[kvmtool,v2,0/3] vfio-pci: Support INTx mode re-enabling

Message

Leo Yan March 20, 2019, 6:20 a.m. UTC

When enable vfio-pci mode for NIC driver on Juno board, the IRQ is
failed to forward properly from host to guest, finally root caused this
issue is related with kvmtool cannot re-enable INTx mode properly.

So the basic working flow to reproduce this issue is as below:

    Host             Guest
-------------  --------------------
  INTx mode
                 MSI enable failed in NIC driver
                 MSI disable in NIC driver
                 Switch back to INTx mode --> kvmtool doesn't support

So this patch is to support INTx mode re-enabling; 0001/0002 patches
are only minor fixing up for eventfd releasing and remove useless FDs
reservation for INTx.  0003 patch is the core patch for supporting
INTx mode re-enabling, when kvmtool detects MSI is disabled it
rollbacks to INTx mode.

This patch set has been tested on Juno-r2 board.

Leo Yan (3):
  vfio-pci: Release INTx's unmask eventfd properly
  vfio-pci: Remove useless FDs reservation in vfio_pci_enable_intx()
  vfio-pci: Re-enable INTx mode when disable MSI/MSIX

 include/kvm/vfio.h |  1 +
 vfio/pci.c         | 61 +++++++++++++++++++++++++++++++++++++---------
 2 files changed, 50 insertions(+), 12 deletions(-)