KVM: PPC: Book3S HV: Sanitize special-purpose register values on guest exit

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commit ccec44563b upstream.

Thomas Huth discovered that a guest could cause a hard hang of a
host CPU by setting the Instruction Authority Mask Register (IAMR)
to a suitable value.  It turns out that this is because when the
code was added to context-switch the new special-purpose registers
(SPRs) that were added in POWER8, we forgot to add code to ensure
that they were restored to a sane value on guest exit.

This adds code to set those registers where a bad value could
compromise the execution of the host kernel to a suitable neutral
value on guest exit.

Fixes: b005255e12
Reported-by: Thomas Huth <thuth@redhat.com>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Paul Mackerras 2016-03-05 19:34:39 +11:00 • committed by Greg Kroah-Hartman

parent 7893953054

commit 1c463a390a

1 changed files with 14 additions and 0 deletions

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arch/powerpc/kvm/book3s_hv_rmhandlers.S

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