[Xen-devel] [PATCH][XEN] construct_dom0: Initialize variable before use

["Christoph Egger" <Christoph.Egger@xxxxxxx>]

Hi!

Attached patch initializes d->arch.physaddr_bitsize properly for a
64bit Dom0/64bit hypervisor.
This bug has been found when booting a NetBSD/Xen Dom0 with more
than 4GB RAM.

Without this fix, d->arch.physaddr_bitsize is 0 in 
domain_clamp_alloc_bitsize(). This causes all attempts to 
XENMEM_increase_reservation with bits > 0 to fail. More precisely,
__alloc_domheap_pages() returns NULL.
This impacts Xen heap allocation in general.
Question: How did that work on Linux Dom0?

I think, initializing physaddr_bitsize to 64 unconditionally is ok because in
construct_dom0() it is overridden with the proper value when you boot
64bit hypervisor with a 32bit Dom0. If the hypervisor is not 64bit,
physaddr_bitsize isn't used at all anyway.

Signed-off-by: Christoph Egger <Christoph.Egger@xxxxxxx>


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Operating System Research Center

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Attachment: xen_dom0.diff
Description: Text document

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