tree d1220ae25501292494c3954e2b45eb1b22afd642
parent a7cfa7ac1236937dac431845596a39ba27364a00
author James Hogan <james.hogan@imgtec.com> 1475874065 +0100
committer James Hogan <james.hogan@imgtec.com> 1486135253 +0000

KVM: MIPS/TLB: Fix off-by-one in TLB invalidate

kvm_mips_host_tlb_inv() uses the TLBP instruction to probe the host TLB
for an entry matching the given guest virtual address, and determines
whether a match was found based on whether CP0_Index > 0. This is
technically incorrect as an index of 0 (with the high bit clear) is a
perfectly valid TLB index.

This is harmless at the moment due to the use of at least 1 wired TLB
entry for the KVM commpage, however we will soon be ridding ourselves of
that particular wired entry so lets fix the condition in case the entry
needing invalidation does land at TLB index 0.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: "Radim Krčmář" <rkrcmar@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: linux-mips@linux-mips.org
Cc: kvm@vger.kernel.org