[PATCH v2 4/6] KVM: arm64: Don't let userspace write to PMCR_EL0.N when the vcpu has EL2

[Marc Zyngier]

Now that userspace can provide its limit for hte maximum number of
counters, prevent it from writing to PMCR_EL0.N, as the value should
be derived from MDCR_EL2.HPMN in that case.

Signed-off-by: Marc Zyngier <maz at kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 73d68ea37ac21..00b5396492d51 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1216,6 +1216,7 @@ static int set_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r,
 	 * with the existing KVM behavior.
 	 */
 	if (!kvm_vm_has_ran_once(kvm) &&
+	    !vcpu_has_nv(vcpu)	      &&
 	    new_n <= kvm_arm_pmu_get_max_counters(kvm))
 		kvm->arch.pmcr_n = new_n;
 
-- 
2.39.2