On Tue, 2016-09-27 at 14:20 -0500, Bjorn Helgaas wrote: > On Mon, Sep 19, 2016 at 09:53:30AM +1000, Gavin Shan wrote: > > In pci_update_resource(), the PCI device's memory decoding (0x2 in > > PCI_COMMAND) is disabled when 64-bits memory BAR is updated if the > > PCI device's memory space wasn't asked to be always on by @pdev-> > > mmio_always_on. The PF's memory decoding might be disabled when > > updating its IOV BARs in the following path. Actually, the PF's > > memory decoding shouldn't be disabled in this scenario as the PF > > has been started to provide services: > > The reason we disable memory decoding while updating a 64-bit BAR is > because we can't do the update atomically, and a half-updated BAR might > conflict with other devices. > > You need to explain what is special about these SR-IOV BARs that makes it > safe to update them non-atomically while decoding is enabled. The IOV BAR won't decode until SR-IOV is enabled right ? Gavin, I don't think we update it "live", so it should be safe... Cheers, Ben. -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
