From 77be224862d3c82f0bc75e359e847052a2a80917 Mon Sep 17 00:00:00 2001
From: "Rodney W. Grimes" <rgrimes@FreeBSD.org>
Date: Thu, 25 Apr 2019 22:52:44 +0000
Subject: [PATCH] Acpi MADT table correction for VM_MAXCPU > 21

The bhyve acpi MADT table was given a static space of 256 (0x100) bytes,
this is enough space to allow VM_MAXCPU to be 21, this patch changes that
so VM_MAXCPU can be of arbitrary value and not overflow the space by
actually calculating the space needed for the table.

PR:			212782
Reviewed by:		Patrick Mooney <patrick.mooney@joyent.com>
Approved by:		bde (mentor), jhb (maintainer)
MFC after:		3 days
Differential Revision:	https://reviews.freebsd.org/D18815
---
 usr.sbin/bhyve/acpi.c | 31 +++++++++++++++++++++++--------
 1 file changed, 23 insertions(+), 8 deletions(-)

diff --git a/usr.sbin/bhyve/acpi.c b/usr.sbin/bhyve/acpi.c
index f6e129ebee66..1ed1ab6c6074 100644
--- a/usr.sbin/bhyve/acpi.c
+++ b/usr.sbin/bhyve/acpi.c
@@ -39,7 +39,9 @@
  *  The tables are placed in the guest's ROM area just below 1MB physical,
  * above the MPTable.
  *
- *  Layout
+ *  Layout (No longer correct at FADT and beyond due to properly
+ *  calculating the size of the MADT to allow for changes to
+ *  VM_MAXCPU above 21 which overflows this layout.)
  *  ------
  *   RSDP  ->   0xf2400    (36 bytes fixed)
  *     RSDT  ->   0xf2440    (36 bytes + 4*7 table addrs, 4 used)
@@ -74,18 +76,31 @@ __FBSDID("$FreeBSD$");
 #include "pci_emul.h"
 
 /*
- * Define the base address of the ACPI tables, and the offsets to
- * the individual tables
+ * Define the base address of the ACPI tables, the sizes of some tables, 
+ * and the offsets to the individual tables,
  */
 #define BHYVE_ACPI_BASE		0xf2400
 #define RSDT_OFFSET		0x040
 #define XSDT_OFFSET		0x080
 #define MADT_OFFSET		0x100
-#define FADT_OFFSET		0x200
-#define	HPET_OFFSET		0x340
-#define	MCFG_OFFSET		0x380
-#define FACS_OFFSET		0x3C0
-#define DSDT_OFFSET		0x400
+/*
+ * The MADT consists of:
+ *	44		Fixed Header
+ *	8 * maxcpu	Processor Local APIC entries
+ *	12		I/O APIC entry
+ *	2 * 10		Interrupt Source Override entires
+ *	6		Local APIC NMI entry
+ */
+#define	MADT_SIZE		(44 + VM_MAXCPU*8 + 12 + 2*10 + 6)
+#define	FADT_OFFSET		(MADT_OFFSET + MADT_SIZE)
+#define	FADT_SIZE		0x140
+#define	HPET_OFFSET		(FADT_OFFSET + FADT_SIZE)
+#define	HPET_SIZE		0x40
+#define	MCFG_OFFSET		(HPET_OFFSET + HPET_SIZE)
+#define	MCFG_SIZE		0x40
+#define	FACS_OFFSET		(MCFG_OFFSET + MCFG_SIZE)
+#define	FACS_SIZE		0x40
+#define	DSDT_OFFSET		(FACS_OFFSET + FACS_SIZE)
 
 #define	BHYVE_ASL_TEMPLATE	"bhyve.XXXXXXX"
 #define BHYVE_ASL_SUFFIX	".aml"