Merge tag 'x86-core-2023-10-29-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 core updates from Thomas Gleixner:

 - Limit the hardcoded topology quirk for Hygon CPUs to those which have
   a model ID less than 4.

   The newer models have the topology CPUID leaf 0xB correctly
   implemented and are not affected.

 - Make SMT control more robust against enumeration failures

   SMT control was added to allow controlling SMT at boottime or
   runtime. The primary purpose was to provide a simple mechanism to
   disable SMT in the light of speculation attack vectors.

   It turned out that the code is sensible to enumeration failures and
   worked only by chance for XEN/PV. XEN/PV has no real APIC enumeration
   which means the primary thread mask is not set up correctly. By
   chance a XEN/PV boot ends up with smp_num_siblings == 2, which makes
   the hotplug control stay at its default value "enabled". So the mask
   is never evaluated.

   The ongoing rework of the topology evaluation caused XEN/PV to end up
   with smp_num_siblings == 1, which sets the SMT control to "not
   supported" and the empty primary thread mask causes the hotplug core
   to deny the bringup of the APS.

   Make the decision logic more robust and take 'not supported' and 'not
   implemented' into account for the decision whether a CPU should be
   booted or not.

 - Fake primary thread mask for XEN/PV

   Pretend that all XEN/PV vCPUs are primary threads, which makes the
   usage of the primary thread mask valid on XEN/PV. That is consistent
   with because all of the topology information on XEN/PV is fake or
   even non-existent.

 - Encapsulate topology information in cpuinfo_x86

   Move the randomly scattered topology data into a separate data
   structure for readability and as a preparatory step for the topology
   evaluation overhaul.

 - Consolidate APIC ID data type to u32

   It's fixed width hardware data and not randomly u16, int, unsigned
   long or whatever developers decided to use.

 - Cure the abuse of cpuinfo for persisting logical IDs.

   Per CPU cpuinfo is used to persist the logical package and die IDs.
   That's really not the right place simply because cpuinfo is subject
   to be reinitialized when a CPU goes through an offline/online cycle.

   Use separate per CPU data for the persisting to enable the further
   topology management rework. It will be removed once the new topology
   management is in place.

 - Provide a debug interface for inspecting topology information

   Useful in general and extremly helpful for validating the topology
   management rework in terms of correctness or "bug" compatibility.

* tag 'x86-core-2023-10-29-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (23 commits)
  x86/apic, x86/hyperv: Use u32 in hv_snp_boot_ap() too
  x86/cpu: Provide debug interface
  x86/cpu/topology: Cure the abuse of cpuinfo for persisting logical ids
  x86/apic: Use u32 for wakeup_secondary_cpu[_64]()
  x86/apic: Use u32 for [gs]et_apic_id()
  x86/apic: Use u32 for phys_pkg_id()
  x86/apic: Use u32 for cpu_present_to_apicid()
  x86/apic: Use u32 for check_apicid_used()
  x86/apic: Use u32 for APIC IDs in global data
  x86/apic: Use BAD_APICID consistently
  x86/cpu: Move cpu_l[l2]c_id into topology info
  x86/cpu: Move logical package and die IDs into topology info
  x86/cpu: Remove pointless evaluation of x86_coreid_bits
  x86/cpu: Move cu_id into topology info
  x86/cpu: Move cpu_core_id into topology info
  hwmon: (fam15h_power) Use topology_core_id()
  scsi: lpfc: Use topology_core_id()
  x86/cpu: Move cpu_die_id into topology info
  x86/cpu: Move phys_proc_id into topology info
  x86/cpu: Encapsulate topology information in cpuinfo_x86
  ...

