-)

--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -6116,12 +6116,7 @@ int kvm_arch_vcpu_setup(struct kvm_vcpu
 	if (r == 0)
 		r = kvm_mmu_setup(vcpu);
 	vcpu_put(vcpu);
-	if (r < 0)
-		goto free_vcpu;
 
-	return 0;
-free_vcpu:
-	kvm_x86_ops->vcpu_free(vcpu);
 	return r;
 }
 
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -1616,18 +1616,18 @@ static int kvm_vm_ioctl_create_vcpu(stru
 
 	r = kvm_arch_vcpu_setup(vcpu);
 	if (r)
-		return r;
+		goto vcpu_destroy;
 
 	mutex_lock(&kvm->lock);
 	if (atomic_read(&kvm->online_vcpus) == KVM_MAX_VCPUS) {
 		r = -EINVAL;
-		goto vcpu_destroy;
+		goto unlock_vcpu_destroy;
 	}
 
 	kvm_for_each_vcpu(r, v, kvm)
 		if (v->vcpu_id == id) {
 			r = -EEXIST;
-			goto vcpu_destroy;
+			goto unlock_vcpu_destroy;
 		}
 
 	BUG_ON(kvm->vcpus[atomic_read(&kvm->online_vcpus)]);
@@ -1637,7 +1637,7 @@ static int kvm_vm_ioctl_create_vcpu(stru
 	r = create_vcpu_fd(vcpu);
 	if (r < 0) {
 		kvm_put_kvm(kvm);
-		goto vcpu_destroy;
+		goto unlock_vcpu_destroy;
 	}
 
 	kvm->vcpus[atomic_read(&kvm->online_vcpus)] = vcpu;
@@ -1651,8 +1651,9 @@ static int kvm_vm_ioctl_create_vcpu(stru
 	mutex_unlock(&kvm->lock);
 	return r;
 
-vcpu_destroy:
+unlock_vcpu_destroy:
 	mutex_unlock(&kvm->lock);
+vcpu_destroy:
 	kvm_arch_vcpu_destroy(vcpu);
 	return r;
 }


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