From a3da93580202ac9075d4e96f73c8435b9d7262c1 Mon Sep 17 00:00:00 2001 From: Marc Zyngier Date: Thu, 12 Nov 2020 18:50:06 +0000 Subject: [PATCH] KVM: arm64: Remove dead PMU sysreg decoding code 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. Reviewed-by: Alexandru Elisei Signed-off-by: Marc Zyngier --- arch/arm64/kvm/sys_regs.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c index 3bd4cc40536b6..dd7a73468286d 100644 --- a/arch/arm64/kvm/sys_regs.c +++ b/arch/arm64/kvm/sys_regs.c @@ -717,7 +717,7 @@ static bool access_pmu_evcntr(struct kvm_vcpu *vcpu, struct sys_reg_params *p, const struct sys_reg_desc *r) { - u64 idx; + u64 idx = ~0UL; if (r->CRn == 9 && r->CRm == 13) { if (r->Op2 == 2) { @@ -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 */ @@ -748,10 +746,11 @@ static bool access_pmu_evcntr(struct kvm_vcpu *vcpu, return false; idx = ((r->CRm & 3) << 3) | (r->Op2 & 7); - } else { - return false; } + /* Catch any decoding mistake */ + WARN_ON(idx == ~0UL); + if (!pmu_counter_idx_valid(vcpu, idx)) return false; -- 2.39.5