Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted

Pull networking updates from Jakub Kicinski:
 "Core:

   - Add dedicated kmem_cache for typical/small skb->head, avoid having
     to access struct page at kfree time, and improve memory use.

   - Introduce sysctl to set default RPS configuration for new netdevs.

   - Define Netlink protocol specification format which can be used to
     describe messages used by each family and auto-generate parsers.
     Add tools for generating kernel data structures and uAPI headers.

   - Expose all net/core sysctls inside netns.

   - Remove 4s sleep in netpoll if carrier is instantly detected on
     boot.

   - Add configurable limit of MDB entries per port, and port-vlan.

   - Continue populating drop reasons throughout the stack.

   - Retire a handful of legacy Qdiscs and classifiers.

  Protocols:

   - Support IPv4 big TCP (TSO frames larger than 64kB).

   - Add IP_LOCAL_PORT_RANGE socket option, to control local port range
     on socket by socket basis.

   - Track and report in procfs number of MPTCP sockets used.

   - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path
     manager.

   - IPv6: don't check net.ipv6.route.max_size and rely on garbage
     collection to free memory (similarly to IPv4).

   - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986).

   - ICMP: add per-rate limit counters.

   - Add support for user scanning requests in ieee802154.

   - Remove static WEP support.

   - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate
     reporting.

   - WiFi 7 EHT channel puncturing support (client & AP).

  BPF:

   - Add a rbtree data structure following the "next-gen data structure"
     precedent set by recently added linked list, that is, by using
     kfunc + kptr instead of adding a new BPF map type.

   - Expose XDP hints via kfuncs with initial support for RX hash and
     timestamp metadata.

   - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to
     better support decap on GRE tunnel devices not operating in collect
     metadata.

   - Improve x86 JIT's codegen for PROBE_MEM runtime error checks.

   - Remove the need for trace_printk_lock for bpf_trace_printk and
     bpf_trace_vprintk helpers.

   - Extend libbpf's bpf_tracing.h support for tracing arguments of
     kprobes/uprobes and syscall as a special case.

   - Significantly reduce the search time for module symbols by
     livepatch and BPF.

   - Enable cpumasks to be used as kptrs, which is useful for tracing
     programs tracking which tasks end up running on which CPUs in
     different time intervals.

   - Add support for BPF trampoline on s390x and riscv64.

   - Add capability to export the XDP features supported by the NIC.

   - Add __bpf_kfunc tag for marking kernel functions as kfuncs.

   - Add cgroup.memory=nobpf kernel parameter option to disable BPF
     memory accounting for container environments.

  Netfilter:

   - Remove the CLUSTERIP target. It has been marked as obsolete for
     years, and we still have WARN splats wrt races of the out-of-band
     /proc interface installed by this target.

   - Add 'destroy' commands to nf_tables. They are identical to the
     existing 'delete' commands, but do not return an error if the
     referenced object (set, chain, rule...) did not exist.

  Driver API:

   - Improve cpumask_local_spread() locality to help NICs set the right
     IRQ affinity on AMD platforms.

   - Separate C22 and C45 MDIO bus transactions more clearly.

   - Introduce new DCB table to control DSCP rewrite on egress.

   - Support configuration of Physical Layer Collision Avoidance (PLCA)
     Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of
     shared medium Ethernet.

   - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing
     preemption of low priority frames by high priority frames.

   - Add support for controlling MACSec offload using netlink SET.

   - Rework devlink instance refcounts to allow registration and
     de-registration under the instance lock. Split the code into
     multiple files, drop some of the unnecessarily granular locks and
     factor out common parts of netlink operation handling.

   - Add TX frame aggregation parameters (for USB drivers).

   - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning
     messages with notifications for debug.

   - Allow offloading of UDP NEW connections via act_ct.

   - Add support for per action HW stats in TC.

   - Support hardware miss to TC action (continue processing in SW from
     a specific point in the action chain).

   - Warn if old Wireless Extension user space interface is used with
     modern cfg80211/mac80211 drivers. Do not support Wireless
     Extensions for Wi-Fi 7 devices at all. Everyone should switch to
     using nl80211 interface instead.

   - Improve the CAN bit timing configuration. Use extack to return
     error messages directly to user space, update the SJW handling,
     including the definition of a new default value that will benefit
     CAN-FD controllers, by increasing their oscillator tolerance.

