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 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 ae0e161c7fc9..c679d7b59f9b 100644 --- a/drivers/vfio/pci/vfio_pci_core.c +++ b/drivers/vfio/pci/vfio_pci_core.c @@ -1111,7 +1111,9 @@ 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 && + !pci_msix_can_alloc_dyn(vdev->pdev))) 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; -- 2.34.1