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

From: Chalamarla, Tirumalesh
Date: Thu May 05 2016 - 13:59:12 EST

Hi Eric,

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

On 5/4/16, 8:18 AM, "linux-arm-kernel on behalf of Eric Auger" <linux-arm-kernel-bounces@xxxxxxxxxxxxxxxxxxx on behalf of eric.auger@xxxxxxxxxx> 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:
>Best Regards
>Applies on top of PART 1/3. Also depends on
>[PATCH 1/3] iommu: Add MMIO mapping type,
>Git: complete series available at
>This branch contains all parts in v9.
>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:
>- 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(-)
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