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authorThomas Gleixner <tglx@linutronix.de>2016-11-09 16:35:51 +0100
committerThomas Gleixner <tglx@linutronix.de>2016-11-09 21:05:01 +0100
commitd49597fd3bc7d9534de55e9256767f073be1b33a (patch)
tree3a04f0d328888d42d936728d622ffbd43c7c847a /arch
parentx86/cpu/AMD: Fix cpu_llc_id for AMD Fam17h systems (diff)
downloadlinux-d49597fd3bc7d9534de55e9256767f073be1b33a.tar.xz
linux-d49597fd3bc7d9534de55e9256767f073be1b33a.zip
x86/cpu: Deal with broken firmware (VMWare/XEN)
Both ACPI and MP specifications require that the APIC id in the respective tables must be the same as the APIC id in CPUID. The kernel retrieves the physical package id from the APIC id during the ACPI/MP table scan and builds the physical to logical package map. The physical package id which is used after a CPU comes up is retrieved from CPUID. So we rely on ACPI/MP tables and CPUID agreeing in that respect. There exist VMware and XEN implementations which violate the spec. As a result the physical to logical package map, which relies on the ACPI/MP tables does not work on those systems, because the CPUID initialized physical package id does not match the firmware id. This causes system crashes and malfunction due to invalid package mappings. The only way to cure this is to sanitize the physical package id after the CPUID enumeration and yell when the APIC ids are different. Fix up the initial APIC id, which is fine as it is only used printout purposes. If the physical package IDs differ yell and use the package information from the ACPI/MP tables so the existing logical package map just works. Chas provided the resulting dmesg output for his affected 4 virtual sockets, 1 core per socket VM: [Firmware Bug]: CPU1: APIC id mismatch. Firmware: 1 CPUID: 2 [Firmware Bug]: CPU1: Using firmware package id 1 instead of 2 .... Reported-and-tested-by: "Charles (Chas) Williams" <ciwillia@brocade.com>, Reported-by: M. Vefa Bicakci <m.v.b@runbox.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Alok Kataria <akataria@vmware.com> Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com> Cc: #4.6+ <stable@vger,kernel.org> Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1611091613540.3501@nanos Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/cpu/common.c32
1 files changed, 30 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 9bd910a7dd0a..cc9e980c68ec 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -979,6 +979,35 @@ static void x86_init_cache_qos(struct cpuinfo_x86 *c)
}
/*
+ * The physical to logical package id mapping is initialized from the
+ * acpi/mptables information. Make sure that CPUID actually agrees with
+ * that.
+ */
+static void sanitize_package_id(struct cpuinfo_x86 *c)
+{
+#ifdef CONFIG_SMP
+ unsigned int pkg, apicid, cpu = smp_processor_id();
+
+ apicid = apic->cpu_present_to_apicid(cpu);
+ pkg = apicid >> boot_cpu_data.x86_coreid_bits;
+
+ if (apicid != c->initial_apicid) {
+ pr_err(FW_BUG "CPU%u: APIC id mismatch. Firmware: %x CPUID: %x\n",
+ cpu, apicid, c->initial_apicid);
+ c->initial_apicid = apicid;
+ }
+ if (pkg != c->phys_proc_id) {
+ pr_err(FW_BUG "CPU%u: Using firmware package id %u instead of %u\n",
+ cpu, pkg, c->phys_proc_id);
+ c->phys_proc_id = pkg;
+ }
+ c->logical_proc_id = topology_phys_to_logical_pkg(pkg);
+#else
+ c->logical_proc_id = 0;
+#endif
+}
+
+/*
* This does the hard work of actually picking apart the CPU stuff...
*/
static void identify_cpu(struct cpuinfo_x86 *c)
@@ -1103,8 +1132,7 @@ static void identify_cpu(struct cpuinfo_x86 *c)
#ifdef CONFIG_NUMA
numa_add_cpu(smp_processor_id());
#endif
- /* The boot/hotplug time assigment got cleared, restore it */
- c->logical_proc_id = topology_phys_to_logical_pkg(c->phys_proc_id);
+ sanitize_package_id(c);
}
/*