[PATCH 0/10][v4] Enable MSI for KVM assigned device kernel part

[Sheng Yang <sheng@linux.intel.com>]

Hi, Avi

Here is v4 for MSI on assigned devices.

v3->v4

1. After discuss with Xiantao, we decide to delay MSI enabling for IA64, so
I've temporary wrapped MSI critical part with #ifdef CONFIG_X86. These are
expected to be removed soon before 2.6.28 release.

2. Fix two wrong usage of macro.

The userspace patch would follow soon.

Another significant change from v2 is, this patchset not only enable MSI for
MSI capable guests(patch 1-9), also enable MSI by default for all guests(patch
10). I implement a MSI to INTx convert in patch 10, which is a little tricky,
but don't have much trouble in theory (the only thing we are worried is about
device would use different "register" to indicate interrupt reason for INTx
mode and MSI mode, but didn't find this kind of device yet). We may need a
black/white list for device which can work in this way. This also avoid host
sharing interrupt trouble, and provide better scalability for the guest which
lacks of MSI capablility. The patch also provide non-sharing host INTx support
for legacy devices. So we suggest this can be a default solution for current
KVM device assignment support.

Comments are welcome!

--
regards
Yang, Sheng