Re: [Qemu-devel] [PATCH] pci: fix requester id with PCI bridges

[Peter Xu <peterx@redhat.com>]

On Wed, May 11, 2016 at 02:40:30PM +0800, Peter Xu wrote:
> Recently I encountered issue when debugging Intel IOMMU IR codes,
> that interrupts are not working correctly with PCI bridges (reported
> by Radim). This patch fixes the problem. I assume requester ID
> should be the devfn on root PCI bus (that's how I understand it
> before, and also in guest kernel, IRTE entry SID is filled in that
> way), however I failed to find any good document to confirm
> this. Please let me know if this is correct (or I made any
> mistake).

One thing to mention is that, this patch does *not* fix the problem
if directly applied, because IR patchset introduced another patch
that also need a similar fix. In case if there is someone (Radim?)
who would like to try this patch, we need to apply this patch as
well:

---8<---

diff --git a/target-i386/kvm.c b/target-i386/kvm.c
index 80b3251..0876a1c 100644
--- a/target-i386/kvm.c
+++ b/target-i386/kvm.c
@@ -3342,7 +3342,8 @@ int kvm_arch_fixup_msi_route(struct kvm_irq_routing_entry *route,
         src.data = route->u.msi.data;

         ret = class->int_remap(iommu, &src, &dst, dev ? \
-                               pci_requester_id(dev) : X86_IOMMU_SID_INVALID);
+                               pci_requester_id_recursive(dev) : \
+                               X86_IOMMU_SID_INVALID);
         if (ret) {
             trace_kvm_x86_fixup_msi_error(route->gsi);
             return 1;

--->8---

This should be able to be applied directly onto IR v6 patchset as
well.

Thanks,

-- peterx