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Re: [Qemu-devel] [PATCH v1 8/8] usb/ehci: Put RAM in undefined MMIO regi
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] [PATCH v1 8/8] usb/ehci: Put RAM in undefined MMIO regions |
Date: |
Thu, 25 Oct 2012 14:28:54 +0100 |
On 25 October 2012 14:21, Avi Kivity <address@hidden> wrote:
> On 10/25/2012 03:12 PM, Peter Maydell wrote:
>> (2) what should the memory system do for accesses where there is
>> no memory region? This is really system specific as it depends
>> what the bus fabric does. For ARM the usual thing would be to
>> generate a decode error response which will result in the guest
>> CPU taking a data abort or prefetch abort. I don't think our
>> memory system currently has any way of saying "for this access
>> generate an exception"...
>>
>
> You could easily have the top-level container have ->ops that generate
> an exception.
Ah, yes, there's an 'accepts' callback. (That's kind of awkward
as an API because it means your decode logic gets spread between
read, write and accept: there are some devices where it would be
nice to have the 'default:' case of the address switch say "unknown
offset, raise decode error". If the read callback took a uint64_t*
rather than returning the read data, we could make both read and
write return a success/decode-error type of status result.)
-- PMM
- [Qemu-devel] [PATCH v1 4/8] usb/ehci: Add usb-ehci-sysbus, (continued)
- [Qemu-devel] [PATCH v1 4/8] usb/ehci: Add usb-ehci-sysbus, Peter Crosthwaite, 2012/10/25
- [Qemu-devel] [PATCH v1 8/8] usb/ehci: Put RAM in undefined MMIO regions, Peter Crosthwaite, 2012/10/25
- Re: [Qemu-devel] [PATCH v1 8/8] usb/ehci: Put RAM in undefined MMIO regions, Gerd Hoffmann, 2012/10/25
- Re: [Qemu-devel] [PATCH v1 8/8] usb/ehci: Put RAM in undefined MMIO regions, Peter Crosthwaite, 2012/10/25
- Re: [Qemu-devel] [PATCH v1 8/8] usb/ehci: Put RAM in undefined MMIO regions, Peter Maydell, 2012/10/25
- Re: [Qemu-devel] [PATCH v1 8/8] usb/ehci: Put RAM in undefined MMIO regions, Avi Kivity, 2012/10/25
- Re: [Qemu-devel] [PATCH v1 8/8] usb/ehci: Put RAM in undefined MMIO regions,
Peter Maydell <=
- Re: [Qemu-devel] [PATCH v1 8/8] usb/ehci: Put RAM in undefined MMIO regions, Avi Kivity, 2012/10/25
- Re: [Qemu-devel] [PATCH v1 8/8] usb/ehci: Put RAM in undefined MMIO regions, Peter Maydell, 2012/10/25
- Re: [Qemu-devel] [PATCH v1 8/8] usb/ehci: Put RAM in undefined MMIO regions, Avi Kivity, 2012/10/25
- Re: [Qemu-devel] [PATCH v1 8/8] usb/ehci: Put RAM in undefined MMIO regions, Peter Crosthwaite, 2012/10/25
- Re: [Qemu-devel] [PATCH v1 8/8] usb/ehci: Put RAM in undefined MMIO regions, Peter Maydell, 2012/10/25
- Re: [Qemu-devel] [PATCH v1 8/8] usb/ehci: Put RAM in undefined MMIO regions, Avi Kivity, 2012/10/25
[Qemu-devel] [PATCH v1 7/8] usb/ehci: Debug mode compile fixes, Peter Crosthwaite, 2012/10/25
[Qemu-devel] [PATCH v1 6/8] usb/ehci: Guard definition of EHCI_DEBUG, Peter Crosthwaite, 2012/10/25
[Qemu-devel] [PATCH v1 5/8] xilinx_zynq: add USB controllers, Peter Crosthwaite, 2012/10/25