xen/vcpu: Simplify xen_vcpu related code

[karo-tx-linux.git] / arch / x86 / xen / enlighten.c

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index a5ffcbb20cc006adb1635436b6fa020a07fbb9d9..96b745e3f56cccc86c14d92f14befe6e4ab6db46 100644 (file)
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -106,6 +106,35 @@ int xen_cpuhp_setup(int (*cpu_up_prepare_cb)(unsigned int),
        return rc >= 0 ? 0 : rc;
 }
 
+/*
+ * On restore, set the vcpu placement up again.
+ * If it fails, then we're in a bad state, since
+ * we can't back out from using it...
+ */
+void xen_vcpu_restore(void)
+{
+       int cpu;
+
+       for_each_possible_cpu(cpu) {
+               bool other_cpu = (cpu != smp_processor_id());
+               bool is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up, xen_vcpu_nr(cpu),
+                                               NULL);
+
+               if (other_cpu && is_up &&
+                   HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL))
+                       BUG();
+
+               xen_setup_runstate_info(cpu);
+
+               if (xen_have_vcpu_info_placement)
+                       xen_vcpu_setup(cpu);
+
+               if (other_cpu && is_up &&
+                   HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL))
+                       BUG();
+       }
+}
+
 static void clamp_max_cpus(void)
 {
 #ifdef CONFIG_SMP
@@ -114,6 +143,17 @@ static void clamp_max_cpus(void)
 #endif
 }
 
+void xen_vcpu_info_reset(int cpu)
+{
+       if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS) {
+               per_cpu(xen_vcpu, cpu) =
+                       &HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)];
+       } else {
+               /* Set to NULL so that if somebody accesses it we get an OOPS */
+               per_cpu(xen_vcpu, cpu) = NULL;
+       }
+}
+
 void xen_vcpu_setup(int cpu)
 {
        struct vcpu_register_vcpu_info info;
@@ -137,40 +177,45 @@ void xen_vcpu_setup(int cpu)
                if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu))
                        return;
        }
-       if (xen_vcpu_nr(cpu) < MAX_VIRT_CPUS)
-               per_cpu(xen_vcpu, cpu) =
-                       &HYPERVISOR_shared_info->vcpu_info[xen_vcpu_nr(cpu)];
+
+       xen_vcpu_info_reset(cpu);
+
+       if (xen_have_vcpu_info_placement) {
+               vcpup = &per_cpu(xen_vcpu_info, cpu);
+               info.mfn = arbitrary_virt_to_mfn(vcpup);
+               info.offset = offset_in_page(vcpup);
+
+               /*
+                * Check to see if the hypervisor will put the vcpu_info
+                * structure where we want it, which allows direct access via
+                * a percpu-variable.
+                * N.B. This hypercall can _only_ be called once per CPU.
+                * Subsequent calls will error out with -EINVAL. This is due to
+                * the fact that hypervisor has no unregister variant and this
+                * hypercall does not allow to over-write info.mfn and
+                * info.offset.
+                */
+               err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info,
+                                        xen_vcpu_nr(cpu), &info);
+
+               if (err) {
+                       pr_warn_once("register_vcpu_info failed: cpu=%d err=%d\n",
+                                    cpu, err);
+                       xen_have_vcpu_info_placement = 0;
+               } else {
+                       /*
+                        * This cpu is using the registered vcpu info, even if
+                        * later ones fail to.
+                        */
+                       per_cpu(xen_vcpu, cpu) = vcpup;
+               }
+       }
 
        if (!xen_have_vcpu_info_placement) {
                if (cpu >= MAX_VIRT_CPUS)
                        clamp_max_cpus();
                return;
        }
-
-       vcpup = &per_cpu(xen_vcpu_info, cpu);
-       info.mfn = arbitrary_virt_to_mfn(vcpup);
-       info.offset = offset_in_page(vcpup);
-
-       /* Check to see if the hypervisor will put the vcpu_info
-          structure where we want it, which allows direct access via
-          a percpu-variable.
-          N.B. This hypercall can _only_ be called once per CPU. Subsequent
-          calls will error out with -EINVAL. This is due to the fact that
-          hypervisor has no unregister variant and this hypercall does not
-          allow to over-write info.mfn and info.offset.
-        */
-       err = HYPERVISOR_vcpu_op(VCPUOP_register_vcpu_info, xen_vcpu_nr(cpu),
-                                &info);
-
-       if (err) {
-               printk(KERN_DEBUG "register_vcpu_info failed: err=%d\n", err);
-               xen_have_vcpu_info_placement = 0;
-               clamp_max_cpus();
-       } else {
-               /* This cpu is using the registered vcpu info, even if
-                  later ones fail to. */
-               per_cpu(xen_vcpu, cpu) = vcpup;
-       }
 }
 
 void xen_reboot(int reason)