Hi Jason, > -----Original Message----- > From: Jason Gunthorpe <[email protected]> > Sent: Wednesday, July 22, 2020 10:35 AM > To: Dey, Megha <[email protected]> > Cc: Jiang, Dave <[email protected]>; [email protected]; [email protected]; > [email protected]; [email protected]; [email protected]; > [email protected]; [email protected]; [email protected]; Pan, Jacob > jun <[email protected]>; Raj, Ashok <[email protected]>; Liu, Yi L > <[email protected]>; Lu, Baolu <[email protected]>; Tian, Kevin > <[email protected]>; Kumar, Sanjay K <[email protected]>; Luck, > Tony <[email protected]>; Lin, Jing <[email protected]>; Williams, Dan J > <[email protected]>; [email protected]; [email protected]; > [email protected]; Hansen, Dave <[email protected]>; > [email protected]; [email protected]; [email protected]; > [email protected]; Ortiz, Samuel <[email protected]>; Hossain, Mona > <[email protected]>; [email protected]; linux- > [email protected]; [email protected]; [email protected]; > [email protected] > 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 <[email protected]> > > > > > > > > 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
