Merge tag 'x86_misc_for_v6.14_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull misc x86 updates from Borislav Petkov:

 - The first part of a restructuring of AMD's representation of a
   northbridge which is legacy now, and the creation of the new AMD node
   concept which represents the Zen architecture of having a collection
   of I/O devices within an SoC. Those nodes comprise the so-called data
   fabric on Zen.

   This has at least one practical advantage of not having to add a PCI
   ID each time a new data fabric PCI device releases. Eventually, the
   lot more uniform provider of data fabric functionality amd_node.c
   will be used by all the drivers which need it

 - Smaller cleanups

* tag 'x86_misc_for_v6.14_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/amd_node: Use defines for SMN register offsets
  x86/amd_node: Remove dependency on AMD_NB
  x86/amd_node: Update __amd_smn_rw() error paths
  x86/amd_nb: Move SMN access code to a new amd_node driver
  x86/amd_nb, hwmon: (k10temp): Simplify amd_pci_dev_to_node_id()
  x86/amd_nb: Simplify function 3 search
  x86/amd_nb: Use topology info to get AMD node count
  x86/amd_nb: Simplify root device search
  x86/amd_nb: Simplify function 4 search
  x86: Start moving AMD node functionality out of AMD_NB
  x86/amd_nb: Clean up early_is_amd_nb()
  x86/amd_nb: Restrict init function to AMD-based systems
  x86/mtrr: Rename mtrr_overwrite_state() to guest_force_mtrr_state()

6 files changed, 242 insertions, 284 deletions

diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index f7918980667a..b43eb7e384eb 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -119,6 +119,7 @@ obj-$(CONFIG_EARLY_PRINTK)	+= early_printk.o
 obj-$(CONFIG_HPET_TIMER) 	+= hpet.o
 
 obj-$(CONFIG_AMD_NB)		+= amd_nb.o
+obj-$(CONFIG_AMD_NODE)		+= amd_node.o
 obj-$(CONFIG_DEBUG_NMI_SELFTEST) += nmi_selftest.o
 
 obj-$(CONFIG_KVM_GUEST)		+= kvm.o kvmclock.o
diff --git a/arch/x86/kernel/amd_nb.c b/arch/x86/kernel/amd_nb.c
index 9fe9972d2071..11fac09e3a8c 100644
--- a/arch/x86/kernel/amd_nb.c
+++ b/arch/x86/kernel/amd_nb.c
@@ -15,66 +15,8 @@
 #include <linux/pci_ids.h>
 #include <asm/amd_nb.h>
 
-#define PCI_DEVICE_ID_AMD_17H_ROOT		0x1450
-#define PCI_DEVICE_ID_AMD_17H_M10H_ROOT		0x15d0
-#define PCI_DEVICE_ID_AMD_17H_M30H_ROOT		0x1480
-#define PCI_DEVICE_ID_AMD_17H_M60H_ROOT		0x1630
-#define PCI_DEVICE_ID_AMD_17H_MA0H_ROOT		0x14b5
-#define PCI_DEVICE_ID_AMD_19H_M10H_ROOT		0x14a4
-#define PCI_DEVICE_ID_AMD_19H_M40H_ROOT		0x14b5
-#define PCI_DEVICE_ID_AMD_19H_M60H_ROOT		0x14d8
-#define PCI_DEVICE_ID_AMD_19H_M70H_ROOT		0x14e8
-#define PCI_DEVICE_ID_AMD_1AH_M00H_ROOT		0x153a
-#define PCI_DEVICE_ID_AMD_1AH_M20H_ROOT		0x1507
-#define PCI_DEVICE_ID_AMD_1AH_M60H_ROOT		0x1122
-#define PCI_DEVICE_ID_AMD_MI200_ROOT		0x14bb
-#define PCI_DEVICE_ID_AMD_MI300_ROOT		0x14f8
-
-#define PCI_DEVICE_ID_AMD_17H_DF_F4		0x1464
-#define PCI_DEVICE_ID_AMD_17H_M10H_DF_F4	0x15ec
-#define PCI_DEVICE_ID_AMD_17H_M30H_DF_F4	0x1494
-#define PCI_DEVICE_ID_AMD_17H_M60H_DF_F4	0x144c
-#define PCI_DEVICE_ID_AMD_17H_M70H_DF_F4	0x1444
-#define PCI_DEVICE_ID_AMD_17H_MA0H_DF_F4	0x1728
-#define PCI_DEVICE_ID_AMD_19H_DF_F4		0x1654
-#define PCI_DEVICE_ID_AMD_19H_M10H_DF_F4	0x14b1
-#define PCI_DEVICE_ID_AMD_19H_M40H_DF_F4	0x167d
-#define PCI_DEVICE_ID_AMD_19H_M50H_DF_F4	0x166e
-#define PCI_DEVICE_ID_AMD_19H_M60H_DF_F4	0x14e4
-#define PCI_DEVICE_ID_AMD_19H_M70H_DF_F4	0x14f4
-#define PCI_DEVICE_ID_AMD_19H_M78H_DF_F4	0x12fc
-#define PCI_DEVICE_ID_AMD_1AH_M00H_DF_F4	0x12c4
-#define PCI_DEVICE_ID_AMD_1AH_M20H_DF_F4	0x16fc
-#define PCI_DEVICE_ID_AMD_1AH_M60H_DF_F4	0x124c
-#define PCI_DEVICE_ID_AMD_1AH_M70H_DF_F4	0x12bc
-#define PCI_DEVICE_ID_AMD_MI200_DF_F4		0x14d4
-#define PCI_DEVICE_ID_AMD_MI300_DF_F4		0x152c
-
-/* Protect the PCI config register pairs used for SMN. */
-static DEFINE_MUTEX(smn_mutex);
-
 static u32 *flush_words;
 
