[PATCH v2 27/39] xen/riscv: introduce arch_move_irqs()

When migrating a vCPU between pCPUs the hypervisor must also migrate
the associated virtual interrupt state. arch_move_irqs() is the
per-arch hook called by generic code to trigger that.

Replace the static inline BUG_ON placeholder in asm/irq.h with a real
implementation in intc.c dispatching through a new move_irqs vintc_ops
callback. Wire it up in vAPLIC, which delegates to imsic_migrate_vcpu()
which itself still a stub to be implemented in follow-up patches.

Note that technically ASSERT() in arch_move_irqs() could be skipped as
it will be anyway NULL pointer dereference (and a trap will occur) if
something isn't properly initialized but sometimes it is harder to
find place where NULL pointer derefence happened as it isn't
guaraunted that all necessary registers will be filled with something
useful.
As at the moment I don't find any case when ->move_irqs() could be
skipped, the check that ->move_irq isn't NULL is added to ASSERT()
instead of adding "if ( ...->move_irq) vitnc->ops->move_irqs(v)".

Signed-off-by: Oleksii Kurochko <[email protected]>
---
Changes in v2:
 - New patch.
---
---
 xen/arch/riscv/imsic.c             | 5 +++++
 xen/arch/riscv/include/asm/imsic.h | 2 ++
 xen/arch/riscv/include/asm/intc.h  | 3 +++
 xen/arch/riscv/include/asm/irq.h   | 5 +----
 xen/arch/riscv/intc.c              | 8 ++++++++
 xen/arch/riscv/vaplic.c            | 1 +
 6 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/xen/arch/riscv/imsic.c b/xen/arch/riscv/imsic.c
index 3787f270d8e3..b0c4a9e2d728 100644
--- a/xen/arch/riscv/imsic.c
+++ b/xen/arch/riscv/imsic.c
@@ -686,3 +686,8 @@ int __init vimsic_make_domu_dt_node(struct kernel_info *kinfo,
 
     return fdt_end_node(fdt);
 }
+
+void imsic_migrate_vcpu(struct vcpu *v)
+{
+    BUG_ON("unimplemented");
+}
diff --git a/xen/arch/riscv/include/asm/imsic.h b/xen/arch/riscv/include/asm/imsic.h
index 73129c3c9ea7..57d8c729ac0d 100644
--- a/xen/arch/riscv/include/asm/imsic.h
+++ b/xen/arch/riscv/include/asm/imsic.h
@@ -112,4 +112,6 @@ int vimsic_make_domu_dt_node(struct kernel_info *kinfo, unsigned int *phandle);
 void imsic_ctxt_switch_from(struct vcpu *v);
 void imsic_ctxt_switch_to(struct vcpu *v);
 
+void imsic_migrate_vcpu(struct vcpu *v);
+
 #endif /* ASM_RISCV_IMSIC_H */
diff --git a/xen/arch/riscv/include/asm/intc.h b/xen/arch/riscv/include/asm/intc.h
index 62e1410156c7..b5ab39aa2b39 100644
--- a/xen/arch/riscv/include/asm/intc.h
+++ b/xen/arch/riscv/include/asm/intc.h
@@ -70,6 +70,9 @@ struct vintc_ops {
 
     /* Restore vINTC state of the vCPU being switched in */
     void (*ctxt_switch_to)(struct vcpu *v);
+
+    /* Move interrupts of vCPU to a different pCPU */
+    void (*move_irqs)(struct vcpu *v);
 };
 
 struct vintc {
diff --git a/xen/arch/riscv/include/asm/irq.h b/xen/arch/riscv/include/asm/irq.h
index 66067747dc0f..314b8ee0e00c 100644
--- a/xen/arch/riscv/include/asm/irq.h
+++ b/xen/arch/riscv/include/asm/irq.h
@@ -41,10 +41,7 @@ struct irq_desc *irq_to_desc(unsigned int irq);
 struct cpu_user_regs;
 struct dt_device_node;
 
-static inline void arch_move_irqs(struct vcpu *v)
-{
-    BUG_ON("unimplemented");
-}
+void arch_move_irqs(struct vcpu *v);
 
 int platform_get_irq(const struct dt_device_node *device, int index);
 
diff --git a/xen/arch/riscv/intc.c b/xen/arch/riscv/intc.c
index 9fff501b9c25..b3a16ae9be67 100644
--- a/xen/arch/riscv/intc.c
+++ b/xen/arch/riscv/intc.c
@@ -192,3 +192,11 @@ void vintc_ctxt_switch_to(struct vcpu *v)
 
     ops->ctxt_switch_to(v);
 }
+
+/* Move vCPU's IRQs from one pCPU to another */
+void arch_move_irqs(struct vcpu *v)
+{
+    const struct vintc_ops *ops = v->domain->arch.vintc->ops;
+
+    ops->move_irqs(v);
+}
diff --git a/xen/arch/riscv/vaplic.c b/xen/arch/riscv/vaplic.c
index 6c60fe2baf0c..0c75ba2fb2fe 100644
--- a/xen/arch/riscv/vaplic.c
+++ b/xen/arch/riscv/vaplic.c
@@ -429,6 +429,7 @@ static const struct vintc_ops vintc_ops = {
      */
     .ctxt_switch_from = imsic_ctxt_switch_from,
     .ctxt_switch_to = imsic_ctxt_switch_to,
+    .move_irqs = imsic_migrate_vcpu,
 };
 
 int domain_vaplic_init(struct domain *d)
-- 
2.55.0