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authorBjorn Helgaas <bhelgaas@google.com>2016-11-29 01:43:06 +0300
committerBjorn Helgaas <bhelgaas@google.com>2016-11-30 03:05:09 +0300
commit546ba9f8f22f71b0202b6ba8967be5cc6dae4e21 (patch)
tree34c3b82c568c81e50a723aed5d2ec05684422bcb /drivers/pci/iov.c
parent6ffa2489c51da77564a0881a73765ea2169f955d (diff)
downloadlinux-546ba9f8f22f71b0202b6ba8967be5cc6dae4e21.tar.xz
PCI: Don't update VF BARs while VF memory space is enabled
If we update a VF BAR while it's enabled, there are two potential problems: 1) Any driver that's using the VF has a cached BAR value that is stale after the update, and 2) We can't update 64-bit BARs atomically, so the intermediate state (new lower dword with old upper dword) may conflict with another device, and an access by a driver unrelated to the VF may cause a bus error. Warn about attempts to update VF BARs while they are enabled. This is a programming error, so use dev_WARN() to get a backtrace. Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Diffstat (limited to 'drivers/pci/iov.c')
-rw-r--r--drivers/pci/iov.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index aa499543473f..2480b3879182 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -584,6 +584,7 @@ void pci_iov_update_resource(struct pci_dev *dev, int resno)
struct resource *res = dev->resource + resno;
int vf_bar = resno - PCI_IOV_RESOURCES;
struct pci_bus_region region;
+ u16 cmd;
u32 new;
int reg;
@@ -595,6 +596,13 @@ void pci_iov_update_resource(struct pci_dev *dev, int resno)
if (!iov)
return;
+ pci_read_config_word(dev, iov->pos + PCI_SRIOV_CTRL, &cmd);
+ if ((cmd & PCI_SRIOV_CTRL_VFE) && (cmd & PCI_SRIOV_CTRL_MSE)) {
+ dev_WARN(&dev->dev, "can't update enabled VF BAR%d %pR\n",
+ vf_bar, res);
+ return;
+ }
+
/*
* Ignore unimplemented BARs, unused resource slots for 64-bit
* BARs, and non-movable resources, e.g., those described via