On 10/06/2011 05:03 PM, Nishanth Aravamudan wrote:
> We have observed the following on Power systems with SR-IOV capable
> adapters:
>
> lpfc 0002:01:00.0: device not available because of BAR 7 [0x000000-0x00ffff] collisions
>
> The issue is that on Power systems, PCI BARs cannot be remapped and VF
> BARs might have values that collide. As far as I can tell, the current
> SR-IOV code cannot be supported on Power and so it seems like we could
> provide a hook for an architecture that might set CONFIG_PCI_IOV to
> disable SR-IOV support (potentially at run-time).
>
I'd rather see an off/on switch because in a short while when powerpc does
support SRIOV there maybe no users of the code you've suggested.
-----8<------
[PATCH] Add a kernel parameter that disables SRIOV
Add sriov=[0|1] as a kernel parameter to disable or enable SRIOV. This is
useful for debugging SRIOV issues vs. bare-metal issues.
Signed-off-by: Prarit Bhargava <prarit@xxxxxxxxxx>
---
Documentation/kernel-parameters.txt | 4 ++++
drivers/pci/iov.c | 30 +++++++++++++++++++++++++++++-
2 files changed, 33 insertions(+), 1 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 854ed5c..235b5c5 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -2385,6 +2385,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
spia_pedr=
spia_peddr=
+ sriov= [HW]
+ Format: [0|1]
+ Enable or disable SRIOV support in kernel.
+
stacktrace [FTRACE]
Enabled the stack tracer on boot up.
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index 42fae47..da96e3f 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -408,6 +408,19 @@ static void sriov_disable(struct pci_dev *dev)
iov->nr_virtfn = 0;
}
+static unsigned int sriov_enabled = 1;
+static int __init do_sriov_enable(char *str)
+{
+ get_option(&str, &sriov_enabled);
+ if (!sriov_enabled)
+ printk(KERN_INFO "SRIOV: Disabled\n");
+ else
+ printk(KERN_INFO "SRIOV: Enabled\n");
+
+ return 1;
+}
+__setup("sriov=", do_sriov_enable);
+
static int sriov_init(struct pci_dev *dev, int pos)
{
int i;
@@ -419,6 +432,12 @@ static int sriov_init(struct pci_dev *dev, int pos)
struct resource *res;
struct pci_dev *pdev;
+ if (!sriov_enabled) {
+ rc = -EPERM;
+ /* in theory no flags should have been set ... */
+ goto failed;
+ }
+
if (dev->pcie_type != PCI_EXP_TYPE_RC_END &&
dev->pcie_type != PCI_EXP_TYPE_ENDPOINT)
return -ENODEV;
@@ -614,7 +633,10 @@ resource_size_t pci_sriov_resource_alignment(struct pci_dev *dev, int resno)
struct resource tmp;
enum pci_bar_type type;
int reg = pci_iov_resource_bar(dev, resno, &type);
-
+
+ if (!sriov_enabled)
+ return 0;
+
if (!reg)
return 0;
@@ -667,6 +689,9 @@ int pci_enable_sriov(struct pci_dev *dev, int nr_virtfn)
{
might_sleep();
+ if (!sriov_enabled)
+ return -EPERM;
+
if (!dev->is_physfn)
return -ENODEV;
@@ -682,6 +707,9 @@ void pci_disable_sriov(struct pci_dev *dev)
{
might_sleep();
+ if (!sriov_enabled)
+ return;
+
if (!dev->is_physfn)
return;
--
1.7.1
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