  New hardware / drivers:

   - Ethernet:
      - nVidia BlueField-3 support (control traffic driver)
      - Ethernet support for imx93 SoCs
      - Motorcomm yt8531 gigabit Ethernet PHY
      - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA)
      - Microchip LAN8841 PHY (incl. cable diagnostics and PTP)
      - Amlogic gxl MDIO mux

   - WiFi:
      - RealTek RTL8188EU (rtl8xxxu)
      - Qualcomm Wi-Fi 7 devices (ath12k)

   - CAN:
      - Renesas R-Car V4H

  Drivers:

   - Bluetooth:
      - Set Per Platform Antenna Gain (PPAG) for Intel controllers.

   - Ethernet NICs:
      - Intel (1G, igc):
         - support TSN / Qbv / packet scheduling features of i226 model
      - Intel (100G, ice):
         - use GNSS subsystem instead of TTY
         - multi-buffer XDP support
         - extend support for GPIO pins to E823 devices
      - nVidia/Mellanox:
         - update the shared buffer configuration on PFC commands
         - implement PTP adjphase function for HW offset control
         - TC support for Geneve and GRE with VF tunnel offload
         - more efficient crypto key management method
         - multi-port eswitch support
      - Netronome/Corigine:
         - add DCB IEEE support
         - support IPsec offloading for NFP3800
      - Freescale/NXP (enetc):
         - support XDP_REDIRECT for XDP non-linear buffers
         - improve reconfig, avoid link flap and waiting for idle
         - support MAC Merge layer
      - Other NICs:
         - sfc/ef100: add basic devlink support for ef100
         - ionic: rx_push mode operation (writing descriptors via MMIO)
         - bnxt: use the auxiliary bus abstraction for RDMA
         - r8169: disable ASPM and reset bus in case of tx timeout
         - cpsw: support QSGMII mode for J721e CPSW9G
         - cpts: support pulse-per-second output
         - ngbe: add an mdio bus driver
         - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing
         - r8152: handle devices with FW with NCM support
         - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation
         - virtio-net: support multi buffer XDP
         - virtio/vsock: replace virtio_vsock_pkt with sk_buff
         - tsnep: XDP support

   - Ethernet high-speed switches:
      - nVidia/Mellanox (mlxsw):
         - add support for latency TLV (in FW control messages)
      - Microchip (sparx5):
         - separate explicit and implicit traffic forwarding rules, make
           the implicit rules always active
         - add support for egress DSCP rewrite
         - IS0 VCAP support (Ingress Classification)
         - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS
           etc.)
         - ES2 VCAP support (Egress Access Control)
         - support for Per-Stream Filtering and Policing (802.1Q,
           8.6.5.1)

   - Ethernet embedded switches:
      - Marvell (mv88e6xxx):
         - add MAB (port auth) offload support
         - enable PTP receive for mv88e6390
      - NXP (ocelot):
         - support MAC Merge layer
         - support for the the vsc7512 internal copper phys
      - Microchip:
         - lan9303: convert to PHYLINK
         - lan966x: support TC flower filter statistics
         - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x
         - lan937x: support Credit Based Shaper configuration
         - ksz9477: support Energy Efficient Ethernet
      - other:
         - qca8k: convert to regmap read/write API, use bulk operations
         - rswitch: Improve TX timestamp accuracy

   - Intel WiFi (iwlwifi):
      - EHT (Wi-Fi 7) rate reporting
      - STEP equalizer support: transfer some STEP (connection to radio
        on platforms with integrated wifi) related parameters from the
        BIOS to the firmware.

   - Qualcomm 802.11ax WiFi (ath11k):
      - IPQ5018 support
      - Fine Timing Measurement (FTM) responder role support
      - channel 177 support

   - MediaTek WiFi (mt76):
      - per-PHY LED support
      - mt7996: EHT (Wi-Fi 7) support
      - Wireless Ethernet Dispatch (WED) reset support
      - switch to using page pool allocator

   - RealTek WiFi (rtw89):
      - support new version of Bluetooth co-existance

   - Mobile:
      - rmnet: support TX aggregation"

* tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits)
  page_pool: add a comment explaining the fragment counter usage
  net: ethtool: fix __ethtool_dev_mm_supported() implementation
  ethtool: pse-pd: Fix double word in comments
  xsk: add linux/vmalloc.h to xsk.c
  sefltests: netdevsim: wait for devlink instance after netns removal
  selftest: fib_tests: Always cleanup before exit
  net/mlx5e: Align IPsec ASO result memory to be as required by hardware
  net/mlx5e: TC, Set CT miss to the specific ct action instance
  net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG
  net/mlx5: Refactor tc miss handling to a single function
  net/mlx5: Kconfig: Make tc offload depend on tc skb extension
  net/sched: flower: Support hardware miss to tc action
  net/sched: flower: Move filter handle initialization earlier
  net/sched: cls_api: Support hardware miss to tc action
  net/sched: Rename user cookie and act cookie
  sfc: fix builds without CONFIG_RTC_LIB
  sfc: clean up some inconsistent indentings
  net/mlx4_en: Introduce flexible array to silence overflow warning
  net: lan966x: Fix possible deadlock inside PTP
  net/ulp: Remove redundant ->clone() test in inet_clone_ulp().
  ...

