> -----Original Message-----
> From: Jerin Jacob Kollanukkaran <jer...@marvell.com>
> Sent: Tuesday, July 16, 2019 1:51 AM
> To: Hyong Youb Kim (hyonkim) <hyon...@cisco.com>; David Marchand
> <david.march...@redhat.com>; Thomas Monjalon
> <tho...@monjalon.net>; Ferruh Yigit <ferruh.yi...@intel.com>
> Cc: dev@dpdk.org; John Daley (johndale) <johnd...@cisco.com>; Shahed
> Shaikh <shsha...@marvell.com>; Nithin Kumar Dabilpuram
> <ndabilpu...@marvell.com>
> Subject: RE: [RFC PATCH] vfio: avoid re-installing irq handler
>
> > -----Original Message-----
> > From: Hyong Youb Kim <hyon...@cisco.com>
> > Sent: Monday, July 15, 2019 9:28 PM
> > To: David Marchand <david.march...@redhat.com>; Thomas Monjalon
> > <tho...@monjalon.net>; Jerin Jacob Kollanukkaran <jer...@marvell.com>;
> > Ferruh Yigit <ferruh.yi...@intel.com>
> > Cc: dev@dpdk.org; John Daley <johnd...@cisco.com>; Hyong Youb Kim
> > <hyon...@cisco.com>
> > Subject: [EXT] [RFC PATCH] vfio: avoid re-installing irq handler
> >
> > A rough patch for the approach mentioned earlier. It is only for discussion.
> > http://mails.dpdk.org/archives/dev/2019-July/138113.html
> >
> > To try this out, first revert the following then apply.
> > commit 89aac60e0be9 ("vfio: fix interrupts race condition")
>
> Yes. This patch has to be to reverted. It changes the existing interrupt
> behavior and does not address the MSIX case as well.
>
> I think, The clean fix would be to introduce rte_intr_mask() and
> rte_intr_unmask() by abstracting the INTX and MSIX differences
> And let qede driver call it as needed.
>
> Thoughts?
Hi,
You are proposing these?
- Add rte_intr_mask_intx, rte_intr_unmask_intx.
No APIs for masking MSI/MSI-X as vfio-pci does not support that.
- Modify PMD irq handlers to use rte_intr_unmask_intx as necessary.
That might be too intrusive. And too much work for the sake of
INTx.. Anyone really using/needing INTx these days? :-)
The following drivers call rte_intr_enable from their irq handlers. So
with explicit rte_intr_unmask_intx, all these would need to do "if
using intx, unmask"?
atlantic, avp, axgbe, bnx2x, e1000, fm10k, ice, ixgbe, nfp, qede, sfc,
vmxnet3
And nfp seems to rely on rte_intr_enable to re-install irq handler to
unmask a vector in MSI-X Table?
if (hw->ctrl & NFP_NET_CFG_CTRL_MSIXAUTO) {
/* If MSI-X auto-masking is used, clear the entry */
rte_wmb();
rte_intr_enable(&pci_dev->intr_handle);
With David's patch and mine, this handler would have to first
rte_intr_disable() and then enable, if such unmasking is really
necessary..
As for the semantics of rte_intr_enable/disable, I am ok as is.
- "enable": put things in a state where NIC can send an interrupt, and
PMD/app gets a callback.
Whether this involves unmasking for INTx is hidden.
- "disable": put things in a state where NIC cannot send an interrupt.
Regardless of vfio changes, we should probably remove rte_intr_enable
from qede_interrupt_handler (the MSI/MSI-X interrupt handler), to make
usage/intention clear..
Thanks.
-Hyong
