We drop the mmu lock between freeing memory and allocating the roots; this allows some other vcpu to sneak in and allocate memory. While the race is benign (resulting only in temporary overallocation, not oom) it is simple and easy to fix by moving the freeing close to the allocation. Signed-off-by: Avi Kivity <avi@xxxxxxxxxx> --- arch/x86/kvm/mmu.c | 5 ++--- 1 files changed, 2 insertions(+), 3 deletions(-) diff --git a/arch/x86/kvm/mmu.c b/arch/x86/kvm/mmu.c index 95bee9d..6857a2f 100644 --- a/arch/x86/kvm/mmu.c +++ b/arch/x86/kvm/mmu.c @@ -2067,6 +2067,7 @@ static int mmu_alloc_roots(struct kvm_vcpu *vcpu) root_gfn = 0; } spin_lock(&vcpu->kvm->mmu_lock); + kvm_mmu_free_some_pages(vcpu->kvm); sp = kvm_mmu_get_page(vcpu, root_gfn, 0, PT64_ROOT_LEVEL, direct, ACC_ALL, NULL); @@ -2097,6 +2098,7 @@ static int mmu_alloc_roots(struct kvm_vcpu *vcpu) root_gfn = i << 30; } spin_lock(&vcpu->kvm->mmu_lock); + kvm_mmu_free_some_pages(vcpu->kvm); sp = kvm_mmu_get_page(vcpu, root_gfn, i << 30, PT32_ROOT_LEVEL, direct, ACC_ALL, NULL); @@ -2470,9 +2472,6 @@ int kvm_mmu_load(struct kvm_vcpu *vcpu) r = mmu_topup_memory_caches(vcpu); if (r) goto out; - spin_lock(&vcpu->kvm->mmu_lock); - kvm_mmu_free_some_pages(vcpu); - spin_unlock(&vcpu->kvm->mmu_lock); r = mmu_alloc_roots(vcpu); spin_lock(&vcpu->kvm->mmu_lock); mmu_sync_roots(vcpu); -- 1.7.0.4 -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
