arm64: KVM: vgic-v3: Do not save an LR known to be empty

On exit, any empty LR will be signaled in ICH_ELRSR_EL2. Which
means that we do not have to save it, and we can just clear
its state in the in-memory copy.

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

1 files changed, 9 insertions, 2 deletions

diff --git a/arch/arm64/kvm/hyp/vgic-v3-sr.c b/arch/arm64/kvm/hyp/vgic-v3-sr.c
index 61a5e46b4335..0db426e6c13e 100644
--- a/arch/arm64/kvm/hyp/vgic-v3-sr.c
+++ b/arch/arm64/kvm/hyp/vgic-v3-sr.c
@@ -187,8 +187,15 @@ void __hyp_text __vgic_v3_save_state(struct kvm_vcpu *vcpu)
                 save_maint_int_state(vcpu, max_lr_idx + 1);
 
                 for (i = 0; i <= max_lr_idx; i++) {
-                        if (vcpu->arch.vgic_cpu.live_lrs & (1UL << i))
-                                cpu_if->vgic_lr[i] = __gic_v3_get_lr(i);
+                        if (!(vcpu->arch.vgic_cpu.live_lrs & (1UL << i)))
+                                continue;
+
+                        if (cpu_if->vgic_elrsr & (1 << i)) {
+                                cpu_if->vgic_lr[i] &= ~ICH_LR_STATE;
+                                continue;
+                        }
+
+                        cpu_if->vgic_lr[i] = __gic_v3_get_lr(i);
                 }
 
                 switch (nr_pri_bits) {