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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 with TCEs which can cause early exit from the handler and
leave 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.

Fixes: 121f80ba68 ("KVM: PPC: VFIO: Add in-kernel acceleration for VFIO")
Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20190826045520.92153-1-aik@ozlabs.ru
alistair/sunxi64-5.4-dsi
Alexey Kardashevskiy 2019-08-26 14:55:20 +10:00 committed by Michael Ellerman
parent da15c03b04
commit 4f916593be
2 changed files with 8 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
arch/powerpc/kvm/book3s_64_vio.c
View File

@ -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,

6
arch/powerpc/kvm/book3s_64_vio_hv.c
View File

@ -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,