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Re: [Qemu-ppc] [PATCH] spapr_pci: turn IOMMU root into an I/O region
From: |
Alexander Graf |
Subject: |
Re: [Qemu-ppc] [PATCH] spapr_pci: turn IOMMU root into an I/O region |
Date: |
Wed, 27 Aug 2014 12:57:23 +0200 |
User-agent: |
Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:31.0) Gecko/20100101 Thunderbird/31.0 |
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 <address@hidden>
> ---
> 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?
Can't we instead just populate the iommu_root memory region with the MSI
subregion?
Alex