pc: Update rtc_cmos on CPU hot-plug

It provides updated currently available CPUs count to BIOS on reboot.

Signed-off-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Andreas Färber <afaerber@suse.de>

2 files changed, 27 insertions, 0 deletions

diff --git a/hw/i386/pc.c b/hw/i386/pc.c
index 29d2703330..867add7ab0 100644
--- a/hw/i386/pc.c
+++ b/hw/i386/pc.c
@@ -338,6 +338,21 @@ static void pc_cmos_init_late(void *opaque)
     qemu_unregister_reset(pc_cmos_init_late, opaque);
 }
 
+typedef struct RTCCPUHotplugArg {
+    Notifier cpu_added_notifier;
+    ISADevice *rtc_state;
+} RTCCPUHotplugArg;
+
+static void rtc_notify_cpu_added(Notifier *notifier, void *data)
+{
+    RTCCPUHotplugArg *arg = container_of(notifier, RTCCPUHotplugArg,
+                                         cpu_added_notifier);
+    ISADevice *s = arg->rtc_state;
+
+    /* increment the number of CPUs */
+    rtc_set_memory(s, 0x5f, rtc_get_memory(s, 0x5f) + 1);
+}
+
 void pc_cmos_init(ram_addr_t ram_size, ram_addr_t above_4g_mem_size,
                   const char *boot_device,
                   ISADevice *floppy, BusState *idebus0, BusState *idebus1,
@@ -346,6 +361,7 @@ void pc_cmos_init(ram_addr_t ram_size, ram_addr_t above_4g_mem_size,
     int val, nb, i;
     FDriveType fd_type[2] = { FDRIVE_DRV_NONE, FDRIVE_DRV_NONE };
     static pc_cmos_init_late_arg arg;
+    static RTCCPUHotplugArg cpu_hotplug_cb;
 
     /* various important CMOS locations needed by PC/Bochs bios */
 
@@ -384,6 +400,10 @@ void pc_cmos_init(ram_addr_t ram_size, ram_addr_t above_4g_mem_size,
 
     /* set the number of CPU */
     rtc_set_memory(s, 0x5f, smp_cpus - 1);
+    /* init CPU hotplug notifier */
+    cpu_hotplug_cb.rtc_state = s;
+    cpu_hotplug_cb.cpu_added_notifier.notify = rtc_notify_cpu_added;
+    qemu_register_cpu_added_notifier(&cpu_hotplug_cb.cpu_added_notifier);
 
     /* set boot devices, and disable floppy signature check if requested */
     if (set_boot_dev(s, boot_device, fd_bootchk)) {
diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c
index afbd0db298..481604de35 100644
--- a/hw/timer/mc146818rtc.c
+++ b/hw/timer/mc146818rtc.c
@@ -680,6 +680,13 @@ void rtc_set_memory(ISADevice *dev, int addr, int val)
         s->cmos_data[addr] = val;
 }
 
+int rtc_get_memory(ISADevice *dev, int addr)
+{
+    RTCState *s = MC146818_RTC(dev);
+    assert(addr >= 0 && addr <= 127);
+    return s->cmos_data[addr];
+}
+
 static void rtc_set_date_from_host(ISADevice *dev)
 {
     RTCState *s = MC146818_RTC(dev);