diff mbox series

[RFC,v2,1/1] hw/arm/sbsa-ref: Support CXL Host Bridge & CFMW

Message ID 20241105104346.417102-2-wangyuquan1236@phytium.com.cn
State New
Headers show
Series Sbsa-ref CXL Enablement | expand

Commit Message

Yuquan Wang Nov. 5, 2024, 10:43 a.m. UTC
This creates a default pxb-cxl (bus_nr=0xc0) bridge with two
cxl root ports on sbsa-ref. And the memory layout places 64K
space for the cxl host bridge register regions(CHBCR) in the
sbsa-ref memmap.

In addition, this support indepentent mmio32(32M) & mmio64(1M)
space for cxl components.

To provide CFMWs on sbsa-ref, this extends 1TB space from the
hole above RAM Memory [SBSA_MEM] for CXL Fixed Memory Window.

Signed-off-by: Yuquan Wang <wangyuquan1236@phytium.com.cn>
---
 docs/system/arm/sbsa.rst  |   4 ++
 hw/arm/sbsa-ref.c         | 122 +++++++++++++++++++++++++++++++++++++-
 hw/cxl/cxl-host-stubs.c   |   2 +
 hw/cxl/cxl-host.c         |   2 +-
 include/hw/cxl/cxl_host.h |   2 +
 5 files changed, 130 insertions(+), 2 deletions(-)

Comments

Jonathan Cameron Nov. 7, 2024, 12:04 p.m. UTC | #1
On Tue,  5 Nov 2024 18:43:46 +0800
"Yuquan Wang" <wangyuquan1236@phytium.com.cn> wrote:

> This creates a default pxb-cxl (bus_nr=0xc0) bridge with two
> cxl root ports on sbsa-ref. And the memory layout places 64K
> space for the cxl host bridge register regions(CHBCR) in the
> sbsa-ref memmap.
> 
> In addition, this support indepentent mmio32(32M) & mmio64(1M)
> space for cxl components.

Those are too small.  Might work today but not sustainable.

I'm a bit surprised it was this simple to move the MMIO Space away
from what is normally done for PXBs.
I think it might work because the GPEX memory windows are effectively
unlimited in size but I'd like some more eyes on this from people
familiar with how all that works and whether there might be some
corner cases that you haven't seen yet.

Otherwise this looks ok to me.

> 
> To provide CFMWs on sbsa-ref, this extends 1TB space from the
> hole above RAM Memory [SBSA_MEM] for CXL Fixed Memory Window.
> 
> Signed-off-by: Yuquan Wang <wangyuquan1236@phytium.com.cn>
> ---
>  docs/system/arm/sbsa.rst  |   4 ++
>  hw/arm/sbsa-ref.c         | 122 +++++++++++++++++++++++++++++++++++++-
>  hw/cxl/cxl-host-stubs.c   |   2 +
>  hw/cxl/cxl-host.c         |   2 +-
