KVM: PPC: Book3S: Fix incorrect guest-to-user-translation error handling
commit06ab420a84f0955360dca6c34faf2658d8cff1ce
authorAlexey Kardashevskiy <aik@ozlabs.ru>
Tue, 3 Sep 2019 20:16:27 +0000 (3 16:16 -0400)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Fri, 6 Sep 2019 08:21:00 +0000 (6 10:21 +0200)
treeb00d0b37bfd349077e91712dd70e3cd90a9ddb95
parentd5054c17d9fe31596e4e7a6c008e9361f6e0f776
KVM: PPC: Book3S: Fix incorrect guest-to-user-translation error handling

[ 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
arch/powerpc/kvm/book3s_64_vio_hv.c