Messages in this thread | | | From | "Dey, Megha" <> | Subject | RE: [PATCH RFC v2 04/18] irq/dev-msi: Introduce APIs to allocate/free dev-msi interrupts | Date | Wed, 5 Aug 2020 20:19:36 +0000 |
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Hi Jason,
> -----Original Message----- > From: Jason Gunthorpe <jgg@mellanox.com> > Sent: Wednesday, July 22, 2020 10:35 AM > To: Dey, Megha <megha.dey@intel.com> > Cc: Jiang, Dave <dave.jiang@intel.com>; vkoul@kernel.org; maz@kernel.org; > bhelgaas@google.com; rafael@kernel.org; gregkh@linuxfoundation.org; > tglx@linutronix.de; hpa@zytor.com; alex.williamson@redhat.com; Pan, Jacob > jun <jacob.jun.pan@intel.com>; Raj, Ashok <ashok.raj@intel.com>; Liu, Yi L > <yi.l.liu@intel.com>; Lu, Baolu <baolu.lu@intel.com>; Tian, Kevin > <kevin.tian@intel.com>; Kumar, Sanjay K <sanjay.k.kumar@intel.com>; Luck, > Tony <tony.luck@intel.com>; Lin, Jing <jing.lin@intel.com>; Williams, Dan J > <dan.j.williams@intel.com>; kwankhede@nvidia.com; eric.auger@redhat.com; > parav@mellanox.com; Hansen, Dave <dave.hansen@intel.com>; > netanelg@mellanox.com; shahafs@mellanox.com; yan.y.zhao@linux.intel.com; > pbonzini@redhat.com; Ortiz, Samuel <samuel.ortiz@intel.com>; Hossain, Mona > <mona.hossain@intel.com>; dmaengine@vger.kernel.org; linux- > kernel@vger.kernel.org; x86@kernel.org; linux-pci@vger.kernel.org; > kvm@vger.kernel.org > Subject: Re: [PATCH RFC v2 04/18] irq/dev-msi: Introduce APIs to allocate/free > dev-msi interrupts > > On Wed, Jul 22, 2020 at 10:05:52AM -0700, Dey, Megha wrote: > > > > > > On 7/21/2020 9:25 AM, Jason Gunthorpe wrote: > > > On Tue, Jul 21, 2020 at 09:02:41AM -0700, Dave Jiang wrote: > > > > From: Megha Dey <megha.dey@intel.com> > > > > > > > > The dev-msi interrupts are to be allocated/freed only for custom > > > > devices, not standard PCI-MSIX devices. > > > > > > > > These interrupts are device-defined and they are distinct from the > > > > already existing msi interrupts: > > > > pci-msi: Standard PCI MSI/MSI-X setup format > > > > platform-msi: Platform custom, but device-driver opaque MSI > > > > setup/control > > > > arch-msi: fallback for devices not assigned to the generic PCI > > > > domain > > > > dev-msi: device defined IRQ domain for ancillary devices. For e.g. > > > > DSA portal devices use device specific IMS(Interrupt message store) > interrupts. > > > > > > > > dev-msi interrupts are represented by their own device-type. That > > > > means > > > > dev->msi_list is never contended for different interrupt types. It > > > > will either be all PCI-MSI or all device-defined. > > > > > > Not sure I follow this, where is the enforcement that only dev-msi > > > or normal MSI is being used at one time on a single struct device? > > > > > > > So, in the dev_msi_alloc_irqs, I first check if the dev_is_pci.. > > If it is a pci device, it is forbidden to use dev-msi and must use the > > pci subsystem calls. dev-msi is to be used for all other custom > > devices, mdev or otherwise. > > What prevents creating a dev-msi directly on the struct pci_device ?
In the next patchset, I have explicitly added code which denies PCI devices from using the dev_msi alloc/free APIS > > Jason
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