[Xen-devel] [PATCH]Add MSI support to PV_dom0

["Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx>]

Jeremy, attached is basic MSI support to PV_dom0.  Please have a look on it.

Thanks
Yunhong Jiang

The pci_wrapper.patch add some hook to pci_bus_type, so that Xen will be 
notified when a PCI device is added to system.
 Makefile   |    2 -
 pci_wrap.c |   90 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 91 insertions(+), 1 deletion(-)

The enable_msi.patch add the MSI support to dom0, basically it just allocate 
irq from Xen irq name space.

 arch/x86/include/asm/xen/pci.h  |   17 +++++++
 arch/x86/kernel/apic/io_apic.c  |   22 +++++++--
 arch/x86/xen/apic.c             |    1
 drivers/xen/events.c            |   91 +++++++++++++++++++++++++++++++++++++++-
 include/xen/interface/physdev.h |   59 +++++++++++++++++++++++++
 5 files changed, 182 insertions(+), 8 deletions(-)

The reenable_msi.patch just remove original function that disable MSI in xen 
environment.

 arch/x86/xen/apic.c |    2 --
 drivers/pci/pci.h   |    2 ++
 include/linux/pci.h |    6 ------
 3 files changed, 2 insertions(+), 8 deletions(-)


Notice:
a) Currently the PCI save/restore is broken. The reason is because 
pci_restore_msi_state() in "drivers/pci/msi.c" will try to restore the MSI 
config depends on device's msi msg information (i.e. content of msi_desc->msg). 
However, that information is wrong in Xen environment because Xen HV owns MSI. 
I'm still trying to find a method to achieve the save/restore without touch the 
common msi.c code, any suggestion is welcome.
b) I notice pci frontend is in a branch. But to support pci frontend without 
touch common PCI function is difficult, I'm still considering it.
c) I'm not sure if xen's irq space should be same as pirq. Basically I think 
irq is dom0 internal structure, while PIRQ is interface between Xen HV/dom0. 
But seems current implementation think these two items are same. I didn't try 
to change it, but that may need improvement.

Attachment: enable_msi.patch
Description: enable_msi.patch

Attachment: pci_wrapper.patch
Description: pci_wrapper.patch

Attachment: reenable_msi.patch
Description: reenable_msi.patch

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