linux-kernel - [PATCH 7/7] KVM/PPC: update the comment of memory barrier in the kvmppc_prepare_to

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Date:	Sun, 13 Mar 2016 11:10:30 +0800
From:	Lan Tianyu <tianyu.lan@...el.com>
To:	agraf@...e.com, gleb@...nel.org, pbonzini@...hat.com,
	benh@...nel.crashing.org, paulus@...ba.org, mpe@...erman.id.au,
	guangrong.xiao@...ux.intel.com
Cc:	Lan Tianyu <tianyu.lan@...el.com>, kvm-ppc@...r.kernel.org,
	kvm@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH 7/7] KVM/PPC:  update the comment of memory barrier in the kvmppc_prepare_to_enter()

The barrier also orders the write to mode from any reads
to the page tables done and so update the comment.

Signed-off-by: Lan Tianyu <tianyu.lan@...el.com>
---
 arch/powerpc/kvm/powerpc.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 19aa59b..6a68730 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -96,6 +96,9 @@ int kvmppc_prepare_to_enter(struct kvm_vcpu *vcpu)
 		 * so we don't miss a request because the requester sees
 		 * OUTSIDE_GUEST_MODE and assumes we'll be checking requests
 		 * before next entering the guest (and thus doesn't IPI).
+		 * This also orders the write to mode from any reads
+		 * to the page tables done while the VCPU is running.
+		 * Please see the comment in kvm_flush_remote_tlbs.
 		 */
 		smp_mb();
 
-- 
1.8.4.rc0.1.g8f6a3e5.dirty