1 files changed, 738 insertions, 0 deletions

diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c
new file mode 100644
index 000000000..13cde44c6
--- /dev/null
+++ b/drivers/cxl/acpi.c
@@ -0,0 +1,738 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright(c) 2021 Intel Corporation. All rights reserved. */
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/acpi.h>
+#include <linux/pci.h>
+#include <asm/div64.h>
+#include "cxlpci.h"
+#include "cxl.h"
+
+#define CXL_RCRB_SIZE	SZ_8K
+
+struct cxl_cxims_data {
+	int nr_maps;
+	u64 xormaps[];
+};
+
+/*
+ * Find a targets entry (n) in the host bridge interleave list.
+ * CXL Specfication 3.0 Table 9-22
+ */
+static int cxl_xor_calc_n(u64 hpa, struct cxl_cxims_data *cximsd, int iw,
+			  int ig)
+{
+	int i = 0, n = 0;
+	u8 eiw;
+
+	/* IW: 2,4,6,8,12,16 begin building 'n' using xormaps */
+	if (iw != 3) {
+		for (i = 0; i < cximsd->nr_maps; i++)
+			n |= (hweight64(hpa & cximsd->xormaps[i]) & 1) << i;
+	}
+	/* IW: 3,6,12 add a modulo calculation to 'n' */
+	if (!is_power_of_2(iw)) {
+		if (ways_to_eiw(iw, &eiw))
+			return -1;
+		hpa &= GENMASK_ULL(51, eiw + ig);
+		n |= do_div(hpa, 3) << i;
+	}
+	return n;
+}
+
+static struct cxl_dport *cxl_hb_xor(struct cxl_root_decoder *cxlrd, int pos)
+{
+	struct cxl_cxims_data *cximsd = cxlrd->platform_data;
+	struct cxl_switch_decoder *cxlsd = &cxlrd->cxlsd;
+	struct cxl_decoder *cxld = &cxlsd->cxld;
+	int ig = cxld->interleave_granularity;
+	int iw = cxld->interleave_ways;
+	int n = 0;
+	u64 hpa;
+
+	if (dev_WARN_ONCE(&cxld->dev,
+			  cxld->interleave_ways != cxlsd->nr_targets,
+			  "misconfigured root decoder\n"))
+		return NULL;
+
+	hpa = cxlrd->res->start + pos * ig;
+
+	/* Entry (n) is 0 for no interleave (iw == 1) */
+	if (iw != 1)
+		n = cxl_xor_calc_n(hpa, cximsd, iw, ig);
+
+	if (n < 0)
+		return NULL;
+
+	return cxlrd->cxlsd.target[n];
+}
+
+struct cxl_cxims_context {
+	struct device *dev;
+	struct cxl_root_decoder *cxlrd;
+};
+
+static int cxl_parse_cxims(union acpi_subtable_headers *header, void *arg,
+			   const unsigned long end)
+{
+	struct acpi_cedt_cxims *cxims = (struct acpi_cedt_cxims *)header;
+	struct cxl_cxims_context *ctx = arg;
+	struct cxl_root_decoder *cxlrd = ctx->cxlrd;
+	struct cxl_decoder *cxld = &cxlrd->cxlsd.cxld;
+	struct device *dev = ctx->dev;
+	struct cxl_cxims_data *cximsd;
+	unsigned int hbig, nr_maps;
+	int rc;
+
+	rc = eig_to_granularity(cxims->hbig, &hbig);
+	if (rc)
+		return rc;
+
+	/* Does this CXIMS entry apply to the given CXL Window? */
+	if (hbig != cxld->interleave_granularity)
+		return 0;
+
+	/* IW 1,3 do not use xormaps and skip this parsing entirely */
+	if (is_power_of_2(cxld->interleave_ways))
+		/* 2, 4, 8, 16 way */
+		nr_maps = ilog2(cxld->interleave_ways);
+	else
+		/* 6, 12 way */
+		nr_maps = ilog2(cxld->interleave_ways / 3);
+
+	if (cxims->nr_xormaps < nr_maps) {
+		dev_dbg(dev, "CXIMS nr_xormaps[%d] expected[%d]\n",
+			cxims->nr_xormaps, nr_maps);
+		return -ENXIO;
+	}
+
+	cximsd = devm_kzalloc(dev, struct_size(cximsd, xormaps, nr_maps),
+			      GFP_KERNEL);
+	if (!cximsd)
+		return -ENOMEM;
+	memcpy(cximsd->xormaps, cxims->xormap_list,
