On 05/22/2011 03:06 PM, Blue Swirl wrote:
On Sun, May 22, 2011 at 2:36 PM, Avi Kivity<avi@xxxxxxxxxx> wrote: > On 05/22/2011 12:32 PM, Blue Swirl wrote: >> >> >> > +void memory_region_add_coalescing(MemoryRegion *mr, >> >> > + target_phys_addr_t offset, >> >> > + target_phys_addr_t size); >> >> > +/* Disable MMIO coalescing for the region. */ >> >> > +void memory_region_clear_coalescing(MemoryRegion *mr); >> >> >> >> Perhaps the interface could be more generic, like >> >> +void memory_region_set_property(MemoryRegion *mr, unsigned flags); >> >> +void memory_region_clear_property(MemoryRegion *mr, unsigned flags); >> >> >> > >> > Coalescing is a complex property, not just a boolean attribute. We >> > probably >> > will have a number of boolean attributes later, though. >> >> But what is the difference between adding coalescing to an area and >> setting the bit property 'coalescing' to an area? At least what you >> propose now is not so complex that it couldn't be handled as a single >> bit. > > Look at the API - add_coalescing() sets the coalescing property on a > subrange of the memory region, not the entire region. Right, but doesn't the same apply to any other properties, they may apply to a full range or just a subrange?
We'll know when we have more properties. I expect most will be region-wide.
> > Subregions are first-class regions. In fact all regions are subregions > except the root. Oh, I see now. Maybe the comments should describe this. Or perhaps the terms should be something like 'bus/bridge/root' and 'region' instead of 'region' and 'subregion'?
Problem is, memory_region_add_subregion() adds both sub-bridges and leaf regions.
It's quite possible that BAR 0 will be a leaf region, and BAR 1 will be a sub-bridge.
Can you suggest an alternative naming for the API?
> It's a tree of regions, each level adding an offset, clipping, and perhaps > other attributes, with the leaves providing actual memory (mmio or RAM). I thought that there are two classes of regions, like PCI device vs. a single BAR.
It's true in a way, except the mapping is not 1:1. -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