-static const struct pci_device_id amd_root_ids[] = {
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_ROOT) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M10H_ROOT) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M30H_ROOT) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M60H_ROOT) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_MA0H_ROOT) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M10H_ROOT) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M40H_ROOT) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M60H_ROOT) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M70H_ROOT) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M00H_ROOT) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M20H_ROOT) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M60H_ROOT) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI200_ROOT) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI300_ROOT) },
-	{}
-};
-
-#define PCI_DEVICE_ID_AMD_CNB17H_F4     0x1704
-
 static const struct pci_device_id amd_nb_misc_ids[] = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_K8_NB_MISC) },
 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_10H_NB_MISC) },
@@ -84,70 +26,6 @@ static const struct pci_device_id amd_nb_misc_ids[] = {
 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M60H_NB_F3) },
 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_NB_F3) },
 	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_M30H_NB_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_DF_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M10H_DF_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M30H_DF_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M60H_DF_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_MA0H_DF_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CNB17H_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M70H_DF_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_DF_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M10H_DF_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M40H_DF_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M50H_DF_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M60H_DF_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M70H_DF_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M78H_DF_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M00H_DF_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M20H_DF_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M60H_DF_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M70H_DF_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI200_DF_F3) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI300_DF_F3) },
-	{}
-};
-
-static const struct pci_device_id amd_nb_link_ids[] = {
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_NB_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M30H_NB_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_15H_M60H_NB_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_NB_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_16H_M30H_NB_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_DF_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M10H_DF_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M30H_DF_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M60H_DF_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_M70H_DF_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_17H_MA0H_DF_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_DF_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M10H_DF_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M40H_DF_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M50H_DF_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M60H_DF_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M70H_DF_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_19H_M78H_DF_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_CNB17H_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M00H_DF_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M20H_DF_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M60H_DF_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_1AH_M70H_DF_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI200_DF_F4) },
-	{ PCI_DEVICE(PCI_VENDOR_ID_AMD, PCI_DEVICE_ID_AMD_MI300_DF_F4) },
-	{}
-};
-
-static const struct pci_device_id hygon_root_ids[] = {
-	{ PCI_DEVICE(PCI_VENDOR_ID_HYGON, PCI_DEVICE_ID_AMD_17H_ROOT) },
-	{}
-};
-
-static const struct pci_device_id hygon_nb_misc_ids[] = {
-	{ PCI_DEVICE(PCI_VENDOR_ID_HYGON, PCI_DEVICE_ID_AMD_17H_DF_F3) },
-	{}
-};
-
-static const struct pci_device_id hygon_nb_link_ids[] = {
-	{ PCI_DEVICE(PCI_VENDOR_ID_HYGON, PCI_DEVICE_ID_AMD_17H_DF_F4) },
 	{}
 };
 
@@ -178,176 +56,37 @@ struct amd_northbridge *node_to_amd_nb(int node)
 }
 EXPORT_SYMBOL_GPL(node_to_amd_nb);
 