+	       nr_maps * sizeof(*cximsd->xormaps));
+	cximsd->nr_maps = nr_maps;
+	cxlrd->platform_data = cximsd;
+
+	return 0;
+}
+
+static unsigned long cfmws_to_decoder_flags(int restrictions)
+{
+	unsigned long flags = CXL_DECODER_F_ENABLE;
+
+	if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_TYPE2)
+		flags |= CXL_DECODER_F_TYPE2;
+	if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_TYPE3)
+		flags |= CXL_DECODER_F_TYPE3;
+	if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_VOLATILE)
+		flags |= CXL_DECODER_F_RAM;
+	if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_PMEM)
+		flags |= CXL_DECODER_F_PMEM;
+	if (restrictions & ACPI_CEDT_CFMWS_RESTRICT_FIXED)
+		flags |= CXL_DECODER_F_LOCK;
+
+	return flags;
+}
+
+static int cxl_acpi_cfmws_verify(struct device *dev,
+				 struct acpi_cedt_cfmws *cfmws)
+{
+	int rc, expected_len;
+	unsigned int ways;
+
+	if (cfmws->interleave_arithmetic != ACPI_CEDT_CFMWS_ARITHMETIC_MODULO &&
+	    cfmws->interleave_arithmetic != ACPI_CEDT_CFMWS_ARITHMETIC_XOR) {
+		dev_err(dev, "CFMWS Unknown Interleave Arithmetic: %d\n",
+			cfmws->interleave_arithmetic);
+		return -EINVAL;
+	}
+
+	if (!IS_ALIGNED(cfmws->base_hpa, SZ_256M)) {
+		dev_err(dev, "CFMWS Base HPA not 256MB aligned\n");
+		return -EINVAL;
+	}
+
+	if (!IS_ALIGNED(cfmws->window_size, SZ_256M)) {
+		dev_err(dev, "CFMWS Window Size not 256MB aligned\n");
+		return -EINVAL;
+	}
+
+	rc = eiw_to_ways(cfmws->interleave_ways, &ways);
+	if (rc) {
+		dev_err(dev, "CFMWS Interleave Ways (%d) invalid\n",
+			cfmws->interleave_ways);
+		return -EINVAL;
+	}
+
+	expected_len = struct_size(cfmws, interleave_targets, ways);
+
+	if (cfmws->header.length < expected_len) {
+		dev_err(dev, "CFMWS length %d less than expected %d\n",
+			cfmws->header.length, expected_len);
+		return -EINVAL;
+	}
+
+	if (cfmws->header.length > expected_len)
+		dev_dbg(dev, "CFMWS length %d greater than expected %d\n",
+			cfmws->header.length, expected_len);
+
+	return 0;
+}
+
+/*
+ * Note, @dev must be the first member, see 'struct cxl_chbs_context'
+ * and mock_acpi_table_parse_cedt()
+ */
+struct cxl_cfmws_context {
+	struct device *dev;
+	struct cxl_port *root_port;
+	struct resource *cxl_res;
+	int id;
+};
+
+static int cxl_parse_cfmws(union acpi_subtable_headers *header, void *arg,
+			   const unsigned long end)
+{
+	int target_map[CXL_DECODER_MAX_INTERLEAVE];
+	struct cxl_cfmws_context *ctx = arg;
+	struct cxl_port *root_port = ctx->root_port;
+	struct resource *cxl_res = ctx->cxl_res;
+	struct cxl_cxims_context cxims_ctx;
+	struct cxl_root_decoder *cxlrd;
+	struct device *dev = ctx->dev;
+	struct acpi_cedt_cfmws *cfmws;
+	cxl_calc_hb_fn cxl_calc_hb;
+	struct cxl_decoder *cxld;
+	unsigned int ways, i, ig;
+	struct resource *res;
+	int rc;
+
+	cfmws = (struct acpi_cedt_cfmws *) header;
+
+	rc = cxl_acpi_cfmws_verify(dev, cfmws);
+	if (rc) {
+		dev_err(dev, "CFMWS range %#llx-%#llx not registered\n",
+			cfmws->base_hpa,
+			cfmws->base_hpa + cfmws->window_size - 1);
+		return 0;
+	}
+
+	rc = eiw_to_ways(cfmws->interleave_ways, &ways);
+	if (rc)
+		return rc;
+	rc = eig_to_granularity(cfmws->granularity, &ig);
+	if (rc)
+		return rc;
