On 12/07/16 04:59, Andrey Grodzovsky wrote: > Hello > > Some background - > > We are trying to run Qualcomm Atheros AR928X Wireless Network Adapter > and have a crash right on driver load, following are our observations > and questions. > > Jurgen's observation - > > " The Atheros card "Qualcomm Atheros AR928X Wireless Network Adapter > (PCI-Express) (rev 01)" is plugged into the host system (datatron). > When I attach it to the DomU - the module "ath9k" is automatically > loaded, but it gives an exception "iowrite32+0x2b/0x30". > No idea what the issue is (tried also with another Atheros Card > (ath10k) - similar problem). When I try an Intel card, it works. > (the card also works on the Dom0 - so the Linux driver and HW is OK)." > > Debugging - > > After some investigation with kgdb and iommu trace on DomU it seems > the iomap of PCI BAR for the device returns a a mapping f which first > 0x1000 bytes are read only and that causes access violation when > trying to write registers mapped to this area (all the regs with > offset < 0x1000) - why this happens i still don't know. Register > writes with offsets > 0x1000 are fine. > > Running same driver on Dom0 is totally fine > > Bellow the sigsev backtrace and xen dmesg from DomU > > As can be seen there is ioremap_ of size 0x10000 starting > at ffffc900402c0000 but as i said, i noticed that anything bellow > ffffc900402c*1000 *is not writable (from gdb using set addr = val) and > only readable while anything above this address is writeable. > > Question - > > Please give any advise on this issue and especially how to approach > debugging this both on Domu and Dom0 and where in xen code to look for > possible issues.
First of all, is this a PV or HVM domU ? Is this BAR the same BAR which has the MSI-X table in? For safety, Xen has to trap and emulate updates to the MSI/MSI-X configuration. It is possible that that logic has gone wrong. ~Andrew
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