-static struct pci_dev *next_northbridge(struct pci_dev *dev,
-					const struct pci_device_id *ids)
-{
-	do {
-		dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev);
-		if (!dev)
-			break;
-	} while (!pci_match_id(ids, dev));
-	return dev;
-}
-
-/*
- * SMN accesses may fail in ways that are difficult to detect here in the called
- * functions amd_smn_read() and amd_smn_write(). Therefore, callers must do
- * their own checking based on what behavior they expect.
- *
- * For SMN reads, the returned value may be zero if the register is Read-as-Zero.
- * Or it may be a "PCI Error Response", e.g. all 0xFFs. The "PCI Error Response"
- * can be checked here, and a proper error code can be returned.
- *
- * But the Read-as-Zero response cannot be verified here. A value of 0 may be
- * correct in some cases, so callers must check that this correct is for the
- * register/fields they need.
- *
- * For SMN writes, success can be determined through a "write and read back"
- * However, this is not robust when done here.
- *
- * Possible issues:
- *
- * 1) Bits that are "Write-1-to-Clear". In this case, the read value should
- *    *not* match the write value.
- *
- * 2) Bits that are "Read-as-Zero"/"Writes-Ignored". This information cannot be
- *    known here.
- *
- * 3) Bits that are "Reserved / Set to 1". Ditto above.
- *
- * Callers of amd_smn_write() should do the "write and read back" check
- * themselves, if needed.
- *
- * For #1, they can see if their target bits got cleared.
- *
- * For #2 and #3, they can check if their target bits got set as intended.
- *
- * This matches what is done for RDMSR/WRMSR. As long as there's no #GP, then
- * the operation is considered a success, and the caller does their own
- * checking.
- */
-static int __amd_smn_rw(u16 node, u32 address, u32 *value, bool write)
-{
-	struct pci_dev *root;
-	int err = -ENODEV;
-
-	if (node >= amd_northbridges.num)
-		goto out;
-
-	root = node_to_amd_nb(node)->root;
-	if (!root)
-		goto out;
-
-	mutex_lock(&smn_mutex);
-
-	err = pci_write_config_dword(root, 0x60, address);
-	if (err) {
-		pr_warn("Error programming SMN address 0x%x.\n", address);
-		goto out_unlock;
-	}
-
-	err = (write ? pci_write_config_dword(root, 0x64, *value)
-		     : pci_read_config_dword(root, 0x64, value));
-
-out_unlock:
-	mutex_unlock(&smn_mutex);
-
-out:
-	return err;
-}
-
-int __must_check amd_smn_read(u16 node, u32 address, u32 *value)
-{
-	int err = __amd_smn_rw(node, address, value, false);
-
-	if (PCI_POSSIBLE_ERROR(*value)) {
-		err = -ENODEV;
-		*value = 0;
-	}
-
-	return err;
-}
-EXPORT_SYMBOL_GPL(amd_smn_read);
-
-int __must_check amd_smn_write(u16 node, u32 address, u32 value)
-{
-	return __amd_smn_rw(node, address, &value, true);
-}
-EXPORT_SYMBOL_GPL(amd_smn_write);
-
-
 static int amd_cache_northbridges(void)
 {
-	const struct pci_device_id *misc_ids = amd_nb_misc_ids;
-	const struct pci_device_id *link_ids = amd_nb_link_ids;
-	const struct pci_device_id *root_ids = amd_root_ids;
-	struct pci_dev *root, *misc, *link;
 	struct amd_northbridge *nb;
-	u16 roots_per_misc = 0;
-	u16 misc_count = 0;
-	u16 root_count = 0;
-	u16 i, j;
+	u16 i;
 
 	if (amd_northbridges.num)
 		return 0;
 
-	if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON) {
-		root_ids = hygon_root_ids;
-		misc_ids = hygon_nb_misc_ids;
-		link_ids = hygon_nb_link_ids;
-	}
-
-	misc = NULL;
-	while ((misc = next_northbridge(misc, misc_ids)))
-		misc_count++;
-
-	if (!misc_count)
-		return -ENODEV;
-
-	root = NULL;
-	while ((root = next_northbridge(root, root_ids)))
-		root_count++;
+	amd_northbridges.num = amd_num_nodes();
 
-	if (root_count) {
-		roots_per_misc = root_count / misc_count;
-
-		/*
-		 * There should be _exactly_ N roots for each DF/SMN
-		 * interface.
-		 */
-		if (!roots_per_misc || (root_count % roots_per_misc)) {
-			pr_info("Unsupported AMD DF/PCI configuration found\n");
-			return -ENODEV;
-		}
-	}
-
-	nb = kcalloc(misc_count, sizeof(struct amd_northbridge), GFP_KERNEL);
+	nb = kcalloc(amd_northbridges.num, sizeof(struct amd_northbridge), GFP_KERNEL);
 	if (!nb)
 		return -ENOMEM;
 
 	amd_northbridges.nb = nb;
-	amd_northbridges.num = misc_count;
 
