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| author | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2012-09-25 22:48:24 +0200 |
|---|---|---|
| committer | Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> | 2012-09-25 23:26:28 +0200 |
| commit | c341ca45ce56143804ef5a8f4db753e554e640b4 (patch) | |
| tree | bc26c8eb1cf98658a7a8d23293f21d243c5a70c1 | |
| parent | xen-pciback: properly clean up after calling pcistub_device_find() (diff) | |
| download | linux-c341ca45ce56143804ef5a8f4db753e554e640b4.tar.xz linux-c341ca45ce56143804ef5a8f4db753e554e640b4.zip | |
xen/pciback: Restore the PCI config space after an FLR.
When we do an FLR, or D0->D3_hot we may lose the BARs as the
device has turned itself off (and on). This means the device cannot
function unless the pci_restore_state is called - which it is
when the PCI device is unbound from the Xen PCI backend driver.
For PV guests it ends up calling pci_enable_device / pci_enable_msi[x]
which does the proper steps
That however is not happening if a HVM guest is run as QEMU
deals with PCI configuration space. QEMU also requires that the
device be "parked" under the ownership of a pci-stub driver to
guarantee that the PCI device is not being used. Hence we
follow the same incantation as pci_reset_function does - by
doing an FLR, then restoring the PCI configuration space.
The result of this patch is that when you run lspci, you get
now this:
- Region 0: [virtual] Memory at fe8c0000 (32-bit, non-prefetchable) [size=128K]
- Region 1: [virtual] Memory at fe800000 (32-bit, non-prefetchable) [size=512K]
+ Region 0: Memory at fe8c0000 (32-bit, non-prefetchable) [size=128K]
+ Region 1: Memory at fe800000 (32-bit, non-prefetchable) [size=512K]
Region 2: I/O ports at c000 [size=32]
- Region 3: [virtual] Memory at fe8e0000 (32-bit, non-prefetchable) [size=16K]
+ Region 3: Memory at fe8e0000 (32-bit, non-prefetchable) [size=16K]
The [virtual] means that lspci read those entries from SysFS but when
it read them from the device it got a different value (0xfffffff).
CC: stable@vger.kernel.org #only for 3.5, 3.6
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
| -rw-r--r-- | drivers/xen/xen-pciback/pci_stub.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/xen/xen-pciback/pci_stub.c b/drivers/xen/xen-pciback/pci_stub.c index acec6faff885..e5a0c13e2ad4 100644 --- a/drivers/xen/xen-pciback/pci_stub.c +++ b/drivers/xen/xen-pciback/pci_stub.c @@ -362,6 +362,7 @@ static int __devinit pcistub_init_device(struct pci_dev *dev) else { dev_dbg(&dev->dev, "reseting (FLR, D3, etc) the device\n"); __pci_reset_function_locked(dev); + pci_restore_state(dev); } /* Now disable the device (this also ensures some private device * data is setup before we export) |