PCI: handle SR-IOV Virtual Function Migration

Add or remove a Virtual Function after receiving a Migrate In or Out
Request.

Reviewed-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Yu Zhao <yu.zhao@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

2 files changed, 123 insertions, 0 deletions

diff --git a/drivers/pci/iov.c b/drivers/pci/iov.c
index d0ff8ad8f7ba..7227efc760db 100644
--- a/drivers/pci/iov.c
+++ b/drivers/pci/iov.c
@@ -179,6 +179,97 @@ static void virtfn_remove(struct pci_dev *dev, int id, int reset)
         pci_dev_put(dev);
 }
 
+static int sriov_migration(struct pci_dev *dev)
+{
+        u16 status;
+        struct pci_sriov *iov = dev->sriov;
+
+        if (!iov->nr_virtfn)
+                return 0;
+
+        if (!(iov->cap & PCI_SRIOV_CAP_VFM))
+                return 0;
+
+        pci_read_config_word(dev, iov->pos + PCI_SRIOV_STATUS, &status);
+        if (!(status & PCI_SRIOV_STATUS_VFM))
+                return 0;
+
+        schedule_work(&iov->mtask);
+
+        return 1;
+}
+
+static void sriov_migration_task(struct work_struct *work)
+{
+        int i;
+        u8 state;
+        u16 status;
+        struct pci_sriov *iov = container_of(work, struct pci_sriov, mtask);
+
+        for (i = iov->initial; i < iov->nr_virtfn; i++) {
+                state = readb(iov->mstate + i);
+                if (state == PCI_SRIOV_VFM_MI) {
+                        writeb(PCI_SRIOV_VFM_AV, iov->mstate + i);
+                        state = readb(iov->mstate + i);
+                        if (state == PCI_SRIOV_VFM_AV)
+                                virtfn_add(iov->self, i, 1);
+                } else if (state == PCI_SRIOV_VFM_MO) {
+                        virtfn_remove(iov->self, i, 1);
+                        writeb(PCI_SRIOV_VFM_UA, iov->mstate + i);
+                        state = readb(iov->mstate + i);
+                        if (state == PCI_SRIOV_VFM_AV)
+                                virtfn_add(iov->self, i, 0);
+                }
+        }
+
+        pci_read_config_word(iov->self, iov->pos + PCI_SRIOV_STATUS, &status);
+        status &= ~PCI_SRIOV_STATUS_VFM;
+        pci_write_config_word(iov->self, iov->pos + PCI_SRIOV_STATUS, status);
+}
+
+static int sriov_enable_migration(struct pci_dev *dev, int nr_virtfn)
+{
+        int bir;
+        u32 table;
+        resource_size_t pa;
+        struct pci_sriov *iov = dev->sriov;
+
+        if (nr_virtfn <= iov->initial)
+                return 0;
+
+        pci_read_config_dword(dev, iov->pos + PCI_SRIOV_VFM, &table);
+        bir = PCI_SRIOV_VFM_BIR(table);
+        if (bir > PCI_STD_RESOURCE_END)
+                return -EIO;
+
+        table = PCI_SRIOV_VFM_OFFSET(table);
+        if (table + nr_virtfn > pci_resource_len(dev, bir))
+                return -EIO;
+
+        pa = pci_resource_start(dev, bir) + table;
+        iov->mstate = ioremap(pa, nr_virtfn);
+        if (!iov->mstate)
+                return -ENOMEM;
+
+        INIT_WORK(&iov->mtask, sriov_migration_task);
+
+        iov->ctrl |= PCI_SRIOV_CTRL_VFM | PCI_SRIOV_CTRL_INTR;
+        pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
+
+        return 0;
+}
+
+static void sriov_disable_migration(struct pci_dev *dev)
+{
+        struct pci_sriov *iov = dev->sriov;
+
+        iov->ctrl &= ~(PCI_SRIOV_CTRL_VFM | PCI_SRIOV_CTRL_INTR);
+        pci_write_config_word(dev, iov->pos + PCI_SRIOV_CTRL, iov->ctrl);
+
+        cancel_work_sync(&iov->mtask);
+        iounmap(iov->mstate);
+}
+
 static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
 {
         int rc;
@@ -261,6 +352,12 @@ static int sriov_enable(struct pci_dev *dev, int nr_virtfn)
                         goto failed;
         }
 
+        if (iov->cap & PCI_SRIOV_CAP_VFM) {
+                rc = sriov_enable_migration(dev, nr_virtfn);
+                if (rc)
+                        goto failed;
+        }
+
         kobject_uevent(&dev->dev.kobj, KOBJ_CHANGE);
         iov->nr_virtfn = nr_virtfn;
 
@@ -290,6 +387,9 @@ static void sriov_disable(struct pci_dev *dev)
         if (!iov->nr_virtfn)
                 return;
 
+        if (iov->cap & PCI_SRIOV_CAP_VFM)
+                sriov_disable_migration(dev);
+
         for (i = 0; i < iov->nr_virtfn; i++)
                 virtfn_remove(dev, i, 0);
 
@@ -559,3 +659,22 @@ void pci_disable_sriov(struct pci_dev *dev)
         sriov_disable(dev);
 }
 EXPORT_SYMBOL_GPL(pci_disable_sriov);
+
+/**
+ * pci_sriov_migration - notify SR-IOV core of Virtual Function Migration
+ * @dev: the PCI device
+ *
+ * Returns IRQ_HANDLED if the IRQ is handled, or IRQ_NONE if not.
+ *
+ * Physical Function driver is responsible to register IRQ handler using
+ * VF Migration Interrupt Message Number, and call this function when the
+ * interrupt is generated by the hardware.
+ */
+irqreturn_t pci_sriov_migration(struct pci_dev *dev)
+{
+        if (!dev->is_physfn)
+                return IRQ_NONE;
+
+        return sriov_migration(dev) ? IRQ_HANDLED : IRQ_NONE;
+}
+EXPORT_SYMBOL_GPL(pci_sriov_migration);
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 0f1c7d103509..22dcfdb75d91 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -1,6 +1,8 @@
 #ifndef DRIVERS_PCI_H
 #define DRIVERS_PCI_H
 
+#include <linux/workqueue.h>
+
 #define PCI_CFG_SPACE_SIZE      256
 #define PCI_CFG_SPACE_EXP_SIZE  4096
 
@@ -218,6 +220,8 @@ struct pci_sriov {
         struct pci_dev *dev;    /* lowest numbered PF */
         struct pci_dev *self;   /* this PF */
         struct mutex lock;      /* lock for VF bus */
+        struct work_struct mtask; /* VF Migration task */
+        u8 __iomem *mstate;     /* VF Migration State Array */
 };
 
 #ifdef CONFIG_PCI_IOV