linux-kernel - [PATCH] KVM: PPC: Book3S HV: Remove vcpu->arch.dec usage

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Date:   Tue, 19 Dec 2017 15:56:24 +0100
From:   Alexander Graf <agraf@...e.de>
To:     kvm-ppc@...r.kernel.org
Cc:     linuxppc-dev@...ts.ozlabs.org, linux-kernel@...r.kernel.org,
        kvm@...r.kernel.org, Paul Mackerras <paulus@...abs.org>
Subject: [PATCH] KVM: PPC: Book3S HV: Remove vcpu->arch.dec usage

On Book3S in HV mode, we don't use the vcpu->arch.dec field at all.
Instead, all logic is built around vcpu->arch.dec_expires.

So let's remove the one remaining piece of code that was setting it.

Signed-off-by: Alexander Graf <agraf@...e.de>

---

Looking through the DEC logic, I fail to see any code that allows
save or restore of DEC. Do we maybe miss out on that register for
(live) migration?
---
 arch/powerpc/kvm/book3s_hv_rmhandlers.S | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/powerpc/kvm/book3s_hv_rmhandlers.S b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
index 2659844784b8..c8ffd69adfec 100644
--- a/arch/powerpc/kvm/book3s_hv_rmhandlers.S
+++ b/arch/powerpc/kvm/book3s_hv_rmhandlers.S
@@ -957,7 +957,6 @@ ALT_FTR_SECTION_END_IFCLR(CPU_FTR_ARCH_300)
 	mftb	r7
 	subf	r3,r7,r8
 	mtspr	SPRN_DEC,r3
-	std	r3,VCPU_DEC(r4)
 
 	ld	r5, VCPU_SPRG0(r4)
 	ld	r6, VCPU_SPRG1(r4)
-- 
2.12.3