6 files changed, 170 insertions, 25 deletions

diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
index af7b204b9215..d8c57636b9ce 100644
--- a/drivers/vfio/Kconfig
+++ b/drivers/vfio/Kconfig
@@ -8,11 +8,17 @@ config VFIO_IOMMU_SPAPR_TCE
         depends on VFIO && SPAPR_TCE_IOMMU
         default n
 
+config VFIO_SPAPR_EEH
+        tristate
+        depends on EEH && VFIO_IOMMU_SPAPR_TCE
+        default n
+
 menuconfig VFIO
         tristate "VFIO Non-Privileged userspace driver framework"
         depends on IOMMU_API
         select VFIO_IOMMU_TYPE1 if X86
         select VFIO_IOMMU_SPAPR_TCE if (PPC_POWERNV || PPC_PSERIES)
+        select VFIO_SPAPR_EEH if (PPC_POWERNV || PPC_PSERIES)
         select ANON_INODES
         help
           VFIO provides a framework for secure userspace device drivers.
diff --git a/drivers/vfio/Makefile b/drivers/vfio/Makefile
index 50e30bc75e85..0b035b12600a 100644
--- a/drivers/vfio/Makefile
+++ b/drivers/vfio/Makefile
@@ -1,5 +1,5 @@
 obj-$(CONFIG_VFIO) += vfio.o
 obj-$(CONFIG_VFIO_IOMMU_TYPE1) += vfio_iommu_type1.o
 obj-$(CONFIG_VFIO_IOMMU_SPAPR_TCE) += vfio_iommu_spapr_tce.o
-obj-$(CONFIG_EEH) += vfio_spapr_eeh.o
+obj-$(CONFIG_VFIO_SPAPR_EEH) += vfio_spapr_eeh.o
 obj-$(CONFIG_VFIO_PCI) += pci/
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index e2ee80f36e3e..f7825332a325 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -37,6 +37,10 @@ module_param_named(nointxmask, nointxmask, bool, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(nointxmask,
                   "Disable support for PCI 2.3 style INTx masking.  If this resolves problems for specific devices, report lspci -vvvxxx to linux-pci@vger.kernel.org so the device can be fixed automatically via the broken_intx_masking flag.");
 
+static DEFINE_MUTEX(driver_lock);
+
+static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev);
+
 static int vfio_pci_enable(struct vfio_pci_device *vdev)
 {
         struct pci_dev *pdev = vdev->pdev;
@@ -44,6 +48,9 @@ static int vfio_pci_enable(struct vfio_pci_device *vdev)
         u16 cmd;
         u8 msix_pos;
 
+        /* Don't allow our initial saved state to include busmaster */
+        pci_clear_master(pdev);
+
         ret = pci_enable_device(pdev);
         if (ret)
                 return ret;
@@ -99,7 +106,8 @@ static void vfio_pci_disable(struct vfio_pci_device *vdev)
         struct pci_dev *pdev = vdev->pdev;
         int bar;
 
-        pci_disable_device(pdev);
+        /* Stop the device from further DMA */
+        pci_clear_master(pdev);
 
         vfio_pci_set_irqs_ioctl(vdev, VFIO_IRQ_SET_DATA_NONE |
                                 VFIO_IRQ_SET_ACTION_TRIGGER,
@@ -117,6 +125,8 @@ static void vfio_pci_disable(struct vfio_pci_device *vdev)
                 vdev->barmap[bar] = NULL;
         }
 
+        vdev->needs_reset = true;
+
         /*
          * If we have saved state, restore it.  If we can reset the device,
          * even better.  Resetting with current state seems better than
@@ -128,7 +138,7 @@ static void vfio_pci_disable(struct vfio_pci_device *vdev)
                         __func__, dev_name(&pdev->dev));
 
                 if (!vdev->reset_works)
-                        return;
+                        goto out;
 
                 pci_save_state(pdev);
         }
@@ -148,46 +158,55 @@ static void vfio_pci_disable(struct vfio_pci_device *vdev)
                 if (ret)
                         pr_warn("%s: Failed to reset device %s (%d)\n",
                                 __func__, dev_name(&pdev->dev), ret);
+                else
+                        vdev->needs_reset = false;
         }
 
         pci_restore_state(pdev);
+out:
+        pci_disable_device(pdev);
+
+        vfio_pci_try_bus_reset(vdev);
 }
 
 static void vfio_pci_release(void *device_data)
 {
         struct vfio_pci_device *vdev = device_data;
 
-        if (atomic_dec_and_test(&vdev->refcnt)) {
+        mutex_lock(&driver_lock);
+
+        if (!(--vdev->refcnt)) {
                 vfio_spapr_pci_eeh_release(vdev->pdev);
                 vfio_pci_disable(vdev);
         }
 
