powerpc: Turn off CPU_FTR_P9_TM_HV_ASSIST in non-hypervisor mode

When doing nested virtualization, it is only necessary to do the
transactional memory hypervisor assist at level 0, that is, when
we are in hypervisor mode.  Nested hypervisors can just use the TM
facilities as architected.  Therefore we should clear the
CPU_FTR_P9_TM_HV_ASSIST bit when we are not in hypervisor mode,
along with the CPU_FTR_HVMODE bit.

Doing this will not change anything at this stage because the only
code that tests CPU_FTR_P9_TM_HV_ASSIST is in HV KVM, which currently
can only be used when when CPU_FTR_HVMODE is set.

Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

diff --git a/arch/powerpc/kernel/cpu_setup_power.S b/arch/powerpc/kernel/cpu_setup_power.S
index 458b928dbd8447008a7f6c83ff9db27d06d7508d..c317080db771e2b960765a879644b41df7b51ec0 100644 (file)
--- a/arch/powerpc/kernel/cpu_setup_power.S
+++ b/arch/powerpc/kernel/cpu_setup_power.S
@@ -147,8 +147,8 @@ __init_hvmode_206:
        rldicl. r0,r3,4,63
        bnelr
        ld      r5,CPU_SPEC_FEATURES(r4)
-       LOAD_REG_IMMEDIATE(r6,CPU_FTR_HVMODE)
-       xor     r5,r5,r6
+       LOAD_REG_IMMEDIATE(r6,CPU_FTR_HVMODE | CPU_FTR_P9_TM_HV_ASSIST)
+       andc    r5,r5,r6
        std     r5,CPU_SPEC_FEATURES(r4)
        blr