diff options
| author | Alexander Graf <agraf@suse.de> | 2010-08-02 21:24:48 +0200 |
|---|---|---|
| committer | Avi Kivity <avi@redhat.com> | 2010-10-24 10:52:06 +0200 |
| commit | e7c1d14e3bf40b87e6a3f68964b36dbb2c875c0f (patch) | |
| tree | 2dd5d3e6f3ac88f532b790cc4215d349c8b95790 /arch/powerpc | |
| parent | 2e602847d9c2d6b487bda62bbbe550db40ca912f (diff) | |
KVM: PPC: Make invalidation code more reliable
There is a race condition in the pte invalidation code path where we can't
be sure if a pte was invalidated already. So let's move the spin lock around
to get rid of the race.
Signed-off-by: Alexander Graf <agraf@suse.de>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kvm/book3s_mmu_hpte.c | 14 |
1 files changed, 8 insertions, 6 deletions
diff --git a/arch/powerpc/kvm/book3s_mmu_hpte.c b/arch/powerpc/kvm/book3s_mmu_hpte.c index bd6a7676d0c..79751d8dd13 100644 --- a/arch/powerpc/kvm/book3s_mmu_hpte.c +++ b/arch/powerpc/kvm/book3s_mmu_hpte.c @@ -92,10 +92,6 @@ static void free_pte_rcu(struct rcu_head *head) static void invalidate_pte(struct kvm_vcpu *vcpu, struct hpte_cache *pte) { - /* pte already invalidated? */ - if (hlist_unhashed(&pte->list_pte)) - return; - trace_kvm_book3s_mmu_invalidate(pte); /* Different for 32 and 64 bit */ @@ -103,18 +99,24 @@ static void invalidate_pte(struct kvm_vcpu *vcpu, struct hpte_cache *pte) spin_lock(&vcpu->arch.mmu_lock); + /* pte already invalidated in between? */ + if (hlist_unhashed(&pte->list_pte)) { + spin_unlock(&vcpu->arch.mmu_lock); + return; + } + hlist_del_init_rcu(&pte->list_pte); hlist_del_init_rcu(&pte->list_pte_long); hlist_del_init_rcu(&pte->list_vpte); hlist_del_init_rcu(&pte->list_vpte_long); - spin_unlock(&vcpu->arch.mmu_lock); - if (pte->pte.may_write) kvm_release_pfn_dirty(pte->pfn); else kvm_release_pfn_clean(pte->pfn); + spin_unlock(&vcpu->arch.mmu_lock); + vcpu->arch.hpte_cache_count--; call_rcu(&pte->rcu_head, free_pte_rcu); } |