Check that the processor to be woken up APIC ID is addressable in the
current APIC mode.
Note that in practice systems with APIC IDs > 255 should already have
x2APIC enabled by the firmware, and hence this is mostly a safety
belt.
Signed-off-by: Roger Pau Monné <roger....@citrix.com>
---
xen/arch/x86/smpboot.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/xen/arch/x86/smpboot.c b/xen/arch/x86/smpboot.c
index fa691b6ba0..484d344c44 100644
--- a/xen/arch/x86/smpboot.c
+++ b/xen/arch/x86/smpboot.c
@@ -1317,6 +1317,13 @@ int __cpu_up(unsigned int cpu)
if ( (apicid = x86_cpu_to_apicid[cpu]) == BAD_APICID )
return -ENODEV;
+ if ( (!x2apic_enabled || !iommu_intremap) && (apicid >> 8) )
+ {
+ printk("Processor with APIC ID %u cannot be onlined in xAPIC mode "
+ "or without interrupt remapping\n", apicid);
+ return -EINVAL;
+ }
+
if ( (ret = do_boot_cpu(apicid, cpu)) != 0 )
return ret;
--
2.24.0
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