On 2013-05-23 20:04, Peter Maydell wrote:
> On 21 May 2013 11:57, Paolo Bonzini <pbonz...@redhat.com> wrote:
>> +bool address_space_valid(AddressSpace *as, hwaddr addr, int len, bool
>> is_write)
>> +{
>> + AddressSpaceDispatch *d = as->dispatch;
>> + MemoryRegionSection *section;
>> + int l;
>> + hwaddr page;
>> +
>> + while (len > 0) {
>> + page = addr & TARGET_PAGE_MASK;
>> + l = (page + TARGET_PAGE_SIZE) - addr;
>> + if (l > len) {
>> + l = len;
>> + }
>> + section = phys_page_find(d, addr >> TARGET_PAGE_BITS);
>> + if (section->mr == &io_mem_unassigned ||
>> + (is_write && section->mr->readonly)) {
>
> It's kind of bogus that io_mem_unassigned is the only MemoryRegion
> that can be unreadable. Why is 'readonly' a MemoryRegion attribute
> and 'writeonly' not? Shouldn't we be calling the MemoryRegionOps
> accepts() callback here? What about access alignment constraints
> and access size restrictions? What if the validity of the range
> changes between the time you asked and when you actually do the
> access?
>
> The whole API is kind of unconvincing really, especially since
> the only thing we seem to use it for is some parameter checking
> in spapr_llan.c (via a huge pile of intermediate wrappers).I'll also have a use for it: replace isa_is_ioport_assigned. Jan
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