Restore guest CR after exit timing calculation

No instruction which can change Condition Register (CR) should be executed after
Guest CR is loaded. So the guest CR is restored after the Exit Timing in
lightweight_exit executes cmpw, which can clobber CR.

Signed-off-by: Bharat Bhushan <bharat.bhushan@freescale.com>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>

diff --git a/arch/powerpc/kvm/bookehv_interrupts.S b/arch/powerpc/kvm/bookehv_interrupts.S
index 57e2fa4..909e96e 100644 (file)
--- a/arch/powerpc/kvm/bookehv_interrupts.S
+++ b/arch/powerpc/kvm/bookehv_interrupts.S
@@ -580,7 +580,6 @@ lightweight_exit:
        mtlr    r3
        mtxer   r5
        mtctr   r6
-       mtcr    r7
        mtsrr0  r8
        mtsrr1  r9
 
@@ -588,14 +587,20 @@ lightweight_exit:
        /* save enter time */
 1:
        mfspr   r6, SPRN_TBRU
-       mfspr   r7, SPRN_TBRL
+       mfspr   r9, SPRN_TBRL
        mfspr   r8, SPRN_TBRU
        cmpw    r8, r6
-       PPC_STL r7, VCPU_TIMING_LAST_ENTER_TBL(r4)
+       PPC_STL r9, VCPU_TIMING_LAST_ENTER_TBL(r4)
        bne     1b
        PPC_STL r8, VCPU_TIMING_LAST_ENTER_TBU(r4)
 #endif
 
+       /*
+        * Don't execute any instruction which can change CR after
+        * below instruction.
+        */
+       mtcr    r7
+
        /* Finish loading guest volatiles and jump to guest. */
        PPC_LL  r5, VCPU_GPR(r5)(r4)
        PPC_LL  r6, VCPU_GPR(r6)(r4)