On Thu, Aug 27, 2015 at 12:27:53PM -0500, Bjorn Helgaas wrote:
>[+cc Alex]
>
>On Wed, Jul 29, 2015 at 04:52:58PM +0800, Wei Yang wrote:
>> VF BARs are RO zero, so updating VF BARs will not take any effect.
>> See the SR-IOV spec r1.1, sec 3.4.1.11.
>>
>> Also this patch adds a warning in pci_update_resource() in case someone
>> really tries to update it.
>>
>> Signed-off-by: Wei Yang <weiyang@xxxxxxxxxxxxxxxxxx>
>
>I applied this with some whitespace and changelog fixes to
>pci-4.4/virtualization for v4.4, thanks! I will rebase this branch
>v4.3-rc1 or later.
>
>You mentioned the justification (avoids "error updating" messages) on the
>mailing list. It helps me out if you include that in the changelog, but I
>added it for you.
Bjorn,
You are always nice to us :-)
Have a good weekend.
>
>Bjorn
>
>commit fa47e4466c567b43bcf8e152a4425277b6d033d9
>Author: Wei Yang <weiyang@xxxxxxxxxxxxxxxxxx>
>Date: Wed Jul 29 16:52:58 2015 +0800
>
> PCI: Don't try to restore VF BARs
>
> VF BARs are read-only zero, so updating VF BARs will not have any effect.
> See the SR-IOV spec r1.1, sec 3.4.1.11.
>
> Don't update VF BARs in pci_restore_bars().
>
> This avoids spurious "BAR %d: error updating" messages that we see when
> doing vfio pass-through after 6eb7018705de ("vfio-pci: Move idle devices to
> D3hot power state").
>
> [bhelgaas: changelog, fix whitespace]
> Signed-off-by: Wei Yang <weiyang@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
>
>diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
>index 0008c95..1a682f8 100644
>--- a/drivers/pci/pci.c
>+++ b/drivers/pci/pci.c
>@@ -473,7 +473,7 @@ int pci_wait_for_pending(struct pci_dev *dev, int pos, u16 mask)
> }
>
> /**
>- * pci_restore_bars - restore a devices BAR values (e.g. after wake-up)
>+ * pci_restore_bars - restore a device's BAR values (e.g. after wake-up)
> * @dev: PCI device to have its BARs restored
> *
> * Restore the BAR values for a given device, so as to make it
>@@ -483,6 +483,10 @@ static void pci_restore_bars(struct pci_dev *dev)
> {
> int i;
>
>+ /* Per SR-IOV spec 3.4.1.11, VF BARs are RO zero */
>+ if (dev->is_virtfn)
>+ return;
>+
> for (i = 0; i < PCI_BRIDGE_RESOURCES; i++)
> pci_update_resource(dev, i);
> }
>diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
>index 232f925..152de5c 100644
>--- a/drivers/pci/setup-res.c
>+++ b/drivers/pci/setup-res.c
>@@ -36,6 +36,11 @@ void pci_update_resource(struct pci_dev *dev, int resno)
> enum pci_bar_type type;
> struct resource *res = dev->resource + resno;
>
>+ if (dev->is_virtfn) {
>+ dev_warn(&dev->dev, "can't update VF BAR%d\n", resno);
>+ return;
>+ }
>+
> /*
> * Ignore resources for unimplemented BARs and unused resource slots
> * for 64 bit BARs.
--
Richard Yang
Help you, Help me
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