linux-kernel - [PATCH 45/45] KVM: Move vcpu->run page allocation out of kvm_vcpu

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Date:   Mon, 21 Oct 2019 18:59:25 -0700
From:   Sean Christopherson <sean.j.christopherson@...el.com>
To:     Marc Zyngier <maz@...nel.org>, James Hogan <jhogan@...nel.org>,
        Paul Mackerras <paulus@...abs.org>,
        Christian Borntraeger <borntraeger@...ibm.com>,
        Janosch Frank <frankja@...ux.ibm.com>,
        Paolo Bonzini <pbonzini@...hat.com>,
        Radim Krčmář <rkrcmar@...hat.com>
Cc:     James Morse <james.morse@....com>,
        Julien Thierry <julien.thierry.kdev@...il.com>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        David Hildenbrand <david@...hat.com>,
        Cornelia Huck <cohuck@...hat.com>,
        Sean Christopherson <sean.j.christopherson@...el.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
        linux-mips@...r.kernel.org, kvm-ppc@...r.kernel.org,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 45/45] KVM: Move vcpu->run page allocation out of kvm_vcpu_init()

Open code the allocation and freeing of the vcpu->run page in
kvm_vm_ioctl_create_vcpu() and kvm_vcpu_destroy() respectively.  Doing
so allows kvm_vcpu_init() to be a pure init function and eliminates
kvm_vcpu_uninit() entirely.

Signed-off-by: Sean Christopherson <sean.j.christopherson@...el.com>
---
 virt/kvm/kvm_main.c | 34 +++++++++++++---------------------
 1 file changed, 13 insertions(+), 21 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index c079b22032fa..e532c6e606c0 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -287,10 +287,8 @@ void kvm_reload_remote_mmus(struct kvm *kvm)
 	kvm_make_all_cpus_request(kvm, KVM_REQ_MMU_RELOAD);
 }
 
-static int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
+static void kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
 {
-	struct page *page;
-
 	mutex_init(&vcpu->mutex);
 	vcpu->cpu = -1;
 	vcpu->kvm = kvm;
@@ -302,23 +300,11 @@ static int kvm_vcpu_init(struct kvm_vcpu *vcpu, struct kvm *kvm, unsigned id)
 	vcpu->pre_pcpu = -1;
 	INIT_LIST_HEAD(&vcpu->blocked_vcpu_list);
 
-	page = alloc_page(GFP_KERNEL | __GFP_ZERO);
-	if (!page)
-		return -ENOMEM;
-	vcpu->run = page_address(page);
-
 	kvm_vcpu_set_in_spin_loop(vcpu, false);
 	kvm_vcpu_set_dy_eligible(vcpu, false);
 	vcpu->preempted = false;
 	vcpu->ready = false;
 	preempt_notifier_init(&vcpu->preempt_notifier, &kvm_preempt_ops);
-
-	return 0;
-}
-
-static void kvm_vcpu_uninit(struct kvm_vcpu *vcpu)
-{
-	free_page((unsigned long)vcpu->run);
 }
 
 void kvm_vcpu_destroy(struct kvm_vcpu *vcpu)
@@ -332,7 +318,7 @@ void kvm_vcpu_destroy(struct kvm_vcpu *vcpu)
 	 */
 	put_pid(rcu_dereference_protected(vcpu->pid, 1));
 
-	kvm_vcpu_uninit(vcpu);
+	free_page((unsigned long)vcpu->run);
 	kmem_cache_free(kvm_vcpu_cache, vcpu);
 }
 EXPORT_SYMBOL_GPL(kvm_vcpu_destroy);
@@ -2636,6 +2622,7 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
 {
 	int r;
 	struct kvm_vcpu *vcpu;
+	struct page *page;
 
 	if (id >= KVM_MAX_VCPU_ID)
 		return -EINVAL;
@@ -2659,13 +2646,18 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
 		goto vcpu_decrement;
 	}
 
-	r = kvm_vcpu_init(vcpu, kvm, id);
-	if (r)
+	page = alloc_page(GFP_KERNEL | __GFP_ZERO);
+	if (!page) {
+		r = -ENOMEM;
 		goto vcpu_free;
+	}
+	vcpu->run = page_address(page);
+
+	kvm_vcpu_init(vcpu, kvm, id);
 
 	r = kvm_arch_vcpu_create(vcpu);
 	if (r)
-		goto vcpu_uninit;
+		goto vcpu_free_run_page;
 
 	kvm_create_vcpu_debugfs(vcpu);
 
@@ -2702,8 +2694,8 @@ static int kvm_vm_ioctl_create_vcpu(struct kvm *kvm, u32 id)
 	mutex_unlock(&kvm->lock);
 	debugfs_remove_recursive(vcpu->debugfs_dentry);
 	kvm_arch_vcpu_destroy(vcpu);
-vcpu_uninit:
-	kvm_vcpu_uninit(vcpu);
+vcpu_free_run_page:
+	free_page((unsigned long)vcpu->run);
 vcpu_free:
 	kmem_cache_free(kvm_vcpu_cache, vcpu);
 vcpu_decrement:
-- 
2.22.0