On 08/27/2014 08:57 PM, Alexander Graf wrote: > > > On 26.08.14 18:40, Greg Kurz wrote: >> On sPAPR, virtio devices are connected to the PCI bus and use MSI-X. >> Commit cc943c36faa192cd4b32af8fe5edb31894017d35 has modified MSI-X >> so that writes are made using the bus master address space. >> Unfortunately, the MSI-X notification hits unassigned_mem_write and >> never reaches the guest... The most visible effect is that all >> virtio devices are non-fonctionnal on sPAPR. :( >> >> This patch plugs the MSI memory ops to the root IOMMU region, and >> virtio devices work again. I am not sure this is the right way to >> fix: please comment and enlight ! >> >> Signed-off-by: Greg Kurz <gk...@linux.vnet.ibm.com> >> --- >> hw/ppc/spapr_pci.c | 5 +++-- >> 1 file changed, 3 insertions(+), 2 deletions(-) >> >> diff --git a/hw/ppc/spapr_pci.c b/hw/ppc/spapr_pci.c >> index 9ed39a9..b638a3c 100644 >> --- a/hw/ppc/spapr_pci.c >> +++ b/hw/ppc/spapr_pci.c >> @@ -599,8 +599,9 @@ static void spapr_phb_realize(DeviceState *dev, Error >> **errp) >> */ >> sprintf(namebuf, "%s.iommu-root", sphb->dtbusname); >> >> - memory_region_init(&sphb->iommu_root, OBJECT(sphb), >> - namebuf, UINT64_MAX); >> + memory_region_init_io(&sphb->iommu_root, OBJECT(sphb), >> + &spapr_msi_ops, spapr, >> + namebuf, UINT64_MAX); > > This will turn all unallocated accesses in iommu_root into calls to > spapr_msi_ops, no?
It should not, the window is small. > Can't we instead just populate the iommu_root memory region with the MSI > subregion? Makes sense to me. Having one global MSI window sounds like my bug, I just did not any good reason for having it per PHB :) -- Alexey
