On Tue, 18 Apr 2023 10:29:21 -0700
Reinette Chatre <reinette.chatre@xxxxxxxxx> wrote:
> Dynamic MSI-X is supported. Clear VFIO_IRQ_INFO_NORESIZE
> to provide guidance to user space.
>
> Signed-off-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
> ---
> Changes since V2:
> - Use new vdev->has_dyn_msix property instead of calling
> pci_msix_can_alloc_dyn() directly. (Alex)
>
> Changes since RFC V1:
> - Only advertise VFIO_IRQ_INFO_NORESIZE for MSI-X devices that
> can actually support dynamic allocation. (Alex)
>
> drivers/vfio/pci/vfio_pci_core.c | 4 +++-
> include/uapi/linux/vfio.h | 3 +++
> 2 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index a3635a8e54c8..4050ad3388c2 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -1114,7 +1114,9 @@ static int vfio_pci_ioctl_get_irq_info(struct vfio_pci_core_device *vdev,
> if (info.index == VFIO_PCI_INTX_IRQ_INDEX)
> info.flags |=
> (VFIO_IRQ_INFO_MASKABLE | VFIO_IRQ_INFO_AUTOMASKED);
> - else
> + else if ((info.index != VFIO_PCI_MSIX_IRQ_INDEX) ||
> + (info.index == VFIO_PCI_MSIX_IRQ_INDEX &&
> + !vdev->has_dyn_msix))
Isn't this the same as:
(info.index != VFIO_PCI_MSIX_IRQ_INDEX || !vdev->has_dyn_msix)
Thanks,
Alex
> info.flags |= VFIO_IRQ_INFO_NORESIZE;
>
> return copy_to_user(arg, &info, minsz) ? -EFAULT : 0;
> diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h
> index 0552e8dcf0cb..1a36134cae5c 100644
> --- a/include/uapi/linux/vfio.h
> +++ b/include/uapi/linux/vfio.h
> @@ -511,6 +511,9 @@ struct vfio_region_info_cap_nvlink2_lnkspd {
> * then add and unmask vectors, it's up to userspace to make the decision
> * whether to allocate the maximum supported number of vectors or tear
> * down setup and incrementally increase the vectors as each is enabled.
> + * Absence of the NORESIZE flag indicates that vectors can be enabled
> + * and disabled dynamically without impacting other vectors within the
> + * index.
> */
> struct vfio_irq_info {
> __u32 argsz;
