1 files changed, 368 insertions, 0 deletions
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
new file mode 100644
index 000000000..0f68c6da7
--- /dev/null
+++ b/arch/x86/xen/enlighten.c
@@ -0,0 +1,368 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#ifdef CONFIG_XEN_BALLOON_MEMORY_HOTPLUG
+#include <linux/memblock.h>
+#endif
+#include <linux/cpu.h>
+#include <linux/kexec.h>
+#include <linux/slab.h>
+
+#include <xen/xen.h>
+#include <xen/features.h>
+#include <xen/page.h>
+
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+#include <asm/cpu.h>
+#include <asm/e820/api.h> 
+
+#include "xen-ops.h"
+#include "smp.h"
+#include "pmu.h"
+
+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.
+ *
+ */
+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 */
+DEFINE_PER_CPU(uint32_t, xen_vcpu_id);
+EXPORT_PER_CPU_SYMBOL(xen_vcpu_id);
+
+unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START;
+EXPORT_SYMBOL(machine_to_phys_mapping);
+unsigned long  machine_to_phys_nr;
+EXPORT_SYMBOL(machine_to_phys_nr);
+
+struct start_info *xen_start_info;
+EXPORT_SYMBOL_GPL(xen_start_info);
+
+struct shared_info xen_dummy_shared_info;
+
+__read_mostly int xen_have_vector_callback;
+EXPORT_SYMBOL_GPL(xen_have_vector_callback);
+
+/*
+ * NB: These need to live in .data or alike because they're used by
+ * xen_prepare_pvh() which runs before clearing the bss.
+ */
+enum xen_domain_type __ro_after_init xen_domain_type = XEN_NATIVE;
+EXPORT_SYMBOL_GPL(xen_domain_type);
+uint32_t xen_start_flags __section(".data") = 0;
+EXPORT_SYMBOL(xen_start_flags);
+
+/*
+ * Point at some empty memory to start with. We map the real shared_info
+ * page as soon as fixmap is up and running.
+ */
+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);
+	return 0;
+}
+
+int xen_cpuhp_setup(int (*cpu_up_prepare_cb)(unsigned int),
+		    int (*cpu_dead_cb)(unsigned int))
+{
+	int rc;
+
+	rc = cpuhp_setup_state_nocalls(CPUHP_XEN_PREPARE,
+				       "x86/xen/guest:prepare",
+				       cpu_up_prepare_cb, cpu_dead_cb);
+	if (rc >= 0) {
+		rc = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
+					       "x86/xen/guest:online",
+					       xen_cpu_up_online, NULL);
+		if (rc < 0)
+			cpuhp_remove_state_nocalls(CPUHP_XEN_PREPARE);
+	}
+
+	return rc >= 0 ? 0 : rc;
+}
+
+static int xen_vcpu_setup_restore(int cpu)
+{
+	int rc = 0;
+
+	/* Any per_cpu(xen_vcpu) is stale, so reset it */
+	xen_vcpu_info_reset(cpu);
+
+	/*
+	 * For PVH and PVHVM, setup online VCPUs only. The rest will
+	 * be handled by hotplug.
+	 */
+	if (xen_pv_domain() ||
+	    (xen_hvm_domain() && cpu_online(cpu))) {
+		rc = xen_vcpu_setup(cpu);
+	}
+
+	return 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, rc;
+
+	for_each_possible_cpu(cpu) {
+		bool other_cpu = (cpu != smp_processor_id());
+		bool is_up;
+
+		if (xen_vcpu_nr(cpu) == XEN_VCPU_ID_INVALID)
+			continue;
+
+		/* Only Xen 4.5 and higher support this. */
+		is_up = HYPERVISOR_vcpu_op(VCPUOP_is_up,
+					   xen_vcpu_nr(cpu), NULL) > 0;
+
+		if (other_cpu && is_up &&
+		    HYPERVISOR_vcpu_op(VCPUOP_down, xen_vcpu_nr(cpu), NULL))
+			BUG();
+
+		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) &&
+		    HYPERVISOR_vcpu_op(VCPUOP_up, xen_vcpu_nr(cpu), NULL))
+			BUG();
+	}
+}
+
+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;
+	}
+}
+
+int xen_vcpu_setup(int cpu)
+{
+	struct vcpu_register_vcpu_info info;
+	int err;
+	struct vcpu_info *vcpup;
+
+	BUG_ON(HYPERVISOR_shared_info == &xen_dummy_shared_info);
+
+	/*
+	 * This path is called on PVHVM at bootup (xen_hvm_smp_prepare_boot_cpu)
+	 * and at restore (xen_vcpu_restore). Also called for hotplugged
+	 * VCPUs (cpu_init -> xen_hvm_cpu_prepare_hvm).
+	 * However, the hypercall can only be done once (see below) so if a VCPU
+	 * is offlined and comes back online then let's not redo the hypercall.
+	 *
+	 * For PV it is called during restore (xen_vcpu_restore) and bootup
+	 * (xen_setup_vcpu_info_placement). The hotplug mechanism does not
+	 * use this function.
+	 */
+	if (xen_hvm_domain()) {
+		if (per_cpu(xen_vcpu, cpu) == &per_cpu(xen_vcpu_info, cpu))
+			return 0;
+	}
+
+	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)
+		xen_vcpu_info_reset(cpu);
+
+	return ((per_cpu(xen_vcpu, cpu) == NULL) ? -ENODEV : 0);
+}
+
+void xen_reboot(int reason)
+{
+	struct sched_shutdown r = { .reason = reason };
+	int cpu;
+
+	for_each_online_cpu(cpu)
+		xen_pmu_finish(cpu);
+
+	if (HYPERVISOR_sched_op(SCHEDOP_shutdown, &r))
+		BUG();
+}
+
+static int reboot_reason = SHUTDOWN_reboot;
+static bool xen_legacy_crash;
+void xen_emergency_restart(void)
+{
+	xen_reboot(reboot_reason);
+}
+
+static int
+xen_panic_event(struct notifier_block *this, unsigned long event, void *ptr)
+{
+	if (!kexec_crash_loaded()) {
+		if (xen_legacy_crash)
+			xen_reboot(SHUTDOWN_crash);
+
+		reboot_reason = SHUTDOWN_crash;
+
+		/*
+		 * If panic_timeout==0 then we are supposed to wait forever.
+		 * However, to preserve original dom0 behavior we have to drop
+		 * into hypervisor. (domU behavior is controlled by its
+		 * config file)
+		 */
+		if (panic_timeout == 0)
+			panic_timeout = -1;
+	}
+	return NOTIFY_DONE;
+}
+
+static int __init parse_xen_legacy_crash(char *arg)
+{
+	xen_legacy_crash = true;
+	return 0;
+}
+early_param("xen_legacy_crash", parse_xen_legacy_crash);
+
+static struct notifier_block xen_panic_block = {
+	.notifier_call = xen_panic_event,
+	.priority = INT_MIN
+};
+
+int xen_panic_handler_init(void)
+{
+	atomic_notifier_chain_register(&panic_notifier_list, &xen_panic_block);
+	return 0;
+}
+
+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;
+	}
+}
+
+#ifdef CONFIG_HOTPLUG_CPU
+void xen_arch_register_cpu(int num)
+{
+	arch_register_cpu(num);
+}
+EXPORT_SYMBOL(xen_arch_register_cpu);
+
+void xen_arch_unregister_cpu(int num)
+{
+	arch_unregister_cpu(num);
+}
+EXPORT_SYMBOL(xen_arch_unregister_cpu);
+#endif