summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorAlexander Graf <agraf@suse.de>2010-08-02 21:24:48 +0200
committerAvi Kivity <avi@redhat.com>2010-10-24 10:52:06 +0200
commite7c1d14e3bf40b87e6a3f68964b36dbb2c875c0f (patch)
tree2dd5d3e6f3ac88f532b790cc4215d349c8b95790
parent2e602847d9c2d6b487bda62bbbe550db40ca912f (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>
-rw-r--r--arch/powerpc/kvm/book3s_mmu_hpte.c14
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 bd6a7676d0c8..79751d8dd131 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);
}