+	for (i = 0; i < ways; i++)
+		target_map[i] = cfmws->interleave_targets[i];
+
+	res = kzalloc(sizeof(*res), GFP_KERNEL);
+	if (!res)
+		return -ENOMEM;
+
+	res->name = kasprintf(GFP_KERNEL, "CXL Window %d", ctx->id++);
+	if (!res->name)
+		goto err_name;
+
+	res->start = cfmws->base_hpa;
+	res->end = cfmws->base_hpa + cfmws->window_size - 1;
+	res->flags = IORESOURCE_MEM;
+
+	/* add to the local resource tracking to establish a sort order */
+	rc = insert_resource(cxl_res, res);
+	if (rc)
+		goto err_insert;
+
+	if (cfmws->interleave_arithmetic == ACPI_CEDT_CFMWS_ARITHMETIC_MODULO)
+		cxl_calc_hb = cxl_hb_modulo;
+	else
+		cxl_calc_hb = cxl_hb_xor;
+
+	cxlrd = cxl_root_decoder_alloc(root_port, ways, cxl_calc_hb);
+	if (IS_ERR(cxlrd))
+		return 0;
+
+	cxld = &cxlrd->cxlsd.cxld;
+	cxld->flags = cfmws_to_decoder_flags(cfmws->restrictions);
+	cxld->target_type = CXL_DECODER_EXPANDER;
+	cxld->hpa_range = (struct range) {
+		.start = res->start,
+		.end = res->end,
+	};
+	cxld->interleave_ways = ways;
+	/*
+	 * Minimize the x1 granularity to advertise support for any
+	 * valid region granularity
+	 */
+	if (ways == 1)
+		ig = CXL_DECODER_MIN_GRANULARITY;
+	cxld->interleave_granularity = ig;
+
+	if (cfmws->interleave_arithmetic == ACPI_CEDT_CFMWS_ARITHMETIC_XOR) {
+		if (ways != 1 && ways != 3) {
+			cxims_ctx = (struct cxl_cxims_context) {
+				.dev = dev,
+				.cxlrd = cxlrd,
+			};
+			rc = acpi_table_parse_cedt(ACPI_CEDT_TYPE_CXIMS,
+						   cxl_parse_cxims, &cxims_ctx);
+			if (rc < 0)
+				goto err_xormap;
+			if (!cxlrd->platform_data) {
+				dev_err(dev, "No CXIMS for HBIG %u\n", ig);
+				rc = -EINVAL;
+				goto err_xormap;
+			}
+		}
+	}
+	rc = cxl_decoder_add(cxld, target_map);
+err_xormap:
+	if (rc)
+		put_device(&cxld->dev);
+	else
+		rc = cxl_decoder_autoremove(dev, cxld);
+	if (rc) {
+		dev_err(dev, "Failed to add decode range [%#llx - %#llx]\n",
+			cxld->hpa_range.start, cxld->hpa_range.end);
+		return 0;
+	}
+	dev_dbg(dev, "add: %s node: %d range [%#llx - %#llx]\n",
+		dev_name(&cxld->dev),
+		phys_to_target_node(cxld->hpa_range.start),
+		cxld->hpa_range.start, cxld->hpa_range.end);
+
+	return 0;
+
+err_insert:
+	kfree(res->name);
+err_name:
+	kfree(res);
+	return -ENOMEM;
+}
+
+__mock struct acpi_device *to_cxl_host_bridge(struct device *host,
+					      struct device *dev)
+{
+	struct acpi_device *adev = to_acpi_device(dev);
+
+	if (!acpi_pci_find_root(adev->handle))
+		return NULL;
+
+	if (strcmp(acpi_device_hid(adev), "ACPI0016") == 0)
+		return adev;
+	return NULL;
+}
+
+/*
+ * A host bridge is a dport to a CFMWS decode and it is a uport to the
+ * dport (PCIe Root Ports) in the host bridge.
+ */
+static int add_host_bridge_uport(struct device *match, void *arg)
+{
+	struct cxl_port *root_port = arg;
+	struct device *host = root_port->dev.parent;
+	struct acpi_device *hb = to_cxl_host_bridge(host, match);
+	struct acpi_pci_root *pci_root;
+	struct cxl_dport *dport;
+	struct cxl_port *port;
+	struct device *bridge;
+	int rc;
+
+	if (!hb)
+		return 0;
+
+	pci_root = acpi_pci_find_root(hb->handle);
+	bridge = pci_root->bus->bridge;
+	dport = cxl_find_dport_by_dev(root_port, bridge);
+	if (!dport) {
