On Tue, 18 Apr 2023 10:29:19 -0700
Reinette Chatre <reinette.chatre@xxxxxxxxx> wrote:
> Not all MSI-X devices support dynamic MSI-X allocation. Whether
> a device supports dynamic MSI-X should be queried using
> pci_msix_can_alloc_dyn().
>
> Instead of scattering code with pci_msix_can_alloc_dyn(),
> probe this ability once and store it as a property of the
> virtual device.
>
> Suggested-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
> Signed-off-by: Reinette Chatre <reinette.chatre@xxxxxxxxx>
> ---
> Changes since V2:
> - New patch. (Alex)
>
> drivers/vfio/pci/vfio_pci_core.c | 5 ++++-
> include/linux/vfio_pci_core.h | 1 +
> 2 files changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
> index ae0e161c7fc9..a3635a8e54c8 100644
> --- a/drivers/vfio/pci/vfio_pci_core.c
> +++ b/drivers/vfio/pci/vfio_pci_core.c
> @@ -530,8 +530,11 @@ int vfio_pci_core_enable(struct vfio_pci_core_device *vdev)
> vdev->msix_bar = table & PCI_MSIX_TABLE_BIR;
> vdev->msix_offset = table & PCI_MSIX_TABLE_OFFSET;
> vdev->msix_size = ((flags & PCI_MSIX_FLAGS_QSIZE) + 1) * 16;
> - } else
> + vdev->has_dyn_msix = pci_msix_can_alloc_dyn(pdev);
> + } else {
> vdev->msix_bar = 0xFF;
> + vdev->has_dyn_msix = false;
> + }
>
> if (!vfio_vga_disabled() && vfio_pci_is_vga(pdev))
> vdev->has_vga = true;
> diff --git a/include/linux/vfio_pci_core.h b/include/linux/vfio_pci_core.h
> index 148fd1ae6c1c..4f070f2d6fde 100644
> --- a/include/linux/vfio_pci_core.h
> +++ b/include/linux/vfio_pci_core.h
> @@ -67,6 +67,7 @@ struct vfio_pci_core_device {
> u8 msix_bar;
> u16 msix_size;
> u32 msix_offset;
> + bool has_dyn_msix;
> u32 rbar[7];
> bool pci_2_3;
> bool virq_disabled;
Nit, the whole data structure probably needs to be sorted with pahole,
but creating a hole here for locality to other msix fields should
probably be secondary to keeping the structure well packed, which
suggests including this new field among the bools below. Thanks,
Alex
