On 4/10/2023 6:07 AM, Leon Romanovsky wrote: > From: Avihai Horon <avihaih@xxxxxxxxxx> > > According to PCIe spec, Enable Relaxed Ordering value in the VF's PCI > config space is wired to 0 and PF relaxed ordering (RO) setting should > be applied to the VF. In QEMU (and maybe others), when assigning VFs, > the RO bit in PCI config space is not emulated properly and is always > set to 0. > > Therefore, pcie_relaxed_ordering_enabled() always returns 0 for VFs and > VMs and thus MKeys can't be created with RO read even if the PF supports > it. > > pcie_relaxed_ordering_enabled() check was added to avoid a syndrome when > creating a MKey with relaxed ordering (RO) enabled when the driver's > relaxed_ordering_read_pci_enabled HCA capability is out of sync with FW. > With the new relaxed_ordering_read capability this can't happen, as it's > set regardless of RO value in PCI config space and thus can't change > during runtime. > > Hence, to allow RO read in VFs and VMs, use the new HCA capability > relaxed_ordering_read without checking pcie_relaxed_ordering_enabled(). > The old capability checks are kept for backward compatibility with older > FWs. > > Allowing RO in VFs and VMs is valuable since it can greatly improve > performance on some setups. For example, testing throughput of a VF on > an AMD EPYC 7763 and ConnectX-6 Dx setup showed roughly 60% performance > improvement. > > Signed-off-by: Avihai Horon <avihaih@xxxxxxxxxx> > Reviewed-by: Shay Drory <shayd@xxxxxxxxxx> > Reviewed-by: Aya Levin <ayal@xxxxxxxxxx> > Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxx> > --- Reviewed-by: Jacob Keller <jacob.e.keller@xxxxxxxxx>
