- In iflib_msix_init(), VMMs with broken MSI-X activation are trying
to be worked around by manually enabling PCIM_MSIXCTRL_MSIX_ENABLE
before calling pci_alloc_msix(9). Apart from constituting a layering
violation, this has the problem of leaving PCIM_MSIXCTRL_MSIX_ENABLE
enabled when falling back to MSI or INTx when e. g. MSI-X is black-
listed and initially also when disabled via hw.pci.enable_msix. The
later in turn was incorrectly worked around in r325166.
Since r310806, pci(4) itself has code to deal with broken MSI-X
handling of VMMs, so all of these workarounds in iflib(9) can go,
fixing non-working interrupts when falling back to MSI/INTx. In
any case, possibly further adjustments to broken MSI-X activation
of VMMs like enabling r310806 by default in VM environments need to
be placed into pci(4), not iflib(9). [1]
- Also remove the pci_enable_busmaster(9) call from iflib_msix_init(),
which is already more properly invoked from iflib_device_attach().
- When falling back to MSI/INTx, release the MSI-X BAR resource again.
- When falling back to INTx, ensure scctx->isc_vectors is set to 1 and
not to something higher from a device with more than one MSI message
supported.
- Make the nearby ring_state(s) stuff (static) const.
Discussed with: jhb at BSDCan 2018 [1]
Reviewed by: imp, jhb
Differential Revision: https://reviews.freebsd.org/D15729
e4defe55a8