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

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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>
This commit is contained in:
Marc Zyngier 2020-11-12 18:49:28 +00:00
parent 77da43039a
commit b0737e999e
1 changed files with 8 additions and 4 deletions
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12
arch/arm64/kvm/sys_regs.c
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@ -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);