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; patch 0001 is one
minor fixing up for eventfd releasing; patch 0002 introduces a new
function vfio_pci_init_intx() which is used to finish INTx one-time
initialisation; patch 0003 is the core patch for support 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.
== Changes for V4 ==
* Removed the unnecessary comments in patch 0003 (Jean-Philippe).
* Added Jean-Philippe's review tags.
== Changes for V3 ==
* Add new function vfio_pci_init_intx() for one-time initialisation.
* Simplized INTx re-enabling (don't change irq_line anymore at the
runtime).
Leo Yan (3):
vfio-pci: Release INTx's unmask eventfd properly
vfio-pci: Add new function for INTx one-time initialisation
vfio-pci: Re-enable INTx mode when disable MSI/MSIX
include/kvm/vfio.h | 1 +
vfio/pci.c | 95 ++++++++++++++++++++++++++++++----------------
2 files changed, 64 insertions(+), 32 deletions(-)
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2.19.1
