Date:	Thu, 5 May 2016 17:44:24 +0000
From:	"Chalamarla, Tirumalesh" <Tirumalesh.Chalamarla@...iumnetworks.com>
To:	Eric Auger <eric.auger@...aro.org>,
	"eric.auger@...com" <eric.auger@...com>,
	"robin.murphy@....com" <robin.murphy@....com>,
	"alex.williamson@...hat.com" <alex.williamson@...hat.com>,
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	"tglx@...utronix.de" <tglx@...utronix.de>,
	"jason@...edaemon.net" <jason@...edaemon.net>,
	"marc.zyngier@....com" <marc.zyngier@....com>,
	"christoffer.dall@...aro.org" <christoffer.dall@...aro.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
CC:	"julien.grall@....com" <julien.grall@....com>,
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Subject: Re: [PATCH v9 0/8] KVM PCIe/MSI passthrough on ARM/ARM64: kernel part
 2/3: msi changes

Hi Eric,

Does this series supports gicv3-its emulation?
Do we have a tree with all the dependent patches





Thanks,
Tirumalesh. 
On 5/4/16, 8:18 AM, "linux-arm-kernel on behalf of Eric Auger" <linux-arm-kernel-bounces@...ts.infradead.org on behalf of eric.auger@...aro.org> wrote:

