Messages in this thread | | | Date | Mon, 29 Jun 2009 17:28:41 +0300 | From | Avi Kivity <> | Subject | Re: [PATCHv2] kvm: remove in_range and switch to rwsem for iobus |
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On 06/29/2009 05:06 PM, Marcelo Tosatti wrote: > On Sun, Jun 28, 2009 at 10:34:25PM +0300, Michael S. Tsirkin wrote: > >> This changes bus accesses to use high-level kvm_io_bus_read/kvm_io_bus_write >> functions, which utilize read/write semaphore intead of mutex. in_range now >> becomes unused so it is removed from device ops in favor of read/write >> callbacks performing range checks internally. >> >> This allows aliasing (mostly for in-kernel virtio), as well as better error >> handling by making it possible to pass errors up to userspace. And it's enough >> to look at the diffstat to see that it's a better API anyway. >> > > Can you please expand a little on this? Still don't get why making > ->in_range part of ->read / ->write is a good thing. Aliasing? >
Yes, if you have several devices responding to the same port (but different values), in_range() by itself doesn't tell you much. virtio msi support will tie a different iosignalfd to every queue, and queues are notified by writing different values to one pio port.
-- error compiling committee.c: too many arguments to function
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