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[2/3] ppc/kvm: Set the runlatch bit of a CPU just before starting guest

Message ID 20140411103157.27683.79563.stgit@preeti.in.ibm.com (mailing list archive)
State Accepted
Commit fd17dc7b9a8d57150ee0121c4c83edbb7e26eece
Delegated to: Benjamin Herrenschmidt
Headers show

Commit Message

Preeti U Murthy April 11, 2014, 10:31 a.m. UTC 
The secondary threads in the core are kept offline before launching guests
in kvm on powerpc: "371fefd6f2dc4666:KVM: PPC: Allow book3s_hv guests to use
SMT processor modes."

Hence their runlatch bits are cleared. When the secondary threads are called
in to start a guest, their runlatch bits need to be set to indicate that they
are busy. The primary thread has its runlatch bit set though, but there is no
harm in setting this bit once again. Hence set the runlatch bit for all
threads before they start guest.

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>
---

 arch/powerpc/kvm/book3s_hv_rmhandlers.S |    6 ++++++
 1 file changed, 6 insertions(+)
diff mbox

Patch

diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index ffbb871..b254075 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -242,6 +242,12 @@  kvm_novcpu_exit:
  */
 	.globl	kvm_start_guest
 kvm_start_guest:
+
+	/* Set runlatch bit the minute you wake up from nap */
+	mfspr	r1, SPRN_CTRLF
+	ori 	r1, r1, 1
+	mtspr	SPRN_CTRLT, r1
+
 	ld	r2,PACATOC(r13)
 
 	li	r0,KVM_HWTHREAD_IN_KVM