# HG changeset patch
# User Kurt Garloff <kurt@xxxxxxxxxx>
# Node ID b1752c878a7845d812c9b15e721f401d786394b2
# Parent  469478194aef6e987f9281efbc0756749be6eb80
Microcode does not need to have the default size of 2000+48 bytes.
A corresponding patch has gone into Linux 2.6.19; this is the
port to Xen.

Signed-off-by: Kurt Garloff <kurt@xxxxxxxxxx>

Reference: Patch to linux kernel from Sep 27 2006
> # User Shaohua Li <shaohua.li@xxxxxxxxx>
> # Node ID 45898b908138b5d93c2cc7353f061ce54af145dc
> # Parent  f962eab7b82c9bf1a6da69571046e764f5128395
> [PATCH] x86 microcode: don't check the size
> 
> IA32 manual says if micorcode update's size is 0, then the size is
> default size (2048 bytes). But this doesn't suggest all microcode
> update's size should be above 2048 bytes to me. We actually had a
> microcode update whose size is 1024 bytes. The patch just removed the
> check.
> 
> Signed-off-by: Shaohua Li <shaohua.li@xxxxxxxxx>
> Cc: Tigran Aivazian <tigran@xxxxxxxxxxx>
> Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
> Signed-off-by: Linus Torvalds <torvalds@xxxxxxxx>
> 
> committer: Linus Torvalds <torvalds@xxxxxxxxxxx> 1159370778 -0700

diff -r 469478194aef -r b1752c878a78 xen/arch/x86/microcode.c
--- a/xen/arch/x86/microcode.c	Mon Dec 18 00:14:40 2006 +0000
+++ b/xen/arch/x86/microcode.c	Sun Dec 24 17:06:23 2006 +0100
@@ -249,14 +249,14 @@ static int find_matching_ucodes (void)
 		}
 
 		total_size = get_totalsize(&mc_header);
-		if ((cursor + total_size > user_buffer_size) || (total_size < DEFAULT_UCODE_TOTALSIZE)) {
+		if (cursor + total_size > user_buffer_size) {
 			printk(KERN_ERR "microcode: error! Bad data in microcode data file\n");
 			error = -EINVAL;
 			goto out;
 		}
 
 		data_size = get_datasize(&mc_header);
-		if ((data_size + MC_HEADER_SIZE > total_size) || (data_size < DEFAULT_UCODE_DATASIZE)) {
+		if (data_size + MC_HEADER_SIZE > total_size) {
 			printk(KERN_ERR "microcode: error! Bad data in microcode data file\n");
 			error = -EINVAL;
 			goto out;
@@ -459,11 +459,6 @@ int microcode_update(XEN_GUEST_HANDLE(vo
 {
 	int ret;
 
-	if (len < DEFAULT_UCODE_TOTALSIZE) {
-		printk(KERN_ERR "microcode: not enough data\n");
-		return -EINVAL;
-	}
-
 	if (len != (typeof(user_buffer_size))len) {
 		printk(KERN_ERR "microcode: too much data\n");
 		return -E2BIG;