Re: Atheros WiFi - memory paging failure on driver load

[Andrew Cooper <andrew.cooper3@citrix.com>]

[-- Attachment #1.1: Type: text/plain, Size: 2071 bytes --]

On 18/07/16 04:29, Andrey Grodzovsky wrote:
>
>
> On Fri, Jul 15, 2016 at 11:45 PM, Andrey Grodzovsky
> <andrey2805@gmail.com <mailto:andrey2805@gmail.com>> wrote:
>
>
>
>     On Fri, Jul 15, 2016 at 6:04 AM, Andrew Cooper
>     <andrew.cooper3@citrix.com <mailto:andrew.cooper3@citrix.com>> wrote:
>
>         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.
>

Your card is not PCI spec compliant.

The Spec mandates that nothing may exist in any 4k aligned block
covering part of the MSI-X table, precisely so read-only tricks like
this can be done trap&intercept MSI-X updates.



>>
>>         Running same driver on Dom0 is totally fine
>

This is curious.  Dom0 and DomU should be treated identically in this
regard.

~Andrew

[-- Attachment #1.2: Type: text/html, Size: 8985 bytes --]

[-- Attachment #2: Type: text/plain, Size: 127 bytes --]

_______________________________________________
Xen-devel mailing list
Xen-devel@lists.xen.org
https://lists.xen.org/xen-devel