According to the Arm architecture, SMMU-originated memory accesses,
such as fetching commands or writing events for a secure stream, must
target the Secure Physical Address (PA) space. The existing model sends
all DMA to the global non-secure address_space_memory.

This patch introduces the infrastructure to differentiate between secure
and non-secure memory accesses. Firstly, SMMU_SEC_SID_S is added in
SMMUSecSID enum to represent the secure context. Then a weak global
symbol, arm_secure_address_space, is added, which can be provided by the
machine model to represent the Secure PA space.

A new helper, smmu_get_address_space(), selects the target address
space based on SEC_SID. All internal DMA calls
(dma_memory_read/write) will be updated to use this helper in follow-up
patches.

Signed-off-by: Tao Tang <tangtao1634@phytium.com.cn>
---
 hw/arm/smmu-common.c         |  8 ++++++++
 hw/arm/virt.c                |  5 +++++
 include/hw/arm/smmu-common.h | 27 +++++++++++++++++++++++++++
 3 files changed, 40 insertions(+)

diff --git a/hw/arm/smmu-common.c b/hw/arm/smmu-common.c
index 62a7612184..24db448683 100644
--- a/hw/arm/smmu-common.c
+++ b/hw/arm/smmu-common.c
@@ -30,6 +30,14 @@
 #include "hw/arm/smmu-common.h"
 #include "smmu-internal.h"
 
+/* Global state for secure address space availability */
+bool arm_secure_as_available;
+
+void smmu_enable_secure_address_space(void)
+{
+    arm_secure_as_available = true;
+}
+
 /* IOTLB Management */
 
 static guint smmu_iotlb_key_hash(gconstpointer v)
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index 175023897a..83dc62a095 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -92,6 +92,8 @@
 #include "hw/cxl/cxl_host.h"
 #include "qemu/guest-random.h"
 
+AddressSpace arm_secure_address_space;
+
 static GlobalProperty arm_virt_compat[] = {
     { TYPE_VIRTIO_IOMMU_PCI, "aw-bits", "48" },
 };
@@ -2257,6 +2259,9 @@ static void machvirt_init(MachineState *machine)
         memory_region_init(secure_sysmem, OBJECT(machine), "secure-memory",
                            UINT64_MAX);
         memory_region_add_subregion_overlap(secure_sysmem, 0, sysmem, -1);
+        address_space_init(&arm_secure_address_space, secure_sysmem,
+                           "secure-memory-space");
+        smmu_enable_secure_address_space();
     }
 
     firmware_loaded = virt_firmware_init(vms, sysmem,
diff --git a/include/hw/arm/smmu-common.h b/include/hw/arm/smmu-common.h
index b0dae18a62..d54558f94b 100644
--- a/include/hw/arm/smmu-common.h
+++ b/include/hw/arm/smmu-common.h
@@ -43,9 +43,36 @@
 /* StreamID Security state */
 typedef enum SMMUSecSID {
     SMMU_SEC_SID_NS = 0,
+    SMMU_SEC_SID_S,
     SMMU_SEC_SID_NUM,
 } SMMUSecSID;
 
+extern AddressSpace __attribute__((weak)) arm_secure_address_space;
+extern bool arm_secure_as_available;
+void smmu_enable_secure_address_space(void);
+
+/*
+ * Return the address space corresponding to the SEC_SID.
+ * If SEC_SID is Secure, but secure address space is not available,
+ * return NULL and print a warning message.
+ */
+static inline AddressSpace *smmu_get_address_space(SMMUSecSID sec_sid)
+{
+    switch (sec_sid) {
+    case SMMU_SEC_SID_NS:
+        return &address_space_memory;
+    case SMMU_SEC_SID_S:
+        if (!arm_secure_as_available || arm_secure_address_space.root == NULL) {
+            printf("Secure address space requested but not available");
+            return NULL;
+        }
+        return &arm_secure_address_space;
+    default:
+        printf("Unknown SEC_SID value %d", sec_sid);
+        return NULL;
+    }
+}
+
 /*
  * Page table walk error types
  */
-- 
2.34.1