+		dev_dbg(host, "host bridge expected and not found\n");
+		return 0;
+	}
+
+	if (dport->rch) {
+		dev_info(bridge, "host supports CXL (restricted)\n");
+		return 0;
+	}
+
+	rc = devm_cxl_register_pci_bus(host, bridge, pci_root->bus);
+	if (rc)
+		return rc;
+
+	port = devm_cxl_add_port(host, bridge, dport->component_reg_phys,
+				 dport);
+	if (IS_ERR(port))
+		return PTR_ERR(port);
+
+	dev_info(bridge, "host supports CXL\n");
+
+	return 0;
+}
+
+struct cxl_chbs_context {
+	struct device *dev;
+	unsigned long long uid;
+	resource_size_t rcrb;
+	resource_size_t chbcr;
+	u32 cxl_version;
+};
+
+static int cxl_get_chbcr(union acpi_subtable_headers *header, void *arg,
+			 const unsigned long end)
+{
+	struct cxl_chbs_context *ctx = arg;
+	struct acpi_cedt_chbs *chbs;
+
+	if (ctx->chbcr)
+		return 0;
+
+	chbs = (struct acpi_cedt_chbs *) header;
+
+	if (ctx->uid != chbs->uid)
+		return 0;
+
+	ctx->cxl_version = chbs->cxl_version;
+	ctx->rcrb = CXL_RESOURCE_NONE;
+	ctx->chbcr = CXL_RESOURCE_NONE;
+
+	if (!chbs->base)
+		return 0;
+
+	if (chbs->cxl_version != ACPI_CEDT_CHBS_VERSION_CXL11) {
+		ctx->chbcr = chbs->base;
+		return 0;
+	}
+
+	if (chbs->length != CXL_RCRB_SIZE)
+		return 0;
+
+	ctx->rcrb = chbs->base;
+	ctx->chbcr = cxl_rcrb_to_component(ctx->dev, chbs->base,
+					   CXL_RCRB_DOWNSTREAM);
+
+	return 0;
+}
+
+static int add_host_bridge_dport(struct device *match, void *arg)
+{
+	acpi_status rc;
+	struct device *bridge;
+	unsigned long long uid;
+	struct cxl_dport *dport;
+	struct cxl_chbs_context ctx;
+	struct acpi_pci_root *pci_root;
+	struct cxl_port *root_port = arg;
+	struct device *host = root_port->dev.parent;
+	struct acpi_device *hb = to_cxl_host_bridge(host, match);
+
+	if (!hb)
+		return 0;
+
+	rc = acpi_evaluate_integer(hb->handle, METHOD_NAME__UID, NULL, &uid);
+	if (rc != AE_OK) {
+		dev_err(match, "unable to retrieve _UID\n");
+		return -ENODEV;
+	}
+
+	dev_dbg(match, "UID found: %lld\n", uid);
+
+	ctx = (struct cxl_chbs_context) {
+		.dev = match,
+		.uid = uid,
+	};
+	acpi_table_parse_cedt(ACPI_CEDT_TYPE_CHBS, cxl_get_chbcr, &ctx);
+
+	if (!ctx.chbcr) {
+		dev_warn(match, "No CHBS found for Host Bridge (UID %lld)\n",
+			 uid);
+		return 0;
+	}
+
+	if (ctx.rcrb != CXL_RESOURCE_NONE)
+		dev_dbg(match, "RCRB found for UID %lld: %pa\n", uid, &ctx.rcrb);
+
+	if (ctx.chbcr == CXL_RESOURCE_NONE) {
+		dev_warn(match, "CHBCR invalid for Host Bridge (UID %lld)\n",
+			 uid);
+		return 0;
+	}
+
+	dev_dbg(match, "CHBCR found: %pa\n", &ctx.chbcr);
+
+	pci_root = acpi_pci_find_root(hb->handle);
+	bridge = pci_root->bus->bridge;
+	if (ctx.cxl_version == ACPI_CEDT_CHBS_VERSION_CXL11)
+		dport = devm_cxl_add_rch_dport(root_port, bridge, uid,
+					       ctx.chbcr, ctx.rcrb);
+	else
+		dport = devm_cxl_add_dport(root_port, bridge, uid,
+					   ctx.chbcr);
+	if (IS_ERR(dport))
+		return PTR_ERR(dport);
+
+	return 0;
+}
+
+static int add_root_nvdimm_bridge(struct device *match, void *data)
+{
+	struct cxl_decoder *cxld;
+	struct cxl_port *root_port = data;
+	struct cxl_nvdimm_bridge *cxl_nvb;
+	struct device *host = root_port->dev.parent;
+
+	if (!is_root_decoder(match))
+		return 0;
+
+	cxld = to_cxl_decoder(match);
