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x86, apic: Don't use logical-flat mode when CPU hotplug may exceed 8 CPUs

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We need to fall back from logical-flat APIC mode to physical-flat mode
when we have more than 8 CPUs.  However, in the presence of CPU
hotplug(with bios listing not enabled but possible cpus as disabled cpus in
MADT), we have to consider the number of possible CPUs rather than
the number of current CPUs; otherwise we may cross the 8-CPU boundary
when CPUs are added later.

32bit apic code can use more cleanups (like the removal of vendor checks in
32bit default_setup_apic_routing()) and more unifications with 64bit code.
Yinghai has some patches in works already. This patch addresses the boot issue
that is reported in the virtualization guest context.

[ hpa: incorporated function annotation feedback from Yinghai Lu ]

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
LKML-Reference: <1265767304.2833.19.camel@sbs-t61.sc.intel.com>
Acked-by: Shaohui Zheng <shaohui.zheng@intel.com>
Reviewed-by: Yinghai Lu <yinghai@kernel.org>
Cc: <stable@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
This commit is contained in:
Suresh Siddha
2010-02-09 18:01:44 -08:00
committed by H. Peter Anvin
parent cf9db6c41f
commit 681ee44d40
6 changed files with 28 additions and 34 deletions
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29
arch/x86/kernel/apic/probe_32.c
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@@ -52,7 +52,32 @@ static int __init print_ipi_mode(void)
}
late_initcall(print_ipi_mode);
void default_setup_apic_routing(void)
void __init default_setup_apic_routing(void)
{
int version = apic_version[boot_cpu_physical_apicid];
if (num_possible_cpus() > 8) {
switch (boot_cpu_data.x86_vendor) {
case X86_VENDOR_INTEL:
if (!APIC_XAPIC(version)) {
def_to_bigsmp = 0;
break;
}
/* If P4 and above fall through */
case X86_VENDOR_AMD:
def_to_bigsmp = 1;
}
}
#ifdef CONFIG_X86_BIGSMP
generic_bigsmp_probe();
#endif
if (apic->setup_apic_routing)
apic->setup_apic_routing();
}
static void setup_apic_flat_routing(void)
{
#ifdef CONFIG_X86_IO_APIC
printk(KERN_INFO
@@ -103,7 +128,7 @@ struct apic apic_default = {
.init_apic_ldr = default_init_apic_ldr,
.ioapic_phys_id_map = default_ioapic_phys_id_map,
.setup_apic_routing = default_setup_apic_routing,
.setup_apic_routing = setup_apic_flat_routing,
.multi_timer_check = NULL,
.apicid_to_node = default_apicid_to_node,
.cpu_to_logical_apicid = default_cpu_to_logical_apicid,