Re: [Qemu-devel] [RFC v2 01/20] Hierarchical memory region API

[Jan Kiszka]

On 2011-06-28 12:03, Michael S. Tsirkin wrote:
>> +struct MemoryRegion {
>> +    /* All fields are private - violators will be prosecuted */
>> +    const MemoryRegionOps *ops;
>> +    MemoryRegion *parent;
>> +    uint64_t size;
>> +    target_phys_addr_t addr;
>> +    target_phys_addr_t offset;
>> +    ram_addr_t ram_addr;
>> +    bool has_ram_addr;
>> +    MemoryRegion *alias;
>> +    target_phys_addr_t alias_offset;
>> +    unsigned priority;
>> +    bool may_overlap;
>> +    QTAILQ_HEAD(subregions, MemoryRegion) subregions;
>> +    QTAILQ_ENTRY(MemoryRegion) subregions_link;
>> +    QTAILQ_HEAD(coalesced_ranges, CoalescedMemoryRange) coalesced;
>> +    const char *name;
> 
> I'm never completely sure whether these should be target addresses
> or bus addresses or just uint64_t.
> With pci on a 32 bit system you can stick a 64 bit address
> in a BAR and the result will be that it is never accessed
> from the CPU.
> 

Memory regions are not bound to any current or future PCI
specifications. Any fixed bit width would be wrong here, ie. size should
rather be target_phys_addr_t.

Jan

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