Mark CPU present when it is detected

Currently a CPU is marked as present only after it has been kicked off
successfully, i.e. before the CPU is brought up, it is not
present. This patch try to mark CPU as present when it is detected
(either through MPS table or ACPI). If it can't be brought up
successfully, it will be marked as non-present again.  This change is
mainly for CPU hot-plug. As discussed, we'd take two step for physical
CPU hot-add. A CPU is firstly marked as present, and later will bring
as online.

Also, In smp_boot_cpus(), xen need only scan all present CPU, and no
need to loop from 0... NR_CPUS. With this change, the bios_cpu_apicid
is not needed anymore.

Signed-off-by: Jiang, Yunhong <yunhong.jiang@intel.com>

1 files changed, 23 insertions, 11 deletions

diff --git a/xen/arch/x86/mpparse.c b/xen/arch/x86/mpparse.c
index bd94588aa5..7d65c2abaf 100644
--- a/xen/arch/x86/mpparse.c
+++ b/xen/arch/x86/mpparse.c
@@ -71,8 +71,6 @@ static unsigned int __devinitdata num_processors;
 /* Bitmask of physically existing CPUs */
 physid_mask_t phys_cpu_present_map;
 
-u32 bios_cpu_apicid[NR_CPUS] = { [0 ... NR_CPUS-1] = BAD_APICID };
-
 /*
  * Intel MP BIOS table parsing routines:
  */
@@ -101,13 +99,14 @@ static int __init mpf_checksum(unsigned char *mp, int len)
 static int mpc_record; 
 static struct mpc_config_translation *translation_table[MAX_MPC_ENTRY] __initdata;
 
-static void __devinit MP_processor_info (struct mpc_config_processor *m)
+/* Return xen's logical cpu_id of the new added cpu or <0 if error */
+static int __devinit MP_processor_info (struct mpc_config_processor *m)
 {
- 	int ver, apicid;
+ 	int ver, apicid, cpu = 0;
 	physid_mask_t phys_cpu;
  	
 	if (!(m->mpc_cpuflag & CPU_ENABLED))
-		return;
+		return -EINVAL;
 
 	apicid = mpc_apic_id(m, translation_table[mpc_record]);
 
@@ -183,15 +182,27 @@ static void __devinit MP_processor_info (struct mpc_config_processor *m)
 	if (num_processors >= NR_CPUS) {
 		printk(KERN_WARNING "WARNING: NR_CPUS limit of %i reached."
 			"  Processor ignored.\n", NR_CPUS);
-		return;
+		return -ENOSPC;
 	}
 
 	if (num_processors >= maxcpus) {
 		printk(KERN_WARNING "WARNING: maxcpus limit of %i reached."
 			" Processor ignored.\n", maxcpus);
-		return;
+		return -ENOSPC;
 	}
 
+    /* Boot cpu has been marked present in smp_prepare_boot_cpu */
+    if (!(m->mpc_cpuflag & CPU_BOOTPROCESSOR)) {
+        cpu = alloc_cpu_id();
+        if (cpu < 0) {
+            printk(KERN_WARNING "WARNING: Can't alloc cpu_id."
+              " Processor with apicid %i ignored\n", apicid);
+            return cpu;
+        }
+        x86_cpu_to_apicid[cpu] = apicid;
+        cpu_set(cpu, cpu_present_map);
+    }
+
 	cpu_set(num_processors, cpu_possible_map);
 	num_processors++;
 
@@ -202,7 +213,8 @@ static void __devinit MP_processor_info (struct mpc_config_processor *m)
 		 */
 		def_to_bigsmp = 1;
 	}
-	bios_cpu_apicid[num_processors - 1] = m->mpc_apicid;
+
+    return cpu;
 }
 
 static void __init MP_bus_info (struct mpc_config_bus *m)
@@ -826,7 +838,7 @@ void __init mp_register_lapic_address (
 }
 
 
-void __devinit mp_register_lapic (
+int __devinit mp_register_lapic (
 	u8			id, 
 	u8			enabled)
 {
@@ -836,7 +848,7 @@ void __devinit mp_register_lapic (
 	if (MAX_APICS - id <= 0) {
 		printk(KERN_WARNING "Processor #%d invalid (max %d)\n",
 			id, MAX_APICS);
-		return;
+		return -EINVAL;
 	}
 
 	if (id == boot_cpu_physical_apicid)
@@ -853,7 +865,7 @@ void __devinit mp_register_lapic (
 	processor.mpc_reserved[0] = 0;
 	processor.mpc_reserved[1] = 0;
 
-	MP_processor_info(&processor);
+    return MP_processor_info(&processor);
 }
 
 #ifdef	CONFIG_X86_IO_APIC