> Date: Tue, 2 Aug 2016 16:29:52 -0600 > From: alex.william...@redhat.com > To: the_cartograp...@hotmail.com > CC: vfio-users@redhat.com > Subject: Re: [vfio-users] Cannot register eventfd with MSI/MSI-X interrupts > > On Tue, 2 Aug 2016 09:54:19 -0600 > Alex Williamson <alex.william...@redhat.com> wrote: > > > On Tue, 2 Aug 2016 10:21:30 +0000 > > chris thompson <the_cartograp...@hotmail.com> wrote: > > > > > Hi Alex, > > > > > > Thanks for your patience, I noticed the count != 0 issue shortly after, > > > but I get the same EINVAL error anyway when it is zero - but this is > > > because the IRQ does not have a mapping yet. When I change the code to > > > map it then unmap it then I get: > > > IRQx - successful map then unmap > > > MSI - unsuccessful map (and unsuccessful unmap) > > > MSIX - successful map then unmap (despite the device still being in IRQx > > > mode?) > > > Error - successfully map, kernel driver crash on the unmap! > > I remembered that there is a trick here specific to MSI, your device > probably supports more than one MSI vector. MSI is a little bit > special, not all platforms support multiple MSI vectors and they were > pretty much outdated by the much more flexible MSI-X capability for > that reason. To help with this the SET_IRQS ioctl returns negative on > error, 0 on success, and a positive value indicating the available > vectors to retry with if the requested count is not supported/available. > > BTW, this should fix the oops you found: > https://lkml.org/lkml/2016/8/2/1912 > > Thanks, > Alex Hi Alex, Indeed I realise now that the MSI registration ioctl returns 8, > the number of IRQs I would expect (the same as the MSIX ones). The question > is, why doesn't the IRQ_INFO ioctl reply count = 8 like the MSIX one? Instead > it returns 64 (I thought MSI only went up to 32 too?) config IRQ index 1 Info: argsz 0x10, flags 0x9, index 0x1, count 0x40, Register: failed to register interrupt set 1 : 0-63, error 8 Invalid argument config IRQ index 2 Info: argsz 0x10, flags 0x9, index 0x2, count 0x8, Register: successfully registered interrupt set 2 : 0-7, ret 0 Thanks,Chris
_______________________________________________ vfio-users mailing list vfio-users@redhat.com https://www.redhat.com/mailman/listinfo/vfio-users