+	if (!(cxld->flags & CXL_DECODER_F_PMEM))
+		return 0;
+
+	cxl_nvb = devm_cxl_add_nvdimm_bridge(host, root_port);
+	if (IS_ERR(cxl_nvb)) {
+		dev_dbg(host, "failed to register pmem\n");
+		return PTR_ERR(cxl_nvb);
+	}
+	dev_dbg(host, "%s: add: %s\n", dev_name(&root_port->dev),
+		dev_name(&cxl_nvb->dev));
+	return 1;
+}
+
+static struct lock_class_key cxl_root_key;
+
+static void cxl_acpi_lock_reset_class(void *dev)
+{
+	device_lock_reset_class(dev);
+}
+
+static void del_cxl_resource(struct resource *res)
+{
+	kfree(res->name);
+	kfree(res);
+}
+
+static void cxl_set_public_resource(struct resource *priv, struct resource *pub)
+{
+	priv->desc = (unsigned long) pub;
+}
+
+static struct resource *cxl_get_public_resource(struct resource *priv)
+{
+	return (struct resource *) priv->desc;
+}
+
+static void remove_cxl_resources(void *data)
+{
+	struct resource *res, *next, *cxl = data;
+
+	for (res = cxl->child; res; res = next) {
+		struct resource *victim = cxl_get_public_resource(res);
+
+		next = res->sibling;
+		remove_resource(res);
+
+		if (victim) {
+			remove_resource(victim);
+			kfree(victim);
+		}
+
+		del_cxl_resource(res);
+	}
+}
+
+/**
+ * add_cxl_resources() - reflect CXL fixed memory windows in iomem_resource
+ * @cxl_res: A standalone resource tree where each CXL window is a sibling
+ *
+ * Walk each CXL window in @cxl_res and add it to iomem_resource potentially
+ * expanding its boundaries to ensure that any conflicting resources become
+ * children. If a window is expanded it may then conflict with a another window
+ * entry and require the window to be truncated or trimmed. Consider this
+ * situation:
+ *
+ * |-- "CXL Window 0" --||----- "CXL Window 1" -----|
+ * |--------------- "System RAM" -------------|
+ *
+ * ...where platform firmware has established as System RAM resource across 2
+ * windows, but has left some portion of window 1 for dynamic CXL region
+ * provisioning. In this case "Window 0" will span the entirety of the "System
+ * RAM" span, and "CXL Window 1" is truncated to the remaining tail past the end
+ * of that "System RAM" resource.
+ */
+static int add_cxl_resources(struct resource *cxl_res)
+{
+	struct resource *res, *new, *next;
+
+	for (res = cxl_res->child; res; res = next) {
+		new = kzalloc(sizeof(*new), GFP_KERNEL);
+		if (!new)
+			return -ENOMEM;
+		new->name = res->name;
+		new->start = res->start;
+		new->end = res->end;
+		new->flags = IORESOURCE_MEM;
+		new->desc = IORES_DESC_CXL;
+
+		/*
+		 * Record the public resource in the private cxl_res tree for
+		 * later removal.
+		 */
+		cxl_set_public_resource(res, new);
+
+		insert_resource_expand_to_fit(&iomem_resource, new);
+
+		next = res->sibling;
+		while (next && resource_overlaps(new, next)) {
+			if (resource_contains(new, next)) {
+				struct resource *_next = next->sibling;
+
+				remove_resource(next);
+				del_cxl_resource(next);
+				next = _next;
+			} else
+				next->start = new->end + 1;
+		}
+	}
+	return 0;
+}
+
+static int pair_cxl_resource(struct device *dev, void *data)
+{
+	struct resource *cxl_res = data;
+	struct resource *p;
+
+	if (!is_root_decoder(dev))
+		return 0;
+
