[2/2] hw/cxl: Allow tracing component I/O accesses

Commit Message

Philippe Mathieu-Daudé Jan. 22, 2025, 6:56 a.m. UTC

Map the component I/O region as UnimplementedDevice
to be able to trace guest I/O accesses with '-d unimp'.

Signed-off-by: Philippe Mathieu-Daudé <[e-mail]>
---
 include/hw/cxl/cxl_component.h |  3 ++-
 hw/cxl/cxl-component-utils.c   | 14 +++++++++++---
 hw/cxl/Kconfig                 |  1 +
 3 files changed, 14 insertions(+), 4 deletions(-)

Patch

diff --git a/include/hw/cxl/cxl_component.h b/include/hw/cxl/cxl_component.h
index ac61c3f33a5..54fd369a838 100644
--- a/include/hw/cxl/cxl_component.h
+++ b/include/hw/cxl/cxl_component.h
@@ -18,6 +18,7 @@ 
 #include "qemu/range.h"
 #include "hw/cxl/cxl_cdat.h"
 #include "hw/register.h"
+#include "hw/misc/unimp.h"
 #include "qapi/error.h"
 
 enum reg_type {
@@ -218,7 +219,7 @@  typedef struct component_registers {
      *   0xe000 - 0xe3ff CXL ARB/MUX registers
      *   0xe400 - 0xffff RSVD
      */
-    MemoryRegion io;
+    UnimplementedDeviceState io;
 
     uint32_t cache_mem_registers[CXL2_COMPONENT_CM_REGION_SIZE >> 2];
     uint32_t cache_mem_regs_write_mask[CXL2_COMPONENT_CM_REGION_SIZE >> 2];
diff --git a/hw/cxl/cxl-component-utils.c b/hw/cxl/cxl-component-utils.c
index cd116c04012..6d593475d00 100644
--- a/hw/cxl/cxl-component-utils.c
+++ b/hw/cxl/cxl-component-utils.c
@@ -192,17 +192,25 @@  void cxl_component_register_block_init(Object *obj,
                                        const char *type)
 {
     ComponentRegisters *cregs = &cxl_cstate->crb;
+    DeviceState *io_dev;
+    SysBusDevice *io_sbd;
 
     memory_region_init(&cregs->component_registers, obj, type,
                        CXL2_COMPONENT_BLOCK_SIZE);
 
     /* io registers controls link which we don't care about in QEMU */
-    memory_region_init_io(&cregs->io, obj, NULL, NULL, ".io",
-                          CXL2_COMPONENT_IO_REGION_SIZE);
+    object_initialize_child(obj, "io", &cregs->io, TYPE_UNIMPLEMENTED_DEVICE);
+    io_dev = DEVICE(&cregs->io);
+    io_sbd = SYS_BUS_DEVICE(&cregs->io);
+    qdev_prop_set_string(io_dev, "name", ".io");
+    qdev_prop_set_uint64(io_dev, "size", CXL2_COMPONENT_IO_REGION_SIZE);
+    sysbus_realize(io_sbd, &error_fatal);
+
     memory_region_init_io(&cregs->cache_mem, obj, &cache_mem_ops, cxl_cstate,
                           ".cache_mem", CXL2_COMPONENT_CM_REGION_SIZE);
 
-    memory_region_add_subregion(&cregs->component_registers, 0, &cregs->io);
+    memory_region_add_subregion(&cregs->component_registers, 0,
+                                sysbus_mmio_get_region(io_sbd, 0));
     memory_region_add_subregion(&cregs->component_registers,
                                 CXL2_COMPONENT_IO_REGION_SIZE,
                                 &cregs->cache_mem);
diff --git a/hw/cxl/Kconfig b/hw/cxl/Kconfig
index 8e67519b161..d6c7536001e 100644
--- a/hw/cxl/Kconfig
+++ b/hw/cxl/Kconfig
@@ -1,3 +1,4 @@ 
 config CXL
     bool
     default y if PCI_EXPRESS
+    select UNIMP