[Qemu-devel] [PATCH v4 19/22] target/arm: Create tagged ram when MTE is enabled

[Richard Henderson <richard.henderson@linaro.org>]

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 target/arm/cpu.h |  4 ++++
 hw/arm/virt.c    | 33 +++++++++++++++++++++++++++++++++
 target/arm/cpu.c | 21 ++++++++++++++++++---
 3 files changed, 55 insertions(+), 3 deletions(-)

diff --git a/target/arm/cpu.h b/target/arm/cpu.h
index e24d1e082c..6d60d2f37d 100644
--- a/target/arm/cpu.h
+++ b/target/arm/cpu.h
@@ -768,6 +768,9 @@ struct ARMCPU {
     /* MemoryRegion to use for secure physical accesses */
     MemoryRegion *secure_memory;
 
+    /* MemoryRegion to use for allocation tag accesses */
+    MemoryRegion *tag_memory;
+
     /* For v8M, pointer to the IDAU interface provided by board/SoC */
     Object *idau;
 
@@ -2904,6 +2907,7 @@ int cpu_mmu_index(CPUARMState *env, bool ifetch);
 typedef enum ARMASIdx {
     ARMASIdx_NS = 0,
     ARMASIdx_S = 1,
+    ARMASIdx_TAG = 2,
 } ARMASIdx;
 
 /* Return the Exception Level targeted by debug exceptions. */
diff --git a/hw/arm/virt.c b/hw/arm/virt.c
index c7fb5348ae..5be76fc2ee 100644
--- a/hw/arm/virt.c
+++ b/hw/arm/virt.c
@@ -1265,6 +1265,21 @@ static void create_secure_ram(VirtMachineState *vms,
     g_free(nodename);
 }
 
+static void create_tag_ram(VirtMachineState *vms, MachineState *machine,
+                           MemoryRegion *tag_sysmem)
+{
+    MemoryRegion *tagram = g_new(MemoryRegion, 1);
+    hwaddr base = vms->memmap[VIRT_MEM].base / 32;
+    hwaddr size = machine->ram_size / 32;
+
+    memory_region_init_ram(tagram, NULL, "mach-virt.tag", size, &error_fatal);
+    memory_region_add_subregion(tag_sysmem, base, tagram);
+
+    /* ??? Do we really need an fdt entry, or is MemTag enabled sufficient.  */
+    /* ??? We appear to need secure tag mem to go with secure mem.  */
+    /* ??? Does that imply we need a fourth address space?  */
+}
+
 static void *machvirt_dtb(const struct arm_boot_info *binfo, int *fdt_size)
 {
     const VirtMachineState *board = container_of(binfo, VirtMachineState,
@@ -1423,6 +1438,7 @@ static void machvirt_init(MachineState *machine)
     qemu_irq pic[NUM_IRQS];
     MemoryRegion *sysmem = get_system_memory();
     MemoryRegion *secure_sysmem = NULL;
+    MemoryRegion *tag_sysmem = NULL;
     int n, virt_max_cpus;
     MemoryRegion *ram = g_new(MemoryRegion, 1);
     bool firmware_loaded = bios_name || drive_get(IF_PFLASH, 0, 0);
@@ -1584,6 +1600,20 @@ static void machvirt_init(MachineState *machine)
                                      "secure-memory", &error_abort);
         }
 
+        /*
+         * The cpu adds the property iff MemTag is supported.
+         * If it is, we must allocate the ram to back that up.
+         */
+        if (object_property_find(cpuobj, "tag-memory", NULL)) {
+            if (!tag_sysmem) {
+                tag_sysmem = g_new(MemoryRegion, 1);
+                memory_region_init(tag_sysmem, OBJECT(machine),
+                                   "tag-memory", UINT64_MAX / 32);
+            }
+            object_property_set_link(cpuobj, OBJECT(tag_sysmem),
+                                     "tag-memory", &error_abort);
+        }
+
         object_property_set_bool(cpuobj, true, "realized", &error_fatal);
         object_unref(cpuobj);
     }
@@ -1626,6 +1656,9 @@ static void machvirt_init(MachineState *machine)
         create_secure_ram(vms, secure_sysmem);
         create_uart(vms, pic, VIRT_SECURE_UART, secure_sysmem, serial_hd(1));
     }
+    if (tag_sysmem) {
+        create_tag_ram(vms, machine, tag_sysmem);
+    }
 
     vms->highmem_ecam &= vms->highmem && (!firmware_loaded || aarch64);
 
diff --git a/target/arm/cpu.c b/target/arm/cpu.c
index 96f0ff0ec7..96506cf56d 100644
--- a/target/arm/cpu.c
+++ b/target/arm/cpu.c
@@ -870,6 +870,18 @@ void arm_cpu_post_init(Object *obj)
 
     qdev_property_add_static(DEVICE(obj), &arm_cpu_cfgend_property,
                              &error_abort);
+
+#ifndef CONFIG_USER_ONLY
+    if (arm_feature(&cpu->env, ARM_FEATURE_AARCH64) &&
+        cpu_isar_feature(aa64_mte, cpu)) {
+        object_property_add_link(obj, "tag-memory",
+                                 TYPE_MEMORY_REGION,
+                                 (Object **)&cpu->tag_memory,
+                                 qdev_prop_allow_set_link_before_realize,
+                                 OBJ_PROP_LINK_STRONG,
+                                 &error_abort);
+    }
+#endif
 }
 
 static void arm_cpu_finalizefn(Object *obj)
@@ -1182,16 +1194,19 @@ static void arm_cpu_realizefn(DeviceState *dev, Error **errp)
     init_cpreg_list(cpu);
 
 #ifndef CONFIG_USER_ONLY
+    cs->num_ases = 1;
     if (cpu->has_el3 || arm_feature(env, ARM_FEATURE_M_SECURITY)) {
         cs->num_ases = 2;
-
         if (!cpu->secure_memory) {
             cpu->secure_memory = cs->memory;
         }
         cpu_address_space_init(cs, ARMASIdx_S, "cpu-secure-memory",
                                cpu->secure_memory);
-    } else {
-        cs->num_ases = 1;
+    }
+    if (cpu->tag_memory != NULL) {
+        cs->num_ases = 3;
+        cpu_address_space_init(cs, ARMASIdx_TAG, "cpu-tag-memory",
+                               cpu->tag_memory);
     }
     cpu_address_space_init(cs, ARMASIdx_NS, "cpu-memory", cs->memory);
 
-- 
2.17.2