From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: virtualization@lists.linux-foundation.org,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
Andy Lutomirski <luto@amacapital.net>
Subject: Re: virtio DMA API?
Date: Thu, 28 Aug 2014 07:32:23 +1000 [thread overview]
Message-ID: <1409175143.25772.157.camel@pasglop> (raw)
In-Reply-To: <20140827115249.GA16850@redhat.com>
On Wed, 2014-08-27 at 13:52 +0200, Michael S. Tsirkin wrote:
> For x86 as of QEMU 2.0 there's no iommu.
> So a reasonable thing to do for that platform
> might be to always use iommu *if it's there*.
> My understanding is this isn't the case for powerpc?
All 64-bit powerpc have an iommu but not all 32-bit ones.
Also using/emulating one has a cost. Whatever we do shouldn't
impair the fast path of virtio-on-kvm doing direct physical
access.
Cheers,
Ben.
next prev parent reply other threads:[~2014-08-27 21:32 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-25 17:18 virtio DMA API? Andy Lutomirski
2014-08-25 18:54 ` Konrad Rzeszutek Wilk
2014-08-25 19:20 ` Andy Lutomirski
2014-08-27 11:10 ` Rusty Russell
2014-08-27 11:52 ` Michael S. Tsirkin
2014-08-27 19:49 ` Konrad Rzeszutek Wilk
2014-08-27 21:32 ` Benjamin Herrenschmidt [this message]
2014-08-27 14:55 ` Andy Lutomirski
2014-08-27 21:31 ` Benjamin Herrenschmidt
2014-08-29 15:06 ` Konrad Rzeszutek Wilk
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