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Re: [Xen-devel][VTD] 1:1 mapping for dom0 exhausts xenheap on x86/32 wit

To: "Han, Weidong" <weidong.han@xxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel][VTD] 1:1 mapping for dom0 exhausts xenheap on x86/32 with 4G memory
From: Keir Fraser <keir@xxxxxxxxxxxxx>
Date: Fri, 28 Sep 2007 07:41:55 +0100
Cc: "Kay, Allen M" <allen.m.kay@xxxxxxxxx>
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Thread-topic: [Xen-devel][VTD] 1:1 mapping for dom0 exhausts xenheap on x86/32 with 4G memory
User-agent: Microsoft-Entourage/
alloc_domheap_page() instead of alloc_xenheap_page(), and use
map_domain_page() to get temporary mappings when you need them. This costs
nothing on x86/64, where all memory is permanently mapped. Or it is *very*
reasonable to only support vt-d on x86/64 hypervisor. That's the
configuration we care about by far the most, since 32-bit guests run fine on
a 64-bit hypervisor, and of course all vt-d systems will be 64-bit capable.

 -- Keir

On 28/9/07 06:26, "Han, Weidong" <weidong.han@xxxxxxxxx> wrote:

> xenheap size is 9M on x86/32 xen, it's not enough to setup 1:1 page
> tables for dom0. It causes dom0 cannot boot successfully. Setup 1:1 page
> table in domheap still might be a problem since the thinking is to use
> the same 1:1 page table for both dom0 and PV domains. Currently I think
> of two options: 1) go back to original method, that's to say setup page
> table dynamically for dom0; 2) increase xenheap size on x86/32. How do
> you think about? Thanks.
> Weidong

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