git: c8113dad7ed4 - main - Increase MAX_APIC_ID safeguard to 0x800

From: Ed Maste <>
Date: Thu, 27 Oct 2022 16:34:02 UTC
The branch main has been updated by emaste:


commit c8113dad7ed4024376901a834fc239d754292049
Author:     Ed Maste <>
AuthorDate: 2022-10-20 13:04:37 +0000
Commit:     Ed Maste <>
CommitDate: 2022-10-27 16:33:34 +0000

    Increase MAX_APIC_ID safeguard to 0x800
    MAX_APIC_ID must be at least twice MAXCPU.  Increase it to 0x800 so that
    it is possible to set MAXCPU to 512 or 1024 in a custom kernel config
    Note that increasing this limit does not itself cause any allocations
    to be larger; it just allows madt_parse_cpu() to process higher APIC
    APIC IDs may be sparse and so we can waste memory.  This is independent
    of this change, but becomes more of an issue as the maximum APIC ID
    grows.  This should be addressed with future work.
    Reviewed by:    royger
    MFC after:      1 week
    Sponsored by:   The FreeBSD Foundation
    Differential Revision:
 sys/x86/include/apicvar.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sys/x86/include/apicvar.h b/sys/x86/include/apicvar.h
index ff6bb97d7f80..28b9f83894fb 100644
--- a/sys/x86/include/apicvar.h
+++ b/sys/x86/include/apicvar.h
@@ -77,7 +77,7 @@
 #define	xAPIC_MAX_APIC_ID	0xfe
 #define	xAPIC_ID_ALL		0xff
-#define	MAX_APIC_ID		0x200
+#define	MAX_APIC_ID		0x800
 #define	APIC_ID_ALL		0xffffffff