Subject: [PATCH v9 0/8] KVM PCIe/MSI passthrough on ARM/ARM64: kernel part 2/3: msi changes

From: [email-masked] (Eric Auger)
Date: Mon, 9 May 2016 09:48:38 +0200

Hi Chalarmala,
On 05/05/2016 07:44 PM, Chalamarla, Tirumalesh wrote:
> Hi Eric,
> 
> Does this series supports gicv3-its emulation?
> Do we have a tree with all the dependent patches
GICv3 ITS emulation support comes with:
[PATCH v4 00/12] KVM: arm64: GICv3 ITS emulation
http://permalink.gmane.org/gmane.comp.emulators.kvm.arm.devel/5738

My series just allows PCI device MSI transactions to reach the host MSI
frame through the SMMU. Only host GICv2m has been tested at the moment
with a guest exposed with a GICv2m too.

Best Regards

Eric

> 
> 
> 
> 
> 
> Thanks,
> Tirumalesh. 
> On 5/4/16, 8:18 AM, "linux-arm-kernel on behalf of Eric Auger" <linux-arm-kernel-bounces at lists.infradead.org on behalf of [email-masked]> 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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