Re: [Xen-devel] RE: [Xen-bugs] [Bug 122] Dom0 fails to boot on SLES 9 machines compiledwith x86 PAE mode ON

["Natasha Jarymowycz" <natasha@xxxxxxxxxx>]

On Wed, 3 Aug 2005 15:40:38 +0100, Ian Pratt <m+Ian.Pratt@xxxxxxxxxxxx> wrote:

> > I think it's probably a property of the SLES 9 compiler used
> > to compile Xen and Linux. I have two identical machines, one
> > with SLES 9 and the other with RHEL 4, and the RHEL 4 box
> > works fine. Also, I have a 3rd machine of a different model
> > loaded with SLES 9 which is also not booting with PAE 'on'.
> > That points to SLES 9.
> Is it still the case with the very latest tree, i.e. where the default
> build is pentiumpro rather than pentium4?

I'm seeing this on an x440 with SLES 9, using changeset 6003.
Interestingly, I make it past this point if I specify mem=4G at boot.

The crash happens very early on when booting Xen so I don't
think Linux can be the problem.  I tossed some printk's into
paging_init() (that's where the last line of output came
from in the original boot log) to see if it dies in that function.

It seems to die somewhere in this code as I see the first printk message,
but not the last as it is about to exit:

xen/arch/x86/x86_32/mm.c, starting at line 95:
    printk("paging_init: about to allocate and map machine-to-phys table\n");
    /*
     * Allocate and map the machine-to-phys table and create read-only mapping
     * of MPT for guest-OS use.  Without PAE we'll end up with one 4MB page,
     * with PAE we'll allocate 2MB pages depending on the amount of memory
     * installed, but at least 4MB to cover 4GB address space.  This is needed
     * to make PCI I/O memory address lookups work in guests.
     */
    if ( (mpt_size = max_page * 4) < (4*1024*1024) )
        mpt_size = 4*1024*1024;
    for ( i = 0; i < (mpt_size >> L2_PAGETABLE_SHIFT); i++ )
    {
        if ( (pg = alloc_domheap_pages(NULL, PAGETABLE_ORDER, 0)) == NULL )
            panic("Not enough memory to bootstrap Xen.\n");
        idle_pg_table_l2[l2_linear_offset(RDWR_MPT_VIRT_START) + i] =
            l2e_from_page(pg, PAGE_HYPERVISOR | _PAGE_PSE);
        idle_pg_table_l2[l2_linear_offset(RO_MPT_VIRT_START) + i] =
            l2e_from_page(pg, (__PAGE_HYPERVISOR | _PAGE_PSE) & ~_PAGE_RW);
    }
    memset((void *)RDWR_MPT_VIRT_START, 0x55, mpt_size);

    /* Create page tables for ioremap(). */
    for ( i = 0; i < (IOREMAP_MBYTES >> (L2_PAGETABLE_SHIFT - 20)); i++ )
    {
        ioremap_pt = alloc_xenheap_page();
        clear_page(ioremap_pt);
        idle_pg_table_l2[l2_linear_offset(IOREMAP_VIRT_START) + i] =
            l2e_from_page(virt_to_page(ioremap_pt), __PAGE_HYPERVISOR);
    }

    /* Set up mapping cache for domain pages. */
    mapcache_order = get_order(MAPCACHE_MBYTES << (20 - PAGETABLE_ORDER));
    mapcache = alloc_xenheap_pages(mapcache_order);
    memset(mapcache, 0, PAGE_SIZE << mapcache_order);
    for ( i = 0; i < (MAPCACHE_MBYTES >> (L2_PAGETABLE_SHIFT - 20)); i++ )
        idle_pg_table_l2[l2_linear_offset(MAPCACHE_VIRT_START) + i] =
            l2e_from_page(virt_to_page(mapcache) + i, __PAGE_HYPERVISOR);

   printk("paging_init: exiting function\n");
}



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