Re: [PATCH kernel] KVM: PPC: Fix incorrect guest-to-user-translation error handling
From: Michael Ellerman <hidden>
Date: 2019-09-02 03:10:59
On Mon, 2019-08-26 at 04:55:20 UTC, Alexey Kardashevskiy wrote:
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: 121f80ba68f1 ("KVM: PPC: VFIO: Add in-kernel acceleration for VFIO")
Signed-off-by: Alexey Kardashevskiy <redacted>Applied to powerpc topic/ppc-kvm, thanks. https://git.kernel.org/powerpc/c/4f916593be9da38c5cf0d3a5c386b57beb70f422 cheers