KVM: arm64: gic-v5: Enlighten arch timer for GICv5

Now that GICv5 has arrived, the arch timer requires some TLC to
address some of the key differences introduced with GICv5.

For PPIs on GICv5, the queue_irq_unlock irq_op is used as AP lists are
not required at all for GICv5. The arch timer also introduces an
irq_op - get_input_level. Extend the arch-timer-provided irq_ops to
include the PPI op for vgic_v5 guests.

When possible, DVI (Direct Virtual Interrupt) is set for PPIs when
using a vgic_v5, which directly inject the pending state into the
guest. This means that the host never sees the interrupt for the guest
for these interrupts. This has three impacts.

* First of all, the kvm_cpu_has_pending_timer check is updated to
  explicitly check if the timers are expected to fire.

* Secondly, for mapped timers (which use DVI) they must be masked on
  the host prior to entering a GICv5 guest, and unmasked on the return
  path. This is handled in set_timer_irq_phys_masked.

* Thirdly, it makes zero sense to attempt to inject state for a DVI'd
  interrupt. Track which timers are direct, and skip the call to
  kvm_vgic_inject_irq() for these.

The final, but rather important, change is that the architected PPIs
for the timers are made mandatory for a GICv5 guest. Attempts to set
them to anything else are actively rejected. Once a vgic_v5 is
initialised, the arch timer PPIs are also explicitly reinitialised to
ensure the correct GICv5-compatible PPIs are used - this also adds in
the GICv5 PPI type to the intid.

Signed-off-by: Sascha Bischoff <sascha.bischoff@arm.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Link: https://patch.msgid.link/20260319154937.3619520-32-sascha.bischoff@arm.com
Signed-off-by: Marc Zyngier <maz@kernel.org>

2 files changed, 13 insertions, 1 deletions

diff --git a/include/kvm/arm_arch_timer.h b/include/kvm/arm_arch_timer.h
index 7310841f4512..a7754e0a2ef4 100644
--- a/include/kvm/arm_arch_timer.h
+++ b/include/kvm/arm_arch_timer.h
@@ -10,6 +10,8 @@
 #include <linux/clocksource.h>
 #include <linux/hrtimer.h>
 
+#include <linux/irqchip/arm-gic-v5.h>
+
 enum kvm_arch_timers {
 	TIMER_PTIMER,
 	TIMER_VTIMER,
@@ -47,7 +49,7 @@ struct arch_timer_vm_data {
 	u64	poffset;
 
 	/* The PPI for each timer, global to the VM */
-	u8	ppi[NR_KVM_TIMERS];
+	u32	ppi[NR_KVM_TIMERS];
 };
 
 struct arch_timer_context {
@@ -74,6 +76,9 @@ struct arch_timer_context {
 
 	/* Duplicated state from arch_timer.c for convenience */
 	u32				host_timer_irq;
+
+	/* Is this a direct timer? */
+	bool				direct;
 };
 
 struct timer_map {
@@ -130,6 +135,10 @@ void kvm_timer_init_vhe(void);
 #define timer_vm_data(ctx)		(&(timer_context_to_vcpu(ctx)->kvm->arch.timer_data))
 #define timer_irq(ctx)			(timer_vm_data(ctx)->ppi[arch_timer_ctx_index(ctx)])
 
+#define get_vgic_ppi(k, i) (((k)->arch.vgic.vgic_model != KVM_DEV_TYPE_ARM_VGIC_V5) ? \
+			    (i) : (FIELD_PREP(GICV5_HWIRQ_ID, i) |	\
+				   FIELD_PREP(GICV5_HWIRQ_TYPE, GICV5_HWIRQ_TYPE_PPI)))
+
 u64 kvm_arm_timer_read_sysreg(struct kvm_vcpu *vcpu,
 			      enum kvm_arch_timers tmr,
 			      enum kvm_arch_timer_regs treg);
diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
index a5ddccf7ef3b..8cc3a7b4d815 100644
--- a/include/kvm/arm_vgic.h
+++ b/include/kvm/arm_vgic.h
@@ -627,6 +627,9 @@ void vgic_v4_commit(struct kvm_vcpu *vcpu);
 int vgic_v4_put(struct kvm_vcpu *vcpu);
 
 int vgic_v5_finalize_ppi_state(struct kvm *kvm);
+bool vgic_v5_ppi_queue_irq_unlock(struct kvm *kvm, struct vgic_irq *irq,
+				  unsigned long flags);
+void vgic_v5_set_ppi_dvi(struct kvm_vcpu *vcpu, struct vgic_irq *irq, bool dvi);
 
 bool vgic_state_is_nested(struct kvm_vcpu *vcpu);