On 9 September 2013 17:00, Michael S. Tsirkin <m...@redhat.com> wrote: > On Mon, Sep 09, 2013 at 03:58:36PM +0100, Peter Maydell wrote: >> On 9 September 2013 15:51, Marcel Apfelbaum <marce...@redhat.com> wrote: >> > On Mon, 2013-09-09 at 15:21 +0100, Peter Maydell wrote: >> >> No, it's perfectly possible for a bus master transaction >> >> to abort. The PC's host controller happens to be set up so >> >> that bus master DMA covers the whole of the PCI memory space >> >> and so it's probably not possible to get an abort on that >> >> platform, but this isn't necessarily the case. For instance >> >> the versatilePB's PCI controller only responds to accesses >> >> within its programmed MMIO BAR ranges, so if the device >> >> or the controller have been misconfigured you can get an >> >> abort when the device tries to do DMA. (This usually causes >> >> the device to decide something has gone seriously wrong. >> > Thanks, I am not familiar with versatilePB, I may be able >> > to code it, I don't know how to test it >> >> Don't worry about testing versatilePB particularly; you >> just need to make sure your code can cope with master >> aborts by device initiated transactions. > > Device in question being PCI host right?
No, in the scenario described above the device doing the write and getting the abort is the EHCI USB controller. -- PMM
