From: Paolo Bonzini <pbonzini@redhat.com>
To: Alexander Graf <agraf@suse.de>, Igor Mammedov <imammedo@redhat.com>
Cc: qemu-stable@nongnu.org, qemu-ppc@nongnu.org,
stuart.yoder@freescale.com, kvm@vger.kernel.org,
qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [PATCH] kvm: Fix memory slot page alignment logic
Date: Mon, 10 Nov 2014 14:54:49 +0100 [thread overview]
Message-ID: <5460C3A9.30706@redhat.com> (raw)
In-Reply-To: <5460BACA.9000702@suse.de>
On 10/11/2014 14:16, Alexander Graf wrote:
> No, because in that case you would map something as RAM that really
> isn't RAM.
>
> Imagine you have the following memory layout:
>
> 0x1000 page size
>
> 1) 0x00000 - 0x10000 RAM
> 2) 0x10000 - 0x10100 MMIO
> 3) 0x10100 - 0x20000 RAM
>
> Then you want to map 1) as memory slot and 4) from 0x11000 onwards as
> memory slot.
>
> You can't map the page from 0x10000 - 0x11000 as memory slot, because
> part of it is MMIO.
Right. The partial RAM page remains marked as MMIO as far as KVM is
concerned, so accesses are slow and you cannot run code from it.
However, it is fundamental that MMIO areas are not marked as RAM.
Paolo
next prev parent reply other threads:[~2014-11-10 13:55 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-07 21:18 [Qemu-devel] [PATCH] kvm: Fix memory slot page alignment logic Alexander Graf
2014-11-07 21:24 ` [Qemu-devel] [Qemu-ppc] " Alexander Graf
2014-11-10 12:31 ` [Qemu-devel] " Igor Mammedov
2014-11-10 13:16 ` Alexander Graf
2014-11-10 13:54 ` Paolo Bonzini [this message]
2014-11-10 13:55 ` Peter Maydell
2014-11-10 14:48 ` Alexander Graf
2014-11-10 13:55 ` Igor Mammedov
2014-11-10 14:47 ` Alexander Graf
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