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authorPreeti U Murthy <preeti@linux.vnet.ibm.com>2014-04-11 16:02:08 +0530
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>2014-04-28 16:32:49 +1000
commit582b910edafd283dfab78f41f437a92a65ee5103 (patch)
tree2b9e435aacb14de28c5c573b09f75ab4d645d3a1
parentfd17dc7b9a8d57150ee0121c4c83edbb7e26eece (diff)
ppc/kvm: Clear the runlatch bit of a vcpu before napping
When the guest cedes the vcpu or the vcpu has no guest to run it naps. Clear the runlatch bit of the vcpu before napping to indicate an idle cpu. Signed-off-by: Preeti U Murthy <preeti@linux.vnet.ibm.com> Acked-by: Paul Mackerras <paulus@samba.org> Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
-rw-r--r--arch/powerpc/kvm/book3s_hv_rmhandlers.S12
1 files changed, 11 insertions, 1 deletions
diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index b25407533618..b031f932c0cc 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -315,6 +315,11 @@ kvm_no_guest:
li r0, KVM_HWTHREAD_IN_NAP
stb r0, HSTATE_HWTHREAD_STATE(r13)
kvm_do_nap:
+ /* Clear the runlatch bit before napping */
+ mfspr r2, SPRN_CTRLF
+ clrrdi r2, r2, 1
+ mtspr SPRN_CTRLT, r2
+
li r3, LPCR_PECE0
mfspr r4, SPRN_LPCR
rlwimi r4, r3, 0, LPCR_PECE0 | LPCR_PECE1
@@ -2005,8 +2010,13 @@ END_FTR_SECTION_IFCLR(CPU_FTR_ARCH_206)
/*
* Take a nap until a decrementer or external or doobell interrupt
- * occurs, with PECE1, PECE0 and PECEDP set in LPCR
+ * occurs, with PECE1, PECE0 and PECEDP set in LPCR. Also clear the
+ * runlatch bit before napping.
*/
+ mfspr r2, SPRN_CTRLF
+ clrrdi r2, r2, 1
+ mtspr SPRN_CTRLT, r2
+
li r0,1
stb r0,HSTATE_HWTHREAD_REQ(r13)
mfspr r5,SPRN_LPCR