From: Pavel Fedin <p.fedin@samsung.com>
To: 'Eric Auger' <eric.auger@linaro.org>,
eric.auger@st.com, alex.williamson@redhat.com,
will.deacon@arm.com, christoffer.dall@linaro.org,
marc.zyngier@arm.com, linux-arm-kernel@lists.infradead.org,
kvmarm@lists.cs.columbia.edu, kvm@vger.kernel.org
Cc: patches@linaro.org, linux-kernel@vger.kernel.org,
iommu@lists.linux-foundation.org
Subject: RE: [PATCH 00/10] KVM PCIe/MSI passthrough on ARM/ARM64
Date: Tue, 26 Jan 2016 20:25:06 +0300 [thread overview]
Message-ID: <000001d1585e$8097d7e0$81c787a0$@samsung.com> (raw)
In-Reply-To: <1453813968-2024-1-git-send-email-eric.auger@linaro.org>
Hello!
I'd like just to clarify some things for myself and better wrap my head around it...
> On x86 all accesses to the 1MB PA region [FEE0_0000h - FEF0_000h] are directed
> as interrupt messages: accesses to this special PA window directly target the
> APIC configuration space and not DRAM, meaning the downstream IOMMU is bypassed.
So, this is effectively the same as always having hardwired 1:1 mappings on all IOMMUs, isn't it ?
If so, then we can't we just do the same, just by forcing similar 1:1 mapping? This is what i tried to do in my patchset. All of
you are talking about a situation which arises when we are emulating different machine with different physical addresses layout. And
e. g. if our host has MSI at 0xABADCAFE, our target could have valid RAM at the same location, and we need to handle it somehow,
therefore we have to move our MSI window out of target's RAM. But how does this work on a PC then? What if our host is PC, and we
want to emulate some ARM board, which has RAM at FE00 0000 ? Or does it mean that PC architecture is flawed and can reliably handle
PCI passthrough only for itself ?
Kind regards,
Pavel Fedin
Senior Engineer
Samsung Electronics Research center Russia
next prev parent reply other threads:[~2016-01-26 17:25 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-26 13:12 [PATCH 00/10] KVM PCIe/MSI passthrough on ARM/ARM64 Eric Auger
2016-01-26 13:12 ` [PATCH 01/10] iommu: Add DOMAIN_ATTR_MSI_MAPPING attribute Eric Auger
2016-01-26 13:12 ` [PATCH 02/10] vfio: expose MSI mapping requirement through VFIO_IOMMU_GET_INFO Eric Auger
[not found] ` <1453813968-2024-1-git-send-email-eric.auger-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2016-01-26 13:12 ` [PATCH 03/10] vfio_iommu_type1: add reserved binding RB tree management Eric Auger
2016-01-28 21:51 ` [PATCH 00/10] KVM PCIe/MSI passthrough on ARM/ARM64 Alex Williamson
[not found] ` <1454017899.23148.0.camel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2016-01-29 14:35 ` Eric Auger
2016-01-29 19:33 ` Alex Williamson
[not found] ` <1454096004.9301.1.camel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
2016-01-29 21:25 ` Eric Auger
[not found] ` <56ABD8E0.6080409-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2016-02-01 14:03 ` Will Deacon
2016-02-03 12:50 ` Christoffer Dall
2016-02-03 13:10 ` Will Deacon
[not found] ` <20160203131057.GA20217-5wv7dgnIgG8@public.gmane.org>
2016-02-03 15:36 ` Christoffer Dall
2016-02-05 17:32 ` ARM PCI/MSI KVM passthrough with GICv2M Eric Auger
[not found] ` <56B4DC97.60904-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2016-02-05 18:17 ` Alex Williamson
[not found] ` <20160205111700.726ac061-1yVPhWWZRC1BDLzU/O5InQ@public.gmane.org>
2016-02-08 9:48 ` Christoffer Dall
2016-02-08 13:27 ` Eric Auger
2016-01-26 13:12 ` [PATCH 04/10] vfio: introduce VFIO_IOVA_RESERVED vfio_dma type Eric Auger
2016-01-26 13:12 ` [PATCH 05/10] vfio/type1: attach a reserved iova domain to vfio_domain Eric Auger
2016-01-26 13:12 ` [PATCH 06/10] vfio: introduce vfio_group_alloc_map_/unmap_free_reserved_iova Eric Auger
[not found] ` <1453813968-2024-7-git-send-email-eric.auger-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2016-01-26 16:17 ` kbuild test robot
2016-01-26 16:37 ` Eric Auger
2016-01-26 13:12 ` [PATCH 07/10] vfio: pci: cache the vfio_group in vfio_pci_device Eric Auger
2016-01-26 13:12 ` [PATCH 08/10] vfio: introduce vfio_group_require_msi_mapping Eric Auger
2016-01-26 13:12 ` [PATCH 09/10] vfio-pci: create an iommu mapping for msi address Eric Auger
[not found] ` <1453813968-2024-10-git-send-email-eric.auger-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2016-01-26 14:43 ` kbuild test robot
[not found] ` <201601262259.1kktHLzi%fengguang.wu-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>
2016-01-26 15:14 ` Eric Auger
2016-01-26 13:12 ` [PATCH 10/10] vfio: allow the user to register reserved iova range for MSI mapping Eric Auger
2016-01-26 16:42 ` kbuild test robot
[not found] ` <1453813968-2024-11-git-send-email-eric.auger-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
2016-01-26 18:32 ` kbuild test robot
2016-01-26 17:25 ` Pavel Fedin [this message]
2016-01-27 8:52 ` [PATCH 00/10] KVM PCIe/MSI passthrough on ARM/ARM64 Eric Auger
2016-01-28 7:13 ` Pavel Fedin
2016-01-28 9:50 ` Eric Auger
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