[PATCH v1 18/27] xen/riscv: add vaplic access check

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

Provide a mechanism for the virtual APLIC to determine whether a guest
access targets the physical APLIC MMIO region.

This is required to correctly identify and route guest APLIC accesses.

Co-developed-by: Romain Caritey <Romain.Caritey@xxxxxxxxxxxxx>
Signed-off-by: Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>
---
 xen/arch/riscv/aplic.c            |  1 +
 xen/arch/riscv/include/asm/intc.h |  3 +++
 xen/arch/riscv/vaplic.c           | 15 +++++++++++++++
 3 files changed, 19 insertions(+)

diff --git a/xen/arch/riscv/aplic.c b/xen/arch/riscv/aplic.c
index e139946a05a0..754b444a2a13 100644
--- a/xen/arch/riscv/aplic.c
+++ b/xen/arch/riscv/aplic.c
@@ -38,6 +38,7 @@ static struct aplic_priv aplic = {
 
 static struct intc_info __ro_after_init aplic_info = {
     .hw_version = INTC_APLIC,
+    .private = &aplic,
 };
 
 static void __init aplic_init_hw_interrupts(void)
diff --git a/xen/arch/riscv/include/asm/intc.h 
b/xen/arch/riscv/include/asm/intc.h
index 76d2fd09cb8b..e6b6c179415a 100644
--- a/xen/arch/riscv/include/asm/intc.h
+++ b/xen/arch/riscv/include/asm/intc.h
@@ -25,6 +25,9 @@ struct intc_info {
 
     /* number of irqs */
     unsigned int num_irqs;
+
+    /* private data pointer of the interrupt controller */
+    void *private;
 };
 
 struct intc_hw_operations {
diff --git a/xen/arch/riscv/vaplic.c b/xen/arch/riscv/vaplic.c
index 0c69f087cf4d..82e74a609ee6 100644
--- a/xen/arch/riscv/vaplic.c
+++ b/xen/arch/riscv/vaplic.c
@@ -127,6 +127,20 @@ int vaplic_map_device_irqs_to_domain(struct domain *d,
     return 0;
 }
 
+static int cf_check vaplic_is_access(const struct vcpu *vcpu,
+                                     const unsigned long addr)
+{
+    const struct vaplic *vaplic = to_vaplic(vcpu->domain->arch.vintc);
+    const struct aplic_priv *priv = vaplic->base.info->private;
+    const paddr_t paddr_end = priv->paddr_start + priv->size;
+
+    /* check if it is an APLIC access */
+    if ( priv->paddr_start <= addr && addr < paddr_end )
+        return 1;
+
+    return 0;
+}
+
 static int __init cf_check vcpu_vaplic_init(struct vcpu *v)
 {
     int rc = 0;
@@ -143,6 +157,7 @@ static int __init cf_check vcpu_vaplic_init(struct vcpu *v)
 static const struct vintc_ops vaplic_ops = {
     .vcpu_init = vcpu_vaplic_init,
     .map_device_irqs_to_domain = vaplic_map_device_irqs_to_domain,
+    .is_access = vaplic_is_access,
 };
 
 static struct vintc * __init vaplic_alloc(void)
-- 
2.53.0