-	link = misc = root = NULL;
 	for (i = 0; i < amd_northbridges.num; i++) {
-		node_to_amd_nb(i)->root = root =
-			next_northbridge(root, root_ids);
-		node_to_amd_nb(i)->misc = misc =
-			next_northbridge(misc, misc_ids);
-		node_to_amd_nb(i)->link = link =
-			next_northbridge(link, link_ids);
+		node_to_amd_nb(i)->root = amd_node_get_root(i);
+		node_to_amd_nb(i)->misc = amd_node_get_func(i, 3);
 
 		/*
-		 * If there are more PCI root devices than data fabric/
-		 * system management network interfaces, then the (N)
-		 * PCI roots per DF/SMN interface are functionally the
-		 * same (for DF/SMN access) and N-1 are redundant.  N-1
-		 * PCI roots should be skipped per DF/SMN interface so
-		 * the following DF/SMN interfaces get mapped to
-		 * correct PCI roots.
+		 * Each Northbridge must have a 'misc' device.
+		 * If not, then uninitialize everything.
 		 */
-		for (j = 1; j < roots_per_misc; j++)
-			root = next_northbridge(root, root_ids);
+		if (!node_to_amd_nb(i)->misc) {
+			amd_northbridges.num = 0;
+			kfree(nb);
+			return -ENODEV;
+		}
+
+		node_to_amd_nb(i)->link = amd_node_get_func(i, 4);
 	}
 
 	if (amd_gart_present())
@@ -385,7 +124,6 @@ static int amd_cache_northbridges(void)
  */
 bool __init early_is_amd_nb(u32 device)
 {
-	const struct pci_device_id *misc_ids = amd_nb_misc_ids;
 	const struct pci_device_id *id;
 	u32 vendor = device & 0xffff;
 
@@ -393,11 +131,11 @@ bool __init early_is_amd_nb(u32 device)
 	    boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
 		return false;
 
-	if (boot_cpu_data.x86_vendor == X86_VENDOR_HYGON)
-		misc_ids = hygon_nb_misc_ids;
+	if (cpu_feature_enabled(X86_FEATURE_ZEN))
+		return false;
 
 	device >>= 16;
-	for (id = misc_ids; id->vendor; id++)
+	for (id = amd_nb_misc_ids; id->vendor; id++)
 		if (vendor == id->vendor && device == id->device)
 			return true;
 	return false;
@@ -582,6 +320,10 @@ static __init void fix_erratum_688(void)
 
 static __init int init_amd_nbs(void)
 {
+	if (boot_cpu_data.x86_vendor != X86_VENDOR_AMD &&
+	    boot_cpu_data.x86_vendor != X86_VENDOR_HYGON)
+		return 0;
+
 	amd_cache_northbridges();
 	amd_cache_gart();
 