>  include/hw/cxl/cxl_host.h |   2 +
>  5 files changed, 130 insertions(+), 2 deletions(-)
> 
> diff --git a/docs/system/arm/sbsa.rst b/docs/system/arm/sbsa.rst
> index 2bf3fc8d59..21b88e88e7 100644
> --- a/docs/system/arm/sbsa.rst
> +++ b/docs/system/arm/sbsa.rst
> @@ -28,6 +28,7 @@ The ``sbsa-ref`` board supports:
>    - E1000E ethernet card on PCIe bus
>    - Bochs display adapter on PCIe bus
>    - A generic SBSA watchdog device
> +  - CXL host bridge and CXL fixed memory window
>  
>  
>  Board to firmware interface
> @@ -92,3 +93,6 @@ Platform version changes:
>  
>  0.4
>    CPU topology information is present in devicetree.
> +
> +0.5
> +  CXL host bridge and CXL fixed memory window are supported.
> diff --git a/hw/arm/sbsa-ref.c b/hw/arm/sbsa-ref.c
> index e3195d5449..655dc82863 100644
> --- a/hw/arm/sbsa-ref.c
> +++ b/hw/arm/sbsa-ref.c
> @@ -36,12 +36,18 @@
>  #include "hw/arm/smmuv3.h"
>  #include "hw/block/flash.h"
>  #include "hw/boards.h"
> +#include "hw/cxl/cxl.h"
> +#include "hw/cxl/cxl_host.h"
>  #include "hw/ide/ide-bus.h"
>  #include "hw/ide/ahci-sysbus.h"
>  #include "hw/intc/arm_gicv3_common.h"
>  #include "hw/intc/arm_gicv3_its_common.h"
>  #include "hw/loader.h"
> +#include "hw/pci/pci_bridge.h"
> +#include "hw/pci/pci_bus.h"
> +#include "hw/pci/pcie_port.h"
>  #include "hw/pci-host/gpex.h"
> +#include "hw/pci-bridge/pci_expander_bridge.h"
>  #include "hw/qdev-properties.h"
>  #include "hw/usb.h"
>  #include "hw/usb/xhci.h"
> @@ -94,6 +100,10 @@ enum {
>      SBSA_SECURE_MEM,
>      SBSA_AHCI,
>      SBSA_XHCI,
> +    SBSA_CXL_HOST,
> +    SBSA_CXL_MMIO,
> +    SBSA_CXL_MMIO_HIGH,
> +    SBSA_CXL_FIXED_WINDOW,
>  };
>  
>  struct SBSAMachineState {
> @@ -105,6 +115,8 @@ struct SBSAMachineState {
>      int psci_conduit;
>      DeviceState *gic;
>      PFlashCFI01 *flash[2];
> +    CXLState cxl_devices_state;
> +    PCIBus *cxlbus;
>  };
>  
>  #define TYPE_SBSA_MACHINE   MACHINE_TYPE_NAME("sbsa-ref")
> @@ -132,6 +144,10 @@ static const MemMapEntry sbsa_ref_memmap[] = {
>      /* Space here reserved for more SMMUs */
>      [SBSA_AHCI] =               { 0x60100000, 0x00010000 },
>      [SBSA_XHCI] =               { 0x60110000, 0x00010000 },
> +    /* 64KiB CXL Host Bridge Registers space */
> +    [SBSA_CXL_HOST] =           { 0x60120000, 0x00010000 },

