Re: [PATCH v3 5/5] Revert "vfio/pci: Disable INTx fast path if using split irqchip"

[Alex Williamson <alex.williamson@redhat.com>]

On Tue, 17 Mar 2020 15:50:42 -0400
Peter Xu <peterx@redhat.com> wrote:

> With the resamplefd list introduced, we can savely enable VFIO INTx
> fast path again with split irqchip so it can still be faster than the
> complete slow path.
> 
> Reviewed-by: Eric Auger <eric.auger@redhat.com>
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  hw/vfio/pci.c | 12 ------------
>  1 file changed, 12 deletions(-)

Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
Acked-by: Alex Williamson <alex.williamson@redhat.com>

> diff --git a/hw/vfio/pci.c b/hw/vfio/pci.c
> index 09703362df..1c0aa27386 100644
> --- a/hw/vfio/pci.c
> +++ b/hw/vfio/pci.c
> @@ -124,18 +124,6 @@ static void vfio_intx_enable_kvm(VFIOPCIDevice *vdev, Error **errp)
>          return;
>      }
>  
> -    if (kvm_irqchip_is_split()) {
> -        /*
> -         * VFIO INTx is currently not working with split kernel
> -         * irqchip for level triggered interrupts.  Go the slow path
> -         * as long as split is enabled so we can be at least
> -         * functional (even with poor performance).
> -         *
> -         * TODO: Remove this after all things fixed up.
> -         */
> -        return;
> -    }
> -
>      /* Get to a known interrupt state */
>      qemu_set_fd_handler(irq_fd, NULL, NULL, vdev);
>      vfio_mask_single_irqindex(&vdev->vbasedev, VFIO_PCI_INTX_IRQ_INDEX);