diff options
| author | Marcelo Tosatti <mtosatti@redhat.com> | 2009-09-18 17:29:26 -0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-10-05 09:32:25 -0700 |
| commit | 7b05aacb73a87411552cf83ab0a0bf519d47ef2f (patch) | |
| tree | 25db0754ba5703ef3d1164b386991a3fe4119dc4 /arch | |
| parent | 1cb6728f666f55ecfcf79a9713c6f2b23d1b2925 (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>
Diffstat (limited to 'arch')
| -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 a5cdb35af510..e74574e32f1c 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2713,12 +2713,14 @@ 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 |