> +    /* 32M CXL 32-bit MMIO space */
> +    [SBSA_CXL_MMIO] =           { 0x60130000, 0x02000000 },
>      /* Space here reserved for other devices */
>      [SBSA_PCIE_PIO] =           { 0x7fff0000, 0x00010000 },
>      /* 32-bit address PCIE MMIO space */
> @@ -141,6 +157,10 @@ static const MemMapEntry sbsa_ref_memmap[] = {
>      /* ~1TB PCIE MMIO space (4GB to 1024GB boundary) */
>      [SBSA_PCIE_MMIO_HIGH] =     { 0x100000000ULL, 0xFF00000000ULL },
>      [SBSA_MEM] =                { 0x10000000000ULL, RAMLIMIT_BYTES },
> +    /* 1M CXL 64-bit MMIO space */
> +    [SBSA_CXL_MMIO_HIGH] =           { 0x90000000000ULL, 0x00100000 },

As above, make this bigger.  CXL devices can have substantial BARs.

> +    /* 1TB CXL FIXED WINDOW space */
> +    [SBSA_CXL_FIXED_WINDOW] =   { 0xA0000000000ULL, 0x10000000000ULL },
>  };
>  
>  static const int sbsa_ref_irqmap[] = {
> @@ -216,7 +236,7 @@ static void create_fdt(SBSAMachineState *sms)
>       *                        fw compatibility.
>       */
>      qemu_fdt_setprop_cell(fdt, "/", "machine-version-major", 0);
> -    qemu_fdt_setprop_cell(fdt, "/", "machine-version-minor", 4);
> +    qemu_fdt_setprop_cell(fdt, "/", "machine-version-minor", 5);
>  
>      if (ms->numa_state->have_numa_distance) {
>          int size = nb_numa_nodes * nb_numa_nodes * 3 * sizeof(uint32_t);
> @@ -629,6 +649,35 @@ static void create_smmu(const SBSAMachineState *sms, PCIBus *bus)
>      }
>  }
>  
> +static void create_pxb_cxl(SBSAMachineState *sms, PCIBus *bus)
> +{
> +    DeviceState *qdev = qdev_new(TYPE_PXB_CXL_DEV);
> +    PCIDevice *dev = PCI_DEVICE(qdev);
> +    CXLHost *host;
> +    PCIHostState *cxl;
> +    PCIDevice *cxlrp;
> +    PCIEPort *p;
> +    PCIESlot *s;
> +    int i;
> +
> +    sms->cxl_devices_state.is_enabled = true;
> +    qdev_prop_set_uint32(qdev, "bus_nr", 0xc0);
> +    pci_realize_and_unref(dev, bus, &error_fatal);
> +
> +    host = PXB_CXL_DEV(dev)->cxl_host_bridge;
> +    cxl = PCI_HOST_BRIDGE(host);
> +    sms->cxlbus = cxl->bus;
> +
> +    for (i = 0; i < 2; i++) {
> +        cxlrp = pci_new(-1, "cxl-rp");
> +        p = PCIE_PORT(cxlrp);
> +        s = PCIE_SLOT(cxlrp);
> +        p->port = i;
> +        s->slot = i;
> +        pci_realize_and_unref(cxlrp, sms->cxlbus, &error_fatal);
> +    }
> +}
> +
>  static void create_pcie(SBSAMachineState *sms)
>  {
>      hwaddr base_ecam = sbsa_ref_memmap[SBSA_PCIE_ECAM].base;
> @@ -638,6 +687,10 @@ static void create_pcie(SBSAMachineState *sms)
>      hwaddr base_mmio_high = sbsa_ref_memmap[SBSA_PCIE_MMIO_HIGH].base;
>      hwaddr size_mmio_high = sbsa_ref_memmap[SBSA_PCIE_MMIO_HIGH].size;
>      hwaddr base_pio = sbsa_ref_memmap[SBSA_PCIE_PIO].base;
> +    hwaddr cxl_base_mmio = sbsa_ref_memmap[SBSA_CXL_MMIO].base;
> +    hwaddr cxl_size_mmio = sbsa_ref_memmap[SBSA_CXL_MMIO].size;
> +    hwaddr cxl_base_mmio_high = sbsa_ref_memmap[SBSA_CXL_MMIO_HIGH].base;
> +    hwaddr cxl_size_mmio_high = sbsa_ref_memmap[SBSA_CXL_MMIO_HIGH].size;
>      int irq = sbsa_ref_irqmap[SBSA_PCIE];
>      MachineClass *mc = MACHINE_GET_CLASS(sms);
>      MemoryRegion *mmio_alias, *mmio_alias_high, *mmio_reg;
> @@ -686,6 +739,67 @@ static void create_pcie(SBSAMachineState *sms)
>      pci_create_simple(pci->bus, -1, "bochs-display");
>  
>      create_smmu(sms, pci->bus);
> +
> +    /* Map CXL MMIO space */
> +    mmio_alias = g_new0(MemoryRegion, 1);
> +    mmio_reg = sysbus_mmio_get_region(SYS_BUS_DEVICE(dev), 1);
> +    memory_region_init_alias(mmio_alias, OBJECT(dev), "cxl-mmio",
> +                             mmio_reg, cxl_base_mmio, cxl_size_mmio);
> +    memory_region_add_subregion(get_system_memory(), cxl_base_mmio, mmio_alias);
> +
> +    /* Map CXL MMIO_HIGH space */
> +    mmio_alias_high = g_new0(MemoryRegion, 1);
> +    memory_region_init_alias(mmio_alias_high, OBJECT(dev), "cxl-mmio-high",
> +                             mmio_reg, cxl_base_mmio_high, cxl_size_mmio_high);
> +    memory_region_add_subregion(get_system_memory(), cxl_base_mmio_high,
> +                                mmio_alias_high);
> +
> +    create_pxb_cxl(sms, pci->bus);
> +}

