Re: [PATCH v2 3/9] arm64: KVM: PMU: Inject UNDEF on non-privileged accesses

Christoffer Dall
2017-03-28T12:43:06Z

On Mon, Mar 27, 2017 at 05:03:39PM +0100, Marc Zyngier wrote:
> access_pminten() and access_pmuserenr() can only be accessed when
> the CPU is in a priviledged mode. If it is not, let's inject an
> UNDEF exception.
>
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Reviewed-by: Christoffer Dall <cdall@linaro.org>

> ---
> arch/arm64/kvm/sys_regs.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
> index d98ce9a52291..5e3ce7890b35 100644
> --- a/arch/arm64/kvm/sys_regs.c
> +++ b/arch/arm64/kvm/sys_regs.c
> @@ -709,8 +709,10 @@ 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))
> + if (!vcpu_mode_priv(vcpu)) {
> + kvm_inject_undefined(vcpu);
> return false;
> + }
>
> if (p->is_write) {
> u64 val = p->regval & mask;
> @@ -780,8 +782,10 @@ static bool access_pmuserenr(struct kvm_vcpu *vcpu, struct sys_reg_params *p,
> return trap_raz_wi(vcpu, p, r);
>
> if (p->is_write) {
> - if (!vcpu_mode_priv(vcpu))
> + if (!vcpu_mode_priv(vcpu)) {
> + kvm_inject_undefined(vcpu);
> return false;
> + }
>
> vcpu_sys_reg(vcpu, PMUSERENR_EL0) = p->regval
> & ARMV8_PMU_USERENR_MASK;
> --
> 2.11.0
>