From: Avi Kivity <avi@redhat.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Pekka Enberg <penberg@kernel.org>,
Sasha Levin <levinsasha928@gmail.com>,
asias.hejun@gmail.com, prasadjoshi124@gmail.com,
gorcunov@gmail.com, kvm@vger.kernel.org
Subject: Re: [PATCH 1/2] kvm tools: Add memory gap for larger RAM sizes
Date: Wed, 11 May 2011 12:06:00 +0300 [thread overview]
Message-ID: <4DCA5178.9030402@redhat.com> (raw)
In-Reply-To: <20110511084402.GB7112@elte.hu>
On 05/11/2011 11:44 AM, Ingo Molnar wrote:
> >
> > It doesn't work in general - if you have a PCI device with a BAR
> > (like a video card framebuffer), then you need allocations for main
> > memory (0+) and pci (0xe000000+). You can't have a contiguous
> > mapping on i386 containing both.
>
> I think in tools/kvm/ we can ignore i386 hosts that would like to map more RAM
> than they have virtual address space for ...
>
> Guests up to 1-2 gigs of RAM will still work fine.
>
It doesn't work. Consider a guest with 128MB of RAM mapped at 0-128MB
and an 8MB framebuffer mapped at 0xe0000000. There's no way to present
this in a contiguous space.
Well, I guess you can map the framebuffer lower, but that means giving
up memory hotplug if you ever wish to implement it (and doesn't allow
the guest to remap the framebuffer if it wishes to).
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2011-05-11 16:17 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-05-10 21:05 [PATCH 1/2] kvm tools: Add memory gap for larger RAM sizes Sasha Levin
2011-05-10 21:05 ` [PATCH 2/2] kvm tools: Prevent PFN wraparound Sasha Levin
2011-05-10 21:09 ` Pekka Enberg
2011-05-11 5:37 ` [PATCH 1/2] kvm tools: Add memory gap for larger RAM sizes Pekka Enberg
2011-05-11 6:21 ` Sasha Levin
2011-05-11 6:26 ` Pekka Enberg
2011-05-11 7:10 ` Ingo Molnar
2011-05-11 8:30 ` Avi Kivity
2011-05-11 8:44 ` Ingo Molnar
2011-05-11 9:06 ` Avi Kivity [this message]
2011-05-11 9:28 ` Pekka Enberg
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