xen/acpi: ACPI cpu hotplug

This patch implement real Xen ACPI cpu hotplug driver as module.
When loaded, it replaces Xen stub driver.

For booting existed cpus, the driver enumerates them.
For hotadded cpus, which added at runtime and notify OS via
device or container event, the driver is invoked to add them,
parsing cpu information, hypercalling to Xen hypervisor to add
them, and finally setting up new /sys interface for them.

Signed-off-by: Liu Jinsong <jinsong.liu@intel.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/drivers/xen/pcpu.c b/drivers/xen/pcpu.c
index 067fcfa1723e..0836a18675b1 100644
--- a/drivers/xen/pcpu.c
+++ b/drivers/xen/pcpu.c
@@ -333,6 +333,41 @@ static irqreturn_t xen_pcpu_interrupt(int irq, void *dev_id)
         return IRQ_HANDLED;
 }
 
+/* Sync with Xen hypervisor after cpu hotadded */
+void xen_pcpu_hotplug_sync(void)
+{
+        schedule_work(&xen_pcpu_work);
+}
+EXPORT_SYMBOL_GPL(xen_pcpu_hotplug_sync);
+
+/*
+ * For hypervisor presented cpu, return logic cpu id;
+ * For hypervisor non-presented cpu, return -ENODEV.
+ */
+int xen_pcpu_id(uint32_t acpi_id)
+{
+        int cpu_id = 0, max_id = 0;
+        struct xen_platform_op op;
+
+        op.cmd = XENPF_get_cpuinfo;
+        while (cpu_id <= max_id) {
+                op.u.pcpu_info.xen_cpuid = cpu_id;
+                if (HYPERVISOR_dom0_op(&op)) {
+                        cpu_id++;
+                        continue;
+                }
+
+                if (acpi_id == op.u.pcpu_info.acpi_id)
+                        return cpu_id;
+                if (op.u.pcpu_info.max_present > max_id)
+                        max_id = op.u.pcpu_info.max_present;
+                cpu_id++;
+        }
+
+        return -ENODEV;
+}
+EXPORT_SYMBOL_GPL(xen_pcpu_id);
+
 static int __init xen_pcpu_init(void)
 {
         int irq, ret;