From: Longpeng <longpeng2@xxxxxxxxxx> We can enable SRIOV and add VFs by /sys/bus/pci/devices/..../sriov_numvfs, but this operation needs to spend lots of time if there has a large amount of VFs. For example, if the machine has 10 PFs and 250 VFs per-PF, enable all the VFs concurrently would cost about 200-250ms. However most of them are not need to be used at the moment, so we can enable SRIOV first but add VFs on demand. This series introduces two interfaces: 1. sriov_numvfs_no_scan: enable SRIOV without add the VFs. 2. sriov_scan_vf_id: add a specific VF. Longpeng (4): pci/sriov: extract sriov_numvfs common helper pci/sriov: add vf_bitmap to mark the vf id allocation pci/sriov: add sriov_numfs_no_scan interface pci/sriov: add sriov_scan_vf_id interface drivers/pci/iov.c | 162 +++++++++++++++++++++++++++++++++++++++++----- drivers/pci/pci.h | 1 + 2 files changed, 148 insertions(+), 15 deletions(-) -- 2.23.0