queue-4.19/powerpc-fsl-flush-branch-predictor-when-entering-kvm.patch

   1 From foo@baz Fri Mar 29 16:04:51 CET 2019
   2 From: Michael Ellerman <mpe@ellerman.id.au>
   3 Date: Fri, 29 Mar 2019 22:26:15 +1100
   4 Subject: powerpc/fsl: Flush branch predictor when entering KVM
   5 To: stable@vger.kernel.org, gregkh@linuxfoundation.org
   6 Cc: linuxppc-dev@ozlabs.org, diana.craciun@nxp.com, msuchanek@suse.de, christophe.leroy@c-s.fr
   7 Message-ID: <20190329112620.14489-28-mpe@ellerman.id.au>
   8
   9 From: Diana Craciun <diana.craciun@nxp.com>
  10
  11 commit e7aa61f47b23afbec41031bc47ca8d6cb6516abc upstream.
  12
  13 Switching from the guest to host is another place
  14 where the speculative accesses can be exploited.
  15 Flush the branch predictor when entering KVM.
  16
  17 Signed-off-by: Diana Craciun <diana.craciun@nxp.com>
  18 Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
  19 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  20 ---
  21  arch/powerpc/kvm/bookehv_interrupts.S |    4 ++++
  22  1 file changed, 4 insertions(+)
  23
  24 --- a/arch/powerpc/kvm/bookehv_interrupts.S
  25 +++ b/arch/powerpc/kvm/bookehv_interrupts.S
  26 @@ -75,6 +75,10 @@
  27         PPC_LL  r1, VCPU_HOST_STACK(r4)
  28         PPC_LL  r2, HOST_R2(r1)
  29
  30 +START_BTB_FLUSH_SECTION
  31 +       BTB_FLUSH(r10)
  32 +END_BTB_FLUSH_SECTION
  33 +
  34         mfspr   r10, SPRN_PID
  35         lwz     r8, VCPU_HOST_PID(r4)
  36         PPC_LL  r11, VCPU_SHARED(r4)