Messages in this thread | | | Subject | Re: [RFC v3 00/10] KVM PCIe/MSI passthrough on ARM/ARM64 and IOVA reserved regions | From | Auger Eric <> | Date | Wed, 30 Nov 2016 15:08:17 +0100 |
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Hi Will,
On 30/11/2016 11:37, Will Deacon wrote: > On Wed, Nov 30, 2016 at 10:49:33AM +0100, Auger Eric wrote: >> On 15/11/2016 14:09, Eric Auger wrote: >>> Following LPC discussions, we now report reserved regions through >>> iommu-group sysfs reserved_regions attribute file. >>> >>> Reserved regions are populated through the IOMMU get_resv_region callback >>> (former get_dm_regions), now implemented by amd-iommu, intel-iommu and >>> arm-smmu. >>> >>> The intel-iommu reports the [FEE0_0000h - FEF0_000h] MSI window as an >>> IOMMU_RESV_NOMAP reserved region. >>> >>> arm-smmu reports the MSI window (arbitrarily located at 0x8000000 and >>> 1MB large) and the PCI host bridge windows. >>> >>> The series integrates a not officially posted patch from Robin: >>> "iommu/dma: Allow MSI-only cookies". >>> >>> This series currently does not address IRQ safety assessment. >> >> I will respin this series taking into account Joerg's comment. Does >> anyone have additional comments or want to put forward some conceptual >> issues with the current direction and with this implementation? >> >> As for the IRQ safety assessment, in a first step I would propose to >> remove the IOMMU_CAP_INTR_REMAP from arm-smmus and consider the >> assignment as unsafe. Any objection? > > Well, yeah, because it's perfectly safe with GICv3.
Well except if you have an MSI controller in-between the device and the sMMU (typically embedded in the host bridge). Detecting this situation is not straightforward; hence my proposal.
Thanks
Eric > > Will > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
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