[PATCH] kvm: fix GFP_KERNEL allocation in atomic section in kvm_dev_ioctl_create_vcpu()

fix an GFP_KERNEL allocation in atomic section: kvm_dev_ioctl_create_vcpu()
called kvm_mmu_init(), which calls alloc_pages(), while holding the vcpu.

The fix is to set up the MMU state in two phases: kvm_mmu_create() and
kvm_mmu_setup().

(NOTE: free_vcpus does an kvm_mmu_destroy() call so there's no need for any
extra teardown branch on allocation/init failure here.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Cc: Avi Kivity <avi@qumranet.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 6 insertions, 4 deletions

diff --git a/drivers/kvm/kvm_main.c b/drivers/kvm/kvm_main.c
index 973544553cba..ce7fe640f18d 100644
--- a/drivers/kvm/kvm_main.c
+++ b/drivers/kvm/kvm_main.c
@@ -522,12 +522,14 @@ static int kvm_dev_ioctl_create_vcpu(struct kvm *kvm, int n)
         if (r < 0)
                 goto out_free_vcpus;
 
-        kvm_arch_ops->vcpu_load(vcpu);
+        r = kvm_mmu_create(vcpu);
+        if (r < 0)
+                goto out_free_vcpus;
 
-        r = kvm_arch_ops->vcpu_setup(vcpu);
+        kvm_arch_ops->vcpu_load(vcpu);
+        r = kvm_mmu_setup(vcpu);
         if (r >= 0)
-                r = kvm_mmu_init(vcpu);
-
+                r = kvm_arch_ops->vcpu_setup(vcpu);
         vcpu_put(vcpu);
 
         if (r < 0)