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  1. 02 Jul, 2019 22 commits
  3. 01 Jul, 2019 15 commits
  5. 25 Jun, 2019 1 commit
    • Nicholas Piggin's avatar
      powerpc/64s/exception: Fix machine check early corrupting AMR · e13e7cd4
      Nicholas Piggin authored 
      The early machine check runs in real mode, so locking is unnecessary.
Worse, the windup does not restore AMR, so this can result in a false
KUAP fault after a recoverable machine check hits inside a user copy
operation.

Fix this similarly to HMI by just avoiding the kuap lock in the
early machine check handler (it will be set by the late handler that
runs in virtual mode if that runs). If the virtual mode handler is
reached, it will lock and restore the AMR.

Fixes: 890274c2 ("powerpc/64s: Implement KUAP for Radix MMU")
Cc: Russell Currey <ruscur@russell.cc>
Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      e13e7cd4
  7. 20 Jun, 2019 2 commits
    • Suraj Jitindar Singh's avatar
      KVM: PPC: Book3S HV: Clear pending decrementer exceptions on nested guest entry · 3c25ab35
      Suraj Jitindar Singh authored 
      If we enter an L1 guest with a pending decrementer exception then this
is cleared on guest exit if the guest has writtien a positive value
into the decrementer (indicating that it handled the decrementer
exception) since there is no other way to detect that the guest has
handled the pending exception and that it should be dequeued. In the
event that the L1 guest tries to run a nested (L2) guest immediately
after this and the L2 guest decrementer is negative (which is loaded
by L1 before making the H_ENTER_NESTED hcall), then the pending
decrementer exception isn't cleared and the L2 entry is blocked since
L1 has a pending exception, even though L1 may have already handled
the exception and written a positive value for it's decrementer. This
results in a loop of L1 trying to enter the L2 guest and L0 blocking
the entry since L1 has an interrupt pending with the outcome being
that L2 never gets to run and hangs.

Fix this by clearing any pending decrementer exceptions when L1 makes
the H_ENTER_NESTED hcall since it won't do this if it's decrementer
has gone negative, and anyway it's decrementer has been communicated
to L0 in the hdec_expires field and L0 will return control to L1 when
this goes negative by delivering an H_DECREMENTER exception.

Fixes: 95a6432c ("KVM: PPC: Book3S HV: Streamlined guest entry/exit path on P9 for radix guests")
Cc: stable@vger.kernel.org # v4.20+
Signed-off-by: default avatarSuraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      3c25ab35
    • Suraj Jitindar Singh's avatar
      KVM: PPC: Book3S HV: Signed extend decrementer value if not using large decrementer · 86953770
      Suraj Jitindar Singh authored 
      On POWER9 the decrementer can operate in large decrementer mode where
the decrementer is 56 bits and signed extended to 64 bits. When not
operating in this mode the decrementer behaves as a 32 bit decrementer
which is NOT signed extended (as on POWER8).

Currently when reading a guest decrementer value we don't take into
account whether the large decrementer is enabled or not, and this
means the value will be incorrect when the guest is not using the
large decrementer. Fix this by sign extending the value read when the
guest isn't using the large decrementer.

Fixes: 95a6432c ("KVM: PPC: Book3S HV: Streamlined guest entry/exit path on P9 for radix guests")
Cc: stable@vger.kernel.org # v4.20+
Signed-off-by: default avatarSuraj Jitindar Singh <sjitindarsingh@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      86953770
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