I'm trying to find a proper way to indicate
the capability of interrupt remapping on PPC64
because we need this to determine whether it is
safe to mmap MSI-X table in VFIO driver.
There is a existing flag for this in the IOMMU
space:
enum iommu_cap {
IOMMU_CAP_CACHE_COHERENCY,
---> IOMMU_CAP_INTR_REMAP,
IOMMU_CAP_NOEXEC,
};
But it seems to be not a good idea to use
bus_set_iommu() to add this flag on PPC64 which
never set/use iommu_ops.
Eric also posted a patchset [1] to abstract
this capability on MSI controller side for ARM.
But I found we also never use msi_domain_info
on PPC64. We have to rework the MSI code on
PPC64 to support msi_domain_ops if we want to
use msi_domain_info.
Then I noticed that interrupt remapping is
abstracted on PCI host bridge side on PPC64.
So I'm thinking whether we could add a new
bit to pci_bus_flags to indicate this
capability, like this patch does.
Compared with IOMMU_CAP_INTR_REMAP, this
flag is more common. Any arch can set/use this
easily. And it can provide a better granularity
(pci_bus_type -> pci_bus).
[1] http://www.spinics.net/lists/kvm/msg130262.html
Signed-off-by: Yongji Xie <xyjxie@xxxxxxxxxxxxxxxxxx>
---
arch/powerpc/platforms/powernv/pci-ioda.c | 8 ++++++++
include/linux/pci.h | 1 +
2 files changed, 9 insertions(+)
diff --git a/arch/powerpc/platforms/powernv/pci-ioda.c b/arch/powerpc/platforms/powernv/pci-ioda.c
index f90dc04..9557638 100644
--- a/arch/powerpc/platforms/powernv/pci-ioda.c
+++ b/arch/powerpc/platforms/powernv/pci-ioda.c
@@ -3080,6 +3080,12 @@ static void pnv_pci_ioda_fixup(void)
pnv_npu_ioda_fixup();
}
+int pnv_pci_ioda_root_bridge_prepare(struct pci_host_bridge *bridge)
+{
+ bridge->bus->bus_flags |= PCI_BUS_FLAGS_MSI_REMAP;
+ return 0;
+}
+
/*
* Returns the alignment for I/O or memory windows for P2P
* bridges. That actually depends on how PEs are segmented.
@@ -3364,6 +3370,8 @@ static void __init pnv_pci_init_ioda_phb(struct device_node *np,
*/
ppc_md.pcibios_fixup = pnv_pci_ioda_fixup;
+ ppc_md.pcibios_root_bridge_prepare = pnv_pci_ioda_root_bridge_prepare;
+
if (phb->type == PNV_PHB_NPU)
hose->controller_ops = pnv_npu_ioda_controller_ops;
else
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 27df4a6..741dcaf 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -193,6 +193,7 @@ typedef unsigned short __bitwise pci_bus_flags_t;
enum pci_bus_flags {
PCI_BUS_FLAGS_NO_MSI = (__force pci_bus_flags_t) 1,
PCI_BUS_FLAGS_NO_MMRBC = (__force pci_bus_flags_t) 2,
+ PCI_BUS_FLAGS_MSI_REMAP = (__force pci_bus_flags_t) 3,
};
/* These values come from the PCI Express Spec */
--
1.7.9.5
--
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