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[Xen-devel] is there any way to avoid lazy updates to page attribute bit

To: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-devel] is there any way to avoid lazy updates to page attribute bits?
From: "Kip Macy" <kip.macy@xxxxxxxxx>
Date: Tue, 19 Feb 2008 18:34:58 -0800
Delivery-date: Tue, 19 Feb 2008 18:35:26 -0800
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I'm finding that regardless of which update method I use - writeable
page tables, HYPERVISOR_update_va_mapping, or HYPERVISOR_mmu_update
that xen will frequently only update the address bits in the page
table at the time of the hypercall - presumably setting the attribute
bits some time later when the mapping is accessed. This is fairly
problematic for me in that freebsd relies on the page attribute bits
in the page table accurately reflecting the attributes that were set
for a mapping. Is it now necessary for PV guests to maintain page
attribute data outside of the page tables?


-Kip

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