+	for (p = cxl_res->child; p; p = p->sibling) {
+		struct cxl_root_decoder *cxlrd = to_cxl_root_decoder(dev);
+		struct cxl_decoder *cxld = &cxlrd->cxlsd.cxld;
+		struct resource res = {
+			.start = cxld->hpa_range.start,
+			.end = cxld->hpa_range.end,
+			.flags = IORESOURCE_MEM,
+		};
+
+		if (resource_contains(p, &res)) {
+			cxlrd->res = cxl_get_public_resource(p);
+			break;
+		}
+	}
+
+	return 0;
+}
+
+static int cxl_acpi_probe(struct platform_device *pdev)
+{
+	int rc;
+	struct resource *cxl_res;
+	struct cxl_port *root_port;
+	struct device *host = &pdev->dev;
+	struct acpi_device *adev = ACPI_COMPANION(host);
+	struct cxl_cfmws_context ctx;
+
+	device_lock_set_class(&pdev->dev, &cxl_root_key);
+	rc = devm_add_action_or_reset(&pdev->dev, cxl_acpi_lock_reset_class,
+				      &pdev->dev);
+	if (rc)
+		return rc;
+
+	cxl_res = devm_kzalloc(host, sizeof(*cxl_res), GFP_KERNEL);
+	if (!cxl_res)
+		return -ENOMEM;
+	cxl_res->name = "CXL mem";
+	cxl_res->start = 0;
+	cxl_res->end = -1;
+	cxl_res->flags = IORESOURCE_MEM;
+
+	root_port = devm_cxl_add_port(host, host, CXL_RESOURCE_NONE, NULL);
+	if (IS_ERR(root_port))
+		return PTR_ERR(root_port);
+
+	rc = bus_for_each_dev(adev->dev.bus, NULL, root_port,
+			      add_host_bridge_dport);
+	if (rc < 0)
+		return rc;
+
+	rc = devm_add_action_or_reset(host, remove_cxl_resources, cxl_res);
+	if (rc)
+		return rc;
+
+	ctx = (struct cxl_cfmws_context) {
+		.dev = host,
+		.root_port = root_port,
+		.cxl_res = cxl_res,
+	};
+	rc = acpi_table_parse_cedt(ACPI_CEDT_TYPE_CFMWS, cxl_parse_cfmws, &ctx);
+	if (rc < 0)
+		return -ENXIO;
+
+	rc = add_cxl_resources(cxl_res);
+	if (rc)
+		return rc;
+
+	/*
+	 * Populate the root decoders with their related iomem resource,
+	 * if present
+	 */
+	device_for_each_child(&root_port->dev, cxl_res, pair_cxl_resource);
+
+	/*
+	 * Root level scanned with host-bridge as dports, now scan host-bridges
+	 * for their role as CXL uports to their CXL-capable PCIe Root Ports.
+	 */
+	rc = bus_for_each_dev(adev->dev.bus, NULL, root_port,
+			      add_host_bridge_uport);
+	if (rc < 0)
+		return rc;
+
+	if (IS_ENABLED(CONFIG_CXL_PMEM))
+		rc = device_for_each_child(&root_port->dev, root_port,
+					   add_root_nvdimm_bridge);
+	if (rc < 0)
+		return rc;
+
+	/* In case PCI is scanned before ACPI re-trigger memdev attach */
+	cxl_bus_rescan();
+	return 0;
+}
+
+static const struct acpi_device_id cxl_acpi_ids[] = {
+	{ "ACPI0017" },
+	{ },
+};
+MODULE_DEVICE_TABLE(acpi, cxl_acpi_ids);
+
+static const struct platform_device_id cxl_test_ids[] = {
+	{ "cxl_acpi" },
+	{ },
+};
+MODULE_DEVICE_TABLE(platform, cxl_test_ids);
+
+static struct platform_driver cxl_acpi_driver = {
+	.probe = cxl_acpi_probe,
+	.driver = {
+		.name = KBUILD_MODNAME,
+		.acpi_match_table = cxl_acpi_ids,
+	},
+	.id_table = cxl_test_ids,
+};
+
+static int __init cxl_acpi_init(void)
+{
+	return platform_driver_register(&cxl_acpi_driver);
+}
+
+static void __exit cxl_acpi_exit(void)
+{
+	platform_driver_unregister(&cxl_acpi_driver);
+	cxl_bus_drain();
+}
+
+module_init(cxl_acpi_init);
+module_exit(cxl_acpi_exit);
+MODULE_LICENSE("GPL v2");
+MODULE_IMPORT_NS(CXL);
+MODULE_IMPORT_NS(ACPI);