Re: RFC/Patch: Support for other bootloaders

[Christian Limpach <christian.limpach@gmail.com>]

On Mon, 21 Mar 2005 10:46:02 -0500, Michal Ostrowski
<mostrows@watson.ibm.com> wrote:
> 
> I need to net-boot xen on an HS20 blade.  HS20's have a Broadcom NIC,
> which is not supported by grub.  The attached patch allows me to build a
> Xen image which I can boot using PXELinux  (and the entire SysLinux
> family of boot-loaders).

I think this breaks multiboot support because of:
+void __init __start_xen(void *params)
+{
...
+    multiboot_info_t *mbi = NULL;
+    
+    if (MULTIBOOT_BOOTLOADER_MAGIC == *(u32*)params ) 
+    {
+        mbi = (struct multiboot_info_t*)__va(mbi);

I think this should be:
+    if (MULTIBOOT_BOOTLOADER_MAGIC == *(u32*)__va(params) ) 
+    {
+        mbi = (struct multiboot_info_t*)__va(params);

Also, have you tested your changes on a SMP or HT machine?  I think
you're lucky if it works at all because you rearranged some of the
tests, and now the test for multiboot is no longer protected by the
test if we're running on a secondary cpu (%ebx == 0).

Finally, I think the updated mbootpack is a sufficient solution --
we're trying to fix a limitation in most bootloaders and interposing
something which works around this limitation seems like a sane
approach...

    christian


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