From: Paolo Bonzini <pbonzini@redhat.com>
To: "Edgar E. Iglesias" <edgar.iglesias@gmail.com>,
Peter Maydell <peter.maydell@linaro.org>
Cc: Peter Crosthwaite <peter.crosthwaite@xilinx.com>,
Richard Henderson <rth@twiddle.net>,
QEMU Developers <qemu-devel@nongnu.org>,
Greg Bellows <greg.bellows@linaro.org>
Subject: Re: [Qemu-devel] Supporting multiple CPU AddressSpaces and memory transaction attributes
Date: Wed, 13 May 2015 11:28:38 +0200 [thread overview]
Message-ID: <55531946.9080501@redhat.com> (raw)
In-Reply-To: <20150513064105.GZ10142@toto>
On 13/05/2015 08:41, Edgar E. Iglesias wrote:
> I think it would be nice if address_space_translate_for_iotlb
> was allowed to modify the attributes so that an IOMMU in front
> of a CPU could for example down-grade a secure to a non-secure accesse
> (once we add IOMMU support in front of CPUs). If I understood correctly
> the memattrs would stay as a separate field in the iotlb, so this
> would be easy to implement?
Yes, it should.
> The naive implementation I have keeps pointers to AS and the memattrs
> in the iotlb. address_space_translate_for_iotlb walks any IOMMU
> translate() fns, if it hits a RAM it returns the host addr as usual.
How is the TLB invalidated on IOMMU changes?
Paolo
> If it hits MMIO behind IOMMUs it returns the first memsection, i.e
> the one pointing to the iommu-ops and lets the IO access helpers
> deal with the access via address_space_rw (for every IO access, slow).
next prev parent reply other threads:[~2015-05-13 9:28 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-04 17:47 [Qemu-devel] Supporting multiple CPU AddressSpaces and memory transaction attributes Peter Maydell
2014-09-06 0:26 ` Peter Crosthwaite
2014-09-06 10:30 ` Peter Maydell
2014-09-07 1:47 ` Edgar E. Iglesias
2014-09-08 11:53 ` Peter Maydell
2014-09-09 1:09 ` Edgar E. Iglesias
2015-05-12 14:47 ` Peter Maydell
2015-05-13 6:41 ` Edgar E. Iglesias
2015-05-13 9:28 ` Paolo Bonzini [this message]
2015-05-13 11:21 ` Edgar E. Iglesias
2015-05-13 11:36 ` Paolo Bonzini
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