From: Nicholas Piggin <npiggin@gmail.com>
Date: Sun, 12 Mar 2017 17:03:49 +0000 (+1000)
Subject: KVM: PPC: Book3S HV: Use msgsync with hypervisor doorbells on POWER9
X-Git-Tag: v4.13-rc7~14^2~6
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=bd0fdb191c8523a9126bb14ac1b22cb47698ebf5;p=users%2Fjedix%2Flinux-maple.git

KVM: PPC: Book3S HV: Use msgsync with hypervisor doorbells on POWER9

When msgsnd is used for IPIs to other cores, msgsync must be executed by
the target to order stores performed on the source before its msgsnd
(provided the source executes the appropriate sync).

Fixes: 1704a81ccebc ("KVM: PPC: Book3S HV: Use msgsnd for IPIs to other cores on POWER9")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Paul Mackerras <paulus@ozlabs.org>
---

diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index c52184a8efdf..9c9c983b864f 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -1291,6 +1291,9 @@ END_FTR_SECTION_IFSET(CPU_FTR_HAS_PPR)
 	/* Hypervisor doorbell - exit only if host IPI flag set */
 	cmpwi	r12, BOOK3S_INTERRUPT_H_DOORBELL
 	bne	3f
+BEGIN_FTR_SECTION
+	PPC_MSGSYNC
+END_FTR_SECTION_IFSET(CPU_FTR_ARCH_300)
 	lbz	r0, HSTATE_HOST_IPI(r13)
 	cmpwi	r0, 0
 	beq	4f