Re: [PATCH net-26 4/5] cxgb4vf: Quiesce Virtual Interfaces on shutdown ...

When a Virtual Machine is rebooted, KVM currently fails to issue a Function
Level Reset against any "Attached PCI Devices" (AKA "PCI Passthrough").  In
addition to leaving the attached device in a random state in the next booted
kernel (which sort of violates the entire idea of a reboot reseting hardware
state), this leaves our peer thinking that the link is still up.  (Note that
a bug has been filed with the KVM folks, #25332, but there's been no
response on that as of yet.)  So, we add a "->shutdown()" method for the
Virtual Function PCI Device to handle administrative shutdowns like a
reboot.

Signed-off-by: Casey Leedom <redacted>
---
drivers/net/cxgb4vf/cxgb4vf_main.c |   41 ++++++++++++++++++++++++++++++++++++
1 files changed, 41 insertions(+), 0 deletions(-)

diff --git a/drivers/net/cxgb4vf/cxgb4vf_main.c b/drivers/net/cxgb4vf/cxgb4vf_main.c
index daac6ed..f78d6e1 100644
--- a/drivers/net/cxgb4vf/cxgb4vf_main.c
+++ b/drivers/net/cxgb4vf/cxgb4vf_main.c

@@ -2886,6 +2886,46 @@ static void __devexit cxgb4vf_pci_remove(struct pci_dev *pdev)

}

/*
+ * "Shutdown" quiesce the device, stopping Ingress Packet and Interrupt
+ * delivery.
+ */
+static void __devexit cxgb4vf_pci_shutdown(struct pci_dev *pdev)
+{
+     struct adapter *adapter;
+     int pidx;
+
+     adapter = pci_get_drvdata(pdev);
+     if (!adapter)
+             return;
+
+     /*
+      * Disable all Virtual Interfaces.  This will shut down the
+      * delivery of all ingress packets into the chip for these
+      * Virtual Interfaces.
+      */
+     for_each_port(adapter, pidx) {
+             struct net_device *netdev;
+             struct port_info *pi;
+
+             if (!test_bit(pidx, &adapter->registered_device_map))
+                     continue;
+
+             netdev = adapter->port[pidx];
+             if (!netdev)
+                     continue;
+
+             pi = netdev_priv(netdev);
+             t4vf_enable_vi(adapter, pi->viid, false, false);
+     }
+
+     /*
+      * Free up all Queues which will prevent further DMA and
+      * Interrupts allowing various internal pathways to drain.
+      */
+     t4vf_free_sge_resources(adapter);
+}
+
+/*
 * PCI Device registration data structures.
 */
#define CH_DEVICE(devid, idx) \

@@ -2918,6 +2958,7 @@ static struct pci_driver cxgb4vf_driver = {
      .id_table       = cxgb4vf_pci_tbl,
      .probe          = cxgb4vf_pci_probe,
      .remove         = __devexit_p(cxgb4vf_pci_remove),
+     .shutdown       = __devexit_p(cxgb4vf_pci_shutdown),

};

/*
--
1.7.0.4