Hi Vikas, On 11/17/20 5:36 PM, Vikas Gupta wrote: > Hi Eric, > > On Tue, Nov 17, 2020 at 1:55 PM Auger Eric <eric.auger@xxxxxxxxxx> wrote: >> >> Hi Vikas, >> >> On 11/17/20 9:05 AM, Auger Eric wrote: >>> Hi Vikas, >>> >>> On 11/17/20 7:25 AM, Vikas Gupta wrote: >>>> Hi Eric, >>>> >>>> On Mon, Nov 16, 2020 at 6:44 PM Auger Eric <eric.auger@xxxxxxxxxx> wrote: >>>>> >>>>> Hi Vikas, >>>>> >>>>> On 11/13/20 6:24 PM, Vikas Gupta wrote: >>>>>> Hi Eric, >>>>>> >>>>>> On Fri, Nov 13, 2020 at 12:10 AM Auger Eric <eric.auger@xxxxxxxxxx> wrote: >>>>>>> >>>>>>> Hi Vikas, >>>>>>> >>>>>>> On 11/12/20 6:58 PM, Vikas Gupta wrote: >>>>>>>> This RFC adds support for MSI for platform devices. >>>>>>>> a) MSI(s) is/are added in addition to the normal interrupts. >>>>>>>> b) The vendor specific MSI configuration can be done using >>>>>>>> callbacks which is implemented as msi module. >>>>>>>> c) Adds a msi handling module for the Broadcom platform devices. >>>>>>>> >>>>>>>> Changes from: >>>>>>>> ------------- >>>>>>>> v0 to v1: >>>>>>>> i) Removed MSI device flag VFIO_DEVICE_FLAGS_MSI. >>>>>>>> ii) Add MSI(s) at the end of the irq list of platform IRQs. >>>>>>>> MSI(s) with first entry of MSI block has count and flag >>>>>>>> information. >>>>>>>> IRQ list: Allocation for IRQs + MSIs are allocated as below >>>>>>>> Example: if there are 'n' IRQs and 'k' MSIs >>>>>>>> ------------------------------------------------------- >>>>>>>> |IRQ-0|IRQ-1|....|IRQ-n|MSI-0|MSI-1|MSI-2|......|MSI-k| >>>>>>>> ------------------------------------------------------- >>>>>>> I have not taken time yet to look at your series, but to me you should have >>>>>>> |IRQ-0|IRQ-1|....|IRQ-n|MSI|MSIX >>>>>>> then for setting a given MSIX (i) you would select the MSIx index and >>>>>>> then set start=i count=1. >>>>>> >>>>>> As per your suggestion, we should have, if there are n-IRQs, k-MSIXs >>>>>> and m-MSIs, allocation of IRQs should be done as below >>>>>> >>>>>> |IRQ0|IRQ1|......|IRQ-(n-1)|MSI|MSIX| >>>>>> | | >>>>>> | >>>>>> |MSIX0||MSIX1||MSXI2|....|MSIX-(k-1)| >>>>>> |MSI0||MSI1||MSI2|....|MSI-(m-1)| >>>>> No I really meant this list of indices: IRQ0|IRQ1|......|IRQ-(n-1)|MSI|MSIX| >>>>> and potentially later on IRQ0|IRQ1|......|IRQ-(n-1)|MSI|MSIX| ERR| REQ >>>>> if ERR/REQ were to be added. >>>> I agree on this. Actually the map I drew incorrectly above but wanted >>>> to demonstrate the same. It was a child-parent relationship for MSI >>>> and its members and similarly for MSIX as well. >>>>> >>>>> I think the userspace could query the total number of indices using >>>>> VFIO_DEVICE_GET_INFO and retrieve num_irqs (corresponding to the n wire >>>>> interrupts + MSI index + MSIX index) >>>>> >>>>> Then userspace can loop on all the indices using >>>>> VFIO_DEVICE_GET_IRQ_INFO. For each index it uses count to determine the >>>>> first indices related to wire interrupts (count = 1). Then comes the MSI >>>>> index, and after the MSI index. If any of those is supported, count >1, >>>>> otherwise count=0. The only thing I am dubious about is can the device >>>>> use a single MSI/MSIX? Because my hypothesis here is we use count to >>>>> discriminate between wire first indices and other indices. >>>> I believe count can be one as well, especially for ERR/REQ as you >>>> mentioned above. >>> Given ERR and REQ indices would follow MSI and MSIX ones, MSI index >>> could be recognized by the first index whose count != 1. But indeed I am >>> not sure the number of supported vectors cannot be 1. In your case it is >>> induced by the size of the ring so it is OK but for other devices this >>> may be different. >>> >>> I think we can not rely on the count > 1. Now, this is >>>> blocking and we are not left with options unless we consider adding >>>> more enums in flags in vfio_irq_info to tell userspace that particular >>>> index is wired, MSI, MSIX etc. for the platform device. >>>> What do you think? >>> If count is not reliable to discriminate the first n wired interrupts >>> from the subsequen MSI and MSIx index, Alex suggested to add a >>> capability extension in the vfio_irq_info structure. Something similar >>> to what was done for vfio_region_info. >>> >>> Such kind of thing was attempted in >>> https://lore.kernel.org/kvmarm/20201116110030.32335-8-eric.auger@xxxxxxxxxx/T/#u >>> >>> ` [PATCH v11 07/13] vfio: Use capability chains to handle device >>> specific irq >>> ` [PATCH v11 08/13] vfio/pci: Add framework for custom interrupt indices >>> ` [PATCH v11 09/13] vfio: Add new IRQ for DMA fault reporting >> >> By the way I was mentionning MSI/MSIx in my previous reply but, as Alex >> pointed out, with platform device only a single MSI index does make >> sense, no? > Yes, I think single MSI should be OK. > This single MSI index should be implemented as ext_irqs, similar to, > as you implemented in the mentioned patch. Is my understanding > correct? Yes, if count !=1 cannot be used to detect the MSI index, I think using a capability would do the job and this is aligned with last Alex' suggestion. Thanks Eric > Thanks, > Vikas >> >> Thanks >> >> Eric >>> >>> Note this has not been reviewed yet. >>> >>> Thanks >>> >>> Eric >>> >>>>> >>>>> >>>>> >>>>>> With this implementation user space can know that, at indexes n and >>>>>> n+1, edge triggered interrupts are present. >>>>> note wired interrupts can also be edge ones. >>>>>> We may add an element in vfio_platform_irq itself to allocate MSIs/MSIXs >>>>>> struct vfio_platform_irq{ >>>>>> ..... >>>>>> ..... >>>>>> struct vfio_platform_irq *block; => this points to the block >>>>>> allocation for MSIs/MSIXs and all msi/msix are type of IRQs.As wired interrupts and MSI interrupts coexist, I would store in vdev an >>>>> array of wired interrupts (the existing vdev->irqs) and a new array for >>>>> MSI(x) as done in the PCI code. >>>>> >>>>> vdev->ctx = kcalloc(nvec, sizeof(struct vfio_pci_irq_ctx), GFP_KERNEL); >>>>> >>>>> Does it make sense? >>>> Yes, we can use similar kinds of allocations. >>>> >>>> Thanks, >>>> Vikas >>>>> >>>>>> }; >>>>>> OR >>>>>> Another structure can be defined in 'vfio_pci_private.h' >>>>>> struct vfio_msi_ctx { >>>>>> struct eventfd_ctx *trigger; >>>>>> char *name; >>>>>> }; >>>>>> and >>>>>> struct vfio_platform_irq { >>>>>> ..... >>>>>> ..... >>>>>> struct vfio_msi_ctx *block; => this points to the block allocation >>>>>> for MSIs/MSIXs >>>>>> }; >>>>>> Which of the above two options sounds OK to you? Please suggest. >>>>>> >>>>>>> to me individual MSIs are encoded in the subindex and not in the index. >>>>>>> The index just selects the "type" of interrupt. >>>>>>> >>>>>>> For PCI you just have: >>>>>>> VFIO_PCI_INTX_IRQ_INDEX, >>>>>>> VFIO_PCI_MSI_IRQ_INDEX, -> MSI index and then you play with >>>>>>> start/count >>>>>>> VFIO_PCI_MSIX_IRQ_INDEX, >>>>>>> VFIO_PCI_ERR_IRQ_INDEX, >>>>>>> VFIO_PCI_REQ_IRQ_INDEX, >>>>>>> >>>>>>> (include/uapi/linux/vfio.h) >>>>>> >>>>>> In pci case, type of interrupts is fixed so they can be 'indexed' by >>>>>> these enums but for VFIO platform user space will need to iterate all >>>>>> (num_irqs) indexes to know at which indexes edge triggered interrupts >>>>>> are present. >>>>> indeed, but can't you loop over all indices looking until count !=1? At >>>>> this point you know if have finished emurating the wires. Holds if >>>>> MSI(x) count !=1 of course. >>>>> >>>>> Thanks >>>>> >>>>> Eric >>>>> >>>>>> >>>>>> Thanks, >>>>>> Vikas >>>>>>> >>>>>>> Thanks >>>>>>> >>>>>>> Eric >>>>>>>> MSI-0 will have count=k set and flags set accordingly. >>>>>>>> >>>>>>>> Vikas Gupta (3): >>>>>>>> vfio/platform: add support for msi >>>>>>>> vfio/platform: change cleanup order >>>>>>>> vfio/platform: add Broadcom msi module >>>>>>>> >>>>>>>> drivers/vfio/platform/Kconfig | 1 + >>>>>>>> drivers/vfio/platform/Makefile | 1 + >>>>>>>> drivers/vfio/platform/msi/Kconfig | 9 + >>>>>>>> drivers/vfio/platform/msi/Makefile | 2 + >>>>>>>> .../vfio/platform/msi/vfio_platform_bcmplt.c | 74 ++++++ >>>>>>>> drivers/vfio/platform/vfio_platform_common.c | 86 ++++++- >>>>>>>> drivers/vfio/platform/vfio_platform_irq.c | 238 +++++++++++++++++- >>>>>>>> drivers/vfio/platform/vfio_platform_private.h | 23 ++ >>>>>>>> 8 files changed, 419 insertions(+), 15 deletions(-) >>>>>>>> create mode 100644 drivers/vfio/platform/msi/Kconfig >>>>>>>> create mode 100644 drivers/vfio/platform/msi/Makefile >>>>>>>> create mode 100644 drivers/vfio/platform/msi/vfio_platform_bcmplt.c >>>>>>>> >>>>>>> >>>>> >>
