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From: Marc Zyngier <maz@kernel.org>
To: linux-arm-kernel@lists.infradead.org,
	kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: James Morse <james.morse@arm.com>,
	Julien Thierry <julien.thierry.kdev@gmail.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Eric Auger <eric.auger@redhat.com>,
	kernel-team@android.com
Subject: [PATCH 6/8] KVM: arm64: Remove dead PMU sysreg decoding code
Date: Fri, 13 Nov 2020 18:26:00 +0000	[thread overview]
Message-ID: <20201113182602.471776-7-maz@kernel.org> (raw)
In-Reply-To: <20201113182602.471776-1-maz@kernel.org>

The handling of traps in access_pmu_evcntr() has a couple of
omminous "else return false;" statements that don't make any sense:
the decoding tree coverse all the registers that trap to this handler,
and returning false implies that we change PC, which we don't.

Get rid of what is evidently dead code.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 3bd4cc40536b..f878d71484d8 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -733,8 +733,6 @@ static bool access_pmu_evcntr(struct kvm_vcpu *vcpu,
 				return false;
 
 			idx = ARMV8_PMU_CYCLE_IDX;
-		} else {
-			return false;
 		}
 	} else if (r->CRn == 0 && r->CRm == 9) {
 		/* PMCCNTR */
@@ -748,8 +746,6 @@ static bool access_pmu_evcntr(struct kvm_vcpu *vcpu,
 			return false;
 
 		idx = ((r->CRm & 3) << 3) | (r->Op2 & 7);
-	} else {
-		return false;
 	}
 
 	if (!pmu_counter_idx_valid(vcpu, idx))
-- 
2.28.0


  parent reply	other threads:[~2020-11-13 18:26 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-11-13 18:25 [PATCH 0/8] KVM: arm64: Disabled PMU handling Marc Zyngier
2020-11-13 18:25 ` [PATCH 1/8] KVM: arm64: Add kvm_vcpu_has_pmu() helper Marc Zyngier
2020-11-13 18:25 ` [PATCH 2/8] KVM: arm64: Set ID_AA64DFR0_EL1.PMUVer to 0 when no PMU support Marc Zyngier
2020-11-13 18:25 ` [PATCH 3/8] KVM: arm64: Refuse illegal KVM_ARM_VCPU_PMU_V3 at reset time Marc Zyngier
2020-11-26 14:59   ` Alexandru Elisei
2020-11-26 15:25     ` Marc Zyngier
2020-11-26 15:49       ` Alexandru Elisei
2020-11-13 18:25 ` [PATCH 4/8] KVM: arm64: Inject UNDEF on PMU access when no PMU configured Marc Zyngier
2020-11-13 18:25 ` [PATCH 5/8] KVM: arm64: Remove PMU RAZ/WI handling Marc Zyngier
2020-11-26 15:06   ` Alexandru Elisei
2020-11-27  8:50     ` Marc Zyngier
2020-11-13 18:26 ` Marc Zyngier [this message]
2020-11-26 15:18   ` [PATCH 6/8] KVM: arm64: Remove dead PMU sysreg decoding code Alexandru Elisei
2020-11-26 15:34     ` Marc Zyngier
2020-11-26 15:54       ` Alexandru Elisei
2020-11-26 15:57         ` Marc Zyngier
2020-11-13 18:26 ` [PATCH 7/8] KVM: arm64: Gate kvm_pmu_update_state() on the PMU feature Marc Zyngier
2020-11-13 18:26 ` [PATCH 8/8] KVM: arm64: Get rid of the PMU ready state Marc Zyngier
2020-11-24 17:28 ` [PATCH 0/8] KVM: arm64: Disabled PMU handling Alexandru Elisei
2020-11-25  8:39   ` Marc Zyngier
2020-11-26 16:34 ` Alexandru Elisei

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