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

[Alex Williamson]

On Tue, 17 Mar 2020 15:50:42 -0400
Peter Xu  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 
> Signed-off-by: Peter Xu 
> ---
>  hw/vfio/pci.c | 12 
>  1 file changed, 12 deletions(-)

Reviewed-by: Alex Williamson 
Acked-by: Alex Williamson 

> 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(>vbasedev, VFIO_PCI_INTX_IRQ_INDEX);

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

[Peter Xu]

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 
Signed-off-by: Peter Xu 
---
 hw/vfio/pci.c | 12 
 1 file changed, 12 deletions(-)

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(>vbasedev, VFIO_PCI_INTX_IRQ_INDEX);
-- 
2.24.1