y bhanu wrote: > Some question about the PCIe drives and SR-IOV. > > setup:4x Ethernet transceivers (82576EB) à PLX PEX8624 switch -> > E5520 chipset -> dual Xeon E5645 CPUs > When tryiny to setup XEN (4.0.1) and PCI pass through, I was getting > the following XEN error: > > “Error: pci: to avoid potential security issue, 0000:16:00.0 is not > allowed to be assigned to guest since it is behind PCIe switch that > does not support or enable ACS.” > > I was able to get around it by enabling the > "(pci-passthrough-strict-check no)" in the /etc/xen/xend-config.sxp > configuration file. > When the below information, Can anyone tell me how much safe it is to > use this CARD for SR-IOV. > Without ACS, a (rogue, errant, mischievous guest) DMA write (or read) from an 82576 attached to one of the bridge2's (below) can be directed to another PCI device (another 82576) attached to another bridge2 (below) attached to the same bridge1. due to address matching by the peer bridge2 (and subtractive decode by bridge1). ACS forces all endpoint (read/write) transactions to go all the way to the root device/bridge before they can be directed down another path of the PCI tree, which enables the IOMMU's in the root bridge's to validate/invalidate the routing of the PCI (read/write) transaction. If the address was rogue/errant/mischievous, the IOMMU would end the transaction, preventing it from being fwd'd to another device (domain), and generate an error (assuming error reporting is on in the IOMMU). > After reading through the following comments in the mailists, I am NOT > sure if it is OK to ignore the above error. > http://lkml.indiana.edu/hypermail/linux/kernel/0910.0/02595.html > https://www.redhat.com/archives/libvir-list/2009-December/msg00709.html > > As you can see below, it using a PLX 8624. > Will I be able to get the get such a configuration working with SR-IOV safely. > > Setup is something like > bridge1 - bridge2 - Intel 82576 device > | 2nd Intel 82576 device > - bridge2 - Intel 82576 device > 2nd Intel 82576 device > .... (so forth) > > PCI-tree below: > -[0000:00]-+-00.0 Intel Corporation 5520 I/O Hub to ESI Port > +-03.0-[0d-17]----00.0-[0e-17]--+-04.0-[17]-- > | +-05.0-[15-16]--+-00.0 > Intel Corporation 82576 Gigabit Network Connection > | | \-00.1 > Intel Corporation 82576 Gigabit Network Connection > | +-06.0-[13-14]--+-00.0 > Intel Corporation 82576 Gigabit Network Connection > | | \-00.1 > Intel Corporation 82576 Gigabit Network Connection > | +-08.0-[11-12]--+-00.0 > Intel Corporation 82576 Gigabit Network Connection > | | \-00.1 > Intel Corporation 82576 Gigabit Network Connection > | \-09.0-[0f-10]--+-00.0 > Intel Corporation 82576 Gigabit Network Connection > | \-00.1 > Intel Corporation 82576 Gigabit Network Connection > > Bridge devices below: > 0d:00.0 PCI bridge: PLX Technology, Inc. PEX 8624 24-lane, 6-Port PCI > Express Gen 2 (5.0 GT/s) Switch [ExpressLane] (rev bb) > 0e:04.0 PCI bridge: PLX Technology, Inc. PEX 8624 24-lane, 6-Port PCI > Express Gen 2 (5.0 GT/s) Switch [ExpressLane] (rev bb) > 0e:05.0 PCI bridge: PLX Technology, Inc. PEX 8624 24-lane, 6-Port PCI > Express Gen 2 (5.0 GT/s) Switch [ExpressLane] (rev bb) > 0e:06.0 PCI bridge: PLX Technology, Inc. PEX 8624 24-lane, 6-Port PCI > Express Gen 2 (5.0 GT/s) Switch [ExpressLane] (rev bb) > 0e:08.0 PCI bridge: PLX Technology, Inc. PEX 8624 24-lane, 6-Port PCI > Express Gen 2 (5.0 GT/s) Switch [ExpressLane] (rev bb) > 0e:09.0 PCI bridge: PLX Technology, Inc. PEX 8624 24-lane, 6-Port PCI > Express Gen 2 (5.0 GT/s) Switch [ExpressLane] (rev bb) > > Bhanu > -- > 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 -- 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