diff --git a/arch/x86/kernel/amd_node.c b/arch/x86/kernel/amd_node.c
new file mode 100644
index 000000000000..d2ec7fd555c5
--- /dev/null
+++ b/arch/x86/kernel/amd_node.c
@@ -0,0 +1,215 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * AMD Node helper functions and common defines
+ *
+ * Copyright (c) 2024, Advanced Micro Devices, Inc.
+ * All Rights Reserved.
+ *
+ * Author: Yazen Ghannam <Yazen.Ghannam@amd.com>
+ */
+
+#include <asm/amd_node.h>
+
+/*
+ * AMD Nodes are a physical collection of I/O devices within an SoC. There can be one
+ * or more nodes per package.
+ *
+ * The nodes are software-visible through PCI config space. All nodes are enumerated
+ * on segment 0 bus 0. The device (slot) numbers range from 0x18 to 0x1F (maximum 8
+ * nodes) with 0x18 corresponding to node 0, 0x19 to node 1, etc. Each node can be a
+ * multi-function device.
+ *
+ * On legacy systems, these node devices represent integrated Northbridge functionality.
+ * On Zen-based systems, these node devices represent Data Fabric functionality.
+ *
+ * See "Configuration Space Accesses" section in BKDGs or
+ * "Processor x86 Core" -> "Configuration Space" section in PPRs.
+ */
+struct pci_dev *amd_node_get_func(u16 node, u8 func)
+{
+	if (node >= MAX_AMD_NUM_NODES)
+		return NULL;
+
+	return pci_get_domain_bus_and_slot(0, 0, PCI_DEVFN(AMD_NODE0_PCI_SLOT + node, func));
+}
+
+#define DF_BLK_INST_CNT		0x040
+#define	DF_CFG_ADDR_CNTL_LEGACY	0x084
+#define	DF_CFG_ADDR_CNTL_DF4	0xC04
+
+#define DF_MAJOR_REVISION	GENMASK(27, 24)
+
+static u16 get_cfg_addr_cntl_offset(struct pci_dev *df_f0)
+{
+	u32 reg;
+
+	/*
+	 * Revision fields added for DF4 and later.
+	 *
+	 * Major revision of '0' is found pre-DF4. Field is Read-as-Zero.
+	 */
+	if (pci_read_config_dword(df_f0, DF_BLK_INST_CNT, &reg))
+		return 0;
+
+	if (reg & DF_MAJOR_REVISION)
+		return DF_CFG_ADDR_CNTL_DF4;
+
+	return DF_CFG_ADDR_CNTL_LEGACY;
+}
+
+struct pci_dev *amd_node_get_root(u16 node)
+{
+	struct pci_dev *root;
+	u16 cntl_off;
+	u8 bus;
+
+	if (!cpu_feature_enabled(X86_FEATURE_ZEN))
+		return NULL;
+
+	/*
+	 * D18F0xXXX [Config Address Control] (DF::CfgAddressCntl)
+	 * Bits [7:0] (SecBusNum) holds the bus number of the root device for
+	 * this Data Fabric instance. The segment, device, and function will be 0.
+	 */
+	struct pci_dev *df_f0 __free(pci_dev_put) = amd_node_get_func(node, 0);
+	if (!df_f0)
+		return NULL;
+
+	cntl_off = get_cfg_addr_cntl_offset(df_f0);
+	if (!cntl_off)
+		return NULL;
+
+	if (pci_read_config_byte(df_f0, cntl_off, &bus))
+		return NULL;
+
+	/* Grab the pointer for the actual root device instance. */
+	root = pci_get_domain_bus_and_slot(0, bus, 0);
+
+	pci_dbg(root, "is root for AMD node %u\n", node);
+	return root;
+}
+
+static struct pci_dev **amd_roots;
+
+/* Protect the PCI config register pairs used for SMN. */
+static DEFINE_MUTEX(smn_mutex);
+
+#define SMN_INDEX_OFFSET	0x60
+#define SMN_DATA_OFFSET		0x64
+
+/*
+ * SMN accesses may fail in ways that are difficult to detect here in the called
+ * functions amd_smn_read() and amd_smn_write(). Therefore, callers must do
+ * their own checking based on what behavior they expect.
+ *
+ * For SMN reads, the returned value may be zero if the register is Read-as-Zero.
+ * Or it may be a "PCI Error Response", e.g. all 0xFFs. The "PCI Error Response"
+ * can be checked here, and a proper error code can be returned.
+ *
+ * But the Read-as-Zero response cannot be verified here. A value of 0 may be
+ * correct in some cases, so callers must check that this correct is for the
+ * register/fields they need.
+ *
+ * For SMN writes, success can be determined through a "write and read back"
+ * However, this is not robust when done here.
+ *
+ * Possible issues:
+ *
+ * 1) Bits that are "Write-1-to-Clear". In this case, the read value should
+ *    *not* match the write value.
+ *
+ * 2) Bits that are "Read-as-Zero"/"Writes-Ignored". This information cannot be
+ *    known here.
+ *
+ * 3) Bits that are "Reserved / Set to 1". Ditto above.
+ *
+ * Callers of amd_smn_write() should do the "write and read back" check
+ * themselves, if needed.
+ *
+ * For #1, they can see if their target bits got cleared.
+ *
+ * For #2 and #3, they can check if their target bits got set as intended.
+ *
+ * This matches what is done for RDMSR/WRMSR. As long as there's no #GP, then
+ * the operation is considered a success, and the caller does their own
+ * checking.
+ */
+static int __amd_smn_rw(u8 i_off, u8 d_off, u16 node, u32 address, u32 *value, bool write)
+{
+	struct pci_dev *root;
+	int err = -ENODEV;
+
+	if (node >= amd_num_nodes())
+		return err;
+
+	root = amd_roots[node];
+	if (!root)
+		return err;
+
+	guard(mutex)(&smn_mutex);
+
+	err = pci_write_config_dword(root, i_off, address);
+	if (err) {
+		pr_warn("Error programming SMN address 0x%x.\n", address);
+		return pcibios_err_to_errno(err);
+	}
+
+	err = (write ? pci_write_config_dword(root, d_off, *value)
+		     : pci_read_config_dword(root, d_off, value));
+
+	return pcibios_err_to_errno(err);
+}
+
+int __must_check amd_smn_read(u16 node, u32 address, u32 *value)
+{
+	int err = __amd_smn_rw(SMN_INDEX_OFFSET, SMN_DATA_OFFSET, node, address, value, false);
+
+	if (PCI_POSSIBLE_ERROR(*value)) {
+		err = -ENODEV;
+		*value = 0;
+	}
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(amd_smn_read);
+
+int __must_check amd_smn_write(u16 node, u32 address, u32 value)
+{
+	return __amd_smn_rw(SMN_INDEX_OFFSET, SMN_DATA_OFFSET, node, address, &value, true);
+}
+EXPORT_SYMBOL_GPL(amd_smn_write);
+
+static int amd_cache_roots(void)
+{
+	u16 node, num_nodes = amd_num_nodes();
+
+	amd_roots = kcalloc(num_nodes, sizeof(*amd_roots), GFP_KERNEL);
+	if (!amd_roots)
+		return -ENOMEM;
+
+	for (node = 0; node < num_nodes; node++)
+		amd_roots[node] = amd_node_get_root(node);
+
+	return 0;
+}
+
+static int __init amd_smn_init(void)
+{
+	int err;
+
+	if (!cpu_feature_enabled(X86_FEATURE_ZEN))
+		return 0;
+
+	guard(mutex)(&smn_mutex);
+
+	if (amd_roots)
+		return 0;
+
+	err = amd_cache_roots();
+	if (err)
+		return err;
+
+	return 0;
+}
+
+fs_initcall(amd_smn_init);
diff --git a/arch/x86/kernel/cpu/mtrr/generic.c b/arch/x86/kernel/cpu/mtrr/generic.c
index 7b29ebda024f..2fdfda2b60e4 100644
--- a/arch/x86/kernel/cpu/mtrr/generic.c
+++ b/arch/x86/kernel/cpu/mtrr/generic.c
@@ -423,7 +423,7 @@ void __init mtrr_copy_map(void)
 }
 