+        mutex_unlock(&driver_lock);
+
         module_put(THIS_MODULE);
 }
 
 static int vfio_pci_open(void *device_data)
 {
         struct vfio_pci_device *vdev = device_data;
-        int ret;
+        int ret = 0;
 
         if (!try_module_get(THIS_MODULE))
                 return -ENODEV;
 
-        if (atomic_inc_return(&vdev->refcnt) == 1) {
+        mutex_lock(&driver_lock);
+
+        if (!vdev->refcnt) {
                 ret = vfio_pci_enable(vdev);
                 if (ret)
                         goto error;
 
-                ret = vfio_spapr_pci_eeh_open(vdev->pdev);
-                if (ret) {
-                        vfio_pci_disable(vdev);
-                        goto error;
-                }
+                vfio_spapr_pci_eeh_open(vdev->pdev);
         }
-
-        return 0;
+        vdev->refcnt++;
 error:
-        module_put(THIS_MODULE);
+        mutex_unlock(&driver_lock);
+        if (ret)
+                module_put(THIS_MODULE);
         return ret;
 }
 
@@ -843,7 +862,6 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
         vdev->irq_type = VFIO_PCI_NUM_IRQS;
         mutex_init(&vdev->igate);
         spin_lock_init(&vdev->irqlock);
-        atomic_set(&vdev->refcnt, 0);
 
         ret = vfio_add_group_dev(&pdev->dev, &vfio_pci_ops, vdev);
         if (ret) {
@@ -858,12 +876,15 @@ static void vfio_pci_remove(struct pci_dev *pdev)
 {
         struct vfio_pci_device *vdev;
 
+        mutex_lock(&driver_lock);
+
         vdev = vfio_del_group_dev(&pdev->dev);
-        if (!vdev)
-                return;
+        if (vdev) {
+                iommu_group_put(pdev->dev.iommu_group);
+                kfree(vdev);
+        }
 
-        iommu_group_put(pdev->dev.iommu_group);
-        kfree(vdev);
+        mutex_unlock(&driver_lock);
 }
 
 static pci_ers_result_t vfio_pci_aer_err_detected(struct pci_dev *pdev,
@@ -906,6 +927,110 @@ static struct pci_driver vfio_pci_driver = {
         .err_handler    = &vfio_err_handlers,
 };
 
+/*
+ * Test whether a reset is necessary and possible.  We mark devices as
+ * needs_reset when they are released, but don't have a function-local reset
+ * available.  If any of these exist in the affected devices, we want to do
+ * a bus/slot reset.  We also need all of the affected devices to be unused,
+ * so we abort if any device has a non-zero refcnt.  driver_lock prevents a
+ * device from being opened during the scan or unbound from vfio-pci.
+ */
+static int vfio_pci_test_bus_reset(struct pci_dev *pdev, void *data)
+{
+        bool *needs_reset = data;
+        struct pci_driver *pci_drv = ACCESS_ONCE(pdev->driver);
+        int ret = -EBUSY;
+
+        if (pci_drv == &vfio_pci_driver) {
+                struct vfio_device *device;
+                struct vfio_pci_device *vdev;
+
+                device = vfio_device_get_from_dev(&pdev->dev);
+                if (!device)
+                        return ret;
+
+                vdev = vfio_device_data(device);
+                if (vdev) {
+                        if (vdev->needs_reset)
+                                *needs_reset = true;
+
+                        if (!vdev->refcnt)
+                                ret = 0;
+                }
+
+                vfio_device_put(device);
+        }
+
+        /*
+         * TODO: vfio-core considers groups to be viable even if some devices
+         * are attached to known drivers, like pci-stub or pcieport.  We can't
+         * freeze devices from being unbound to those drivers like we can
+         * here though, so it would be racy to test for them.  We also can't
+         * use device_lock() to prevent changes as that would interfere with
+         * PCI-core taking device_lock during bus reset.  For now, we require
+         * devices to be bound to vfio-pci to get a bus/slot reset on release.
+         */
+
+        return ret;
+}
+
+/* Clear needs_reset on all affected devices after successful bus/slot reset */
+static int vfio_pci_clear_needs_reset(struct pci_dev *pdev, void *data)
+{
+        struct pci_driver *pci_drv = ACCESS_ONCE(pdev->driver);
+
+        if (pci_drv == &vfio_pci_driver) {
+                struct vfio_device *device;
+                struct vfio_pci_device *vdev;
+
+                device = vfio_device_get_from_dev(&pdev->dev);
+                if (!device)
+                        return 0;
+
+                vdev = vfio_device_data(device);
+                if (vdev)
+                        vdev->needs_reset = false;
+
+                vfio_device_put(device);
+        }
+
+        return 0;
+}
+
+/*
+ * Attempt to do a bus/slot reset if there are devices affected by a reset for
+ * this device that are needs_reset and all of the affected devices are unused
+ * (!refcnt).  Callers of this function are required to hold driver_lock such
+ * that devices can not be unbound from vfio-pci or opened by a user while we
+ * test for and perform a bus/slot reset.
+ */
+static void vfio_pci_try_bus_reset(struct vfio_pci_device *vdev)
+{
+        bool needs_reset = false, slot = false;
+        int ret;
+
+        if (!pci_probe_reset_slot(vdev->pdev->slot))
+                slot = true;
+        else if (pci_probe_reset_bus(vdev->pdev->bus))
+                return;
+
+        if (vfio_pci_for_each_slot_or_bus(vdev->pdev,
+                                          vfio_pci_test_bus_reset,
+                                          &needs_reset, slot) || !needs_reset)
+                return;
+
+        if (slot)
+                ret = pci_try_reset_slot(vdev->pdev->slot);
+        else
+                ret = pci_try_reset_bus(vdev->pdev->bus);
+
+        if (ret)
+                return;
+
+        vfio_pci_for_each_slot_or_bus(vdev->pdev,
+                                      vfio_pci_clear_needs_reset, NULL, slot);
+}
+
 static void __exit vfio_pci_cleanup(void)
 {
         pci_unregister_driver(&vfio_pci_driver);
diff --git a/drivers/vfio/pci/vfio_pci_private.h b/drivers/vfio/pci/vfio_pci_private.h
index 9c6d5d0f3b02..671c17a6e6d0 100644
--- a/drivers/vfio/pci/vfio_pci_private.h
+++ b/drivers/vfio/pci/vfio_pci_private.h
@@ -54,8 +54,9 @@ struct vfio_pci_device {
         bool                    extended_caps;
         bool                    bardirty;
         bool                    has_vga;
+        bool                    needs_reset;
         struct pci_saved_state  *pci_saved_state;
-        atomic_t                refcnt;
+        int                     refcnt;
         struct eventfd_ctx      *err_trigger;
 };
 