>  
>  static void *sbsa_ref_dtb(const struct arm_boot_info *binfo, int *fdt_size)
> @@ -821,6 +935,12 @@ static void sbsa_ref_init(MachineState *machine)
>  
>      create_pcie(sms);
>  
> +    create_cxl_host_reg_region(sms);
> +    create_cxl_fixed_window_region(sms, sysmem);
> +    pxb_cxl_hook_up_registers(&sms->cxl_devices_state, sms->cxlbus,
> +                              &error_fatal);
> +    sbsa_cxl_fmws_link_targets(sms, &error_fatal);
> +
>      create_secure_ec(secure_sysmem);
>  
>      sms->bootinfo.ram_size = machine->ram_size;
> diff --git a/hw/cxl/cxl-host-stubs.c b/hw/cxl/cxl-host-stubs.c
> index cae4afcdde..aea94933ba 100644
> --- a/hw/cxl/cxl-host-stubs.c
> +++ b/hw/cxl/cxl-host-stubs.c
> @@ -11,5 +11,7 @@
>  void cxl_fmws_link_targets(CXLState *stat, Error **errp) {};
>  void cxl_machine_init(Object *obj, CXLState *state) {};
>  void cxl_hook_up_pxb_registers(PCIBus *bus, CXLState *state, Error **errp) {};
> +void cxl_fixed_memory_window_config(CXLState *cxl_state,
> +                        CXLFixedMemoryWindowOptions *object, Error **errp) {};
>  
>  const MemoryRegionOps cfmws_ops;
> diff --git a/hw/cxl/cxl-host.c b/hw/cxl/cxl-host.c
> index e9f2543c43..d408c7db15 100644
> --- a/hw/cxl/cxl-host.c
> +++ b/hw/cxl/cxl-host.c
> @@ -22,7 +22,7 @@
>  #include "hw/pci/pcie_port.h"
>  #include "hw/pci-bridge/pci_expander_bridge.h"
>  
> -static void cxl_fixed_memory_window_config(CXLState *cxl_state,
> +void cxl_fixed_memory_window_config(CXLState *cxl_state,
>                                             CXLFixedMemoryWindowOptions *object,
>                                             Error **errp)
>  {
> diff --git a/include/hw/cxl/cxl_host.h b/include/hw/cxl/cxl_host.h
> index c9bc9c7c50..f3184733aa 100644
> --- a/include/hw/cxl/cxl_host.h
> +++ b/include/hw/cxl/cxl_host.h
> @@ -16,6 +16,8 @@
>  void cxl_machine_init(Object *obj, CXLState *state);
>  void cxl_fmws_link_targets(CXLState *stat, Error **errp);
>  void cxl_hook_up_pxb_registers(PCIBus *bus, CXLState *state, Error **errp);
> +void cxl_fixed_memory_window_config(CXLState *cxl_state,
> +                        CXLFixedMemoryWindowOptions *object, Error **errp);
>  
>  extern const MemoryRegionOps cfmws_ops;
>
Marcin Juszkiewicz Nov. 12, 2024, 5:10 p.m. UTC | #2
W dniu 7.11.2024 o 13:04, Jonathan Cameron pisze:
> On Tue,  5 Nov 2024 18:43:46 +0800
> "Yuquan Wang"<wangyuquan1236@phytium.com.cn> wrote:
> 
>> This creates a default pxb-cxl (bus_nr=0xc0) bridge with two
>> cxl root ports on sbsa-ref. And the memory layout places 64K
>> space for the cxl host bridge register regions(CHBCR) in the
>> sbsa-ref memmap.
>>
>> In addition, this support indepentent mmio32(32M) & mmio64(1M)
>> space for cxl components.

> Those are too small.  Might work today but not sustainable.
> 
> I'm a bit surprised it was this simple to move the MMIO Space away
> from what is normally done for PXBs.
> I think it might work because the GPEX memory windows are effectively
> unlimited in size but I'd like some more eyes on this from people
> familiar with how all that works and whether there might be some
> corner cases that you haven't seen yet.

I see the same problem as with multiple PCIe buses (for NUMA systems):

pci 0000:c0:00.0: bridge window [io  size 0x1000]: can't assign; no space
pci 0000:c0:00.0: bridge window [io  size 0x1000]: failed to assign
pci 0000:c0:01.0: bridge window [io  size 0x1000]: can't assign; no space
pci 0000:c0:01.0: bridge window [io  size 0x1000]: failed to assign

I do not know how it looks on real hardware (all my systems have one
PCIe bus) but shouldn't each host bridge have own separate resource
windows for config space, buses, mmio etc.?

