[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] Failed to access register with invalid access size alignment

  • To: Jan Beulich <JBeulich@xxxxxxxx>
  • From: "Zytaruk, Kelly" <Kelly.Zytaruk@xxxxxxx>
  • Date: Tue, 23 Sep 2014 15:16:23 +0000
  • Accept-language: en-US
  • Cc: "Xen-devel@xxxxxxxxxxxxx" <Xen-devel@xxxxxxxxxxxxx>
  • Delivery-date: Tue, 23 Sep 2014 15:16:44 +0000
  • List-id: Xen developer discussion <xen-devel.lists.xen.org>
  • Thread-index: Ac9Opoupy07MovPYRzKc1uEI6nkmAQAk16oAIgG+acA=
  • Thread-topic: [Xen-devel] Failed to access register with invalid access size alignment

Hi Jan,

Just saw this message from you, must have missed it earlier.  I paused the 
guest on the access and found the EIP address pointing to an OS port access 
function in the Windows guest.  I wasn't able to gather any stack trace 
information so I couldn't tell how it was originally called.  I don't see any 
failures on bare metal so I presume that this is either a non-required access 
or it just happens to return a result that the caller is happy with.


> -----Original Message-----
> From: Jan Beulich [mailto:JBeulich@xxxxxxxx]
> Sent: Thursday, April 03, 2014 4:41 AM
> To: Zytaruk, Kelly
> Cc: Xen-devel@xxxxxxxxxxxxx
> Subject: Re: [Xen-devel] Failed to access register with invalid access size
> alignment
> >>> On 02.04.14 at 21:28, <Kelly.Zytaruk@xxxxxxx> wrote:
> > I have seen the subject-line error message in a few posts but I
> > haven't yet seen a resolution for it yet.  Has anyone resolved this problem?
> >
> > The full error line from the log file is; [00:05.0]
> > xen_pt_pci_config_access_check: Error: Failed to access register with
> > invalid access size alignment. (addr: 0x0e, len: 4)
> >
> > Address 0x0e in PCIe config space is 2 byte aligned and can't be
> > accessed as a 4 byte read.
> And hence one would think that it should be addressed in the guest OS rather
> than Xen or qemu. But of course it depends to some degree on whether real
> hardware permits the mis-aligned accesses - we may need to relax the
> restrictions if so.
> Did you manage to find out where the bad request originates, and how it
> behaves when run on bare hardware?
> Jan

Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.