Re: [Qemu-devel] [PATCH RFC 0/3] pci: complete master abort protocol

[Marcel Apfelbaum <marcel.a@redhat.com>]

On Mon, 2013-09-02 at 15:30 +0100, Peter Maydell wrote:
> On 2 September 2013 15:13, Marcel Apfelbaum <marcel.a@redhat.com> wrote:
> > Note: The series is incomplete, for review only
> >
> > PCI spec requires that a transaction that has not been claimed
> > by any PCI bus devices will be terminated by the initiator
> > with "master abort". For read transactions -1(FFFFFFFF) is returned and
> > writes are silently dropped. (already implemented in quemu)
> 
> ...but only erroneously and by breaking a pile of other boards.
:(
Let's find a way to fix it... Please suggest
> 
> > Note:
> > For the moment the code assumes that all the reads/writes on
> > pci address space are done by the cpu.
> 
> This is a bogus assumption in the presence of bus mastering
> PCI devices, which aren't exactly uncommon.
As I said, the series is work in progress. Tracking down
the real initiator of a read/write to the pci address space
seems to be difficult. I am looking into it and opened
to suggestions.
Marcel
 
> 
> -- PMM
>