diff --git a/drivers/vfio/vfio_spapr_eeh.c b/drivers/vfio/vfio_spapr_eeh.c
index f834b4ce1431..86dfceb9201f 100644
--- a/drivers/vfio/vfio_spapr_eeh.c
+++ b/drivers/vfio/vfio_spapr_eeh.c
@@ -9,20 +9,27 @@
  * published by the Free Software Foundation.
  */
 
+#include <linux/module.h>
 #include <linux/uaccess.h>
 #include <linux/vfio.h>
 #include <asm/eeh.h>
 
+#define DRIVER_VERSION  "0.1"
+#define DRIVER_AUTHOR   "Gavin Shan, IBM Corporation"
+#define DRIVER_DESC     "VFIO IOMMU SPAPR EEH"
+
 /* We might build address mapping here for "fast" path later */
-int vfio_spapr_pci_eeh_open(struct pci_dev *pdev)
+void vfio_spapr_pci_eeh_open(struct pci_dev *pdev)
 {
-        return eeh_dev_open(pdev);
+        eeh_dev_open(pdev);
 }
+EXPORT_SYMBOL_GPL(vfio_spapr_pci_eeh_open);
 
 void vfio_spapr_pci_eeh_release(struct pci_dev *pdev)
 {
         eeh_dev_release(pdev);
 }
+EXPORT_SYMBOL_GPL(vfio_spapr_pci_eeh_release);
 
 long vfio_spapr_iommu_eeh_ioctl(struct iommu_group *group,
                                 unsigned int cmd, unsigned long arg)
@@ -85,3 +92,9 @@ long vfio_spapr_iommu_eeh_ioctl(struct iommu_group *group,
 
         return ret;
 }
+EXPORT_SYMBOL(vfio_spapr_iommu_eeh_ioctl);
+
+MODULE_VERSION(DRIVER_VERSION);
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index 25a0fbd4b998..d3204115f15d 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -98,16 +98,16 @@ extern int vfio_external_user_iommu_id(struct vfio_group *group);
 extern long vfio_external_check_extension(struct vfio_group *group,
                                           unsigned long arg);
 
+struct pci_dev;
 #ifdef CONFIG_EEH
-extern int vfio_spapr_pci_eeh_open(struct pci_dev *pdev);
+extern void vfio_spapr_pci_eeh_open(struct pci_dev *pdev);
 extern void vfio_spapr_pci_eeh_release(struct pci_dev *pdev);
 extern long vfio_spapr_iommu_eeh_ioctl(struct iommu_group *group,
                                        unsigned int cmd,
                                        unsigned long arg);
 #else
-static inline int vfio_spapr_pci_eeh_open(struct pci_dev *pdev)
+static inline void vfio_spapr_pci_eeh_open(struct pci_dev *pdev)
 {
-        return 0;
 }
 
 static inline void vfio_spapr_pci_eeh_release(struct pci_dev *pdev)