1 files changed, 19 insertions, 10 deletions

diff --git a/arch/x86/kernel/apic/apic.c b/arch/x86/kernel/apic/apic.c
index 760adac3d1a82..41093cf20acdc 100644
--- a/arch/x86/kernel/apic/apic.c
+++ b/arch/x86/kernel/apic/apic.c
@@ -36,6 +36,8 @@
 #include <linux/smp.h>
 #include <linux/mm.h>
 
+#include <xen/xen.h>
+
 #include <asm/trace/irq_vectors.h>
 #include <asm/irq_remapping.h>
 #include <asm/pc-conf-reg.h>
@@ -70,7 +72,7 @@ unsigned int num_processors;
 unsigned disabled_cpus;
 
 /* Processor that is doing the boot up */
-unsigned int boot_cpu_physical_apicid __ro_after_init = -1U;
+u32 boot_cpu_physical_apicid __ro_after_init = BAD_APICID;
 EXPORT_SYMBOL_GPL(boot_cpu_physical_apicid);
 
 u8 boot_cpu_apic_version __ro_after_init;
@@ -85,7 +87,7 @@ physid_mask_t phys_cpu_present_map;
  * disable_cpu_apicid=<int>, mostly used for the kdump 2nd kernel to
  * avoid undefined behaviour caused by sending INIT from AP to BSP.
  */
-static unsigned int disabled_cpu_apicid __ro_after_init = BAD_APICID;
+static u32 disabled_cpu_apicid __ro_after_init = BAD_APICID;
 
 /*
  * This variable controls which CPUs receive external NMIs.  By default,
@@ -109,7 +111,7 @@ static inline bool apic_accessible(void)
 /*
  * Map cpu index to physical APIC ID
  */
-DEFINE_EARLY_PER_CPU_READ_MOSTLY(u16, x86_cpu_to_apicid, BAD_APICID);
+DEFINE_EARLY_PER_CPU_READ_MOSTLY(u32, x86_cpu_to_apicid, BAD_APICID);
 DEFINE_EARLY_PER_CPU_READ_MOSTLY(u32, x86_cpu_to_acpiid, U32_MAX);
 EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_apicid);
 EXPORT_EARLY_PER_CPU_SYMBOL(x86_cpu_to_acpiid);
@@ -1763,7 +1765,7 @@ static void __x2apic_enable(void)
 static int __init setup_nox2apic(char *str)
 {
 	if (x2apic_enabled()) {
-		int apicid = native_apic_msr_read(APIC_ID);
+		u32 apicid = native_apic_msr_read(APIC_ID);
 
 		if (apicid >= 255) {
 			pr_warn("Apicid: %08x, cannot enforce nox2apic\n",
@@ -2316,13 +2318,11 @@ static int nr_logical_cpuids = 1;
 /*
  * Used to store mapping between logical CPU IDs and APIC IDs.
  */
-int cpuid_to_apicid[] = {
-	[0 ... NR_CPUS - 1] = -1,
-};
+u32 cpuid_to_apicid[] = { [0 ... NR_CPUS - 1] = BAD_APICID, };
 
 bool arch_match_cpu_phys_id(int cpu, u64 phys_id)
 {
-	return phys_id == cpuid_to_apicid[cpu];
+	return phys_id == (u64)cpuid_to_apicid[cpu];
 }
 
 #ifdef CONFIG_SMP
@@ -2344,6 +2344,15 @@ static int __init smp_init_primary_thread_mask(void)
 {
 	unsigned int cpu;
 
+	/*
+	 * XEN/PV provides either none or useless topology information.
+	 * Pretend that all vCPUs are primary threads.
+	 */
+	if (xen_pv_domain()) {
+		cpumask_copy(&__cpu_primary_thread_mask, cpu_possible_mask);
+		return 0;
+	}
+
 	for (cpu = 0; cpu < nr_logical_cpuids; cpu++)
 		cpu_mark_primary_thread(cpu, cpuid_to_apicid[cpu]);
 	return 0;
@@ -2382,7 +2391,7 @@ static int allocate_logical_cpuid(int apicid)
 	return nr_logical_cpuids++;
 }
 
-static void cpu_update_apic(int cpu, int apicid)
+static void cpu_update_apic(int cpu, u32 apicid)
 {
 #if defined(CONFIG_SMP) || defined(CONFIG_X86_64)
 	early_per_cpu(x86_cpu_to_apicid, cpu) = apicid;
@@ -2535,7 +2544,7 @@ static struct {
 	 */
 	int active;
 	/* r/w apic fields */
-	unsigned int apic_id;
+	u32 apic_id;
 	unsigned int apic_taskpri;
 	unsigned int apic_ldr;
 	unsigned int apic_dfr;