>This series implements the MSI address mapping/unmapping in the MSI layer.
>IOMMU binding happens on pci_enable_msi since this function can sleep and
>return errors. On msi_domain_set_affinity, msi_domain_(de)activate, which
>are not allowed to sleep, we simply look for the already existing binding.
>
>A new MSI domain info flag value is introduced to report whether the msi
>domain implements IRQ remapping. GIC v3 ITS is the first MSI controller
>advertising it. This flag value will be used by VFIO subsystem to
>determine whether MSI forwarding is safe.
>
>More details & context can be found at:
>http://www.linaro.org/blog/core-dump/kvm-pciemsi-passthrough-armarm64/
>
>Best Regards
>
>Eric
>
>Applies on top of PART 1/3. Also depends on
>[PATCH 1/3] iommu: Add MMIO mapping type,
>http://comments.gmane.org/gmane.linux.kernel.iommu/12869
>
>Git: complete series available at
>https://git.linaro.org/people/eric.auger/linux.git/shortlog/refs/heads/v4.6-rc6-pcie-passthrough-v9-msi-v9
>
>This branch contains all parts in v9.
>
>History:
>
>v8 -> v9:
>- use a union in irq_chip_msi_doorbell_info + boolean telling whether the
>  doorbell is percpu
>- decouple irq_data parsing from the actual mapping/unmapping in
>  msi_handle_doorbell_mappings
>- fix misc style issues
>
>v7 -> v8:
>take into account Marc's comments:
>- use iommu_msi_msg_pa_to_va with new proto
>- change in irq_chip_msi_doorbell_info struct definition:
>  prot and size became shared between all doorbells and phys_addr_t __percpu
>- cleanups in v2m irqchip
>- eventually did not touch MSI_FLAG_IRQ_REMAPPING naming
>- On msi_handle_doorbell_mappings, stop on the first irqchip where doorbells
>  can be found
>- fix resource deallocation on mapping failure in msi_domain_alloc_irqs
>
>v6 -> v7:
>- do alloc/map handling on pci_enable_msi and search on msi_(de)domain_activate
>- add msi_doorbell_info callback in irq-chip to retrieve the characteristics
>  of doorbells
>
>RFC v5 -> patch v6:
>- split to ease the review process
>- rebase on default iommu domain code (irq_data_to_msi_mapping_domain
>  checks IOMMU_DOMAIN_DMA type)
>- fix unmap sequence on msi_domain_set_affinity (reported by Marc):
>  unmap the previous doorbell when the new one has been mapped & written to
>  the device, ie. irq_chip_write_msi_msg.
>- "msi: msi_compose wrapper removed" following change above
>- add size parameter to iommu_get_reserved_iova API following Marc's request
>
>RFC v4 -> RFC v5:
>- take into account Thomas' comments on MSI related patches
>  - split "msi: IOMMU map the doorbell address when needed"
>  - increase readability and add comments
>  - fix style issues
> - split "iommu: Add DOMAIN_ATTR_MSI_MAPPING attribute"
> - platform ITS now advertises IOMMU_CAP_INTR_REMAP
> - fix compilation issue with CONFIG_IOMMU API unset
> - arm-smmu-v3 now advertises DOMAIN_ATTR_MSI_MAPPING
>
>RFC v3 -> v4:
>- Move doorbell mapping/unmapping in msi.c
>- fix ref count issue on set_affinity: in case of a change in the address
>  the previous address is decremented
>- doorbell map/unmap now is done on msi composition. Should allow the use
>  case for platform MSI controllers
>- create dma-reserved-iommu.h/c exposing/implementing a new API dedicated
>  to reserved IOVA management (looking like dma-iommu glue)
>- series reordering to ease the review:
>  - first part is related to IOMMU
>  - second related to MSI sub-system
>  - third related to VFIO (except arm-smmu IOMMU_CAP_INTR_REMAP removal)
>- expose the number of requested IOVA pages through VFIO_IOMMU_GET_INFO
>  [this partially addresses Marc's comments on iommu_get/put_single_reserved
>   size/alignment problematic - which I did not ignore - but I don't know
>   how much I can do at the moment]
>
>RFC v2 -> RFC v3:
>- should fix wrong handling of some CONFIG combinations:
>  CONFIG_IOVA, CONFIG_IOMMU_API, CONFIG_PCI_MSI_IRQ_DOMAIN
>- fix MSI_FLAG_IRQ_REMAPPING setting in GICv3 ITS (although not tested)
>
>PATCH v1 -> RFC v2:
>- reverted to RFC since it looks more reasonable ;-) the code is split
>  between VFIO, IOMMU, MSI controller and I am not sure I did the right
>  choices. Also API need to be further discussed.
>- iova API usage in arm-smmu.c.
>- MSI controller natively programs the MSI addr with either the PA or IOVA.
>  This is not done anymore in vfio-pci driver as suggested by Alex.
>- check irq remapping capability of the group
>
>RFC v1 [2] -> PATCH v1:
>- use the existing dma map/unmap ioctl interface with a flag to register a
>  reserved IOVA range. Use the legacy Rb to store this special vfio_dma.
>- a single reserved IOVA contiguous region now is allowed
>- use of an RB tree indexed by PA to store allocated reserved slots
>- use of a vfio_domain iova_domain to manage iova allocation within the
>  window provided by the userspace
>- vfio alloc_map/unmap_free take a vfio_group handle
>- vfio_group handle is cached in vfio_pci_device
>- add ref counting to bindings
>- user modality enabled at the end of the series
>
>
>Eric Auger (8):
>  genirq/msi: Add a new MSI_FLAG_IRQ_REMAPPING flag
>  irqchip/gic-v3-its: ITS advertises MSI_FLAG_IRQ_REMAPPING
>  genirq/msi: export msi_get_domain_info
>  genirq/msi: msi_compose wrapper
>  genirq/irq: introduce msi_doorbell_info
>  irqchip/gicv2m: implement msi_doorbell_info callback
>  genirq/msi: map/unmap the MSI doorbells on msi_domain_alloc/free_irqs
>  genirq/msi: use the MSI doorbell's IOVA when requested
>
> drivers/irqchip/irq-gic-v2m.c                 |  16 +++
> drivers/irqchip/irq-gic-v3-its-pci-msi.c      |   3 +-
> drivers/irqchip/irq-gic-v3-its-platform-msi.c |   3 +-
> include/linux/irq.h                           |  15 ++-
> include/linux/msi.h                           |   2 +
> kernel/irq/msi.c                              | 136 +++++++++++++++++++++++---
> 6 files changed, 161 insertions(+), 14 deletions(-)
>
>-- 
>1.9.1
>
>
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