From 6ce5a090a9a0ea4266a2cad058c69e2f27201e11 Mon Sep 17 00:00:00 2001
From: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Date: Mon, 15 Mar 2010 22:13:30 +0900
Subject: [PATCH] KVM: coalesced_mmio: fix kvm_coalesced_mmio_init()'s error
 handling

kvm_coalesced_mmio_init() keeps to hold the addresses of a coalesced
mmio ring page and dev even after it has freed them.

Also, if this function fails, though it might be rare, it seems to be
suggesting the system's serious state: so we'd better stop the works
following the kvm_creat_vm().

This patch clears these problems.

  We move the coalesced mmio's initialization out of kvm_create_vm().
  This seems to be natural because it includes a registration which
  can be done only when vm is successfully created.

Signed-off-by: Takuya Yoshikawa <yoshikawa.takuya@oss.ntt.co.jp>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
---
 virt/kvm/coalesced_mmio.c |  2 ++
 virt/kvm/kvm_main.c       | 12 ++++++++----
 2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c
index b66001f8754c8..53850177163fb 100644
--- a/virt/kvm/coalesced_mmio.c
+++ b/virt/kvm/coalesced_mmio.c
@@ -120,8 +120,10 @@ int kvm_coalesced_mmio_init(struct kvm *kvm)
 	return ret;
 
 out_free_dev:
+	kvm->coalesced_mmio_dev = NULL;
 	kfree(dev);
 out_free_page:
+	kvm->coalesced_mmio_ring = NULL;
 	__free_page(page);
 out_err:
 	return ret;
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 0db6dfcc84202..55a5d48044992 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -422,9 +422,6 @@ static struct kvm *kvm_create_vm(void)
 	spin_lock(&kvm_lock);
 	list_add(&kvm->vm_list, &vm_list);
 	spin_unlock(&kvm_lock);
-#ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
-	kvm_coalesced_mmio_init(kvm);
-#endif
 out:
 	return kvm;
 
@@ -1753,12 +1750,19 @@ static struct file_operations kvm_vm_fops = {
 
 static int kvm_dev_ioctl_create_vm(void)
 {
-	int fd;
+	int fd, r;
 	struct kvm *kvm;
 
 	kvm = kvm_create_vm();
 	if (IS_ERR(kvm))
 		return PTR_ERR(kvm);
+#ifdef KVM_COALESCED_MMIO_PAGE_OFFSET
+	r = kvm_coalesced_mmio_init(kvm);
+	if (r < 0) {
+		kvm_put_kvm(kvm);
+		return r;
+	}
+#endif
 	fd = anon_inode_getfd("kvm-vm", &kvm_vm_fops, kvm, O_RDWR);
 	if (fd < 0)
 		kvm_put_kvm(kvm);
-- 
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