[PATCH v1 10/17] xen/riscv: introduce vintc_state_{save,restore}()

Virtual interrupt controller state must be preserved across vCPU context
switches: for AIA, a vCPU's guest interrupt file lives in the IMSIC of
the pCPU it runs on, so the related state has to be saved when the vCPU
is descheduled and re-established when it is scheduled again.

Introduce vintc_state_save()/vintc_state_restore() wrappers around new
store_state()/restore_state() hooks in struct vintc_ops, so that the
context switch path can save/restore this state without knowing which
vINTC variant a domain uses.

No callers are wired up yet: the vAPLIC implementation of the hooks is
added by the follow-up patch, and the calls from the context switch path
will be introduced together with vCPU context switch support.

Signed-off-by: Oleksii Kurochko <[email protected]>
---
 xen/arch/riscv/include/asm/intc.h |  9 +++++++++
 xen/arch/riscv/intc.c             | 14 ++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/xen/arch/riscv/include/asm/intc.h b/xen/arch/riscv/include/asm/intc.h
index 2ee5d1533c8e..f4f0ce365c00 100644
--- a/xen/arch/riscv/include/asm/intc.h
+++ b/xen/arch/riscv/include/asm/intc.h
@@ -64,6 +64,12 @@ struct vintc_ops {
 
     /* Deinitialize some vINTC-related stuff for a vCPU */
     void (*vcpu_deinit)(struct vcpu *v);
+
+    /* Store virtual interrupt controller state */
+    void (*store_state)(struct vcpu *v);
+
+    /* Restore virtual interrupt controller state */
+    void (*restore_state)(struct vcpu *v);
 };
 
 struct vintc {
@@ -91,4 +97,7 @@ void domain_vintc_deinit(struct domain *d);
 
 bool vintc_reserve_virq(const struct domain *d, unsigned int virq);
 
+void vintc_state_save(struct vcpu *vcpu);
+void vintc_state_restore(struct vcpu *vcpu);
+
 #endif /* ASM__RISCV__INTERRUPT_CONTOLLER_H */
diff --git a/xen/arch/riscv/intc.c b/xen/arch/riscv/intc.c
index 372c8d3a20f9..879d51337491 100644
--- a/xen/arch/riscv/intc.c
+++ b/xen/arch/riscv/intc.c
@@ -163,3 +163,17 @@ bool vintc_reserve_virq(const struct domain *d, unsigned int virq)
 
     return !test_and_set_bit(virq, d->arch.vintc->used_irqs);
 }
+
+void vintc_state_save(struct vcpu *vcpu)
+{
+    const struct vintc_ops *ops = vcpu->domain->arch.vintc->ops;
+
+    ops->store_state(vcpu);
+}
+
+void vintc_state_restore(struct vcpu *vcpu)
+{
+    const struct vintc_ops *ops = vcpu->domain->arch.vintc->ops;
+
+    ops->restore_state(vcpu);
+}
-- 
2.54.0