diff options
Diffstat (limited to 'arch/x86/xen/enlighten.c')
| -rw-r--r-- | arch/x86/xen/enlighten.c | 116 |
1 files changed, 26 insertions, 90 deletions
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index 95d970359e17..30c6e986a6cd 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -31,25 +31,10 @@ EXPORT_SYMBOL_GPL(hypercall_page); * Pointer to the xen_vcpu_info structure or * &HYPERVISOR_shared_info->vcpu_info[cpu]. See xen_hvm_init_shared_info * and xen_vcpu_setup for details. By default it points to share_info->vcpu_info - * but if the hypervisor supports VCPUOP_register_vcpu_info then it can point - * to xen_vcpu_info. The pointer is used in __xen_evtchn_do_upcall to - * acknowledge pending events. - * Also more subtly it is used by the patched version of irq enable/disable - * e.g. xen_irq_enable_direct and xen_iret in PV mode. - * - * The desire to be able to do those mask/unmask operations as a single - * instruction by using the per-cpu offset held in %gs is the real reason - * vcpu info is in a per-cpu pointer and the original reason for this - * hypercall. - * + * but during boot it is switched to point to xen_vcpu_info. + * The pointer is used in __xen_evtchn_do_upcall to acknowledge pending events. */ DEFINE_PER_CPU(struct vcpu_info *, xen_vcpu); - -/* - * Per CPU pages used if hypervisor supports VCPUOP_register_vcpu_info - * hypercall. This can be used both in PV and PVHVM mode. The structure - * overrides the default per_cpu(xen_vcpu, cpu) value. - */ DEFINE_PER_CPU(struct vcpu_info, xen_vcpu_info); /* Linux <-> Xen vCPU id mapping */ @@ -84,21 +69,6 @@ EXPORT_SYMBOL(xen_start_flags); */ struct shared_info *HYPERVISOR_shared_info = &xen_dummy_shared_info; -/* - * Flag to determine whether vcpu info placement is available on all - * VCPUs. We assume it is to start with, and then set it to zero on - * the first failure. This is because it can succeed on some VCPUs - * and not others, since it can involve hypervisor memory allocation, - * or because the guest failed to guarantee all the appropriate - * constraints on all VCPUs (ie buffer can't cross a page boundary). - * - * Note that any particular CPU may be using a placed vcpu structure, - * but we can only optimise if the all are. - * - * 0: not available, 1: available - */ -int xen_have_vcpu_info_placement = 1; - static int xen_cpu_up_online(unsigned int cpu) { xen_init_lock_cpu(cpu); @@ -124,10 +94,8 @@ int xen_cpuhp_setup(int (*cpu_up_prepare_cb)(unsigned int), return rc >= 0 ? 0 : rc; } -static int xen_vcpu_setup_restore(int cpu) +static void xen_vcpu_setup_restore(int cpu) { - int rc = 0; - /* Any per_cpu(xen_vcpu) is stale, so reset it */ xen_vcpu_info_reset(cpu); @@ -136,11 +104,8 @@ static int xen_vcpu_setup_restore(int cpu) * be handled by hotplug. */ if (xen_pv_domain() || - (xen_hvm_domain() && cpu_online(cpu))) { - rc = xen_vcpu_setup(cpu); - } - - return rc; + (xen_hvm_domain() && cpu_online(cpu))) + xen_vcpu_setup(cpu); } /* @@ -150,7 +115,7 @@ static int xen_vcpu_setup_restore(int cpu) */ void xen_vcpu_restore(void) { - int cpu, rc; + int cpu; for_each_possible_cpu(cpu) { bool other_cpu = (cpu != smp_processor_id()); @@ -170,20 +135,9 @@ void xen_vcpu_restore(void) if (xen_pv_domain() || xen_feature(XENFEAT_hvm_safe_pvclock)) xen_setup_runstate_info(cpu); - rc = xen_vcpu_setup_restore(cpu); - if (rc) - pr_emerg_once("vcpu restore failed for cpu=%d err=%d. " - "System will hang.\n", cpu, rc); - /* - * In case xen_vcpu_setup_restore() fails, do not bring up the - * VCPU. This helps us avoid the resulting OOPS when the VCPU - * accesses pvclock_vcpu_time via xen_vcpu (which is NULL.) - * Note that this does not improve the situation much -- now the - * VM hangs instead of OOPSing -- with the VCPUs that did not - * fail, spinning in stop_machine(), waiting for the failed - * VCPUs to come up. - */ - if (other_cpu && is_up && (rc == 0) && + xen_vcpu_setup_restore(cpu); + + if (other_cpu && is_up && HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL)) BUG(); } @@ -200,7 +154,7 @@ void xen_vcpu_info_reset(int cpu) } } -int xen_vcpu_setup(int cpu) +void xen_vcpu_setup(int cpu) { struct vcpu_register_vcpu_info info; int err; @@ -221,44 +175,26 @@ int xen_vcpu_setup(int cpu) */ if (xen_hvm_domain()) { if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu)) - return 0; + return; } - 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; - } - } + vcpup = &per_cpu(xen_vcpu_info, cpu); + info.mfn = arbitrary_virt_to_mfn(vcpup); + info.offset = offset_in_page(vcpup); - if (!xen_have_vcpu_info_placement) - xen_vcpu_info_reset(cpu); + /* + * 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) + panic("register_vcpu_info failed: cpu=%d err=%d\n", cpu, err); - return ((per_cpu(xen_vcpu, cpu) == NULL) ? -ENODEV : 0); + per_cpu(xen_vcpu, cpu) = vcpup; } void __init xen_banner(void) |