[PATCH v2 3/3] KVM: arm64: Limit clearing of ID_{AA64PFR0,PFR1}_EL1.GIC to userspace irqchip

[Marc Zyngier <maz@kernel.org>]

Now that the idreg's GIC field is in sync with the irqchip, limit
the runtime clearing of these fields to the pathological case where
we do not have an in-kernel GIC.

While we're at it, use the existing API instead of open-coded
accessors to access the ID regs.

Fixes: 5cb57a1aff755 ("KVM: arm64: Zero ID_AA64PFR0_EL1.GIC when no GICv3 is presented to the guest")
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/sys_regs.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index ad82264c6cbe1..8ae2bca816148 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -5609,11 +5609,13 @@ int kvm_finalize_sys_regs(struct kvm_vcpu *vcpu)
 
 	guard(mutex)(&kvm->arch.config_lock);
 
-	if (!(static_branch_unlikely(&kvm_vgic_global_state.gicv3_cpuif) &&
-	      irqchip_in_kernel(kvm) &&
-	      kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3)) {
-		kvm->arch.id_regs[IDREG_IDX(SYS_ID_AA64PFR0_EL1)] &= ~ID_AA64PFR0_EL1_GIC_MASK;
-		kvm->arch.id_regs[IDREG_IDX(SYS_ID_PFR1_EL1)] &= ~ID_PFR1_EL1_GIC_MASK;
+	if (!irqchip_in_kernel(kvm)) {
+		u64 val;
+
+		val = kvm_read_vm_id_reg(kvm, SYS_ID_AA64PFR0_EL1) & ~ID_AA64PFR0_EL1_GIC;
+		kvm_set_vm_id_reg(kvm, SYS_ID_AA64PFR0_EL1, val);
+		val = kvm_read_vm_id_reg(kvm, SYS_ID_PFR1_EL1) & ~ID_PFR1_EL1_GIC;
+		kvm_set_vm_id_reg(kvm, SYS_ID_PFR1_EL1, val);
 	}
 
 	if (vcpu_has_nv(vcpu)) {
-- 
2.47.3