Merge branch 'core-smp-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull core SMP updates from Ingo Molnar:
 "Two main change is generic vCPU pinning and physical CPU SMP-call
  support, for Xen to be able to perform certain calls on specific
  physical CPUs - by Juergen Gross"

* 'core-smp-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  smp: Allocate smp_call_on_cpu() workqueue on stack too
  hwmon: Use smp_call_on_cpu() for dell-smm i8k
  dcdbas: Make use of smp_call_on_cpu()
  xen: Add xen_pin_vcpu() to support calling functions on a dedicated pCPU
  smp: Add function to execute a function synchronously on a CPU
  virt, sched: Add generic vCPU pinning support
  xen: Sync xen header

11 files changed, 274 insertions, 59 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index c8926c1acd22..f2ae3a4bc5c2 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -8860,6 +8860,7 @@ S:	Supported
 F:      Documentation/virtual/paravirt_ops.txt
 F:      arch/*/kernel/paravirt*
 F:      arch/*/include/asm/paravirt.h
+F:      include/linux/hypervisor.h
 
 PARIDE DRIVERS FOR PARALLEL PORT IDE DEVICES
 M:      Tim Waugh <tim@cyberelk.net>
diff --git a/arch/x86/include/asm/hypervisor.h b/arch/x86/include/asm/hypervisor.h
index 055ea9941dd5..67942b6ad4b7 100644
--- a/arch/x86/include/asm/hypervisor.h
+++ b/arch/x86/include/asm/hypervisor.h
@@ -43,6 +43,9 @@ struct hypervisor_x86 {
 
         /* X2APIC detection (run once per boot) */
         bool            (*x2apic_available)(void);
+
+        /* pin current vcpu to specified physical cpu (run rarely) */
+        void            (*pin_vcpu)(int);
 };
 
 extern const struct hypervisor_x86 *x86_hyper;
@@ -56,6 +59,7 @@ extern const struct hypervisor_x86 x86_hyper_kvm;
 extern void init_hypervisor(struct cpuinfo_x86 *c);
 extern void init_hypervisor_platform(void);
 extern bool hypervisor_x2apic_available(void);
+extern void hypervisor_pin_vcpu(int cpu);
 #else
 static inline void init_hypervisor(struct cpuinfo_x86 *c) { }
 static inline void init_hypervisor_platform(void) { }
diff --git a/arch/x86/kernel/cpu/hypervisor.c b/arch/x86/kernel/cpu/hypervisor.c
index 27e46658ebe3..35691a6b0d32 100644
--- a/arch/x86/kernel/cpu/hypervisor.c
+++ b/arch/x86/kernel/cpu/hypervisor.c
@@ -86,3 +86,14 @@ bool __init hypervisor_x2apic_available(void)
                x86_hyper->x2apic_available &&
                x86_hyper->x2apic_available();
 }
+
+void hypervisor_pin_vcpu(int cpu)
+{
+        if (!x86_hyper)
+                return;
+
+        if (x86_hyper->pin_vcpu)
+                x86_hyper->pin_vcpu(cpu);
+        else
+                WARN_ONCE(1, "vcpu pinning requested but not supported!\n");
+}
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index b86ebb1a9a7f..bc9aaba01a22 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1925,6 +1925,45 @@ static void xen_set_cpu_features(struct cpuinfo_x86 *c)
         }
 }
 
+static void xen_pin_vcpu(int cpu)
+{
+        static bool disable_pinning;
+        struct sched_pin_override pin_override;
+        int ret;
+
+        if (disable_pinning)
+                return;
+
+        pin_override.pcpu = cpu;
+        ret = HYPERVISOR_sched_op(SCHEDOP_pin_override, &pin_override);
+
+        /* Ignore errors when removing override. */
+        if (cpu < 0)
+                return;
+
+        switch (ret) {
+        case -ENOSYS:
+                pr_warn("Unable to pin on physical cpu %d. In case of problems consider vcpu pinning.\n",
+                        cpu);
+                disable_pinning = true;
+                break;
+        case -EPERM:
+                WARN(1, "Trying to pin vcpu without having privilege to do so\n");
+                disable_pinning = true;
+                break;
+        case -EINVAL:
+        case -EBUSY:
+                pr_warn("Physical cpu %d not available for pinning. Check Xen cpu configuration.\n",
+                        cpu);
+                break;
+        case 0:
+                break;
+        default:
+                WARN(1, "rc %d while trying to pin vcpu\n", ret);
+                disable_pinning = true;
+        }
+}
+
 const struct hypervisor_x86 x86_hyper_xen = {
         .name                   = "Xen",
         .detect                 = xen_platform,
@@ -1933,6 +1972,7 @@ const struct hypervisor_x86 x86_hyper_xen = {
 #endif
         .x2apic_available       = xen_x2apic_para_available,
         .set_cpu_features       = xen_set_cpu_features,
+        .pin_vcpu               = xen_pin_vcpu,
 };
 EXPORT_SYMBOL(x86_hyper_xen);
 
diff --git a/drivers/firmware/dcdbas.c b/drivers/firmware/dcdbas.c
index 829eec8959f2..2fe1a130189f 100644
--- a/drivers/firmware/dcdbas.c
+++ b/drivers/firmware/dcdbas.c
@@ -23,6 +23,7 @@
 #include <linux/platform_device.h>
 #include <linux/dma-mapping.h>
 #include <linux/errno.h>
+#include <linux/cpu.h>
 #include <linux/gfp.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
@@ -238,33 +239,14 @@ static ssize_t host_control_on_shutdown_store(struct device *dev,
         return count;
 }
 
-/**
- * dcdbas_smi_request: generate SMI request
- *
- * Called with smi_data_lock.
- */
-int dcdbas_smi_request(struct smi_cmd *smi_cmd)
+static int raise_smi(void *par)
 {
-        cpumask_var_t old_mask;
-        int ret = 0;
-
-        if (smi_cmd->magic != SMI_CMD_MAGIC) {
-                dev_info(&dcdbas_pdev->dev, "%s: invalid magic value\n",
-                         __func__);
-                return -EBADR;
-        }
+        struct smi_cmd *smi_cmd = par;
 
-        /* SMI requires CPU 0 */
-        if (!alloc_cpumask_var(&old_mask, GFP_KERNEL))
-                return -ENOMEM;
-
-        cpumask_copy(old_mask, &current->cpus_allowed);
-        set_cpus_allowed_ptr(current, cpumask_of(0));
         if (smp_processor_id() != 0) {
                 dev_dbg(&dcdbas_pdev->dev, "%s: failed to get CPU 0\n",
                         __func__);
-                ret = -EBUSY;
-                goto out;
+                return -EBUSY;
         }
 
         /* generate SMI */
@@ -280,9 +262,28 @@ int dcdbas_smi_request(struct smi_cmd *smi_cmd)
                 : "memory"
         );
 
-out:
-        set_cpus_allowed_ptr(current, old_mask);
-        free_cpumask_var(old_mask);
+        return 0;
+}
+/**
+ * dcdbas_smi_request: generate SMI request
+ *
+ * Called with smi_data_lock.
+ */
+int dcdbas_smi_request(struct smi_cmd *smi_cmd)
+{
+        int ret;
+
+        if (smi_cmd->magic != SMI_CMD_MAGIC) {
+                dev_info(&dcdbas_pdev->dev, "%s: invalid magic value\n",
+                         __func__);
+                return -EBADR;
+        }
+
+        /* SMI requires CPU 0 */
+        get_online_cpus();