From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <201605250554.u4P5sPdK018206@mx0a-001b2d01.pphosted.com> Subject: Re: [PATCH 2/5] iommu: Set PCI_BUS_FLAGS_MSI_REMAP if IOMMU have capability of IRQ remapping To: Bjorn Helgaas References: <1461761010-5452-1-git-send-email-xyjxie@linux.vnet.ibm.com> <1461761010-5452-3-git-send-email-xyjxie@linux.vnet.ibm.com> <20160524211149.GC16463@localhost> Cc: kvm@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, iommu@lists.linux-foundation.org, alex.williamson@redhat.com, bhelgaas@google.com, aik@ozlabs.ru, benh@kernel.crashing.org, paulus@samba.org, mpe@ellerman.id.au, joro@8bytes.org, warrier@linux.vnet.ibm.com, zhong@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com, eric.auger@linaro.org, will.deacon@arm.com, gwshan@linux.vnet.ibm.com, David.Laight@ACULAB.COM, alistair@popple.id.au, ruscur@russell.cc From: Yongji Xie Date: Wed, 25 May 2016 13:54:23 +0800 MIME-Version: 1.0 In-Reply-To: <20160524211149.GC16463@localhost> Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-kernel-owner@vger.kernel.org List-ID: On 2016/5/25 5:11, Bjorn Helgaas wrote: > On Wed, Apr 27, 2016 at 08:43:27PM +0800, Yongji Xie wrote: >> The capability of IRQ remapping is abstracted on IOMMU side on >> some archs. There is a existing flag IOMMU_CAP_INTR_REMAP for this. >> >> To have a universal flag to test this capability for different >> archs on PCI side, we set PCI_BUS_FLAGS_MSI_REMAP for PCI buses >> when IOMMU_CAP_INTR_REMAP is set. >> >> Signed-off-by: Yongji Xie >> --- >> drivers/iommu/iommu.c | 15 +++++++++++++++ >> 1 file changed, 15 insertions(+) >> >> diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c >> index 0e3b009..5d2b6f6 100644 >> --- a/drivers/iommu/iommu.c >> +++ b/drivers/iommu/iommu.c >> @@ -813,6 +813,16 @@ struct iommu_group *pci_device_group(struct device *dev) >> return group; >> } >> >> +static void pci_check_msi_remapping(struct pci_dev *pdev, >> + const struct iommu_ops *ops) >> +{ >> + struct pci_bus *bus = pdev->bus; >> + >> + if (ops->capable(IOMMU_CAP_INTR_REMAP) && >> + !(bus->bus_flags & PCI_BUS_FLAGS_MSI_REMAP)) >> + bus->bus_flags |= PCI_BUS_FLAGS_MSI_REMAP; >> +} > This looks an awful lot like the pci_bus_check_msi_remapping() you add > elsewhere. Why do we need both? I will modify this function as you suggested. And we add this function here because some iommu drivers would be initialed after PCI probing. >> /** >> * iommu_group_get_for_dev - Find or create the IOMMU group for a device >> * @dev: target device >> @@ -871,6 +881,9 @@ static int add_iommu_group(struct device *dev, void *data) >> const struct iommu_ops *ops = cb->ops; >> int ret; >> >> + if (dev_is_pci(dev) && ops->capable) >> + pci_check_msi_remapping(to_pci_dev(dev), ops); >> + >> if (!ops->add_device) >> return 0; >> >> @@ -913,6 +926,8 @@ static int iommu_bus_notifier(struct notifier_block *nb, >> * result in ADD/DEL notifiers to group->notifier >> */ >> if (action == BUS_NOTIFY_ADD_DEVICE) { >> + if (dev_is_pci(dev) && ops->capable) >> + pci_check_msi_remapping(to_pci_dev(dev), ops); > These calls don't smell right either. Why do we need dev_is_pci() > checks here? Some platform devices may also call this. > Can't this be done in the PCI probe path somehow, e.g., > in pci_set_bus_msi_domain() or something? > Yes, this can be done in pci_create_root_bus(). But it could only handle the case that iommu drivers are initialed before PCI probing. Regards, Yongji