Now we squeeze all pcie buses as pcie-pxb devices and this patch adds
cxl to the combo.
diff mbox series

Patch

diff --git a/docs/system/arm/sbsa.rst b/docs/system/arm/sbsa.rst
index 2bf3fc8d59..21b88e88e7 100644
--- a/docs/system/arm/sbsa.rst
+++ b/docs/system/arm/sbsa.rst
@@ -28,6 +28,7 @@  The ``sbsa-ref`` board supports:
   - E1000E ethernet card on PCIe bus
   - Bochs display adapter on PCIe bus
   - A generic SBSA watchdog device
+  - CXL host bridge and CXL fixed memory window
 
 
 Board to firmware interface
@@ -92,3 +93,6 @@  Platform version changes:
 
 0.4
   CPU topology information is present in devicetree.
+
+0.5
+  CXL host bridge and CXL fixed memory window are supported.
diff --git a/hw/arm/sbsa-ref.c b/hw/arm/sbsa-ref.c
index e3195d5449..655dc82863 100644
--- a/hw/arm/sbsa-ref.c
+++ b/hw/arm/sbsa-ref.c
@@ -36,12 +36,18 @@ 
 #include "hw/arm/smmuv3.h"
 #include "hw/block/flash.h"
 #include "hw/boards.h"
+#include "hw/cxl/cxl.h"
+#include "hw/cxl/cxl_host.h"
 #include "hw/ide/ide-bus.h"
 #include "hw/ide/ahci-sysbus.h"
 #include "hw/intc/arm_gicv3_common.h"
 #include "hw/intc/arm_gicv3_its_common.h"
 #include "hw/loader.h"
+#include "hw/pci/pci_bridge.h"
+#include "hw/pci/pci_bus.h"
+#include "hw/pci/pcie_port.h"
 #include "hw/pci-host/gpex.h"
+#include "hw/pci-bridge/pci_expander_bridge.h"
 #include "hw/qdev-properties.h"
 #include "hw/usb.h"
 #include "hw/usb/xhci.h"
@@ -94,6 +100,10 @@  enum {
     SBSA_SECURE_MEM,
     SBSA_AHCI,
     SBSA_XHCI,
+    SBSA_CXL_HOST,
+    SBSA_CXL_MMIO,
+    SBSA_CXL_MMIO_HIGH,
+    SBSA_CXL_FIXED_WINDOW,
 };
 
 struct SBSAMachineState {
@@ -105,6 +115,8 @@  struct SBSAMachineState {
     int psci_conduit;
     DeviceState *gic;
     PFlashCFI01 *flash[2];
+    CXLState cxl_devices_state;
+    PCIBus *cxlbus;
 };
 
 #define TYPE_SBSA_MACHINE   MACHINE_TYPE_NAME("sbsa-ref")
@@ -132,6 +144,10 @@  static const MemMapEntry sbsa_ref_memmap[] = {
     /* Space here reserved for more SMMUs */
     [SBSA_AHCI] =               { 0x60100000, 0x00010000 },
     [SBSA_XHCI] =               { 0x60110000, 0x00010000 },
+    /* 64KiB CXL Host Bridge Registers space */
+    [SBSA_CXL_HOST] =           { 0x60120000, 0x00010000 },
+    /* 32M CXL 32-bit MMIO space */
+    [SBSA_CXL_MMIO] =           { 0x60130000, 0x02000000 },
     /* Space here reserved for other devices */
     [SBSA_PCIE_PIO] =           { 0x7fff0000, 0x00010000 },
     /* 32-bit address PCIE MMIO space */
@@ -141,6 +157,10 @@  static const MemMapEntry sbsa_ref_memmap[] = {
     /* ~1TB PCIE MMIO space (4GB to 1024GB boundary) */
     [SBSA_PCIE_MMIO_HIGH] =     { 0x100000000ULL, 0xFF00000000ULL },
     [SBSA_MEM] =                { 0x10000000000ULL, RAMLIMIT_BYTES },
+    /* 1M CXL 64-bit MMIO space */
+    [SBSA_CXL_MMIO_HIGH] =           { 0x90000000000ULL, 0x00100000 },
+    /* 1TB CXL FIXED WINDOW space */
+    [SBSA_CXL_FIXED_WINDOW] =   { 0xA0000000000ULL, 0x10000000000ULL },
 };
 
 static const int sbsa_ref_irqmap[] = {
@@ -216,7 +236,7 @@  static void create_fdt(SBSAMachineState *sms)
      *                        fw compatibility.
      */
     qemu_fdt_setprop_cell(fdt, "/", "machine-version-major", 0);
-    qemu_fdt_setprop_cell(fdt, "/", "machine-version-minor", 4);
+    qemu_fdt_setprop_cell(fdt, "/", "machine-version-minor", 5);
 
     if (ms->numa_state->have_numa_distance) {
         int size = nb_numa_nodes * nb_numa_nodes * 3 * sizeof(uint32_t);
@@ -629,6 +649,35 @@  static void create_smmu(const SBSAMachineState *sms, PCIBus *bus)
     }
 }
 
