Date: Sun, 6 Apr 2014 19:11:39 +0200 From: =?ISO-8859-1?Q?Roger_Pau_Monn=E9?= <roger.pau@citrix.com> To: "Cherry G. Mathew" <cherry.g.mathew@gmail.com>, Jonni Nakari <jonni@egarden.fi>, <freebsd-xen@freebsd.org> Subject: Re: Status of 64 bit DomU PVs? Message-ID: <53418ACB.6030809@citrix.com> In-Reply-To: <CAEmhiu7kFNdXY1fGo4B-a1yeZ5MbkKGY2h-mGRTa999SirdAbA@mail.gmail.com> References: <CAEmhiu7kFNdXY1fGo4B-a1yeZ5MbkKGY2h-mGRTa999SirdAbA@mail.gmail.com>
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On 05/04/14 15:14, Cherry G. Mathew wrote: > Hi Jonni, > > Date: Sat, 05 Apr 2014 00:39:24 +0300 >> From: Jonni Nakari <jonni@egarden.fi> >> To: freebsd-xen@freebsd.org >> Subject: Status of 64 bit DomU PVs? >> Message-ID: <533F268C.8040909@egarden.fi> >> Content-Type: text/plain; charset=ISO-8859-1; format=flowed >> >> Hello, >> what is the current status of 64 bit paravirtualized FreeBSD? The wiki >> page Xen wiki page [1] states that only i386 kernels can be run in fully >> paravirtualized mode. The wiki page hasn't been updated in a while. Has >> anything changed since the last update? >> >> I would like to run FreeBSD as a DomU on a AMD 64 bit machine that does >> not have hardware accelerated virtualization. That propably means that >> it's not feasible to run a HVM based DomU on the machine? I would also >> like the DomU to be 64 bit to provide more than 4 gigabytes of RAM to >> the ZFS serving FreeBSD. >> >> > I've been working on this for quite some time now (perhaps too long), and > the bad news is that, no, it's not ready for use - the code on the branch > does bring us up to single user mode, but I'm reworking the pmap module > with the wisdom of hindsight. The good news is that it should be ready for > testing "soon" (May, 2014). > > With PV on 64bit, you should be able to have a 64bit address space with > support for 47bit RAM (in theory). > > > >> Or maybe I have misunderstood something. Is it possible to provide more >> than 4 GB RAM for a 32 bit DomU so that it can use all of it for ZFS >> caching? >> >> > On 64bit PV, the DomU is 64bit (although there used to be support for 32bit > PV on 64bit hypervisor until the 3.x hypervisors, iirc). So yes, you should > in *theory*, be able to have more than 4GB ram for your 64bit DomU. Just to clarify, a 64-bit Xen Hypervisor is perfectly capable of running 32-bit PV guests, support for 32-bit guests has never been removed from the hypervisor. Roger.
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