Re: [PATCH 0/4 v12] MSI-X MMIO support for KVM

["Michael S. Tsirkin" <mst@redhat.com>]

On Wed, Mar 02, 2011 at 03:26:53PM +0800, Sheng Yang wrote:
> Change from v10:
> 1. Update according to the comments of Michael.
> 2. Use mmio_needed to exit to userspace according to Marcelo's comments.

PCI-wise, I don't see anything to complain about.
So ack the PCI bits.
You guys decide on the rest.

Several things I suggested previously that are not
related to the PCI point of view:

1. In msix_table_mmio_write, we fill in ext_data even if
   we are not going to exit to userspace in the end.
   It seems a trivial optimization to only do it if we exit.
2. Instead of filling in ext_data, and then copying to vcpu,
   we could fill the data in vcpu directly.
3. MSIX is not an error. So returning -ENOTSYNC to signal
   it is ugly. It would be cleaner to return negative
   value on error, and positive exit code to trigger exit.
4. Patch 4/4 adds whitespace errors that git complains about.

With changes 2 and 3, arch/x86/kvm/x86.c would not
need to know about msix at all.

As I said these are all suggestions unrelated to pci,
and I don't know what Avi/Marcelo think about 1 and 2.
3 and 4 are easy to fix though.


> Sheng Yang (4):
>   KVM: Move struct kvm_io_device to kvm_host.h
>   KVM: Add kvm_io_ext_data to IO handler
>   KVM: Emulate MSI-X table in kernel
>   KVM: Add documents for MSI-X MMIO API
> 
>  Documentation/kvm/api.txt |   58 +++++++++
>  arch/x86/kvm/Makefile     |    2 +-
>  arch/x86/kvm/i8254.c      |    6 +-
>  arch/x86/kvm/i8259.c      |    3 +-
>  arch/x86/kvm/lapic.c      |    3 +-
>  arch/x86/kvm/x86.c        |   42 +++++--
>  include/linux/kvm.h       |   28 +++++
>  include/linux/kvm_host.h  |   64 ++++++++++-
>  virt/kvm/assigned-dev.c   |   41 +++++++
>  virt/kvm/coalesced_mmio.c |    3 +-
>  virt/kvm/eventfd.c        |    2 +-
>  virt/kvm/ioapic.c         |    2 +-
>  virt/kvm/iodev.h          |   31 +----
>  virt/kvm/kvm_main.c       |   40 ++++++-
>  virt/kvm/msix_mmio.c      |  291 +++++++++++++++++++++++++++++++++++++++++++++
>  virt/kvm/msix_mmio.h      |   26 ++++
>  16 files changed, 591 insertions(+), 51 deletions(-)
>  create mode 100644 virt/kvm/msix_mmio.c
>  create mode 100644 virt/kvm/msix_mmio.h