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authorAlexey Kardashevskiy <aik@ozlabs.ru>2019-08-26 14:55:20 +1000
committerPaul Mackerras <paulus@ozlabs.org>2019-08-27 10:59:30 +1000
commitddfd151f3def9258397fcde7a372205a2d661903 (patch)
tree623fd8857f5aa67f70b23be33b76e07bcf5f8a42 /arch
parente4427372398c31f57450565de277f861a4db5b3b (diff)
downloadlwn-ddfd151f3def9258397fcde7a372205a2d661903.tar.gz
lwn-ddfd151f3def9258397fcde7a372205a2d661903.zip
KVM: PPC: Book3S: Fix incorrect guest-to-user-translation error handling
H_PUT_TCE_INDIRECT handlers receive a page with up to 512 TCEs from a guest. Although we verify correctness of TCEs before we do anything with the existing tables, there is a small window when a check in kvmppc_tce_validate might pass and right after that the guest alters the page of TCEs, causing an early exit from the handler and leaving srcu_read_lock(&vcpu->kvm->srcu) (virtual mode) or lock_rmap(rmap) (real mode) locked. This fixes the bug by jumping to the common exit code with an appropriate unlock. Cc: stable@vger.kernel.org # v4.11+ Fixes: 121f80ba68f1 ("KVM: PPC: VFIO: Add in-kernel acceleration for VFIO") Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru> Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/kvm/book3s_64_vio.c6
-rw-r--r--arch/powerpc/kvm/book3s_64_vio_hv.c6
2 files changed, 8 insertions, 4 deletions
diff --git a/arch/powerpc/kvm/book3s_64_vio.c b/arch/powerpc/kvm/book3s_64_vio.c
index e99a14798ab0..c4b606fe73eb 100644
--- a/arch/powerpc/kvm/book3s_64_vio.c
+++ b/arch/powerpc/kvm/book3s_64_vio.c
@@ -660,8 +660,10 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
}
tce = be64_to_cpu(tce);
- if (kvmppc_tce_to_ua(vcpu->kvm, tce, &ua))
- return H_PARAMETER;
+ if (kvmppc_tce_to_ua(vcpu->kvm, tce, &ua)) {
+ ret = H_PARAMETER;
+ goto unlock_exit;
+ }
list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
ret = kvmppc_tce_iommu_map(vcpu->kvm, stt,
diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c
index f50bbeedfc66..b4f20f13b860 100644
--- a/arch/powerpc/kvm/book3s_64_vio_hv.c
+++ b/arch/powerpc/kvm/book3s_64_vio_hv.c
@@ -556,8 +556,10 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu,
unsigned long tce = be64_to_cpu(((u64 *)tces)[i]);
ua = 0;
- if (kvmppc_rm_tce_to_ua(vcpu->kvm, tce, &ua, NULL))
- return H_PARAMETER;
+ if (kvmppc_rm_tce_to_ua(vcpu->kvm, tce, &ua, NULL)) {
+ ret = H_PARAMETER;
+ goto unlock_exit;
+ }
list_for_each_entry_lockless(stit, &stt->iommu_tables, next) {
ret = kvmppc_rm_tce_iommu_map(vcpu->kvm, stt,