From: Doug Chapman <dchapman@redhat.com>
Date: Mon, 14 Jan 2008 18:05:30 -0500
Subject: [ia64] xen: fix bogus IOSAPIC
Message-id: 1200351931.32411.32.camel@athlon
O-Subject: [RHEL5.2 PATCH] fix bogus IOSAPIC on ia64 xen
Bugzilla: 246130

for BZ 246130 - [rhts] ia64 acpi complains of errors

On para-virtualized ia64 xen the ACPI tables do not contain
IOSAPIC entries which leads to the error message:

   Error parsing MADT - no IOSAPIC entries

when booting pv ia64 xen guest.  I am told that the lack
of IOSAPIC entries is intentional by our ia64 experts back
at HP.  We are already ignoring this for the sn2 platform.
This patch extends that for "xen" platform as well.

I am currently pushing this upstream.  Tested by booting
a pv guest with this patch and verifying the error goes
away.

Acked-by: Jarod Wilson <jwilson@redhat.com>
Acked-by: Jon Masters <jcm@redhat.com>
Acked-by: "Stephen C. Tweedie" <sct@redhat.com>
Acked-by: Prarit Bhargava <prarit@redhat.com>

diff --git a/arch/ia64/kernel/acpi.c b/arch/ia64/kernel/acpi.c
index f2bf59d..c9e3aae 100644
--- a/arch/ia64/kernel/acpi.c
+++ b/arch/ia64/kernel/acpi.c
@@ -698,7 +698,7 @@ int __init acpi_boot_init(void)
 
 	if (acpi_table_parse_madt
 	    (ACPI_MADT_IOSAPIC, acpi_parse_iosapic, NR_IOSAPICS) < 1) {
-		if (!ia64_platform_is("sn2"))
+		if (!ia64_platform_is("sn2") && !ia64_platform_is("xen"))
 			printk(KERN_ERR PREFIX
 			       "Error parsing MADT - no IOSAPIC entries\n");
 	}