Patch "x86/cpu: Deal with broken firmware (VMWare/XEN)" has been added to the 4.8-stable tree

* Patch "x86/cpu: Deal with broken firmware (VMWare/XEN)" has been added to the 4.8-stable tree
@ 2016-11-21 10:56 gregkh
  2016-11-22 15:04 ` Borislav Petkov
  0 siblings, 1 reply; 3+ messages in thread
From: gregkh @ 2016-11-21 10:56 UTC (permalink / raw)
  To: tglx, akataria, bigeasy, boris.ostrovsky, bp, ciwillia, gregkh,
	m.v.b, peterz
  Cc: stable, stable-commits


This is a note to let you know that I've just added the patch titled

    x86/cpu: Deal with broken firmware (VMWare/XEN)

to the 4.8-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     x86-cpu-deal-with-broken-firmware-vmware-xen.patch
and it can be found in the queue-4.8 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From d49597fd3bc7d9534de55e9256767f073be1b33a Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Wed, 9 Nov 2016 16:35:51 +0100
Subject: x86/cpu: Deal with broken firmware (VMWare/XEN)

From: Thomas Gleixner <tglx@linutronix.de>

commit d49597fd3bc7d9534de55e9256767f073be1b33a upstream.

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>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1611091613540.3501@nanos
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/x86/kernel/cpu/common.c |   32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

--- 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 cp
 }
 
 /*
+ * 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_
 #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);
 }
 
 /*


Patches currently in stable-queue which might be from tglx@linutronix.de are

queue-4.8/x86-cpu-amd-fix-cpu_llc_id-for-amd-fam17h-systems.patch
queue-4.8/x86-cpu-deal-with-broken-firmware-vmware-xen.patch

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