On 7/17/2019 4:46 PM, Jerin Jacob Kollanukkaran wrote: >> -----Original Message----- >> From: Hyong Youb Kim (hyonkim) <[email protected]> >> Sent: Wednesday, July 17, 2019 4:36 PM >> To: Jerin Jacob Kollanukkaran <[email protected]>; Nithin Kumar >> Dabilpuram <[email protected]>; David Marchand >> <[email protected]>; Thomas Monjalon >> <[email protected]>; Ferruh Yigit <[email protected]>; Bruce >> Richardson <[email protected]> >> Cc: John Daley (johndale) <[email protected]>; Shahed Shaikh >> <[email protected]>; [email protected] >> Subject: RE: [RFC PATCH v3 2/3] eal: add mask and unmask interrupt APIs >> >>> -----Original Message----- >>> From: Jerin Jacob Kollanukkaran <[email protected]> >>> Sent: Wednesday, July 17, 2019 7:44 PM >>> To: Hyong Youb Kim (hyonkim) <[email protected]>; Nithin Kumar >>> Dabilpuram <[email protected]>; David Marchand >>> <[email protected]>; Thomas Monjalon >> <[email protected]>; >>> Ferruh Yigit <[email protected]>; Bruce Richardson >>> <[email protected]> >>> Cc: John Daley (johndale) <[email protected]>; Shahed Shaikh >>> <[email protected]>; [email protected] >>> Subject: RE: [RFC PATCH v3 2/3] eal: add mask and unmask interrupt >>> APIs >>> >>>>> I think, it vary from the perspective of IRQ Chip(or controller) >>>>> vs NIC >>>>> register(Source) PoV. >>>>> Since the API starts from rte_intr_* it is more of controller so >>>>> _ack_ make sense Other reason for ack: >>>>> 1) It will enforce that it needs to be called form ISR >>>>> 2) It would be have been really correct to unmask if >>>>> VFIO+MSIx+Linux supports it >>>>> 3) if it is ack, no need to add unmask counterpart, the _mask_ API >>>>> >>>> Just curious, what you mean by irq controller? Ack/mask/unmask PIOs >>>> all >>> go >>> >>> Programmable Interrupt Controller. Like Intel 8259A, GIC from ARM etc >>> The drivers in linux/drivers/irqchip/ >>> >>>> to the NIC. It is the NIC that asserts/de-asserts irq.. >>>> >>>>>> Besides the name, are we agreeing that we want these? >>>>>> - Unmask if INTx >>>>> Yes >>>>> >>>>>> - Nothing if MSI/MSI-X >>>>> Yes for MSI over VFIO >>>>> No for MSI over UIO/igb_uio >>>>> >>>> I guess I was not clear. For MSI/MSI-X, we do not want to do >>>> mask/unmask regardless of vfio-pci/igb_uio. Below is my comment >>>> about linux/windows/freebsd from an earlier email. Do you disagree? >>>> I am sure there are plenty of kernel NIC driver guys here. Please >>>> correct me if I am mistaken... >>> >>> For some reason, igb_uio kernel driver mask the interrupt for MSIx. >>> We need to ack or unmask if needs to work with MSIX + IGB_UIO. >>> >>> See >>> pci_uio_alloc_resource() >>> if (dev->kdrv == RTE_KDRV_IGB_UIO) >>> dev->intr_handle.type = RTE_INTR_HANDLE_UIO; >>> else { >>> dev->intr_handle.type = RTE_INTR_HANDLE_UIO_INTX; >>> >>> igbuio_pci_irqcontrol() for masking in kernel. >>> >> igb_uio does not auto-mask MSI/MSI-X. > I have not tested igbuio as we don't specific NIC + IGB_UIO platform. > > The observation based on following code. see code under HAVE_PCI_MSI_MASK_IRQ > > static int > igbuio_pci_irqcontrol(struct uio_info *info, s32 irq_state) > { > struct rte_uio_pci_dev *udev = info->priv; > struct pci_dev *pdev = udev->pdev; > > #ifdef HAVE_PCI_MSI_MASK_IRQ > struct irq_data *irq = irq_get_irq_data(udev->info.irq); > #endif > > pci_cfg_access_lock(pdev); > > if (udev->mode == RTE_INTR_MODE_MSIX || udev->mode == > RTE_INTR_MODE_MSI) { > #ifdef HAVE_PCI_MSI_MASK_IRQ > if (irq_state == 1) > pci_msi_unmask_irq(irq); > else > pci_msi_mask_irq(irq); > #else > igbuio_mask_irq(pdev, udev->mode, irq_state); > #endif > } > > if (udev->mode == RTE_INTR_MODE_LEGACY) > pci_intx(pdev, !!irq_state); > > pci_cfg_access_unlock(pdev); > > return 0; > } > >> static irqreturn_t >> igbuio_pci_irqhandler(int irq, void *dev_id) { >> struct rte_uio_pci_dev *udev = (struct rte_uio_pci_dev *)dev_id; >> struct uio_info *info = &udev->info; >> >> /* Legacy mode need to mask in hardware */ >> if (udev->mode == RTE_INTR_MODE_LEGACY && >> !pci_check_and_mask_intx(udev->pdev)) >> return IRQ_NONE; >> >> uio_event_notify(info); >> >> /* Message signal mode, no share IRQ and automasked */ >> return IRQ_HANDLED; >> } >> >> Also tested just now with igb_uio. The driver does not need to call >> rte_intr_enable(), and it keeps getting interrupts without any issues. > If you are sure, we can make MSIX+IGB_UIO as NOP in rte_intr_ack()
Ok. Another problem is that we might not be able to distinguish in case of IGB_UIO at rte_intr_ack() level if underlying interrupt is a INTx or MSIx. See igbuio_pci_enable_interrupts() that finds and stores that mode in uio->mode. So we think leaving the behavior as earlier is needed and simpler as it meets the current expectation. > >> Am I missing something? >> >> -Hyong >> >>> So it is more of making inline with igb_uio kernel driver AND not >>> break The existing drivers which was using rte_intr_enable in ISR with >>> MSIX+IGB_UIO >>> >>> I do agree with that for edge trigged interrupt mask may not require >>> from kernel. >>> But I am not sure why it is added in igb_uio kernel driver. May be it >>> is just legacy. >>> Anyway this wont change schematics, when igb_uio kenrel fixed then the >>> counter Part can be changed in rte_intr_ack(). Ie. it is transparent >>> to drivers. >>> >>>>> I don't have very strong opinion unmask vs ack. I prefer to have >>>>> ack due the reasons stated above. >>>>> If you really have strong opinion on using unmask, we will stick >>>>> with that to make forward progress. >>>>> Let us know. >>>>> >>>> I have no strong opinion either. >>> OK. Lets stick with rte_intr_ack(). >>> >>>> Thanks.. >>>> -Hyong
