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Re: [Qemu-devel] [PATCH v2 11/11] usb/ehci: Put RAM in undefined MMIO re
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] [PATCH v2 11/11] usb/ehci: Put RAM in undefined MMIO regions |
Date: |
Fri, 26 Oct 2012 13:39:34 +0100 |
On 26 October 2012 13:36, Gerd Hoffmann <address@hidden> wrote:
> On 10/26/12 07:47, Peter Crosthwaite wrote:
>> Just put RAM regions in the unimplemented spaces in the MMIO region. These
>> regions have undefined behaviour, but this at least stops QEMU from
>> segfaulting
>> when the guest bangs on these registers (and sucessfully fakes reading and
>> writing the registers with no side effects).
>
> Make that an io region, have the read() handler return 0xff, write
> handler do nothing except maybe logging/tracing the access for debugging
> purposes. That is more correct for unassigned mmio space than backing
> by memory. Adding memory also breaks migration btw.
>
> I somehow still think this should be handled one layer up (i.e. the
> parent region) which could do the approximate arch-specific action.
If it's really in the memory space of the device itself then our device
model should be handling it.
-- PMM
- Re: [Qemu-devel] [PATCH v2 05/11] usb/ehci: seperate out PCIisms, (continued)
[Qemu-devel] [PATCH v2 06/11] usb/ehci: Add Sysbus Infrastructure, Peter Crosthwaite, 2012/10/26
[Qemu-devel] [PATCH v2 07/11] usb/ehci: Add Xilinx ps7 USB controller, Peter Crosthwaite, 2012/10/26
[Qemu-devel] [PATCH v2 09/11] usb/ehci: Guard definition of EHCI_DEBUG, Peter Crosthwaite, 2012/10/26
[Qemu-devel] [PATCH v2 11/11] usb/ehci: Put RAM in undefined MMIO regions, Peter Crosthwaite, 2012/10/26
[Qemu-devel] [PATCH v2 10/11] usb/ehci: Debug mode compile fixes, Peter Crosthwaite, 2012/10/26
[Qemu-devel] [PATCH v2 08/11] xilinx_zynq: add USB controllers, Peter Crosthwaite, 2012/10/26