KVM: MMU: Move kvm_free_some_pages() into critical section

If some other cpu steals mmu pages between our check and an attempt to
allocate, we can run out of mmu pages.  Fix by moving the check into the
same critical section as the allocation.

Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/arch/x86/kvm/paging_tmpl.h b/arch/x86/kvm/paging_tmpl.h
index a35b83a4fef2..349920556be3 100644
--- a/arch/x86/kvm/paging_tmpl.h
+++ b/arch/x86/kvm/paging_tmpl.h
@@ -402,6 +402,7 @@ static int FNAME(page_fault)(struct kvm_vcpu *vcpu, gva_t addr,
         page = gfn_to_page(vcpu->kvm, walker.gfn);
 
         spin_lock(&vcpu->kvm->mmu_lock);
+        kvm_mmu_free_some_pages(vcpu);
         shadow_pte = FNAME(fetch)(vcpu, addr, &walker, user_fault, write_fault,
                                   &write_pt, page);
         pgprintk("%s: shadow pte %p %llx ptwrite %d\n", __FUNCTION__,