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Date:      Mon, 1 Mar 2010 09:59:10 +0000 (GMT)
From:      Alexander Eichner <alexeichi@yahoo.de>
To:        freebsd-hackers@freebsd.org
Subject:   Allocating physical memory without a kernel mapping
Message-ID:  <317657.30145.qm@web27603.mail.ukl.yahoo.com>

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Hi,=0A=0AI'm currently trying to finish the R0 memory implementation[1] of =
FreeBSD for VirtualBox. One of the missing methods allocates physical non c=
ontiguous pages which don't need to have a kernel mapping (rtR0MemObjNative=
AllocPhysNC). I'm using vm_phys_alloc_contig to achieve this. The pages are=
 than mapped into the user space VM process using pmap_enter (rtR0MemObjNat=
iveMapUser) and if they are not needed anymore vm_page_free_toq is used to =
free the pages (rtR0MemObjNativeFree).=0AEverything works as long as the VM=
 runs but if the VM process terminates and I do something else the host wil=
l panic at some point (usually when I try to start a gnome session) with "p=
map_enter: missing reference to page table page <va>"[2].=0AThere seems to =
some problem with the wire count of that page but I can't see what I'm doin=
g wrong at the moment.=0AThanks in advance for any help.=0A=0ARegards,=0AAl=
exander Eichner=0A=0A[1] http://www.virtualbox.org/browser/trunk/src/VBox/R=
untime/r0drv/freebsd/memobj-r0drv-freebsd.c?rev=3D26899=0A[2]http://fxr.wat=
son.org/fxr/source/amd64/amd64/pmap.c?im=3Dbigexcerpts#L3076=0A=0A_________=
_________________________________________=0ADo You Yahoo!?=0ASie sind Spam =
leid? Yahoo! Mail verf=FCgt =FCber einen herausragenden Schutz gegen Massen=
mails. =0Ahttp://mail.yahoo.com 



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