Re: [Qemu-devel] [PATCH v11 04/28] x86-iommu: q35: generalize find_add_as()

[Peter Xu <peterx@redhat.com>]

On Mon, Jul 11, 2016 at 12:11:10PM +0300, David Kiarie wrote:
> On Mon, Jul 11, 2016 at 10:41 AM, Peter Xu <peterx@redhat.com> wrote:
> > On Mon, Jul 11, 2016 at 10:16:11AM +0300, David Kiarie wrote:
> >> On Mon, Jul 11, 2016 at 9:49 AM, Peter Xu <peterx@redhat.com> wrote:
> >> > On Mon, Jul 11, 2016 at 08:46:12AM +0300, David Kiarie wrote:
> >> >> On Mon, Jul 11, 2016 at 8:32 AM, Peter Xu <peterx@redhat.com> wrote:
> >> >> > On Sat, Jul 09, 2016 at 10:14:48AM +0200, Jan Kiszka wrote:
> >> >> >> On 2016-07-05 10:19, Peter Xu wrote:
> >> >> >> > Remove VT-d calls in common q35 codes. Instead, we provide a general
> >> >> >> > find_add_as() for x86-iommu type.
> >> >> >> >
> >> >> >> > Signed-off-by: Peter Xu <peterx@redhat.com>
> >> >> >> > ---
> >> >> >> >  hw/i386/intel_iommu.c         | 15 ++++++++-------
> >> >> >> >  include/hw/i386/intel_iommu.h |  5 -----
> >> >> >> >  include/hw/i386/x86-iommu.h   |  3 +++
> >> >> >> >  3 files changed, 11 insertions(+), 12 deletions(-)
> >> >> >>
> >> >> >> You claim to remove something from "common q35 code", but I don't see
> >> >> >> changes to it. Instead, the patch introduces a method that seems to
> >> >> >> remain unused outside the implementing class (I just grep'ed your tree).
> >> >> >> Anything missing?
> >> >> >
> >> >> > Right. The commit message lost its point after I did the rebase to
> >> >> > Marcel's "-device intel_iommu" patches... Thanks for pointing it out.
> >> >>
> >> >> I think Jan is mainly asking about where the method 'find_add_as()' is
> >> >> being used. Unless I'm too missing something It doesn't seem to be
> >> >> used anywhere outside the implementing class.
> >>
> >> Hi
> >> >
> >> > This patch can be dropped. I was just not sure whether it's the
> >> > correct time to do that. Anyway, we may still need one more patch to
> >> > cleanup this in the future, as I have mentioned in the previous email.
> >>
> >> I think there is a misunderstanding here.
> >>
> >> We (me and Jan) are basically asking did you plan to use "find_add_as"
> >> somewhere and may be missed it ? Why does x86-iommu class need
> >> "find_add_as" ?
> >> The reason is I'm not able to receive IOAPIC
> >> interrupts with AMD IOMMU basing my work on your code. We thought
> >> you'd clarify on where "find_add_as" is used or how you plan to use
> >> it.
> >
> > As mentioned in previous email, before Marcel's patches,
> > vtd_host_dma_iommu() was named q35_host_dma_iommu().
> 
> Okay, that solves it - _before_ the adoption of '-device iommu' so
> you're right, this is not needed anymore.

Right. Actually we should still keep several lines in this patch:

diff --git a/include/hw/i386/intel_iommu.h b/include/hw/i386/intel_iommu.h
index 0794309..e36b896 100644
--- a/include/hw/i386/intel_iommu.h
+++ b/include/hw/i386/intel_iommu.h
@@ -125,9 +125,4 @@ struct IntelIOMMUState {
     VTDBus *vtd_as_by_bus_num[VTD_PCI_BUS_MAX]; /* VTDBus objects indexed by bus number */
 };

-/* Find the VTD Address space associated with the given bus pointer,
- * create a new one if none exists
- */
-VTDAddressSpace *vtd_find_add_as(IntelIOMMUState *s, PCIBus *bus, int devfn);
-
 #endif

Since vtd_find_add_as() is now no longer needed to be exported.
However I plan to do this in standalone patch after this series, as
it's not related to current patch any more.

Thanks,

-- peterx