Re: [PATCH] x86/xen: enable early use of set_fixmap in 32-bit Xen PV guest

[Thomas Gleixner]

On Fri, 17 Aug 2018, Juergen Gross wrote:

> Commit 7b25b9cb0dad83 ("x86/xen/time: Initialize pv xen time in
> init_hypervisor_platform()") moved the mapping of the shared info area
> before pagetable_init(). This breaks booting as 32-bit PV guest as the
> use of set_fixmap isn't possible at this time on 32-bit.
> 
> This can be worked around by populating the needed PMD on 32-bit
> kernel earlier.
> 
> In order not to reimplement populate_extra_pte() using extend_brk()
> for allocating new page tables extend alloc_low_pages() to do that in
> case the early page table pool is not yet available.
> 
> Fixes: 7b25b9cb0dad83

  ^^^ That's missing the subject text

Other than that:

Reviewd-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>