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UPSTREAM: KVM: arm64: Remove dead PMU sysreg decoding code

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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>
(cherry picked from commit a3da935802)
Signed-off-by: Will Deacon <willdeacon@google.com>
Change-Id: I70e709ef540eb13ff7b3f79d2ab507619c0797d4
Bug: 178098380
Test: atest VirtualizationHostTestCases on an EL2-enabled device
This commit is contained in:
Marc Zyngier
2020-11-12 18:50:06 +00:00
committed by Will Deacon
parent b17233cdcb
commit dc736eef6d
1 changed files with 4 additions and 5 deletions
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9
arch/arm64/kvm/sys_regs.c
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@@ -721,7 +721,7 @@ 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) {
@@ -737,8 +737,6 @@ 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 */
@@ -752,10 +750,11 @@ 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;