 /**
- * mtrr_overwrite_state - set static MTRR state
+ * guest_force_mtrr_state - set static MTRR state for a guest
  *
  * Used to set MTRR state via different means (e.g. with data obtained from
  * a hypervisor).
@@ -436,8 +436,8 @@ void __init mtrr_copy_map(void)
  * @num_var: length of the @var array
  * @def_type: default caching type
  */
-void mtrr_overwrite_state(struct mtrr_var_range *var, unsigned int num_var,
-			  mtrr_type def_type)
+void guest_force_mtrr_state(struct mtrr_var_range *var, unsigned int num_var,
+			    mtrr_type def_type)
 {
 	unsigned int i;
 
diff --git a/arch/x86/kernel/cpu/mtrr/mtrr.c b/arch/x86/kernel/cpu/mtrr/mtrr.c
index 989d368be04f..ecbda0341a8a 100644
--- a/arch/x86/kernel/cpu/mtrr/mtrr.c
+++ b/arch/x86/kernel/cpu/mtrr/mtrr.c
@@ -625,7 +625,7 @@ void mtrr_save_state(void)
 static int __init mtrr_init_finalize(void)
 {
 	/*
-	 * Map might exist if mtrr_overwrite_state() has been called or if
+	 * Map might exist if guest_force_mtrr_state() has been called or if
 	 * mtrr_enabled() returns true.
 	 */
 	mtrr_copy_map();
diff --git a/arch/x86/kernel/kvm.c b/arch/x86/kernel/kvm.c
index 21e9e4845354..7a422a6c5983 100644
--- a/arch/x86/kernel/kvm.c
+++ b/arch/x86/kernel/kvm.c
@@ -983,7 +983,7 @@ static void __init kvm_init_platform(void)
 	x86_platform.apic_post_init = kvm_apic_init;
 
 	/* Set WB as the default cache mode for SEV-SNP and TDX */
-	mtrr_overwrite_state(NULL, 0, MTRR_TYPE_WRBACK);
+	guest_force_mtrr_state(NULL, 0, MTRR_TYPE_WRBACK);
 }
 
 #if defined(CONFIG_AMD_MEM_ENCRYPT)