|
From: | Anthony Liguori |
Subject: | Re: [Qemu-devel] [PATCH 1/2] Type-safe ioport callbacks |
Date: | Tue, 26 Oct 2010 12:27:01 -0500 |
User-agent: | Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.12) Gecko/20100915 Lightning/1.0b1 Thunderbird/3.0.8 |
On 10/26/2010 12:18 PM, Avi Kivity wrote:
On 10/26/2010 05:09 PM, Blue Swirl wrote:On Tue, Oct 26, 2010 at 8:05 AM, Avi Kivity<address@hidden> wrote: > On 10/25/2010 08:38 PM, Blue Swirl wrote: >> >> >>> > I don't really see why we need registration; cpu_register_io() takes >> > function pointers, a size, and an opaque, and gives an integer handle>> > in>> > return. With the IOPort object approach, you set up the IOPort with >> > function pointers, size is implied, and the opaque is derived using>> > container_of(); the handle is simply the address of the object. >> >> With the handle, we can separate setting up the structures at device >> level, and mapping the object using only the handle at bus or other >> higher level. Can this be done with the object approach? > > I believe so. The handle is simply an indirect pointer, no? Yes, but then the object should also contain size information. That should not be needed for mapping at higher level.Sorry, I don't follow your meaning.When I said "size is implied" I meant that the IOPort object has a separate function pointer for sizes 1, 2, and 4, so it ioport_register() doesn't need a size parameter. But I don't see how that relates to your comment.
Yeah, I don't think it makes sense to combine "this is how to dispatch I/O" with "this is a region of I/O address space".
I think an IORegion should contain an IOPort structure though. I think the name needs rethinking.
Maybe: struct PortIOHandler; struct MemoryIOHandler; And it would be good to add a memory callback to this series too. Regards, Anthony Liguori
>> The purpose of that patch series was to perform the separation for PCI>> BARs. I wasn't so happy with the series, so I never pushed. >> In fact I think an IOPort is even more suitable; if we need additional> attributes we can use a derived object: > > struct PCIIOPort { > IOPort ioport; > /* additional fields */ > }; One issue with my series was that it would be great if the devices just had some BAR structures (used by PCI layer to map the devices) inside PCI/qdev structures, but I invented that too late. Maybe this can be addressed in your design?It looks to be orthogonal. It would be great to have a BAR object; that object can then use your API, my API, or the existing API.
[Prev in Thread] | Current Thread | [Next in Thread] |