* Yinghai Lu <yinghai@xxxxxxxxxx> [2012-01-27 13:05:41]:
> On Fri, Jan 27, 2012 at 11:10 AM, Vaidyanathan Srinivasan
> <svaidy@xxxxxxxxxxxxxxxxxx> wrote:
> > Hi Ram and Jesse,
> >
> > I found a trivial issue with page size alignment check on IBM POWER
> > box with 64k base page size. In sriov_init(), changing the check from
> > PAGE_SIZE (arch and config dependent) to HW_PAGE_SIZE (always 4k) was
> > required to use one of the sriov adapter as PF since the
> > resource_size() comes up as 0x8000 and PAGE_SIZE would be 0x10000 for
> > pseries boxes.
> >
> > I think resource_size() could be less than SystemPageSize, but I would
> > like your comments/ack/nack on any consequences of checking for only
> > 4k alignment here in a system with larger base page size.
> >
> > Thanks,
> > Vaidy
> >
> > ---
> >
> > pci: check for 4k resource_size alignment in sriov_init
> >
> > pci sriov_init should check for 4k page size alignment of resource_size
> > even if base page size is larger -- like 64k in powerpc.
> >
> > Signed-off-by: Vaidyanathan Srinivasan <svaidy@xxxxxxxxxxxxxxxxxx>
> >
> > diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
> > index 0321fa3..5816fa0 100644
> > --- a/drivers/pci/iov.c
> > +++ b/drivers/pci/iov.c
> > @@ -474,7 +474,7 @@ found:
> > pos + PCI_SRIOV_BAR + i * 4);
> > if (!res->flags)
> > continue;
> > - if (resource_size(res) & (PAGE_SIZE - 1)) {
> > + if (resource_size(res) & (HW_PAGE_SIZE - 1)) {
> > rc = -EIO;
> > goto failed;
> > }
> >
>
> but HW_PAGE_SIZE is only defined for powerpc.
My bad, I picked the #define used in other powerpc code.
> also there is PAGE_SHIFT around in that function.
This gets defined correctly if CONFIG_PPC_64K_PAGES=y. But the actual
problem is the need for a generic 4K #define for x86 and other archs.
> maybe you can just define another MARCO according to IOV spec?
This is a good idea. I could not find an IOV specific requirement.
The resource size has to be a multiple of 4K so that the overall
resource-size() * PCI_SRIOV_TOTAL_VF will be a multiple of 4K or more.
Let me share a patch that has a simple #define in drivers/pci/pci.h,
which is needed to get SRIOV cards started on powerpc box.
--Vaidy
---
pci: check for 4k resource_size alignment in sriov_init
pci sriov_init should check for 4k page size alignment of resource_size
even if base page size is larger like 64k in powerpc.
Signed-off-by: Vaidyanathan Srinivasan <svaidy@xxxxxxxxxxxxxxxxxx>
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 0321fa3..10adede 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -474,7 +474,7 @@ found:
pos + PCI_SRIOV_BAR + i * 4);
if (!res->flags)
continue;
- if (resource_size(res) & (PAGE_SIZE - 1)) {
+ if (resource_size(res) & (HW_PAGE_SIZE_4K - 1)) {
rc = -EIO;
goto failed;
}
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 1009a5e..68703ab 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -6,6 +6,9 @@
#define PCI_CFG_SPACE_SIZE 256
#define PCI_CFG_SPACE_EXP_SIZE 4096
+/* Constants used in the PCI core code */
+#define HW_PAGE_SIZE_4K 0x1000
+
/* Functions internal to the PCI core code */
extern int pci_uevent(struct device *dev, struct kobj_uevent_env *env);
--
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