diff options
| author | Marcelo Tosatti <mtosatti@redhat.com> | 2009-09-18 20:08:03 -0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-10-05 08:27:55 -0700 |
| commit | 005270f475352a33f852cbfb9f49945d7953ea61 (patch) | |
| tree | 65cbd24b70a456862737d21e3dec80cff7245c7d | |
| parent | 3f1538a4dd00709b1c7f6a4fda31cf5daf4b3e46 (diff) | |
KVM: MMU: fix missing locking in alloc_mmu_pages
(cherry picked from commit 6a1ac77110ee3e8d8dfdef8442f3b30b3d83e6a2)
n_requested_mmu_pages/n_free_mmu_pages are used by
kvm_mmu_change_mmu_pages to calculate the number of pages to zap.
alloc_mmu_pages, called from the vcpu initialization path, modifies this
variables without proper locking, which can result in a negative value
in kvm_mmu_change_mmu_pages (say, with cpu hotplug).
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | arch/x86/kvm/mmu.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index a1c5e34e15fd..b70e0ad1094a 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2692,12 +2692,14 @@ static int alloc_mmu_pages(struct kvm_vcpu *vcpu) ASSERT(vcpu); + spin_lock(&vcpu->kvm->mmu_lock); if (vcpu->kvm->arch.n_requested_mmu_pages) vcpu->kvm->arch.n_free_mmu_pages = vcpu->kvm->arch.n_requested_mmu_pages; else vcpu->kvm->arch.n_free_mmu_pages = vcpu->kvm->arch.n_alloc_mmu_pages; + spin_unlock(&vcpu->kvm->mmu_lock); /* * When emulating 32-bit mode, cr3 is only 32 bits even on x86_64. * Therefore we need to allocate shadow page tables in the first |