[PATCH v3 2/3] kvm: Allocate memslots and buses before calling kvm_arch_init_vm

From: Jim Mattson <jmattson@google.com>
To: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <sean.j.christopherson@intel.com>,
	John Sperbeck <jsperbeck@google.com>,
	Junaid Shahid <junaids@google.com>
Cc: Jim Mattson <jmattson@google.com>
Subject: [PATCH v3 2/3] kvm: Allocate memslots and buses before calling kvm_arch_init_vm
Date: Thu, 24 Oct 2019 16:03:26 -0700	[thread overview]
Message-ID: <20191024230327.140935-3-jmattson@google.com> (raw)
In-Reply-To: <20191024230327.140935-1-jmattson@google.com>

This reorganization will allow us to call kvm_arch_destroy_vm in the
event that kvm_create_vm fails after calling kvm_arch_init_vm.

Suggested-by: Junaid Shahid <junaids@google.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
Reviewed-by: Junaid Shahid <junaids@google.com>
---
 virt/kvm/kvm_main.c | 40 +++++++++++++++++++++-------------------
 1 file changed, 21 insertions(+), 19 deletions(-)

diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 525e0dbc623f9..77819597d7e8e 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -627,8 +627,9 @@ static int kvm_create_vm_debugfs(struct kvm *kvm, int fd)
 
 static struct kvm *kvm_create_vm(unsigned long type)
 {
-	int r, i;
 	struct kvm *kvm = kvm_arch_alloc_vm();
+	int r = -ENOMEM;
+	int i;
 
 	if (!kvm)
 		return ERR_PTR(-ENOMEM);
@@ -642,6 +643,25 @@ static struct kvm *kvm_create_vm(unsigned long type)
 	mutex_init(&kvm->slots_lock);
 	INIT_LIST_HEAD(&kvm->devices);
 
+	BUILD_BUG_ON(KVM_MEM_SLOTS_NUM > SHRT_MAX);
+
+	for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
+		struct kvm_memslots *slots = kvm_alloc_memslots();
+
+		if (!slots)
+			goto out_err_no_disable;
+		/* Generations must be different for each address space. */
+		slots->generation = i;
+		rcu_assign_pointer(kvm->memslots[i], slots);
+	}
+
+	for (i = 0; i < KVM_NR_BUSES; i++) {
+		rcu_assign_pointer(kvm->buses[i],
+			kzalloc(sizeof(struct kvm_io_bus), GFP_KERNEL_ACCOUNT));
+		if (!kvm->buses[i])
+			goto out_err_no_disable;
+	}
+
 	r = kvm_arch_init_vm(kvm, type);
 	if (r)
 		goto out_err_no_disable;
@@ -654,28 +674,10 @@ static struct kvm *kvm_create_vm(unsigned long type)
 	INIT_HLIST_HEAD(&kvm->irq_ack_notifier_list);
 #endif
 
-	BUILD_BUG_ON(KVM_MEM_SLOTS_NUM > SHRT_MAX);
-
-	r = -ENOMEM;
-	for (i = 0; i < KVM_ADDRESS_SPACE_NUM; i++) {
-		struct kvm_memslots *slots = kvm_alloc_memslots();
-		if (!slots)
-			goto out_err_no_srcu;
-		/* Generations must be different for each address space. */
-		slots->generation = i;
-		rcu_assign_pointer(kvm->memslots[i], slots);
-	}
-
 	if (init_srcu_struct(&kvm->srcu))
 		goto out_err_no_srcu;
 	if (init_srcu_struct(&kvm->irq_srcu))
 		goto out_err_no_irq_srcu;
-	for (i = 0; i < KVM_NR_BUSES; i++) {
-		rcu_assign_pointer(kvm->buses[i],
-			kzalloc(sizeof(struct kvm_io_bus), GFP_KERNEL_ACCOUNT));
-		if (!kvm->buses[i])
-			goto out_err;
-	}
 
 	r = kvm_init_mmu_notifier(kvm);
 	if (r)
-- 
2.24.0.rc0.303.g954a862665-goog

