Hi Ethan,
On Wed, Sep 16, 2015 at 12:19:53PM +0900, Ethan Zhao wrote:
> After commit 4449f079722c ("PCI: Calculate maximum number of buses
> required for VFs"),the initial value of NumVFs register was left to
> non-zero after sriov_init() and no VFs was enabled in device driver.
> this changed the behaviour of kernel exported by lspci and sysfs etc.
> so this patch restore the NumVFs register to zero after the
> calculation of max_VF_buses was done and before return from
> virtfn_max_buses().
>
> Tested on stable 4.1 and passed building on stable 4.3-rc1
>
> Signed-off-by: Ethan Zhao <ethan.zhao@xxxxxxxxxx>
> Tested-by: Sriharsha Yadagudde <sriharsha.devdas@xxxxxxxxxx>
Can you test the patch below? I'm trying to avoid touching
PCI_SRIOV_NUM_VF in more than one place, and I think it's OK to set it
and test offset/stride at the end, instead of setting NUM_VF to zero,
testing offset/stride, computing max_bus, then setting NUM_VF to zero
again.
Bjorn
commit 8e20e89658f23b8d16b1e21810e9f63c8625129c
Author: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Date: Thu Oct 15 11:31:21 2015 -0500
PCI: Set SR-IOV NumVFs to zero after enumeration
The enumeration path should leave NumVFs set to zero. But after
4449f079722c ("PCI: Calculate maximum number of buses required for VFs"),
we call virtfn_max_buses() in the enumeration path, which changes NumVFs.
This NumVFs change is visible via lspci and sysfs until a driver enables
SR-IOV.
Set NumVFs to zero after virtfn_max_buses() computes the maximum number of
buses.
Fixes: 4449f079722c ("PCI: Calculate maximum number of buses required for VFs")
Based-on-patch-by: Ethan Zhao <ethan.zhao@xxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index ee0ebff..0202ab0 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -384,7 +384,7 @@ static int sriov_init(struct pci_dev *dev, int pos)
int rc;
int nres;
u32 pgsz;
- u16 ctrl, total, offset, stride;
+ u16 ctrl, total;
struct pci_sriov *iov;
struct resource *res;
struct pci_dev *pdev;
@@ -414,11 +414,6 @@ static int sriov_init(struct pci_dev *dev, int pos)
found:
pci_write_config_word(dev, pos + PCI_SRIOV_CTRL, ctrl);
- pci_write_config_word(dev, pos + PCI_SRIOV_NUM_VF, 0);
- pci_read_config_word(dev, pos + PCI_SRIOV_VF_OFFSET, &offset);
- pci_read_config_word(dev, pos + PCI_SRIOV_VF_STRIDE, &stride);
- if (!offset || (total > 1 && !stride))
- return -EIO;
pci_read_config_dword(dev, pos + PCI_SRIOV_SUP_PGSIZE, &pgsz);
i = PAGE_SHIFT > 12 ? PAGE_SHIFT - 12 : 0;
@@ -456,8 +451,6 @@ found:
iov->nres = nres;
iov->ctrl = ctrl;
iov->total_VFs = total;
- iov->offset = offset;
- iov->stride = stride;
iov->pgsz = pgsz;
iov->self = dev;
pci_read_config_dword(dev, pos + PCI_SRIOV_CAP, &iov->cap);
@@ -475,6 +468,11 @@ found:
dev->sriov = iov;
dev->is_physfn = 1;
iov->max_VF_buses = virtfn_max_buses(dev);
+ pci_iov_set_numvfs(dev, 0);
+ if (!iov->offset || (total > 1 && !iov->stride)) {
+ rc = -EIO;
+ goto failed;
+ }
return 0;
@@ -484,6 +482,7 @@ failed:
res->flags = 0;
}
+ dev->sriov = NULL;
kfree(iov);
return rc;
}
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