[PATCH v2 5/9] arm64: KVM: PMU: Inject UNDEF on read access to PMSWINC_EL0

Marc Zyngier
2017-03-27T16:02:09Z

PMSWINC_EL0 is a WO register, so let's UNDEF when reading from it
(in the highly hypothetical case where this doesn't UNDEF at EL1).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
arch/arm64/kvm/sys_regs.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 19a036b4f6ac..f80a61af5e88 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -772,16 +772,15 @@ static bool access_pmswinc(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
if (!kvm_arm_pmu_v3_ready(vcpu))
return trap_raz_wi(vcpu, p, r);

+ if (!p->is_write)
+ return read_from_write_only(vcpu, p);
+
if (pmu_write_swinc_el0_disabled(vcpu))
return false;

- if (p->is_write) {
- mask = kvm_pmu_valid_counter_mask(vcpu);
- kvm_pmu_software_increment(vcpu, p->regval & mask);
- return true;
- }
-
- return false;
+ mask = kvm_pmu_valid_counter_mask(vcpu);
+ kvm_pmu_software_increment(vcpu, p->regval & mask);
+ return true;
}

static bool access_pmuserenr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
--
2.11.0