[Qemu-devel] About Disk I/O and DMA emulation in qemu-kvm

[Le Tan]

Hi, I am now diving into the disk I/O in kvm. But I find that things
are a little messy about this and I am stuck here. I configure the
virtual machine with a virtual IDE disk and DMA support. I need to get
every disk I/O issued by the virtual machine. I know that there are
struct IDEDevie, struct IDEBus, struct IDEDMA etc. in the qemu. But I
just can't figure out the logical relationships among these things and
the general code path of the disk I/O or DMA.
So, how is IDE disk or DMA emulated in qemu-kvm? What is the gerneral
path or logic when the vcpu issues a disk I/O? Can anyone give me the
complete gerneral description or idea of the disk I/O in qemu-kvm? Or
which part of the code should be taken in consideration? Maybe there
are some useful materials?
Maybe the question is a little complicated. Any help is appreciated! Thanks!

--Le Tan