+static void create_pxb_cxl(SBSAMachineState *sms, PCIBus *bus)
+{
+    DeviceState *qdev = qdev_new(TYPE_PXB_CXL_DEV);
+    PCIDevice *dev = PCI_DEVICE(qdev);
+    CXLHost *host;
+    PCIHostState *cxl;
+    PCIDevice *cxlrp;
+    PCIEPort *p;
+    PCIESlot *s;
+    int i;
+
+    sms->cxl_devices_state.is_enabled = true;
+    qdev_prop_set_uint32(qdev, "bus_nr", 0xc0);
+    pci_realize_and_unref(dev, bus, &error_fatal);
+
+    host = PXB_CXL_DEV(dev)->cxl_host_bridge;
+    cxl = PCI_HOST_BRIDGE(host);
+    sms->cxlbus = cxl->bus;
+
+    for (i = 0; i < 2; i++) {
+        cxlrp = pci_new(-1, "cxl-rp");
+        p = PCIE_PORT(cxlrp);
+        s = PCIE_SLOT(cxlrp);
+        p->port = i;
+        s->slot = i;
+        pci_realize_and_unref(cxlrp, sms->cxlbus, &error_fatal);
+    }
+}
+
 static void create_pcie(SBSAMachineState *sms)
 {
     hwaddr base_ecam = sbsa_ref_memmap[SBSA_PCIE_ECAM].base;
@@ -638,6 +687,10 @@  static void create_pcie(SBSAMachineState *sms)
     hwaddr base_mmio_high = sbsa_ref_memmap[SBSA_PCIE_MMIO_HIGH].base;
     hwaddr size_mmio_high = sbsa_ref_memmap[SBSA_PCIE_MMIO_HIGH].size;
     hwaddr base_pio = sbsa_ref_memmap[SBSA_PCIE_PIO].base;
+    hwaddr cxl_base_mmio = sbsa_ref_memmap[SBSA_CXL_MMIO].base;
+    hwaddr cxl_size_mmio = sbsa_ref_memmap[SBSA_CXL_MMIO].size;
+    hwaddr cxl_base_mmio_high = sbsa_ref_memmap[SBSA_CXL_MMIO_HIGH].base;
+    hwaddr cxl_size_mmio_high = sbsa_ref_memmap[SBSA_CXL_MMIO_HIGH].size;
     int irq = sbsa_ref_irqmap[SBSA_PCIE];
     MachineClass *mc = MACHINE_GET_CLASS(sms);
     MemoryRegion *mmio_alias, *mmio_alias_high, *mmio_reg;
@@ -686,6 +739,67 @@  static void create_pcie(SBSAMachineState *sms)
     pci_create_simple(pci->bus, -1, "bochs-display");
 
     create_smmu(sms, pci->bus);
+
+    /* Map CXL MMIO space */
+    mmio_alias = g_new0(MemoryRegion, 1);
+    mmio_reg = sysbus_mmio_get_region(SYS_BUS_DEVICE(dev), 1);
+    memory_region_init_alias(mmio_alias, OBJECT(dev), "cxl-mmio",
+                             mmio_reg, cxl_base_mmio, cxl_size_mmio);
+    memory_region_add_subregion(get_system_memory(), cxl_base_mmio, mmio_alias);
+
+    /* Map CXL MMIO_HIGH space */
+    mmio_alias_high = g_new0(MemoryRegion, 1);
+    memory_region_init_alias(mmio_alias_high, OBJECT(dev), "cxl-mmio-high",
+                             mmio_reg, cxl_base_mmio_high, cxl_size_mmio_high);
+    memory_region_add_subregion(get_system_memory(), cxl_base_mmio_high,
+                                mmio_alias_high);
+
+    create_pxb_cxl(sms, pci->bus);
+}
+
+static void create_cxl_host_reg_region(SBSAMachineState *sms)
+{
+    MemoryRegion *sysmem = get_system_memory();
+    MemoryRegion *mr = &sms->cxl_devices_state.host_mr;
+
+    memory_region_init(mr, OBJECT(sms), "cxl_host_reg",
+                       sbsa_ref_memmap[SBSA_CXL_HOST].size);
+    memory_region_add_subregion(sysmem, sbsa_ref_memmap[SBSA_CXL_HOST].base, mr);
+}
+
+static void create_cxl_fixed_window_region(SBSAMachineState *sms,
+                                           MemoryRegion *mem)
+{
+    char *cxl_host = object_get_canonical_path(OBJECT(sms->cxlbus));
+    hwaddr base = sbsa_ref_memmap[SBSA_CXL_FIXED_WINDOW].base;
+    GList *it;
+    strList host_target = { NULL, cxl_host };
+    CXLFixedMemoryWindowOptions sbsa_ref_cfmwoptions = {
+        .size = 1 * TiB,
+        .has_interleave_granularity = false,
+        .targets = &host_target,
+    };
+    CXLFixedWindow *fw;
+
+    cxl_fixed_memory_window_config(&sms->cxl_devices_state,
+                                       &sbsa_ref_cfmwoptions, &error_fatal);
+
+    it = sms->cxl_devices_state.fixed_windows;
+    fw = it->data;
+    fw->base = base;
+    memory_region_init_io(&fw->mr, OBJECT(sms), &cfmws_ops, fw,
+                            "cxl-fixed-memory-region", fw->size);
+
+    memory_region_add_subregion(mem, fw->base, &fw->mr);
+}
+
+static void sbsa_cxl_fmws_link_targets(SBSAMachineState *sms,
+                                Error **errp)
+{
+    GList *it = sms->cxl_devices_state.fixed_windows;
+    CXLFixedWindow *fw = it->data;
+
+    fw->target_hbs[0] = PXB_CXL_DEV(pci_bridge_get_device(sms->cxlbus));
 }
 
