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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 <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
This commit is contained in:
Marc Zyngier 2020-11-12 18:50:06 +00:00
parent f975ccb08d
commit a3da935802
1 changed files with 4 additions and 5 deletions
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9
arch/arm64/kvm/sys_regs.c
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@ -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;