KVM: arm64: Inject UNDEF on PMU access when no PMU configured

The ARMv8 architecture says that in the absence of FEAT_PMUv3,
all the PMU-related register generate an UNDEF. Let's make
sure that all our PMU handers catch this case by hooking into
check_pmu_access_disabled(), and add checks in a couple of
other places.

Note that we still cannot deliver an exception into the guest
as the offending cases are already caught by the RAZ/WI handling.
But this puts us one step away to architectural compliance.

Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 6629cfde283843e7bb6126d3aa6df42213d8e192..b098d667bb4278fd695ae814cc5391f6d8e66de4 100644 (file)
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -609,8 +609,9 @@ static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 static bool check_pmu_access_disabled(struct kvm_vcpu *vcpu, u64 flags)
 {
        u64 reg = __vcpu_sys_reg(vcpu, PMUSERENR_EL0);
-       bool enabled = (reg & flags) || vcpu_mode_priv(vcpu);
+       bool enabled = kvm_vcpu_has_pmu(vcpu);
 
+       enabled &= (reg & flags) || vcpu_mode_priv(vcpu);
        if (!enabled)
                kvm_inject_undefined(vcpu);
 
@@ -857,10 +858,8 @@ static bool access_pminten(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
        if (!kvm_arm_pmu_v3_ready(vcpu))
                return trap_raz_wi(vcpu, p, r);
 
-       if (!vcpu_mode_priv(vcpu)) {
-               kvm_inject_undefined(vcpu);
+       if (check_pmu_access_disabled(vcpu, 0))
                return false;
-       }
 
        if (p->is_write) {
                u64 val = p->regval & mask;
@@ -928,6 +927,11 @@ static bool access_pmuserenr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
        if (!kvm_arm_pmu_v3_ready(vcpu))
                return trap_raz_wi(vcpu, p, r);
 
+       if (!kvm_vcpu_has_pmu(vcpu)) {
+               kvm_inject_undefined(vcpu);
+               return false;
+       }
+
        if (p->is_write) {
                if (!vcpu_mode_priv(vcpu)) {
                        kvm_inject_undefined(vcpu);