 static void *sbsa_ref_dtb(const struct arm_boot_info *binfo, int *fdt_size)
@@ -821,6 +935,12 @@  static void sbsa_ref_init(MachineState *machine)
 
     create_pcie(sms);
 
+    create_cxl_host_reg_region(sms);
+    create_cxl_fixed_window_region(sms, sysmem);
+    pxb_cxl_hook_up_registers(&sms->cxl_devices_state, sms->cxlbus,
+                              &error_fatal);
+    sbsa_cxl_fmws_link_targets(sms, &error_fatal);
+
     create_secure_ec(secure_sysmem);
 
     sms->bootinfo.ram_size = machine->ram_size;
diff --git a/hw/cxl/cxl-host-stubs.c b/hw/cxl/cxl-host-stubs.c
index cae4afcdde..aea94933ba 100644
--- a/hw/cxl/cxl-host-stubs.c
+++ b/hw/cxl/cxl-host-stubs.c
@@ -11,5 +11,7 @@ 
 void cxl_fmws_link_targets(CXLState *stat, Error **errp) {};
 void cxl_machine_init(Object *obj, CXLState *state) {};
 void cxl_hook_up_pxb_registers(PCIBus *bus, CXLState *state, Error **errp) {};
+void cxl_fixed_memory_window_config(CXLState *cxl_state,
+                        CXLFixedMemoryWindowOptions *object, Error **errp) {};
 
 const MemoryRegionOps cfmws_ops;
diff --git a/hw/cxl/cxl-host.c b/hw/cxl/cxl-host.c
index e9f2543c43..d408c7db15 100644
--- a/hw/cxl/cxl-host.c
+++ b/hw/cxl/cxl-host.c
@@ -22,7 +22,7 @@ 
 #include "hw/pci/pcie_port.h"
 #include "hw/pci-bridge/pci_expander_bridge.h"
 
-static void cxl_fixed_memory_window_config(CXLState *cxl_state,
+void cxl_fixed_memory_window_config(CXLState *cxl_state,
                                            CXLFixedMemoryWindowOptions *object,
                                            Error **errp)
 {
diff --git a/include/hw/cxl/cxl_host.h b/include/hw/cxl/cxl_host.h
index c9bc9c7c50..f3184733aa 100644
--- a/include/hw/cxl/cxl_host.h
+++ b/include/hw/cxl/cxl_host.h
@@ -16,6 +16,8 @@ 
 void cxl_machine_init(Object *obj, CXLState *state);
 void cxl_fmws_link_targets(CXLState *stat, Error **errp);
 void cxl_hook_up_pxb_registers(PCIBus *bus, CXLState *state, Error **errp);
+void cxl_fixed_memory_window_config(CXLState *cxl_state,
+                        CXLFixedMemoryWindowOptions *object, Error **errp);
 
 extern const MemoryRegionOps cfmws_ops;