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Re: [Qemu-devel] [PATCH 1/2] memory: Provide separate handling of unassi
From: |
Andreas Färber |
Subject: |
Re: [Qemu-devel] [PATCH 1/2] memory: Provide separate handling of unassigned io ports accesses |
Date: |
Fri, 09 Aug 2013 18:49:37 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130620 Thunderbird/17.0.7 |
Am 09.08.2013 09:41, schrieb Paolo Bonzini:
> Il 08/08/2013 17:43, Jan Kiszka ha scritto:
>> On 2013-08-08 17:33, Peter Maydell wrote:
>>> On 3 August 2013 09:31, Jan Kiszka <address@hidden> wrote:
>>>> --- a/ioport.c
>>>> +++ b/ioport.c
>>>> @@ -44,6 +44,22 @@ typedef struct MemoryRegionPortioList {
>>>> MemoryRegionPortio ports[];
>>>> } MemoryRegionPortioList;
>>>>
>>>> +static uint64_t unassigned_io_read(void *opaque, hwaddr addr, unsigned
>>>> size)
>>>> +{
>>>> + return -1UL;
>>>
>>> This should probably be "-1ULL", otherwise we'll return
>>> different values on 32 bit and 64 bit hosts. (Actually
>>> managing a 64 bit read of the i/o space is pretty
>>> unlikely, though possibly alpha memory-mapped via the
>>> PCI space might let you do it.)
>>
>> No problem with changing this - but wouldn't 64-bit i/o accesses be a
>> bug? It's not allowed according to PCI, no device can handle it
>> (officially), so no arch should forward such requests from mmio, rather
>> break them up first.
>
> Yes, the impl.max_access_size should never be 8. Though 1ULL would be
> clearer perhaps.
Let's CC rth.
Andreas
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Re: [Qemu-devel] [PATCH 1/2] memory: Provide separate handling of unassigned io ports accesses, Peter Maydell, 2013/08/08