On 2016/5/3 13:34, Tian, Kevin wrote:

quoted

From: Yongji Xie
Sent: Wednesday, April 27, 2016 8:43 PM

This patch enables mmapping MSI-X tables if hardware supports
interrupt remapping which can ensure that a given pci device
can only shoot the MSIs assigned for it.

With MSI-X table mmapped, we also need to expose the
read/write interface which will be used to access MSI-X table.

Signed-off-by: Yongji Xie <redacted>

A curious question here. Does "allow to mmap MSI-X" essentially
mean that KVM guest can directly read/write physical MSI-X
structure then?

Thanks
Kevin

Here we just allow to mmap MSI-X table in kernel. It doesn't
mean all KVM guest can directly read/write physical MSI-X
structure. This should be decided by QEMU. For PPC64
platform, we would allow to passthrough the MSI-X table
because we know guest kernel would not write physical
MSI-X structure when enabling MSI.

Thanks,
Yongji