Hi Jason, > -----Original Message----- > From: Jason Gunthorpe <jgg@xxxxxxxxxxxx> > Sent: Wednesday, July 22, 2020 10:35 AM > To: Dey, Megha <megha.dey@xxxxxxxxx> > Cc: Jiang, Dave <dave.jiang@xxxxxxxxx>; vkoul@xxxxxxxxxx; maz@xxxxxxxxxx; > bhelgaas@xxxxxxxxxx; rafael@xxxxxxxxxx; gregkh@xxxxxxxxxxxxxxxxxxx; > tglx@xxxxxxxxxxxxx; hpa@xxxxxxxxx; alex.williamson@xxxxxxxxxx; Pan, Jacob > jun <jacob.jun.pan@xxxxxxxxx>; Raj, Ashok <ashok.raj@xxxxxxxxx>; Liu, Yi L > <yi.l.liu@xxxxxxxxx>; Lu, Baolu <baolu.lu@xxxxxxxxx>; Tian, Kevin > <kevin.tian@xxxxxxxxx>; Kumar, Sanjay K <sanjay.k.kumar@xxxxxxxxx>; Luck, > Tony <tony.luck@xxxxxxxxx>; Lin, Jing <jing.lin@xxxxxxxxx>; Williams, Dan J > <dan.j.williams@xxxxxxxxx>; kwankhede@xxxxxxxxxx; eric.auger@xxxxxxxxxx; > parav@xxxxxxxxxxxx; Hansen, Dave <dave.hansen@xxxxxxxxx>; > netanelg@xxxxxxxxxxxx; shahafs@xxxxxxxxxxxx; yan.y.zhao@xxxxxxxxxxxxxxx; > pbonzini@xxxxxxxxxx; Ortiz, Samuel <samuel.ortiz@xxxxxxxxx>; Hossain, Mona > <mona.hossain@xxxxxxxxx>; dmaengine@xxxxxxxxxxxxxxx; linux- > kernel@xxxxxxxxxxxxxxx; x86@xxxxxxxxxx; linux-pci@xxxxxxxxxxxxxxx; > kvm@xxxxxxxxxxxxxxx > 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@xxxxxxxxx> > > > > > > > > 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
