From: Joerg Roedel <joro@8bytes.org>
To: Alex Williamson <alex.williamson@redhat.com>
Cc: Auger Eric <eric.auger@redhat.com>,
Will Deacon <will.deacon@arm.com>,
drjones@redhat.com,
Christoffer Dall <christoffer.dall@linaro.org>,
jason@lakedaemon.net, kvm@vger.kernel.org, marc.zyngier@arm.com,
benh@kernel.crashing.org, punit.agrawal@arm.com,
linux-kernel@vger.kernel.org, diana.craciun@nxp.com,
iommu@lists.linux-foundation.org, pranav.sawargaonkar@gmail.com,
arnd@arndb.de, dwmw@amazon.co.uk, jcm@redhat.com,
Don Dutile <ddutile@redhat.com>,
tglx@linutronix.de, robin.murphy@arm.com,
linux-arm-kernel@lists.infradead.org, eric.auger.pro@gmail.com
Subject: Re: Summary of LPC guest MSI discussion in Santa Fe
Date: Fri, 11 Nov 2016 12:19:44 +0100 [thread overview]
Message-ID: <20161111111944.GO2078@8bytes.org> (raw)
In-Reply-To: <20161110104601.0939ba9a@t450s.home>
On Thu, Nov 10, 2016 at 10:46:01AM -0700, Alex Williamson wrote:
> In the case of x86, we know that DMA mappings overlapping the MSI
> doorbells won't be translated correctly, it's not a valid mapping for
> that range, and therefore the iommu driver backing the IOMMU API
> should describe that reserved range and reject mappings to it.
The drivers actually allow mappings to the MSI region via the IOMMU-API,
and I think it should stay this way also for other reserved ranges.
Address space management is done by the IOMMU-API user already (and has
to be done there nowadays), be it a DMA-API implementation which just
reserves these regions in its address space allocator or be it VFIO with
QEMU, which don't map RAM there anyway. So there is no point of checking
this again in the IOMMU drivers and we can keep that out of the
mapping/unmapping fast-path.
> For PCI devices userspace can examine the topology of the iommu group
> and exclude MMIO ranges of peer devices based on the BARs, which are
> exposed in various places, pci-sysfs as well as /proc/iomem. For
> non-PCI or MSI controllers... ???
Right, the hardware resources can be examined. But maybe this can be
extended to also cover RMRR ranges? Then we would be able to assign
devices with RMRR mappings to guests.
Joerg
next prev parent reply other threads:[~2016-11-11 11:19 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-03 21:39 [RFC 0/8] KVM PCIe/MSI passthrough on ARM/ARM64 (Alt II) Eric Auger
2016-11-03 21:39 ` [RFC 1/8] vfio: fix vfio_info_cap_add/shift Eric Auger
2016-11-03 21:39 ` [RFC 2/8] iommu/iova: fix __alloc_and_insert_iova_range Eric Auger
2016-11-03 21:39 ` [RFC 3/8] iommu/dma: Allow MSI-only cookies Eric Auger
2016-11-03 21:39 ` [RFC 4/8] iommu: Add a list of iommu_reserved_region in iommu_domain Eric Auger
2016-11-03 21:39 ` [RFC 5/8] vfio/type1: Introduce RESV_IOVA_RANGE capability Eric Auger
2016-11-03 21:39 ` [RFC 6/8] iommu: Handle the list of reserved regions Eric Auger
2016-11-03 21:39 ` [RFC 7/8] iommu/vt-d: Implement add_reserved_regions callback Eric Auger
2016-11-03 21:39 ` [RFC 8/8] iommu/arm-smmu: implement " Eric Auger
2016-11-04 4:02 ` [RFC 0/8] KVM PCIe/MSI passthrough on ARM/ARM64 (Alt II) Alex Williamson
2016-11-08 2:45 ` Summary of LPC guest MSI discussion in Santa Fe (was: Re: [RFC 0/8] KVM PCIe/MSI passthrough on ARM/ARM64 (Alt II)) Will Deacon
2016-11-08 14:27 ` Summary of LPC guest MSI discussion in Santa Fe Auger Eric
2016-11-08 17:54 ` Will Deacon
2016-11-08 19:02 ` Don Dutile
2016-11-08 19:10 ` Will Deacon
2016-11-09 7:43 ` Auger Eric
2016-11-08 16:02 ` Don Dutile
2016-11-08 20:29 ` Summary of LPC guest MSI discussion in Santa Fe (was: Re: [RFC 0/8] KVM PCIe/MSI passthrough on ARM/ARM64 (Alt II)) Christoffer Dall
2016-11-08 23:35 ` Alex Williamson
2016-11-09 2:52 ` Summary of LPC guest MSI discussion in Santa Fe Don Dutile
2016-11-09 17:03 ` Will Deacon
2016-11-09 18:59 ` Don Dutile
2016-11-09 19:23 ` Christoffer Dall
2016-11-09 20:01 ` Alex Williamson
2016-11-10 14:40 ` Joerg Roedel
2016-11-10 17:07 ` Alex Williamson
2016-11-09 20:31 ` Will Deacon
2016-11-09 22:17 ` Alex Williamson
2016-11-09 22:25 ` Will Deacon
2016-11-09 23:24 ` Alex Williamson
2016-11-09 23:38 ` Will Deacon
2016-11-09 23:59 ` Alex Williamson
2016-11-10 0:14 ` Auger Eric
2016-11-10 0:55 ` Alex Williamson
2016-11-10 2:01 ` Will Deacon
2016-11-10 11:14 ` Auger Eric
2016-11-10 17:46 ` Alex Williamson
2016-11-11 11:19 ` Joerg Roedel [this message]
2016-11-11 15:50 ` Alex Williamson
2016-11-11 16:05 ` Alex Williamson
2016-11-14 15:19 ` Joerg Roedel
2016-11-11 16:25 ` Don Dutile
2016-11-11 16:00 ` Don Dutile
2016-11-10 14:52 ` Joerg Roedel
2016-11-09 20:11 ` Robin Murphy
2016-11-10 15:18 ` Joerg Roedel
2016-11-21 5:13 ` Jon Masters
2016-11-23 20:12 ` Don Dutile
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