[ Upstream commit ddfd151f3def9258397fcde7a372205a2d661903 ]
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 Signed-off-by: Sasha Levin sashal@kernel.org --- arch/powerpc/kvm/book3s_64_vio.c | 6 ++++-- arch/powerpc/kvm/book3s_64_vio_hv.c | 6 ++++-- 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 e14cec6bc3398..2c6cce8e7cfd0 100644 --- a/arch/powerpc/kvm/book3s_64_vio.c +++ b/arch/powerpc/kvm/book3s_64_vio.c @@ -566,8 +566,10 @@ long kvmppc_h_put_tce_indirect(struct kvm_vcpu *vcpu,
if (kvmppc_gpa_to_ua(vcpu->kvm, tce & ~(TCE_PCI_READ | TCE_PCI_WRITE), - &ua, NULL)) - return H_PARAMETER; + &ua, NULL)) { + ret = H_PARAMETER; + goto unlock_exit; + }
list_for_each_entry_lockless(stit, &stt->iommu_tables, next) { ret = kvmppc_tce_iommu_map(vcpu->kvm, diff --git a/arch/powerpc/kvm/book3s_64_vio_hv.c b/arch/powerpc/kvm/book3s_64_vio_hv.c index 648cf6c013489..23d6d1592f117 100644 --- a/arch/powerpc/kvm/book3s_64_vio_hv.c +++ b/arch/powerpc/kvm/book3s_64_vio_hv.c @@ -475,8 +475,10 @@ long kvmppc_rm_h_put_tce_indirect(struct kvm_vcpu *vcpu, ua = 0; if (kvmppc_gpa_to_ua(vcpu->kvm, tce & ~(TCE_PCI_READ | TCE_PCI_WRITE), - &ua, NULL)) - return H_PARAMETER; + &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,